When we’re tired and stressed, a cold or the flu has its best chance of bringing us down. That said, just because this happens during seasonal shifts doesn’t mean we are doomed to get sick. No! There are actually plenty of ways to protect our immune systems from that crummy cold and flu this season. One of our favorite ways to remain extra healthy this Fall and Winter is to maintain a regular movement practice with yoga! 

What is particularly wonderful about a yoga practice is that it can be done pretty much anywhere. You can practice either at a local studio, a neighborhood gym, or in your own home. It doesn’t require much equipment at all; just you, your body, and your breath. Plus, the best part is you can stay in cozy clothes while you practice! What can be better than that when it’s cold and dreary outside, right? Here are our 10 favorite yoga poses that will help to improve your rest, boost your immune system and keep you healthy this cold and flu season:

Child’s Pose (Balasana)

Let’s start with the basics. Child’s Pose is a definite “go-to” pose during cooler temps and stressful days. This simple resting pose eases us into a gentle practice that offers soft compression of the front of your hips, helps to lengthen your spine, decompresses your lower back, and enhances a deep connection with your surroundings. The act of resting your brow bone (Third Eye chakra) on the floor or a yoga block helps elicit a natural sense of grounding and allows us to become more present with our surroundings. We can also bring a pillow or bolster between our knees and under our belly for extra support. We love this pose because it offers us the opportunity to slow down and take stock of what we need in our lives.

Cobra Pose (Bhujangasana)

Cobra (Bhujangasana) is another basic yoga pose. It helps invigorate the back muscles, lengthens the spine, and brings some gentle heat into the body. What could be better in colder weather than a little extra warmth, right? This pose also improves flexibility and posture, alleviates chest congestion, reduces inflammation, and decreases depressive symptoms all while increasing our self-esteem, and toning our arms, back and glutes. How to do it: start by lying on your belly with your palms pressing into the floor. Point your elbows toward your heels and hug them to your ribs. When you inhale, press downward with your feet, thighs, stomach, and hands while lifting your ribs, upper chest, and head upwards. (You can stay lifted and continue breathing to intensify the benefits or come back down to the floor on your exhale if you’re new to the pose.) Practice this for 8-10 rounds of breath before moving on. Can you feel your chest open and breathe with ease? Maybe you feel a little taller? Whatever you may feel, we definitely recommend this pose as a staple pose this season.

Half Frog Pose (Ardha Mandukasana)

Need more time in bed? Perhaps you feel a little sluggish today? If so, we recommend the restorative variation of Half Frog Pose. This deeply relaxing variation is another prone pose (lying on your stomach) and comes quite naturally to belly sleepers. To practice this pose, begin by lying on your stomach with your hands under your forehead. Extend one leg straight while bringing the opposite thigh in line with your hips, bent 90 degrees at your knee. That’s it! For a stronger inner thigh stretch, place a folded blanket under your bent knee for gentle elevation. Restorative yoga classes highlight this pose often because it improves hip mobility, releases tension in the back, invites a sense of well-being, and eases stiff muscles. It also can be therapeutic for symptoms related to poor digestion, high blood pressure, insomnia, some cancer treatments, and stored emotional trauma. Overall, the Half Frog pose is a relaxing way to calm our busy minds and improve our health.

Sphinx Pose (Salamba Bhujangasana)

Are you looking for an easy pose that isn’t too strenuous? Then look no further than Sphinx Pose. Similar to Cobra Pose, this pose is done while lying on your belly on the floor. Simultaneously, we press both our forearms and hands into the mat while lifting our heads, shoulders, and chest up toward the sky. This passive backbend gently lengthens your spine, invigorates the Heart chakra, and strengthens your entire back. It also stretches the front of your hips by targeting the psoas muscles, gently tones the glutes, elevates our moods, and fires up the digestive system. Plus, it helps improve menstrual cramps and irregularities for ladies. So, as the weather continues to turn colder, this is another “go-to” pose in those moments when we need a gentle reminder to take care of ourselves. 

Easy Pose with Mindful Breathwork (Sukhasana & Sama Vrtti Pranayama)

If you’re feeling overwhelmed or run down and need a few extra minutes to yourself, then try practicing Easy Pose (Sukhasana) with some deep, even-paced breathing. Sukha – meaning ‘of ease’ and Asana – meaning ‘posture,’ is a seated pose with one leg crossed in front of the other. (Remember sitting on the floor as a kid? Yeah… just like that.) This basic yoga pose helps us to feel grounded in our environment and encourages us to sit tall and breathe deeply. It also helps decrease stress, improves lung function, reduces blood pressure, enhances cognition and awareness, and improves sleep quality. All of which help to keep our immune systems in balance. Plus, if you can’t sit on the floor for very long, you can do this pose while seated on a cushion or bolster with your back against a wall, in a chair, or supported on pillows right before bed. 

Seated Twist Pose (Ardha Matsyendrasana)

Moving on to another seated posture, Seated Twist Pose (Ardha Matsyendrasana) serves as a rejuvenating and mild strengthening pose. It helps to bring our attention to the trunk of the body (the core) while offering a gentle massage to our vital organs. In yoga theory, practicing twists help to “wring out” stagnant energy, fire up our digestion, and encourage detoxification of the systems that keep us feeling vital. To come into the pose, sit with one leg resting on the floor, bent at the knee with the foot pulled in close to your bum. Cross the opposite leg over the bottom leg and plant the sole of that foot on the floor. Next, twist through your torso in the same direction as the leg on top. Use your hands to anchor yourself into the twist while keeping your spine lifting up. (FYI, this pose can be practiced with your bottom leg extended or instead of bent at the knee.) Maintain steady breathing while settling into the twist. Stay for 8-10 rounds of slow, easy breaths. P.S. you can deepen the pose by looking away from your knees and over the shoulder in the direction you are twisting. 

Supported Revolved Head to Knee Pose (Parivrrta Janu Sirsasana)

We get it… This is a mouthful and sounds crazy, but we promise you can do it! Supported Revolved Head-to-Knee pose is our final seated yoga pose that utilizes several yoga props to support you the whole time. When practiced it lengthens and strengthens the lateral body, which runs down the sides of the body as compared to the front and back. It stimulates our internal organs, especially the kidneys and our liver; both of which tend to ‘feel sluggish’ in colder weather. Plus, this pose also aids in overall digestion and gently stimulates the lymphatic pools in our armpits and inner groin. In this pose, these systems are cleared of stagnant materials, thereby enhancing our whole-body immunity. Want to give it a try? Come to a seated position on the folded ‘edge’ of a blanket. Pull one heel in towards your groin while extending the opposite leg out to the side. Place a yoga block next to your straight leg. On an inhale, raise both arms overhead. On the exhale, lean over toward your extended leg and rest your closest elbow on the block. Here you can support your head in your hand. The other arm continues to reach overhead toward your extended foot. You can either flow with your breath or stay in the pose for a minute or two. Come back to the center slowly and repeat on the other side.

Legs up the Wall Pose (Viparita Kirani)

Truthfully, this is one of our all-time favorite poses! All you need is a wall and a firm pillow or thick blanket. Start by sitting on the floor facing the wall, then lie all the way back. Next, ‘scooch’ your hips close to the wall and place them on the pillow or blanket. Once situated, place your arms out to either side in a natural position and straighten your legs up the wall. When we have our hips elevated above our hearts, it brings the body into a gently inverted position,  which regulates blood flow and moves metabolic waste materials out of the areas of the body that are typically forgotten. Legs Up the Wall pose is incredibly restorative to our metabolism and immune system because it essentially flushes our system and stretches overworked muscles. We think this pose is a “must” to practice throughout Fall and Winter.

Reclined Supine Twist (Supta Matsyendrasana)

As we near the end of our list, you may see we are once again back on the floor. The poses listed above are meant to be nourishing, rejuvenating, and restorative for our immune system. Therefore, when we keep our yoga practice low and slow, we give our bodies the time they need to feel replenished. That brings us to our next pose, Reclined Supine Twist (Supta Matsyendrasana). This pose is done lying on our backs and can incorporate pillows or blocks if desired. Once on the floor, pull one knee to the chest and twist it across the opposite side. (Those extra blocks or pillows can support that leg if there is any tension in the hips or low back.) After settling into the twist, we let gravity assist our shoulders to ease into the floor. Finally, spread the arms out and slowly look the other way to experience the full twist. This pose acts as a mild cleanse for our overall digestive system and many metabolic pathways throughout the body. As mentioned above, when in a twist, we gently compress the vital organs; allowing freshly oxygenated blood to circulate in the body after releasing the twist. By keeping our systems refreshed this season, we better prepare ourselves to fight off those nasty cold and flu symptoms. 

Supported Corpse Pose (Savasana)

Finally, we made it to our last pose, which also happens to be our favorite! Many of you may know that Corpse Pose (Savasana) is the pose typically practiced at the end of most yoga classes. It looks very much like one would expect; lying on our backs with our arms and legs outstretched like a corpse. (Pillows and blankets can also be used to support our heads and under our knees to deepen the sense of relaxation.) That said, even though we may look like a corpse, we are far from that ‘final rest’ in this pose! Supported Corpse Pose allows the body the time needed to integrate all of the benefits from the previous poses. And although it is incredibly restful, falling asleep is not the ultimate goal here. Instead, this is the time when the mind strives to calm and quiet as a means of tapping into our higher sense of consciousness. If practiced regularly, this pose can also serve as a direct channel to a stronger connection with the world around us. When we can achieve that, we experience improved health, a clear mind, and a more present spirit. 

Just a Note

These poses can be practiced individually or as an entire sequence. Whichever you choose, just know these poses will help to keep you feeling replenished as the seasons’ shift. And if you do start to feel a little run-down, these poses can help bring you back into balance. 

Stay well and happy practicing!

We typically think of athletes, movie stars, models, and some rock stars when we talk about “core strength.” But did you know that there are more muscles that make up our core than just those six muscles right above our belly button? There are actually four layers of abdominal muscles, posterior muscles of the back and two other muscle groups deep within the torso that make up our “core.”

All of these need to be strengthened to keep our trunk (torso) healthy, strong and injury-free. 

Most often we see the low back region as the most susceptible to injury. Mainly between the bottom of our ribcage down to the hips and pelvic region. This is because that area is not surrounded by hard matter, like bone needed for added protection. No matter our age it can be truly debilitating to experience lower back pain. Therefore, the best way to maintain a healthy back and core is to regularly train these surrounding muscles as a way to limit injuries, stay strong and enhance mobility throughout life!

So what exercises are best at targeting all of those muscles? Below we have provided a brief anatomy review of the core and listed our top 5 exercises to improve core strength and protect our lower backs from potential injury.

Anatomy Review for The Core:

Abdominals

• Rectus Abdominis (The 6-pack Muscle): This muscle is the most superficial (closest to the surface) in the abdominal muscle group as it lays on top of the other core muscles of the torso. Although this muscle can be targeted and works in conjunction with others in the movement of the trunk, it is considered least protective of the group when it comes to the overall strength of the core. Typically, this muscle is seen as more of an ‘aesthetic’ muscle trained more to look good versus actually building strength.

• External Abdominal Obliques: The next abdominal layer below the Rectus Abdominis. These muscles attach to the front and back of the ribcage, angle downward and insert to the top of the pelvis region on the iliac spine. They essentially wrap around the torso and assist with lateral movement (side bending).

• Internal Abdominal Obliques: Similar to the External Abdominal Obliques, this sheet of muscles also attach to the lower ribs, but are oriented perpendicular to the External Obliques. They make up the abdominal wall that wraps around the torso.

• Transversus Abdominis: This sheet of muscles are the deepest abdominal muscles and like the Internal Obliques, wrap around the trunk of te body. They attach to the lower ribs (7-12th) and onto the back, the pelvis, and the connective tissue of the thoracolumbar region. They assist with stabilization and rotation of the trunk.

Other Core Muscles 

• Erector Spinae and other Paraspinal Muscles: These consist of numerous muscles that run parallel to the backbone. They are both large and small muscle groups, and are attached to a sheath of tendon that connects the vertebrae of the lower spine and the pelvis

• Quadratus Lumborum: The deepest back muscle, the Quadratus Lumborum attaches the lowest ribs and lumbar vertebrae to the posterior iliac spine (the crest of the pelvis.) It helps with the opposite actions of the front abdominal muscles and assists with back bending movements.

• Iliopsoas Group: Another core group, serving as the deepest in the body, are the psoas major, psoas minor and the iliacus muscles. These muscles are stabilizers and lateral movers of the core, as well as lateral rotators of the hip joints. These muscles connect the upper body to the lower body by attaching the anterior lumbar vertebrae, run along the inner pelvis and insert into the lesser trochanter of the femur bones. 

5 Best Exercises to Strengthen these Muscles

Now that we’ve recapped all of the core muscles, let’s break down our favorite exercises to help strengthen our core low back. We love these exercises because they can be done anywhere and don’t require any equipment. Plus, if we want to make them even more challenging, we can always add weights to the mix:

• Regular and Side Planks (On Hands, Elbows and Forearms): We LOVE Planks! Traditional, Forearm and Side Planks are all incredible at helping at building strength in the trunk of the body. These are usually practiced in a static position, one where you hold the shape for as long as possible. That said, there is always the option to add push-up or hip-dips to increase the intensity or target additional muscles. Try holding a Traditional Plank for 30 seconds to see how it feels. If that’s too easy, go for 1 minute. Still too simple? Try for 1 minute in each of these types of Planks and build up from there… You’ll thank us later.

• Sustained Low Boat Pose – Another great strength building technique is the sustained Low Boat pose seen in many yoga practices. Here, we start on our backs. Then we lift the legs, the head and upper shoulders about 3-4 inches off the floor. Only the hips and torso should be touching. After we’ve got that, next we extend the arms past our ears and away from our feet. It may help if we think of the shape of a banana. By holding this shape as long as we can (similar to those planks), we start to activate all of the core abdominal muscles. Lastly, if we want a bigger challenge, there is always the option to flutter-kick the legs or tap our hands to our toes straight up in the middle. Again, try holding this for 30 seconds. If that is a piece of cake, then go for 3-5 reps of 1 minute each.

• Superman or Locust Pose: This exercise is one of our favorites. We think strengthening the back muscles are equally important as the front core and this exercise helps to target the Quadratus Lumborum and our Paraspinal muscle group. During this exercise we will be lying on our stomach. (You may want to use a thick mat or a towel to protect the front of the hips.) Next, reach the arms forward past the ears and lift them up. Do the same thing with the legs, as if you’re flying like Superman. For the yogis out there, this is a variation of Locust Pose. Remember to keep the breath steady while in this shape. Go for 8-10 rounds of lifting up on an inhale and releasing on an exhale. Do that 3-5 times. Lastly, to make this harder, try strapping on some wrist and ankle weights!

• Russian Twists: Here we address some of those deeper muscles, like the External and Internal Obliques, and the Transversus Abdominis, due to the rotating or twisting nature of this exercise. Begin sitting on a mat or towel with the knees bent. Our feet should be about 18 inches away from us resting on the floor. Next, lean back to make an approximate 45-degree angle at the hips. This engages the whole core because we are fighting against gravity. Now we extend our arms out with palms together and keep them straight. From there, we initiate a rotation from side to side while maintaining the 45-degree angle; as those we are drawing a semicircle left to right with our hands.. To increase the challenge we can alway add weight by holding a dumbbell or a medicine ball. If the desire to make this more challenging persists, then try lifting the feet off the floor and hovering them while twisting from side to side.  

• Seated Knee Tucks: We think traditional crunches are a bit overrated. They can put unnecessary strain on the low back and neck, and who wants that, right? Instead, Seated Knee Tucks take that strain off those areas, target all of the core abdominals and help to build strength in the entire trunk. (Not to mention this exercise can really boost that “6-pack” look, if that is something you want.) Start by sitting on a mat or a towel to cushion the seat with your legs straight. Next, place both hands on the ground behind you with elbows bent. Your hands should be flat and the fingers should point towards the feet. Now, lift your legs about 4 inches off the ground and lean back at the same time. Finally, bend your knees while pulling them to your chest and press through your hands so that your torso almost touches your knees in the middle. Repeat. We suggest 3-5 sets of 20 reps. If you want to make it more difficult, add ankle weights. Trust us, you’ll feel it.

What kinds of Injuries happen in basketball?

There are particular injuries that are very common in the game of basketball. Most players experience these kinds of injuries, especially later in their careers. These are, of course, lower body injuries including joint and muscular tears. The most common basketball injuries include sprains and strains, twisted ankles, and fractures.

The most prevalent of these are ankle and knee sprains. While these vary in severity, they are very problematic due to how long they can keep a player off the court. They can also escalate to more severe issues in those areas as well.

In terms of the muscles and ligaments, these injuries are by far more severe than most and can leave you out of commission for far longer than you’d like. An almost career-ending injury in this category would be an ACL tear or Achilles tendon tear.  These are extremely serious injuries that can be career-ending if not treated quickly (and take up to 2 years to fully heal). They occur when the knee joint is twisted, causing the ligaments within it to tear. This usually happens when you pivot on one leg, running full speed and planting your foot in place. It’s very common for NBA players who play power forward or center position because they have so much mass behind them that any kind of sudden stop will cause them to fall forward onto their hands or knees.

Here are some ways that even the best players use to avoid injuries and stay in the game:

Stretching

Just like with any sport proper stretching goes a long way. Stretching helps to decrease your risk of injury as well as helps your joints move through their full range of motion. It also prepares your body for competition. It is important to warm up and stretch before every game, practice, and workout. Warming up and stretching are essential because they help prevent injuries. Warm-ups increase blood flow to the muscles and joints, which helps reduce muscle soreness and stiffness. Stretching increases flexibility, which can prevent overuse injuries such as tendinitis (inflammation of a tendon) or pulled muscles.

There are many different types of stretching, so it is important to know which ones are best for you. Dynamic and static stretching are two common types of stretches that can be done before or after workouts. Dynamic stretching increases your body temperature and heart rate, which helps prepare it for physical activity. Some of the best players in the world like LeBron James include pilates and yoga in their training because of the added benefits.

Staying Hydrated

Stay hydrated by drinking plenty of water and sports drinks throughout the day. Hydration helps with injury prevention in sports by keeping your joints lubricated and your muscles flexible. When you’re dehydrated, the body has to work harder to get oxygen into your system, which means it’s not as efficient at recovering from a workout. That can mean soreness and fatigue the next day or even longer.

Adding to that, dehydration can lead to cramping, which is a common issue for athletes. Cramping is when your muscles become tight and painful, often due to not drinking enough water. You should aim for drinking about three liters of fluids (12 cups) per day. This includes plain water, sports drinks (like Gatorade), juices, and even milk (dairy and non-dairy).

Proper Training

Proper training can easily mitigate a majority of the risk associated with playing basketball. It pushes your body so that it’s able to perform under the physical stress of in-game situations. A variety of training regiments include plyometrics, jumping drills, etc. in order to train your joints and muscles to perform better and last longer. When training, use proper form. A lot of injuries come from improper form, so be sure to focus on your technique. If you’re new to the sport, ask a professional for some tips on how to improve your game.

Consider cross training with weights or resistance bands at least three times a week. This helps build muscle mass that protects bones from injury when you fall or hit something with force (like in basketball). If you have a history of knee injuries, it’s important to stay active and build up your leg muscles. If you don’t have any experience with basketball, consider starting with something that doesn’t require running or jumping such as swimming if you want to get in shape for basketball.

There are numerous ways for players to improve their game. The key is finding a training regimen that works best for them by focusing on what they need most help with. If you are a beginner, it is best to start with the basics. For example, if you have trouble catching and throwing the ball, then focus on those skills first. If you want to improve your shooting ability, then practice shooting at a basket until it becomes second nature.

Preparation and Gear

Most people often overlook proper preparation, but it can help immensely. You should only wear proper basketball performance shoes when playing basketball and make sure the court itself is clean and free of obstruction. This also means you must wear proper attire such as a t-shirt and athletic shorts. 

• Wear the right shoes: Your shoes are one of the most important parts of your basketball gear. You need a pair that provides good support and cushioning, as well as traction so you don’t slip on the court.
• Make sure your shoes fit properly: The wrong size can lead to injuries such as ankle sprains or foot problems. And remember that shoe size varies with different brands, so it’s important to try on several pairs before choosing one.
• Wear a mouth guard: Mouth guards are recommended for all basketball players, especially those who play competitively. They protect your teeth from being knocked out or broken during games, while also keeping your lips from getting cut on another player’s braces.

Basketball is one of many great sports that people play and is beloved around the world but it is prone to causing injuries. Hopefully, using these tips, you can enjoy it without having to worry about possible injuries.

Cell phones give off Radio Frequencies (RF) that can enter our bodies. These RFs have the ability to change our insides without us even noticing. Out of the entire body, the brain is affected the most. When you’re on a call, the phone is usually right next to your ear. This means that it is also very close to your brain. Excessive exposure of radio frequencies to the brain can cause many health concerns. Ranging from minimally intrusive to life-threatening, here are the most notable ones:

Weakening of the Brain-Blood Barrier and Hippocampus

The brain-blood barrier (BBB) is a selective membrane. It allows the selective exchange of substances between the brain and blood. It inhibits the passage of pathogens and other harmful substances.

A study was conducted by Dr. Leif Salford on rats to observe the effects of RFs on their BBBs. After exposing them to RFs for 3 hours a day for 28 days, they saw concerning results. The BBB and hippocampus (responsible for spatial and emotional memory and stress response), among other parts of the brain, deteriorated. 

Brain Tumors and Cancers

Tumors and cancers are one of the most deadly health problems caused by RFs. Extended exposure of RF is said to have harmful effects on the brain and other parts of the body.

RF in cell phones can cause cancerous brain tumors (gliomas), non-cancerous tumors (meningiomas), non-cancerous tumors of the brain connecting to the ear (vestibular schwannomas), and tumors of the salivary glands.

In the beginning, there wasn’t enough evidence to conclude that RFs caused cancer. Then, a team of researchers at the National Toxicology Program conducted a 10-year study on rats. The study concluded that exposure to the RFs emitted by phones caused both brain cancer (glioma) and nerve tissue damage (schwannomas).

Headaches

Due to the amount of screen time that people get, headaches are the most common form of harm from phones. This isn’t due to the Radio Frequencies but it’s because of a couple of other reasons.

When using a cell phone, people are often hunched over. This creates tension in your spine and your neck. For an extended period of time, it can turn into a headache. Additionally, the blue light that is emitted from phones causes the eyes to become fatigued. The constant staring without giving your eyes a break strains them.

The number of hours you use your cell phone is directly linked to the frequency of headaches. Non-stop use can even cause migraines. Both of these types of headaches and migraines appear after extended cell phone usage.

Cell phones give off what is known as “blue light”. Blue light is a type of light that humans are able to see with the naked eye that comes from screens. Over time, this blue light can cause blurry vision, eyestrain, dry eye, macular degeneration, and even cataracts. Wearing blue light glasses can help reduce this type of strain. 

Sleep Disturbance

As precious as sleep is, many people will ruin it without even noticing it. Numerous people will use their phones right before they sleep without thinking about the harm it brings.

Using your phone before bed reduces the production of melatonin. Without melatonin in your body, instead of feeling sleepy, you’ll become more alert. The blue light emitted from phone screens messes with your circadian rhythm and makes your body think it’s still daytime. This has an adverse effect on your slow-wave and rapid eye movement (REM), 2 important stages of sleep.

Children are even more sensitive to blue light and the effects are magnified. Nonetheless, using a phone before you sleep will leave you feeling tired when you wake up.

Higher Absorbance of Radiation in Children

Since children are small, their skulls are thinner. When they’re exposed to the same RF as adults, they absorb more of it, quickly. A child’s brain decomposition is 2 times more than an adult when absorbing RF energy. Children therefore, tend to develop many behavioral and emotional problems early on.

Studies have shown that children that receive high amounts of RF may develop ADHD. Mothers that used cell phones excessively gave birth to babies with higher levels of lead in their blood.

Children that are exposed to high levels of RF energy have an increased risk of developing numerous tumors and cancers as well.

CARROTS IMPROVE YOUR VISION

The myth about carrots improving your eyesight goes as far back as World War II. Although some research has shown that carotenoids (a vitamin in carrots) may help some with age-related macular degeneration (AMD) in preventing blindness; overall, carrots don’t contain anything that could improve vision.

READING IN THE DARK RUINS YOUR EYES

Just like any muscle pushed to its limit, reading in the dark will cause strain on the eyes. The effects of this strain may include headaches, itchy eyes, and increased sensitivity to light; but it does not cause lasting damage.

WATCHING TV CLOSELY WILL GIVE YOU “SQUARE EYES”

Much like how people hold a book close to their faces to read, people sit close to the TV and watch. It isn’t a habit that will decrease your vision, although it’s the popular notion that it will give you square eyes; rather it will cause strain and blurred vision, both of which are temporary.

IF YOU CROSS YOUR EYES THEY’LL STAY THAT WAY

The eyes are primarily controlled by 6 muscles that allow the eyes to move around. Crossing your eyes is just telling your muscles to push inwards; this like other types of pressures exerted on muscles simply causes strain nothing more. There’s no medical evidence that proves your eyes will permanently stay that way.

EYEBALLS CAN BE TRANSPLANTED

Contrary to sci-fi films like The Minority Report, transplanting a whole human eye is not possible. When people say that they had an eye transplant, that usually means that a procedure was done on their cornea. There are way too many nerves connected to the eyeball to surgically transplant it.

STARING AT THE SUNS WON’T HARM YOUR EYES

There is no doubt that sunlight is essential for the health of our eyes, providing us with the essential vitamin D; but staring at the sun will definitely cause permanent damage to your vision. Damage can occur in little as seconds, destroying the photoreceptors in the retina.

20/20 VISION MEANS PERFECT VISION

People often like to flaunt the fact that they have 20/20 vision, but that doesn’t necessarily mean that they have perfect vision. 

20/20 is just an acuity test, which is only one aspect of vision. In order to have perfect vision, your eyes must pass other tests like: peripheral awareness, eye coordination, depth perception, ability to focus, and color vision.

SNEEZING WITH YOUR EYES OPEN WILL MAKE THEM FALL OUT

When you sneeze, it’s an autonomic reflex to close your eyes; but people also believe that you must close your eyes while sneezing otherwise your eyes will fall out. This is an age old myth which is false. The pressure from sneezing will not make your eyes fall out. Eyes open or closed, you can sneeze however you want.

DOING EYE EXERCISES WILL IMPROVE YOUR VISION

Eye exercises exist but is that enough reason to believe that they are effective? 

Although you would hope that they could improve your vision, eye exercises are ineffective. They will not eliminate nearsightedness, farsightedness, astigmatism, or other factors that require you to wear corrective lenses.

WEARING SOMEONE ELSE’S GLASS WILL DESTROY YOUR VISION

Wearing someone else’s prescription glasses may seem like it could permanently do a number on your eyes; but the pain that you feel while wearing them isn’t your eyes getting weaker. Wearing incorrect lenses causes eye strain and headaches, but nothing more than that.

TIP: If you ever wonder about your hydration status, just take a look at the color of your urine next time you go to the bathroom. Clear/pale yellow indicates proper hydration while golden yellow/honey colored urine means you could use more water. 

Basic Anatomy of the Urinary System

• Adrenal Glands: see Endocrine System
• Kidneys: organs that filter blood to remove urea and other wastes as urine
• Ureters: carry filtered urine from the kidneys to the bladder
• Bladder: holds urine until it is signalled for release
• Urethra: duct that allows urine to exit the body
• Aorta: main artery coming from the heart (unfiltered blood)
• Vena Cava: main vein entering the heart (filtered blood)
• Renal Vein: returns filtered blood to the vena cava 
• Renal Artery: sends blood from the aorta into the kidneys for filtration

Filtration

Blood enters the kidneys using the renal arteries. The arteries branch out into small vessels that enter the nephron (filtration center) starting with the glomerulus. Here, the waste products in the blood and some water are squeezed out into the Bowman’s capsule to create a filtrate. This filtrate then moves through the twisty tubes of the nephron and are continuously filtered to remove waste products from the digestion of food. Once the filtrate enters the collecting duct, it is considered “urine” and is sent to the bladder. Blood that remains following filtration exits the kidney through the renal vein and is sent back to the heart. 

Interestingly, chemicals like alcohol can hijack the urinary system and cause it to function incorrectly. Ever noticed you have to urinate more frequently when drinking alcohol? This is primarily due to the fact that alcohol inhibits the release of Antidiuretic Hormone (ADH). ADH is responsible for holding on to water in the kidneys, so when alcohol blocks this more water is released by the kidneys. This means you need to urinate more often and you have a clear, dilute urine. Moreover, this rapid release of water causes you to become dehydrated and often leads to a “hangover” the next day. Make sure if you’re drinking alcohol to also consume water to combat the loss!

Want to know more about the body systems? Check out this article!

Divisions of the Nervous System

The nervous system has several divisions, all branching from the central nervous system (CNS). The CNS houses the brain and spinal cord that act as the central command for all actions of the body. Nerves in the brain and nerves that extend from the spinal cord to the various regions of the body create the peripheral nervous system (PNS). The PNS is responsible for linking the body to the CNS so that signals created by the CNS are able to reach their targets. Within the PNS are the somatic nervous system and the autonomic nervous system. The somatic nervous system controls voluntary body movements, like muscular contractions, and the autonomic nervous system controls involuntary movements, like the dilation of your pupils or rhythm of your heartbeat. Finally, within the autonomic nervous system are the sympathetic (SNS) and parasympathetic (PSNS) systems. The SNS preps the body for action, creating the flight or fight response to stimuli. In contrast, the PSNS relaxes the body, bringing it back to normal after an exciting stimulus.

Structure of a Neuron

Despite how intricate this system may seem, nervous tissue comes from just two types of cells: glial cells and neurons. Glial cells, also known as neuroglia, are found in both the CNS and PNS. These cells protect and support nerve cells called neurons. Neurons are the basic functional unit of the nervous system, transmitting messages around the body. Their unique structure allows them to be very fast, efficient communicators. Neurons have a cell body that holds a nucleus, which acts as the “brain” of the cell. Surrounding the cell body are dendrites, the regions that receive signals. Dendrites send the signal through the axon until it reaches the axon terminals. The signal travels through the axon with the help of Schwann cells that wrap around the axon and act as an insulator. Between these cells are nodes of Ranvier. A typical neuron is shown in this diagram:

Sending a Signal

The process of sending a signal begins with a stimulus. The dendrites of the first neuron in the signal chain receives the stimulus and transmit the signal through the axon. Once through the axon the signal travels down each axon terminal. When the signal reaches the terminal it causes the release of synaptic vesicles that carry a neurotransmitter (chemical messengers). The vesicle fuses with the membrane of the axon terminal, releasing the neurotransmitter into the synaptic cleft, or synapse. The neurotransmitter then travels across the synapse until it reaches another neuron’s dendrites or the target cell/tissue. For example, the mechanism of signaling muscular contraction begins when the neuron that is part of the motor unit releases a neurotransmitter called acetylcholine (Ach) into the synaptic cleft. Ach travels across the cleft until it reaches the Ach receptors in the membrane of the muscle fiber. Once there, channels open to allow an influx of charged particles that signal the release of calcium, starting the contraction process. A diagram of a typical neuromuscular junction is shown below:

The Autonomic Nervous System

As mentioned above, the autonomic nervous system is divided into the parasympathetic and sympathetic systems. A key role of the PSNS is stimulating saliva production in the mouth and stimulating the stomach and intestines to complete digestion. The PSNS maintains a calm state of arousal, with its function often simplified to “rest and digest”. Conversely, the SNS creates alertness in the body. When you are scared, you may notice an increased heart rate, faster breathing, and an energized feeling. This is due to the SNS readying your body to face a potential threat. When the threat is gone, the PSNS will return the body to its normal, calmer state. The diagram below details the effects of the PSNS and SNS on the body and also distinguishes the CNS and PNS from one another:

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Basic Anatomy of the Endocrine System

The endocrine system is a collection of glands that secrete hormones to regulate internal body conditions, also known as homeostasis. While none of the eight major glands of this system are connected to one another, each function in correlation with the others to maintain balance throughout the body. Below, the anatomical position of each gland is shown:

Types of Glands

There are two main types of glands in the body: exocrine and endocrine. Exocrine glands are mostly seen in the integumentary system. Structures like sweat glands, oil glands, and mammary glands utilize ducts to transport their excretions to the surface of the body. Endocrine glands are the opposite, secreting hormones into the bloodstream that are shuttled around the inside of the body. Endocrine glands do not use ducts and secretions never exit the body. Instead, the secretions, called hormones, travel to cells with specific receptor sites to cause a bodily reaction. The main endocrine glands of the endocrine system are shown below:

Hormones

Hormones are the messengers of the body, traveling through the bloodstream to reach a target cell or tissue to cause a reaction. As with antibodies and antigens in the integumentary system, hormones utilize a “lock and key” pairing. Only cells with hormone receptors specific to the released hormone will react. Most of the reactions take time, happening in hours, days, or even weeks. Along with cellular communication, hormones aid in growth and development, sexual function, mood, reproduction, and metabolism. Here is a list of some of the most influential hormones:

• Adrenaline: secreted from the adrenal gland; released in short-term stressful situations to allow for quick responses to the stressor.

• Cortisol: secreted by the adrenal gland; controls the body’s response to long-term psychological and physiological stress. 

• Estrogen: secreted by the ovaries; female sex hormone; plays a role in female reproduction, menstruation, and menopause.

• Growth Hormone: secreted from the pituitary gland; stimulates growth, cellular reproduction, and metabolism.

• Insulin: secreted by the pancreas; converts glucose from food to be used as immediate energy or stores it for later use and maintains blood glucose levels

• Progesterone: secreted by the ovaries, adrenal glands, and placenta (during pregnancy); prepares the body for pregnancy and regulates the monthly cycle.

• Prolactin: secreted by the pituitary gland; only in females following childbirth – causes lactation for feeding the newborn.

• Testosterone: secreted by the testes; male sex hormone; plays a role in male development – forms reproductive tissues, increases muscle mass and body hair.

• Thyroid Hormones: secreted by the thyroid gland; control metabolism in the body to regulate weight, body temperature, and energy levels.

Hormones must be released in amounts that do not go over or under the necessary amount. Again, the endocrine system aims to maintain homeostasis, or internal balance, so the secretion of hormones is highly regulated. 

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Male Reproductive System

• Testicles: produce sperm cells
• Epididymis: collection duct for mature sperm cells 
• Vas Deferens: tube that transports mature sperm to seminal vesicle
• Seminal Vesicle: storage site for sperm until ejaculation
• Prostate Gland: surrounds urethra and secretes a thin, milky fluid (semen) to aid the mobility of sperm 
• Bladder: stores fluid (from drinking or digestion) to be excreted as urine
• Urethra: tube that connects to the tip of the penis to excrete urine and semen
• Penis: male reproductive organ; when erect is inserted in the vagina of a female to transfer sperm for start of reproduction

Female Reproductive System

• Ovary: storage site for eggs
• Fimbriae: finger-like projections that catch eggs after ovulation to move them down the fallopian tube
• Fallopian Tubes: tube that moves egg to the ovary; fertilization usually occurs here
• Uterus: receives fertilized eggs and provides an environment for development of the fetus
• Endometrium: lining of the uterus; gets shed off during menstruation (period)
• Cervix: narrow end of vagina that bridges the uterus and vagina
• Vagina: passageway for menstrual flow; site of insertion for penis during sex; birth canal for developed infant

Gametogenesis

Gametogenesis is the formation of gametes, or sex cells, for the purpose of reproduction. Men produce sperm cells (spermatogenesis) and women produce eggs (oogenesis) that fuse together during fertilization. While men actively produce sperm cells after puberty, the ovaries in the female body house all of the eggs (about 500) she will ever have. The process of producing both gametes is a series of divisions that result in cells with one copy of chromosomes (packages of DNA) to be passed on to the baby. At first, both start as cells with 46 chromosomes, having two sets (one from mom and one from dad). Following division, these are split up to leave the single 23 chromosome sex cells. For men, spermatogenesis creates four sperm cells, each with a unique set of the 23 chromosomes. For women, a small polar body is shed that houses the extra chromosomes resulting in a single ovum that prepares to be fertilized. This chain of divisions is displayed below:

Reproduction

During ovulation, an egg (ovum) is released from the ovary and into the infundibulum. Here, the sperm are able to fertilize the egg by fusing together their genetic material. This now creates the 46 chromosome zygote that will begin to divide and form a new human being. Following fertilization, the zygote travels down the fallopian tube and divides along the way. Once it reaches the uterus, it is a small cluster of identical cells. This ball of cells then implants into the lining of the uterus and begins to hollow out and forms a blastocyst. This process takes about five days. From here the cells continue dividing and growing in size and number to form a baby that will be birthed 9 months later. Below is a visual of the implantation process:

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Basic Anatomy of the Circulatory System

The circulatory system is a vast network of tube-like structures called blood vessels that carry blood around the body. The main organ responsible for getting the blood to its appropriate location is the heart. The heart uses arteries and veins to transport blood around the body. The arteries and veins meet at capillaries, which are very thin tubes that slow blood flow to allow for exchange of gases. There are capillaries throughout the body’s tissues and even in the lungs. 

There are three loops in the circulatory system: the systemic circulation, the pulmonary circulation, and the coronary circulation. The systemic circulation loop covers the entire body, including the limbs and head. Oxygen is delivered to cells and tissues via the arteries and carbon dioxide is returned through the veins. Next, the pulmonary circulation takes deoxygenated blood from the veins and reoxygenates it by passing through the lungs and then returning to the heart to be pumped back into the systemic circulation. Lastly, the coronary circulation loop ensures the heart and its thick muscle tissue are well oxygenated to continually pump blood. The basic flow of blood in the body is expressed in the diagram below:

The Heart

The heart is the driving force behind the entire circulatory system. The human heart has four chambers: the left atrium, right atrium, left ventricle, and right ventricle. The atria are areas where blood collects to be emptied into the ventricle. The ventricle contracts once filled to pump blood away from the heart. Follow the path blood takes through the heart with the numbers on the picture and steps listed below:

1. The superior and inferior vena cavas dump deoxygenated blood into the right atrium
2. The right atrium squirts the blood into the right ventricle through the right AV valve
3. The right ventricle contracts
4. Blood is pumped through the left and right pulmonary arteries
5. Blood is reoxygenated in the lungs
6. Oxygenated blood returns from the lungs and dumps into the left atrium
7. Once full, the right atrium squirts blood into the left ventricle through the left AV valve
8. The left ventricle contracts
9. Blood is pushed through aortic valve
10. Oxygenated blood is pumped to the body

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Parts of the Respiratory System

• Nasal Cavity: air-filled space above and behind the nose
• Nose: opening for incoming or outgoing air
• Mouth: opening for incoming or outgoing air
• Throat: also called pharynx; delivers air from nose and mouth to the trachea
• Epiglottis: small flap that closes when you swallow to prevent food or liquid from going down the trachea
• Esophagus: tube that connects the throat and stomach for food digestion
• Larynx: also called the voice box; hollow organ responsible for creating sound (talking)
• Trachea: connecting passage for throat and lungs
• Lungs: main respiratory organs; brings in oxygen for the body and removes carbon dioxide
• Rib Cage: protects heart and lungs
• Diaphragm: muscle that helps fill and empty lungs
• Pleural Membranes: thin tissue that separates the lungs from the chest cavity
• Bronchi: branches that spread from the trachea into the lungs
• Bronchiole: small branches from the bronchi that lead to alveoli
• Alveoli: very small air sac for exchanging carbon dioxide and oxygen
• Capillary Network: veins and arteries that surround the alveoli for gas exchange

Gas Exchange

Ever wondered how you breathe in oxygen but breathe out carbon dioxide? It all comes down to the tiny air sacs in the lungs called alveoli and red blood cells (RBC). Alveoli are the centers for gas exchange in the respiratory system, keeping a continual supply of oxygen for cells and tissues. Without a constant supply of oxygen during exercise your muscles would be unable to perform. However, none of this would be possible with RBC. They are the cells that carry oxygen and carbon dioxide in the body to allow for gas exchange. Here are the steps your body takes to exchange gases in the lungs:

1. The diaphragm contracts to pull on the lungs, causing them to fill with air from the negative pressure.
2. Lungs and alveoli fill with oxygen.
3. Carbon dioxide in the capillaries diffuses to the alveoli from RBC to be expelled (breathed out) and oxygen diffuses to recently available RBC to be taken to the heart for distribution in the body.
4. Following gas exchange at the alveoli, carbon dioxide is expelled from the lungs and the diaphragm relaxes.

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Basic Anatomy of the Digestive System

The digestive system is pretty complex, having several unique parts to the system. Below is the function of each component, which can be matched to its location in the diagram above. 

• Oral Cavity: Beginning of the digestive tract; mechanically digests food
• Salivary Glands: secrete saliva to break down carbohydrates in the mouth and soften food for swallowing
• Tongue: pushes food into throat to slide down the esophagus
• Esophagus: tube that connects the throat and stomach
• Stomach: holds food while being broken down by enzymes in the stomach
• Liver: secretes bile into small intestine for digesting fat and some vitamins, creates new chemicals for the body with digested molecules, processes nutrients from small intestine, and detoxifies the body from harmful substances (like drugs and alcohol)
• Gallbladder: stores and releases bile from liver into duodenum for fat digestion/absorption
• Pancreas: secretes enzymes to break down fats, carbohydrates, and protein; secretes insulin for maintenance of blood sugar level 
• Pancreatic Duct: 
• Common Bile Duct:
• Small Intestine: connects stomach to large intestine; takes semi-solid food mass and turns it into a liquid
  • Duodenum: first section of small intestine, mostly breaks down food
  • Jejunum: middle section of small intestine, absorbs nutrients 
  • Ileum: last section of small intestine, absorbs nutrients
• Large Intestine (Colon): processes waste for removal; connects small intestine to rectum
  • Ascending Colon: first section of colon, absorbs leftover water and nutrients
  • Transverse Colon: middle section of colon, absorbs water and electrolytes, moves stool forward to descending colon
  • Descending Colon: final section of colon, stores stool/feces to be released from the rectum
• Rectum: connects colon to anus; holds stool until the brain signals a bowel movement
• Anus: final part of digestive tract; controls release of stool 

Stages of Digestion

The digestive system processes food slowly, taking about 6-8 hours for food to move through the stomach and small intestine and then another 36 or so to move it through the colon. In general food will take 24-72 hours to move all the way through. This process is aided by the contraction of smooth muscle that lines most of the digestive tract. The involuntary contractions are wave-like to push food forward in the tract. This is called peristalsis. Peristalsis mainly occurs in the esophagus, small intestine, and colon since they are the major tubular structures for moving food along. Below are the various stages of digestion:

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Epidermis

The epidermis is home to four types of cells: keratinocytes, melanocytes, langerhans cells, and merkel cells. Each of their functions are shown in the graphic below:

As shown, melanocytes are the cells that produce pigmentation in your skin. Interestingly, regardless of skin tone everyone has the same number of melanocytes. The differing factors are the breadth of the cell and color the cells produce – which can be dark/brown or yellow/red. It was found that people originating near the equator had more expression of the darker melanocytes than people who lived near the north or south poles. This was primarily due to the amount of UV exposure. At the equator, UV exposure is much higher, causing the need for more pigmentation to protect the body from cancer. 

The four cell types of the epidermis are housed in five unique layers. Starting at the surface is the stratum corneum, followed by the stratum lucidum, which is only found in the thick skin of your palms and feet. These layers are composed of dead cells that are easily shed and replaced. Next, the stratum granulosum and stratum spinosum are made up of living keratinocytes that arise from the deepest epidermal layer, called the stratum basale. This is a single layer of cells that continually produces the new cells that migrate up the epidermis and are eventually shed.

Dermis

Beneath the epidermis is the dermis, which is subdivided into three layers. The first layer, the papillary layer, is made up of dermal papillae, which look like small projections that create the ridges of our fingerprints and increase friction for better grip. Next, is the reticular layer, which contains numerous structures: oil glands, sweat glands, arteries, veins, and nerves. The oil and sweat glands, hair follicles, and nails are classified as skin appendages. The deepest layer of the dermis is the hypodermis, which mostly consists of fat cells and blood vessels.

Skin Appendages

Oil glands, also called sebaceous glands, are found everywhere but the palms of your hands and soles of your feet. These glands release sebum, an oily substance that softens and lubricates the skin while also protecting the skin from water loss.

Sweat glands, also known as sudoriferous glands, are widely distributed throughout the body with most people having up to three million tiny glands. When you sweat, the body is able to excrete salts and urea while also keeping your body temperature from getting too high. Sweat glands come in two types: eccrine and apocrine. Eccrine glands are found in the palms, forehead, and soles of the foot and arise from bundles in the dermis that use a tube to travel upward through the epidermis. Apocrine glands are far less numerous and only appear around the armpits and groin after puberty; producing a different type of sweat that causes body odor. 

Hair and nails form through keratinization, a process in which new cells at the root harden and are pushed forward. This occurs because the arteries at the root nourish the cells. As more cells accumulate, their nourishment is cut off which leaves hard, dead cells to be pushed onto the surface of the skin. This results in the continued growth of your hair and nails. 

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Basic Anatomy of the Muscular System

There are over 600 muscles in the body. Some of the major muscles are included in the diagram above.

Organization of Skeletal Muscle

Skeletal muscles attach to bones at either an insertion or origin. The insertion of a muscle is the point that is more movable and the origin is the point that is immovable. For example, the biceps brachii (bicep) muscle in your arm inserts just below the elbow and originates in the shoulder region. 

At either of these points, the muscle is connected to the bone via a tendon – a strong, cord-like connective tissue that is able to withstand stress from being stretched. This dense bundle of connective tissue extends from the bone and expands to surround the entire muscle, forming the epimysium. The epimysium acts as an overcoat, wrapping around the fascicles (large bundles of muscle fibers) within the muscle. Each fascicle has its own wrapping called the perimysium. Within each fascicle’s perimysium are muscle fibers, which are further wrapped by an endomysium. The fibers within each endomysium are then divided into myofibrils, which are functional components of muscular contraction.

Method of Muscular Contraction

The functional unit of contraction is known as a sarcomere. There are four major components within the sarcomere: actin, myosin, troponin, and tropomyosin. As discussed above, myofibrils are small, rod-like structures in the muscle. Within each myofibril are smaller, thread-like structures called myofilaments. These filaments are either thick (myosin) or thin (actin) and slide past one another to create contractions. On each thin (actin) filament are cords or tropomyosin, that block the site where myosin attaches to pull the actin fibers. 

Before a muscle can contract, calcium must attach to the troponin protein on actin filaments, causing the tropomyosin to change shape and move out of the way. Once this is complete, the thick (myosin) filaments are able to grab on to the thin (actin) filaments and contract the muscle. For the muscle to relax, calcium supply is shut off, tropomyosin recovers the myosin binding sites on actin filaments, and the filaments slide back to their original position. The process is visually explained in this short video.

Motor Units

In the nervous system there are various cells that are responsible for signalling other cells and tissues in the body called neurons. Specifically, motor neurons are responsible for aiding in muscular contraction. A neuron and the muscle fibers it stimulates is called a motor unit. Within a motor unit, the muscle fiber and neuron do not touch, creating a neuromuscular junction. 

As mentioned before, a muscle requires calcium before it can contract. When chemical messengers diffuse across the space between the neuron and muscle fibers, they signal the release of calcium ions in the muscle, allowing for contraction. Motor units follow an all-or-none principle, meaning that all fibers connected to the signaling neuron are/are not activated. This is similar to flipping a light switch. Either all the lights the switch is connected to will turn on or they will not. 

Muscle Fiber Types

There are three types of muscle fibers in the body: type 1, type 2A, and type 2B. Type 1 fibers are aerobic, having the ability to steadily produce low amounts of force during contraction. These would be seen in endurance athletes like marathon runners. Type 2 fibers are power fibers, being able to produce a high amount of power very quickly. The major difference between types 2A and 2B is the amount of power and duration of power production. Type 2B creates the most power and lasts the least amount of time. These fibers would be highly present in strength athletes like powerlifters.

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Lymphocytes

Your body produces white blood cells, also called leukocytes, as your private army. Each type of leukocyte responds to a particular type of threat. The lymphatic system aids in the body’s defense by producing lymphocytes: B cells, T cells, and NK cells. All three lymphocytes originate from the spongy tissue inside of bones called bone marrow. The migration of the cells following production allows for their specialization. 

• B cells remain in the bone marrow and mature to become factories for antibodies. An antibody is a protein produced by the immune system for fighting invaders, called antigens. Each antibody matches an antigen, like a lock and key, to destroy it. 
• T cells migrate from the bone marrow to the thymus. Once there, they mature into cancer killing machines. T cells monitor foreign substances or mutated cells to prevent the spread of a virus or cancer to other cells.
• NK cells are known as natural killers that go out and attack cancer or virus ridden cells, similar to T cells.

Parts of the System

The lymphatic system displaces excess fluid from cells and tissues (lymph) using several branches of tubes (lymphatic vessels) that span the entire body. Along these vessels are several “pit stops” called lymph nodes. Each lymph node houses numerous immune cells that filter out infected or cancerous cells from the lymph. Once lymph moves past the nodes, it eventually arrives at one of the collecting ducts. Here, the lymph is dumped back into the bloodstream to increase blood volume and the number of white blood cells. The organs of this system are summarized in the graphic below:

Lymph becomes mobile through muscular contraction and changes in pressure surrounding the lymphatic vessels. Essentially, moving the body leads to movement in the system as well. The movement of lymph begins when lymph capillaries (very thin lymph vessels) in the tissues absorb the fluid that the cells do not. Once in the capillary, the lymph is pushed to lymph nodes to be filtered and sent on to the next until it reaches a collecting duct. This process, as well as an overview of the system, are shown in the diagram below:

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There are 206 bones that serve as the rigid support structure of the body and are connected via ligaments. Bones are also connected to muscles by tendons, allowing you to have motion. Further, cartilage often forms the mold for new bone growth and cushions joints between the bones.

Basic Anatomy of the Skeletal System

Axial and Appendicular Skeletons

The skeletal system is subdivided into two divisions: the axial skeleton and appendicular skeleton. In the diagram below, the axial skeleton is highlighted in red and the appendicular skeleton is highlighted in blue.

As shown, the axial skeleton houses the skull, vertebral column, and thoracic cage (ribs and sternum). The primary function of this division is protection of the brain, spinal cord, heart, and lungs. The appendicular skeleton includes everything necessary for the appendages, including the shoulder girdle, hips, and the bones of the legs and arms. The primary function of this division is to allow for movement as the bones that make it up are responsible for our ability to walk, run, lift, or even wave hello.

The Vertebral Column

The vertebral column, or spine, is composed of four vertebrae sections: cervical, thoracic, lumbar, and the sacrum. First, the seven cervical vertebrae are responsible for supporting the head and allowing movement of the neck. Second, the twelve thoracic vertebrae are responsible for providing the foundation for the ribs and thoracic cage. Third, the five lumbar vertebrae support the lower back and the majority of the weight of the upper body. Lastly, the sacral vertebrae consists of five fused vertebrae at the base of the column. The coccyx is just below the sacrum and is also known as the tailbone. Each vertebrae is separated by an intervertebral disc that absorbs shock to cushion the vertebrae.

Joints

There are over 300 joints in the adult human body. Joints, also called articulations, perform two main functions: holding bones together and allowing flexibility in the rigid skeletal system for large-scale movements. The diagram below is an example of a synovial joint. In this type of joint, each end of the connected bones is covered with articular cartilage. This extends out and around the joint to form the articular capsule. The capsule is then supported by a loose synovial membrane on the sides and is filled with synovial fluid. The goal of synovial joints is to reduce friction and absorb shock during body movements.

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Skeletal System – bones, cartilage, tendons, ligaments, joints

• Body support and internal organ protection
• Bones provide storage for minerals
• Bones act as levers for muscular action

Muscular System – muscles attached to bones

• Muscles contract and shorten to allow motion (running, walking, etc.)
• Muscles control facial expression
• Muscles allow manipulation and interaction with the environment

Integumentary System – skin, hair, nails

• Protects organs from drying out, getting an infection, or receiving an injury
• Excretes salts and urea from body 
• Helps in body temperature regulation (sweating)

Lymphatic System – lymphatic vessels, lymph nodes, spleen, thymus

• Cleanses blood of pathogens and other debris
• Houses lymphocytes – cells that act in immune responses to protect the body from foreign substances 

Endocrine System – pituitary, thymus, thyroid, parathyroid, adrenal glands, pineal glands, ovaries, testes, pancreas

• Maintains internal balance (homeostasis), promotes growth and development, hormone production

Nervous System – brain, spinal cord, nerves, sensory receptors

• Allows detection of external and internal changes to create a response by the muscles or glands
• Helps maintain internal balance (homeostasis) by rapid transmission of electrical signals 

Reproductive Systems – males: testes, prostate gland, scrotum, penis, duct system; females: ovaries, uterine tubes, uterus, mammary glands, vagina

• Both produce sex cells, called gametes, that aid in reproduction
  • Men produce sperm
  • Women produce eggs
• Female anatomy provides housing for development of the fetus until birth and mammary glands provide nourishment in the form of milk for the newborn

Respiratory System – nasal cavity, pharynx, larynx, trachea, bronchi, lungs

• Provides a continuous supply of oxygen into the blood while also removing carbon dioxide
• Contributes to acidity or basicity of blood 

Circulatory System – heart and blood vessels

• Transport system that carries substances to and from tissues for exchange
  • Substances include: oxygen, carbon dioxide, nutrients, wastes, hormones, etc.
• Blood is pumped through the vessels by the heart
• Antibodies and other proteins in the blood are involved in immune response 

Digestive System – oral cavity, pharynx, esophagus, stomach, small and large intestines

• Breaks down food to be absorbed by the blood for delivery to cells in the body
• Removes undigested material as feces

Urinary System – kidneys, bladder, ureters, urethra

• Rids body of nitrogen-containing waste (urea, uric acid, ammonia) as a result of breaking down proteins and genetic material
• Maintains water, acid/base balance, and electrolyte concentration of the blood