Breathe in…breathe out. You typically do this 22,000 times a day, and yet it’s something most of us take for granted. It’s true, you don’t have to think much about it, your body just does it—first you inhale, then you exhale. But while taking a breath may seem simple at first glance, under the surface there’s a lot going on.  

If you’ve ever wondered about the science behind how you breathe, you’re in the right place.  

Your Respiratory System 

Eleven organ systems carry out a wide variety of essential functions in your body. And your respiratory system is the one responsible for breathing.  

It’s made up of numerous organs and tissues including:   

1. Diaphragm: This dome-shaped muscle is located at the base of your chest cavity. As it contracts, the volume of the chest cavity increases, creating a lower pressure within the chest to draw air into the body.  
2. Nasal Cavity and Mouth: Each breath of air enters your body through your nose or mouth. Nasal passages help to filter and humidify the air before it reaches the lungs, while your mouth serves as an alternate route. 
3. Pharynx and Larynx: Your pharynx connects your mouth and nasal passages to your esophagus. The larynx is the muscular organ that controls your vocal cords. Together, these structures serve as a crucial gateway to allow air to pass through to your lower respiratory tract. 
4. Trachea (Windpipe): This strong tube reinforced by rings of cartilage allows air to pass to and from your lungs. 
5. Bronchus: Your windpipe splits into two bronchi linking to each of your lungs, where they further divide into many bronchiole passages resembling the branches of a tree. 
6. Lungs: Your primary respiratory organs are a pair of spongy, pinkish-grey structures in your chest cavity. They inflate with air each time you inhale and deflate when you exhale. 
7. Capillaries: These networks of tiny blood vessels pull oxygen from your lungs into your bloodstream.  

Working together, these various organs, tissues, and structures allow you to breathe, speak, smell, and more. But let’s focus on breathing. 

The Process of Breathing 

Breathing has two main parts—inhalation and exhalation—and each requires the coordinated effort of multiple muscles. Prior to and during inhalation your diaphragm and surrounding muscles contract. Your chest expands and your lungs fill with air. As these muscles relax, your chest contracts forcing the air out of your lungs—in other words, you exhale.  

Your body isn’t inhaling and exhaling for fun, it’s fulfilling your need for oxygen.  

Your cells use oxygen (and glucose) to create energy through a process called cellular respiration. For this to take place, however, oxygen needs to get from your lungs to cells throughout your body. This is where blood comes in.  

Gas Exchange in the Alveoli 

Your bronchial tubes branch off into smaller airways, called bronchioles. They’re connected to alveoli—tiny, grape-like air sacs in your lungs that are surrounded by capillaries. This is where gas exchange happens, one of the most important steps of breathing.  

Your alveoli are like microscopic balloons, filling with air each time you breathe in. Oxygen from this air is absorbed by blood passing through the surrounding capillaries. This newly oxygenated blood is then delivered through your body by the cardiovascular system—but let’s save that for another article.  

Cellular respiration creates energy; but it also creates waste products, including carbon dioxide. This carbon dioxide is contained in deoxygenated blood. When blood passes through the capillaries an exchange occurs—oxygen enters the blood (as mentioned above) and carbon dioxide exits the blood, moving to the air held in the alveoli. This air is then exhaled to expel the carbon dioxide from your body.  

How to Keep Your Lungs Healthy 

Your lungs are the center of your respiratory system. And healthy lungs are crucial for efficient, healthy breathing. Fortunately, there are a number of steps you can take to keep your lungs healthy and happy.  

Lungs are sensitive to smoke and pollutants, and breathing these substances in can be harmful to your lung health. Cigarette smoke, including secondhand smoke, can damage the bronchioles and alveoli in your lungs, making it harder for your body to deliver oxygen to its cells. To avoid this, try to stay away from cigarette smoke and smog. If you are going to be exposed to harsh chemicals, excessive air pollution, or other damaging substances, wear a mask or respirator to filter damaging substances out of the air.

Regular exercise can also help your lungs (and heart) work more efficiently. As you exercise, your lungs and the muscles associated with breathing are working overtime to provide your body oxygen. Even light, daily exercise can strengthen your lungs, heart, and other muscles. The stronger these organs and muscles are, the better your body is at delivering oxygen to its cells.  

Respiratory Conditions: Health Factors That Affect Your Lungs 

Environmental factors, such as pollutants, aren’t the only things that can affect your respiratory system. Sicknesses, and chronic health conditions can also impact your ability to breathe.  

Lung capacity naturally decreases with age, meaning as you get older your lungs become less efficient. For older adults, maintaining lung health through exercise and by avoiding damaging substances is extra important.  

Additionally, certain health conditions may require medical assessment and intervention. Whether it’s due to asthma, severe allergies, or a persistent cold, consulting a doctor is often an important step in maintaining the health of your respiratory system. Certain illnesses, such as the common cold and flu, can develop into serious infections and even pneumonia. So if you feel like your respiratory system isn’t working as it should, it’s worth a trip to the doctor.  

The Bottom Line: A Healthy Body Needs Healthy Lungs 

Breathing is a vital part of life. Without oxygen your cells can’t create energy. And without your cells producing energy most organs, tissues, and other body parts can’t do their job. The brain can only go four minutes without oxygen before it suffers permanent damage.  

Needless to say, a healthy respiratory system is indispensable to a healthy lifestyle. So take care of your lungs—you’ve only got two. 

Cells are the building blocks of life, and they come in all shapes and sizes. Some cells are round and small, others are larger and web-like. No matter their look, the cells in your body are highly complex, elegant machines that make life possible.

The variety of cell shapes and sizes is essential. Your body always has a lot going on. Cells need to differentiate and specialize, channeling their energy toward specific tasks. Let’s explore the variety of cells in your body and learn more about their anatomy, function, and individual characteristics.

Go Deep Inside Your Cells

Diversity starts inside the cell— with cellular organelles. These teeny-tiny membrane assemblies fill your cell and help it perform its specific functions. There are many organelles, and you’ll read about a couple of the most important ones.

The organelles that operate inside of cells are necessary for completing designated assignments. Not every cell has every type of organelle. But all cells rely on these structures to work effectively.

Cell Membrane

The lipids that surround the cell and give it shape are organized into a two-layered barrier called a membrane. Cell membranes are made of fats and proteins. The fatty portions of the membrane keep water out of the cell, while the proteins allow nutrients and water to pass through.

Your cells need a membrane to stay organized, compact, and protect their contents from the surrounding body fluids. You can visualize a cell membrane by dropping a bit of oil into a cup of water. The micelles that form from mixing oil and water are a lot like the fatty membrane that encapsulates your cells.

Mitochondria

Mitochondria are the organelles that power the cell. It’s in and around the mitochondria that the food you eat is converted to cellular energy (or ATP as it’s known inside the cell).

Mitochondria are commonly referred to as the “powerhouses” of the cell. But these compact generators weren’t always stuck inside cells. Scientific research suggests that mitochondria were at one time their own cellular bodies. There is unique genetic information stored inside mitochondria. This material is called mitochondrial DNA.

As life evolved, it’s believed mitochondria were recruited by cells as an energy source. Now when cells divide, mitochondria replicate inside the cell along with the other organelles.

Here’s a fun fact: every cell in your body contains mitochondria except red blood cells.

Ribosomes

Cells need to be able to produce proteins. Ribosomes are the center of protein production inside the cell. They use specialized codes to read the information stored in RNA molecules (genetic directions for building proteins). Ribosomes create nucleic acids and proteins from the instructions found in RNA.

Nucleus

In the nucleus, you’ll find all the blueprints for a cell. The nucleus is the cell’s “brain.” It sends out instructions about how the cell should function, and it houses the DNA needed to replicate the cell.

This organelle is often depicted in images as the dark center of a cell. It’s densely packed with DNA that is sensitive to degradation and damage from the environment around it. A double-layered membrane surrounds the nucleus to protect the DNA stored inside.

Cell Types Explained

Now that you understand some of the crucial cellular operation centers, let’s zoom out to discuss different cell types. Hundreds of specialized cells are inside your body right now. A student of science like yourself could spend a lifetime learning about each and every cell type.

Instead of debating the minutia of each type, here are the basics about some of the most common varieties of cells in your body.

1. Skin and Epithelial Cells

The cells you can most easily see are your skin cells. That’s because the largest and outermost organ of your body is made entirely of special skin cells—also called epithelial cells. These epithelial cells that create the meshwork of your skin are the same type of cells that line your digestive tract, blood vessels, and hollow organs.

Skin cells have unique properties. These special attributes help explain the function of your epithelial cells. Here are a few ways skin cells can work in your body:

• Skin cells come together to create tissues that can secrete mucus, sweat, and oil.
• Epithelial cells harden through a process called keratinization to protect your body from invading pathogens and injuries.
• They also pigment the skin. A protein (melanin) in your skin cells that influences your skin color, and whether or not you have freckles.
• Skin cells also keep you hydrated. Those outermost skin cells protecting your softer insides are great at trapping water beneath your skin.
• Inside your body epithelial cells secrete mucus. The lining of your esophagus, nasal passages, and intestines are all made of epithelial cells that lubricate these surfaces.

2. Blood Cells

Red and white blood cells circulate all over your body to deliver oxygen, carry away carbon dioxide waste, and play the starring role in your immune system. Their ubiquitous nature might make them seem simple, but there’s more to these blood cells than you might think.

Red blood cells (RBCs) are also called erythrocytes. They are unique because they do not have a nucleus (unlike most other cells). Because they lack a nucleus, RBCs are hollow in the center—kind of like a donut. Their unique shape makes them more efficient at exchanging and transporting oxygen molecules—their primary role in your body.

Without a nucleus and other organelle structures, RBCs cannot replicate on their own. Instead, your body generates new red blood cells in bone marrow tissue.

RBCs use a protein called hemoglobin to carry oxygen throughout your body. The hemoglobin inside RBCs gives blood its signature red color.

White blood cells (WBCs), or leukocytes, are agents of the immune system. They search for invading pathogens and initiate and complete your body’s immune responses.

There are two main classes of WBCs—granulocytes and mononuclear leukocytes:

• As the name suggests, granulocytes are WBCs filled with granules. Inside each granule are proteins and enzymes that can digest and destroy pathogens. Granulocytes are responsible for the creation of pus, and they play an important role in allergies.
• Mononuclear leukocytes don’t have granules. Instead, they have one large nucleus and special organelles called lysosomes. These lysosomes act like holding cells for microbes and other potential pathogens. Mononuclear leukocytes can use these lysosomes to trap and destroy invaders through a process called endocytosis.

3. Nerve and Brain Cells

The brain is full of spidery cells that allow you to think, read, move, and remember. Brain cells are the main components of your central nervous system. They use chemical messengers called neurotransmitters to communicate between other body cells.

Two kinds of brain cells exist in your body—neurons and glia. Both are necessary for efficient electro-chemical signaling throughout the body.

Neurons are web-shaped brain cells with a central body called a soma. All neurons have branched appendages called dendrites that can receive electro-chemical messages from neighboring neurons. A neuron can transmit signals along the longest portion of its cell body, called the axon.

Glial cells look a lot like neurons, but they differ in one important way: Glia cannot transmit electrical signals like neurons can. Their purpose is to support the transmission of electro-chemical signals from neurons by acting as insulation. Glial cells make it possible for tiny electro-chemical messages to travel the entire length of the body. Their insulating role speeds up signaling across long distances.

4. Muscle Cells

Your heart, hamstrings, and every other muscle in your body are composed of muscle cells—also known as muscle fibers. These fibers wrap tightly around each other like bundles of strong, stretchy cords to create your muscles.

Individual muscle fibers contain filamentous proteins that allow the fiber to lengthen and contract. These proteins are called actin, myosin, and titin. Each has a role in the contraction-relaxation cycle of a muscle fiber.

Nerve cells from the central and peripheral nervous system send messages to muscle fibers to coordinate your movements. Some muscle movements are voluntary, like lifting your hand to wave hello. Other muscle fiber contractions are unconscious or involuntary, such as the constriction of your pupils in bright light.

There are three main types of muscle fibers and muscle tissue, and each kind of tissue utilizes muscle fibers differently:

• Skeletal muscle cells are under conscious control. These muscle fibers attach directly to bones via tendons. Skeletal muscle fibers are long and cylindrical, like tubes that bundle together. These muscle cells are also multi-nucleate, which means they have more than one nucleus.
• Smooth muscles are made up of smooth muscle fibers. You can find smooth muscle fibers inside of the organs of your body. Your eyes, stomach, bladder, intestines, and blood vessels are all built with smooth muscle tissue. Unlike skeletal muscle, you do not have voluntary control over smooth muscle fibers.
• What makes cardiac muscle cells unique is their location. These muscle fibers can only be found in one place—your heart. Cardiac muscle cells are ultra-strong, elastic cells that allow your heart to pump blood in one coordinated and efficient heartbeat.

5. Fat Cells

Fat storage is a sometimes-taboo topic. But the cells that house fat are extremely valuable to your body. Adipocytes are fat cells, and when they assemble together they make up fat tissue.

Try to break out of the “fat = bad” mindset for a minute. Your body stores fat just like a bank stores money. Having fat on hand is essential when your body needs energy. And adipocytes house the fat your body wants or needs to save for later use.

Brown adipocytes are sometimes called “baby fat.” These fat cells are so named because you have lots of brown fat cells during infancy. The primary role of brown fat is thermogenesis (heat) and these adipocytes maintain body heat because they are full of mitochondria. Infants depend on brown fat reserves because they lack the ability to shiver or use other means to warm themselves.

As you age, your supply of brown fat cells shrinks, but doesn’t go away entirely. Current scientific research suggests that the mitochondria that fill brown fat cells disappear as you get older, causing the brown fat you stored in infancy to resemble white fat cells.

The main function of white fat cells is energy storage. When glucose isn’t available from your diet, a process called gluconeogenesis kicks in. Through gluconeogenesis, fat can be broken down and converted to usable glucose molecules to power the rest of the cells in your body. Fat available for gluconeogenesis comes from the white adipocytes you may be trying to burn during exercise.

Cellular Health Comes First

You are the cells in your body, and it’s important to take good care of them. No matter the cellular type, complete nutrition is the best way to help your cells thrive. Focus your eating on foods that will deliver nourishing vitamins, minerals, and macronutrients to your cells. Be picky about what you put into your body. Steer clear of over-processed and nutrient-poor foods. Instead, build your meals with the quality nutrition of whole foods—lean proteins, plant-based fats, fiber, vegetables, and fruit.

Prioritizing the health of your cells will pay dividends in your overall wellness. When your cellular health is soaring, you feel great, too. Channel your energy into supporting your cells with a diet rich in essential vitamins and minerals. Whole nutrition from quality foods can optimize the health and wellbeing of the cells that make you.

Your heart pumps. Your kidneys filter. Your stomach digests. Your brain runs the show. But what about your hard-working, multitasking liver? It doesn’t receive the respect or admiration it so rightly deserves. Learning facts about the liver is the best way to awaken appreciation for your most under-the-radar organ.

This list of 27 facts will finally shine a much-deserved spotlight on the underrated organ’s anatomy, function, and how to support liver health. At the end, you can school your friends and family with facts about the liver that goes beyond the basics to spread the liver love around.

Anatomy Facts About the Liver

1. Skin wins the battle of size for organs overall. But your liver takes the title for largest internal organ—and, weighing in around three pounds, is second overall.
2. You aren’t alone in having a liver. Living things with spinal cords (vertebrates) also have livers. All of them. It’s that important.
3. The liver looks like it has a larger head section and a smaller tail. But it can be further divided into thousands of lobules—tiny segments with their own ducts.
4. Your liver has the capacity to hold 10 percent of your body’s blood. It doesn’t always have that much, but it does go through a lot—handling about 1.5 liters every minute.
5. The liver isn’t just an organ—it’s also a gland. That’s because it secretes bile into the intestines.
6. As long as you have a quarter of your liver left, the organ can fully regenerate to original size and regain full function. This is more of an evolutionary necessity than a neat trick. And it’s the reason liver donors can give someone half their liver and survive.
7. Too much fat is bad for your liver. But it’s normal for this important organ to be comprised of about 10 percent fat.

Liver Facts to Explain the Organ’s Many Important Jobs

8. Speaking of fat, one of the hundreds of jobs the liver has is metabolizing fat. This is done through the bile produced in the liver.
9. Your liver can make up to a liter of metabolism-inducing bile every day.
10. Bile also plays a role in metabolizing your other macronutrients—proteins and carbohydrates. So, the liver’s bile production is key to breaking down a large swath of your diet and making sure it can be used to support your overall health.
11. The liver is more than a production facility and metabolism force. It also provides a warehouse for a variety of important nutrients—including glycogen (stored glucose), iron, copper, and a variety of fat-soluble vitamins.
12. What you put in your body is filtered by your liver. It takes out and deals with dietary nutrients, toxins, drugs, alcohol, and a few hormones.
13. Besides filtering, the liver has many functions connected to blood. Your body’s ability to form blood clots—with the support of vitamin K—is aided by the bile produced in your liver. It also:

• • creates an important protein in blood serum (albumin)
  • pieces together a hormone involved in blood pressure regulation (angiotensinogen)
  • handles bilirubin from broken down hemoglobin

14. Immunity is helped out by the liver. Your two types of immune protection—innate and adaptive—are both supported by processes in your second largest organ.
15. Your liver acts as a switching station that determines whether the body’s nutrient intake—delivered through the portal vein—is stored, further processed, placed in a detoxification process, or sent out as waste.
16. Detox is probably the first place your mind goes when you think of your liver. It deals with detoxifying the substances you take in with a two-phase approach. The first liver detoxification pathway (Phase I) neutralizes compounds, while Phase II deals with byproducts of the first phase and makes substances water soluble for removal.
17. Glutathione is one of the most important antioxidants in your body. You synthesize it and can find glutathione throughout your body. But it’s up to 10 times more concentrated in the liver. That’s because it plays a role in Phase II detoxification.

Facts to Help You Maintain Your Liver Health

18. If you can call organ meats popular (and that depends on your culture and preferences), liver would top the list. Edible animal livers are packed with protein, iron, and various vitamins.
19. Surprise—what you eat has a lot of impact on the organ that deals with your dietary intake. One important aspect of maintaining liver health is eating enough fiber. It works to help out this powerful detox organ through weight-management support and maintaining a healthy gut microbiome.
20. Even though fat is part of your liver’s composition, eating too many fatty foods can hamper the health of your body’s biggest detoxifying organ. Saturated fat is especially harmful, but omega-3 fatty acids and healthier options like olive oil are smart choices.
21. That caffeine jumpstarting your day and keeping your going in the afternoon is processed in your liver. But caffeinated beverages—especially coffee and green tea—have been shown to have benefits that help support liver health.
22. Weight management is important for overall health—and your liver is no different. Carrying extra weight strains the liver and can eventually impact function. Watching your diet and exercising regularly will help manage your weight and support your liver.
23. Easing up on your sugar intake is an important step for managing your weight. And it’s especially impactful for your liver—mostly due to the ties your liver has to glucose storage. One step you can take is switching from sugary drinks to plain water. It will also help you maintain healthy hydration levels.
24. A diet built on a broad foundation of fruits and vegetables is a must for optimal health. Along with an abundance of micronutrients you need for overall health, some plants provide liver-supporting benefits. Eat more broccoli, spinach, berries, grapefruit, and grapes to help maintain your liver health.
25. Your liver is in charge of dealing with the alcohol you drink. While drinking in moderation is more easily tolerated, too many wild nights can stack up and start impacting the degree to which your liver does its many jobs.
26. Medications have to be broken down by the liver so they can be effective. But mixing prescriptions, over-the-counter medicines, and even some supplements can cause issues for your liver. Make sure to follow usage instructions and tell your health-care providers and pharmacists all the supplements and medications you’re taking. They can help you avoid potentially harmful interactions.
27. Protecting your liver means taking proper precautions around environmental toxins. Cleaners and other chemicals you inhale have to be processed and neutralized in the liver. That protection is part of your biggest detoxification organ’s job, but you can make it easier by wearing proper personal protective equipment—like a mask—when dealing with chemicals.

Share These Facts About the Liver

The liver isn’t such a strange, magical detoxifier now. You know more liver facts that shed light on all the important functions and ways to keep yourself healthy. Don’t keep all this liver information to yourself. Share it to help your friends become liver lovers, too.