Tag Archives: respiratory system

The Respiratory System

What Does The Respiratory System Do?

The respiratory system brings air into the body and removes carbon dioxide.

When you breathe in, air enters your nose or mouth and goes down a long tube called the trachea. The trachea branches into two bronchial tubes, or primary bronchi, which go to the lungs. The primary bronchi branch off into even smaller bronchial tubes, or bronchioles. The bronchioles end in the alveoli, or air sacs.

Oxygen follows this path and passes through the walls of the air sacs and blood vessels and enters the blood stream. At the same time, carbon dioxide passes into the lungs and is exhaled.

Respiratory System

What Makes Up The Respiratory System?

The respiratory system can be divided into the upper and lower respiratory tracts.

Upper Respiratory Tract

    Mouth, nose & nasal cavity

    The function of this part of the system is to warm, filter and moisten the incoming air.

    Pharynx

    Here the throat divides into the trachea (wind pipe) and esophagus (food pipe). There is also a small flap of cartilage called the epiglottis which prevents food from entering the trachea.

    Larynx

    This is also known as the voice box as it is where sound is generated. It also helps protect the trachea by producing a strong cough reflex if any solid objects pass the epiglottis.

Lower Respiratory Tract

    Trachea

    Also known as the windpipe, this is the tube which carries air from the throat into the lungs. It ranges from 3/4 inch to 1 inch in diameter and 4 inches to 6 inches in length. The inner membrane of the trachea is covered in tiny hairs called cilia, which catch particles of dust which we can then remove through coughing. The trachea is surrounded by 15-20 C-shaped rings of cartilage at the front and side which help protect the trachea and keep it open. They are not complete circles due to the position of the esophagus immediately behind the trachea and the need for the trachea to partially collapse to allow the expansion of the esophagus when swallowing large pieces of food.

    Bronchi

    The trachea divides into two tubes called bronchi, one entering the left and one entering the right lung. The left bronchi is narrower, longer and more horizontal than the right. Irregular rings of cartilage surround the bronchi, whose walls also consist of smooth muscle. Once inside the lung the bronchi split several ways, forming tertiary bronchi.

    Bronchioles

    Tertiary bronchi continue to divide and become bronchioles, very narrow tubes, less than 1 millimeter in diameter. There is no cartilage within the bronchioles and they lead to alveolar sacs.

    Alveoli

    Individual hollow cavities contained within alveolar sacs (or ducts). Alveoli have very thin walls which permit the exchange of gases Oxygen and Carbon Dioxide. They are surrounded by a network of capillaries, into which the inspired gases pass. There are approximately 3 million alveoli within an average adult lung.

    Diaphragm

    The diaphragm is a broad band of muscle which sits underneath the lungs, attaching to the lower ribs, sternum and lumbar spine and forming the base of the thoracic cavity.

How Does The Respiratory System Work?

At the top of the respiratory system, the nostrils act as the air intake, bringing air into the nose, where it’s warmed and humidified. Tiny hairs called cilia protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.

5 Interesting Facts About The Respiratory System

  1. The right lung is slightly larger than the left.

  2. The breathing rate is faster in children and women than in men.

  3. We breathe about 9 to 20 times every minute.

  4. We inhale and exhale air about 22,000 times per day and in the process, transport about 300 cubic feet of air.

  5. The surface area of the lungs is roughly the same size as a tennis court.

Air can also be taken in through the mouth. These two openings of the airway (the nasal cavity and the mouth) meet at the pharynx, or throat, at the back of the nose and mouth. (The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air.)

At the bottom of the pharynx, this pathway divides in two, one for food (the esophagus, which leads to the stomach) and the other for air. The epiglottis, a small flap of tissue, covers the air-only passage when we swallow, keeping food and liquid from going into the lungs.

The larynx, or voice box, is the uppermost part of the air-only pipe. This short tube contains a pair of vocal cords, which vibrate to make sounds.

The trachea, or windpipe, extends downward from the base of the larynx. It lies partly in the neck and partly in the chest cavity. The walls of the trachea are strengthened by stiff rings of cartilage to keep it open. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs.

At its bottom end, the trachea divides into left and right air tubes called bronchi, which connect to the lungs. Within the lungs, the bronchi branch into smaller bronchi and even smaller tubes called bronchioles. Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each lung houses about 300-400 million alveoli.

The alveoli are surrounded by a mesh of tiny blood vessels called capillaries. Oxygen from the inhaled air passes through the alveoli walls and into the blood.

After absorbing oxygen, the blood leaves the lungs and is carried to your heart. Your heart then pumps it through your body to provide oxygen to the cells of your tissues and organs.

As the cells use the oxygen, carbon dioxide is produced and absorbed into the blood. Your blood then carries the carbon dioxide back to your lungs, where it is removed from the body when you exhale.

The breathing process is aided by a large dome-shaped muscle under the lungs called the diaphragm.

When you breathe in, the diaphragm contracts downward, creating a vacuum that causes a rush of fresh air into the lungs.

The opposite occurs with exhalation, where the diaphragm relaxes upwards, pushing on the lungs, allowing them to deflate.

What Can Go Wrong With Your Respiratory System?

Asthma

Asthma is a chronic inflammatory lung disease that causes airways to tighten and narrow. Often triggered by irritants in the air such as cigarette smoke, asthma involve contraction of the muscles and swelling of the lining of the tiny airways. The resulting narrowing of the airways prevents air from flowing properly, causing wheezing and difficulty breathing, sometimes to the point of being life-threatening.

Bronchiolitis

Not to be confused with bronchitis, bronchiolitis is an inflammation of the bronchioles, the smallest branches of the bronchial tree. Bronchiolitis affects mostly infants and young children, and can cause wheezing and serious difficulty breathing.

Chronic Obstructive Pulmonary Disease (COPD)

COPD is a term that describes two lung diseases — emphysema and chronic bronchitis:

  • Long-term smoking often causes emphysema. In emphysema, the lungs produce an excessive amount of mucus and the alveoli become damaged. It becomes difficult to breathe and get enough oxygen into the blood.

  • In bronchitis, a common disease of adults and teens, the membranes lining the larger bronchial tubes become inflamed and an excessive amount of mucus is produced. The person develops a bad cough to get rid of the mucus. Cigarette smoking is a major cause of chronic bronchitis.

Common Cold

Caused by over 200 different viruses that cause inflammation in the upper respiratory tract, the common cold is the most common respiratory infection. Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat.

Cough

A cough is a symptom of an illness, not an illness itself. There are many different types of cough and many different causes, ranging from not-so-serious to life-threatening. Some of the more common causes aare the common cold, asthma, sinusitis, seasonal allergies and pneumonia. Among the most serious causes of cough are tuberculosis (TB) and whooping cough (pertussis).

Cystic Fibrosis (CF)

Cystic fibrosis is the most common inherited disease affecting the lungs. Affecting primarily the respiratory and digestive systems, CF causes mucus in the body to be abnormally thick and sticky. The mucus can clog the airways in the lungs and make a person more vulnerable to bacterial infections.

Lung Cancer

Caused by an abnormal growth of cells in the lungs, lung cancer is a leading cause of death in the United States and is usually caused by smoking cigarettes. It starts in the lining of the bronchi and takes a long time to develop, so it’s generally a disease in adults. Symptoms include a persistent cough that may bring up blood, chest pain, hoarseness, and shortness of breath.

Pneumonia

This inflammation of the lungs usually occurs because of bacterial or viral infection. Pneumonia causes fever and inflammation of lung tissue, and makes breathing difficult because the lungs have to work harder to transfer oxygen into the bloodstream and remove carbon dioxide from the blood. Common causes of pneumonia are influenza and infection with the bacterium Streptococcus pneumoniae.

Pulmonary Hypertension

This condition occurs when the blood pressure in the arteries of the lungs is abnormally high, which means the heart has to work harder to pump blood against the high pressure.

How Do Your Keep Your Respiratory System Healthy?

To keep your respiratory System healthy, don’t smoke, of course. In addition, be sure to do these things . . .

  1. Live plants. Keeping lots of live plants in your home to increase oxygen levels and absorb CO2 and toxins will contribute to your respiratory health.

  2. Eat a diet rich in nutrients necessary for a healthy respiratory system. According to the University of Maryland Medical Center, low levels of certain nutrients have been linked to lung diseases. It recommends eating foods rich in vitamins A, C and E and the minerals zinc, potassium, selenium and magnesium.

  3. Drink plenty of water. This helps thin mucus secretions that accumulate in your lungs, making it easier to breathe. You typically lose about 6 cups of fluids daily, so you should take in at least this much water each day.

This article is part of a series called “Your Body: An Owner’s Manual” which explains how your body systems work and how to maintain them. The first article in the series included a picture of my wife, fitness coach Kathie Lamir, who exemplifies a healthy body. Pictures of Kathie were so well received that I have included one with each article in the series

Fitness Coach Kathie Lami

Your Body: An Owner’s Manual

There was a time when I didn’t know much more about the human body than that my wife’s was beautiful!

Fitness Guru Kathie LamirSee what I mean?

How strange, I thought. We only get one body. It has to last a lifetime. And the better it works, the better we feel. Why wouldn’t we want to know everything about how it works and how to maintain it?

Yet most of us don’t. We know more about the insides of our car than how our body functions.

Maybe that’s because cars come with owner’s manuals, but your body doesn’t.

Well, problem solved.

This article introduces a 12-part series that will explain how your body works. This series is the instruction manual for your body that you never got.

This initial article will briefly describe the 11 human body systems.

Articles about each of the body systems will follow, one a day. Each article will answer these questions . . .

  1. What Does The System Do?

  2. What Makes Up The System?

  3. How Does The System Work?

  4. What Can Go Wrong With The System?

  5. How Do You Keep The System Healthy?

And each article will include “5 Interesting Facts About The System.”

Before starting this discussion of our body systems, however, you must understand that dividing your body into 11 systems for the purpose of studying them does not mean that they are independent systems. Far from it, they are interconnected and dependent on each other.

In fact, some body parts are part of multiple systems. For example, the long bones (like the femur) are not only part of the skeletal system, but they are also part of the circulatory system because they manufacture blood cells. And the ovaries are part of the endocrine system as well as the reproductive system. More about all of this later . . .

These are the 11 main human body systems, presented in alphabetical order.

Circulatory System

The circulatory system is made up of your heart, blood vessels and blood. Your heart pumps oxygen-rich blood from your left ventricle into your biggest artery, the aorta. From there, the aorta branches into smaller arteries, which then branch into even-smaller arteries that travel all over the body. When blood reaches the smallest blood vessels, called capillaries, an exchange occurs. Oxygen, nutrients and hormones are deposited into the cells and waste material from the cells, such as carbon dioxide, is collected for the return trip to the heart.

Veins carry the blood back to the heart where it enters the right atria, passes through the right ventricle and is sent to your lungs where, in capillaries in the lungs, the waste carbon dioxide is deposited and oxygen is picked up. The newly oxygenated blood returns to the heart and, this time, it enters the left atria. From there it goes to the left ventricle and, from there, it is pumped again .

Click here to learn more about your circulatory system.

Digestive System

Your digestive system consists of organs that break down food into the protein, vitamins, minerals, carbohydrates and fats that your body uses for energy and for building and repairing cells and tissues.

Food passes from your mouth down through a muscular tube called the esophagus, and into the stomach, where food continues to be broken down. The partially digested food passes into the small intestines where it is broken down into nutrients which enter the bloodstream through tiny hair-like projections called villi. The liver, the gallbladder and the pancreas produce enzymes and substances that help with digestion in the small intestine.

The last section of the digestive tract is the large intestine, which includes the cecum, colon, and rectum. Indigestible remains of food are eliminated through the anus.

Click here to learn more about your digestive system.

Endocrine System

The endocrine system is made up of a group of glands that produce the body’s long-distance messengers, or hormones. Hormones are chemicals that control body functions such as metabolism, growth, and sexual development. The glands, which include the pituitary gland, thyroid gland, parathyroid glands, adrenal glands, pineal body, pancreas, ovaries, and testes, release hormones directly into the bloodstream, which transports the hormones to organs and tissues throughout the body.

Click here to learn more about your endocrine system.

Immune System

The immune system is our body’s defense system against infections and diseases. Organs, tissues, cells, and cell products work together to respond to dangerous organisms (like viruses or bacteria) and substances that may enter the body from the environment.

An anatomic response physically prevents threatening substances from entering your body. Examples of the anatomic system include the mucous membranes and the skin. If substances do get by, the inflammatory response goes on attack.

The inflammatory system works by excreting the invaders from your body. Sneezing, runny noses, and fever are examples of the inflammatory system at work.

When the inflammatory response fails, the immune response goes to work. This is the central part of the immune system and it is made up of white blood cells, which fight infection by gobbling up antigens. About a quarter of white blood cells, called the lymphocytes, migrate to the lymph nodes and produce antibodies which fight disease.

Click here to learn more about your immune system.

Lymphatic System

The lymphatic system has three main purposes. It removes excess fluid and waste products from the spaces between the cells and returns them to the blood stream. It aids the immune system in destroying and removing waste, debris, dead blood cells, pathogens, toxins, and cancer cells. And it also absorbs fats and fat-soluble vitamins from the digestive system and delivers these nutrients to be used by the cells of the body.

Click here to learn more about your lymphatic system.

Muscular System

The muscular system is made up of tissues that work with the skeletal system to control movement of the body. Some muscles—like the ones in your arms and legs—are voluntary, meaning that you decide when to move them. Other muscles, like the ones in your stomach, heart, intestines and other organs, are involuntary. This means that they are controlled automatically by the nervous system and hormones—you often don’t even realize they’re at work.

Muscles also generate heat to help regulate your body’s temperature and maintain your posture.

Click here to learn more about your muscular system.

Nervous System

The nervous system is the control system and the network of communication for your body.

Think of your brain as a central computer that controls all voluntary and involuntary bodily functions.

Your “computer” acts through a network that relays messages back and forth from the brain to different parts of the body.

This “network” consists of the spinal cord and nerves. The spinal cord runs from the brain down through the back to nerves which branch out to every organ and part of your body.

When a message comes into the brain from anywhere in the body, the brain tells the body how to react. For example, if you accidentally touch a hot stove, the nerves in your skin shoot a message of pain to your brain. The brain then sends a message back telling the muscles in your hand to pull away. Fortunately, all of this occurs lightning fast.

Click here to learn more about your nervous system.

Reproductive System

The reproductive system allows humans to produce children. Sperm from the male, which is produced in the testes, fertilizes the female’s egg, or ovum, in the fallopian tube. The fertilized egg travels from the fallopian tube to the uterus, where the fetus develops over a period of nine months.

Click here to learn more about your reproductive system.

Respiratory System

The respiratory system brings air into the body and removes carbon dioxide. It includes the nose, trachea, and lungs.

When you breathe in, air enters your nose or mouth and goes down a long tube called the trachea. The trachea branches into two bronchial tubes, or primary bronchi, which go to the lungs. The primary bronchi branch off into even smaller bronchial tubes, or bronchioles. The bronchioles end in the alveoli, or air sacs. Oxygen follows this path and passes through the walls of the air sacs and blood vessels and enters the blood stream. At the same time, carbon dioxide passes into the lungs and is exhaled.

Click here to learn more about your respiratory system.

Skeletal System

The skeletal system has a number of functions, some obvious and some less so. Of course, it supports your body and gives it structure.

However, in addition, your skeletal system works with the bones to allow movement, protects your internal organs, produces blood (in the bone marrow) and stores minerals such as calcium and phosphorous which it releases into the blood when necessary.

Click here to learn more about your skeletal system.

Urinary System

The urinary system eliminates waste from the body, as urine. The kidneys remove waste from the blood. The waste combines with water to form urine. From the kidneys, urine travels down two thin tubes called ureters to the bladder. When the bladder is full, urine is discharged through the urethra.

Click here to learn more about your urinary system.

Oh . . . if you want to learn more from the world’s greatest personal trainer, my wife Kathie Lamir, this is her website.