The Respiratory Systems - Anatomy and Physiology Notes by Doctor_dr2021

Table of Content:

• The Upper Respiratory Tract
• The Lower Respiratory Tract
• Respiratory Disorders
• The Air You Breathe

Figure 12-12 Organs of the respiratory system.

Whether you are running after a bus, singing in a chorus, or talking with a friend, your respiratory system is very important to you. Your respiratory system is made up of your lungs and air passages. These organs carry out the process of respiration, or taking in oxygen from the air and releasing carbon dioxide. Carbon dioxide is a waste product that your cells produce when breaking down glucose for energy. All of the cells in your body need oxygen to carry out their functions. Your respiratory system works closely with your circulatory system to ensure that your body receives enough oxygen.

The Upper Respiratory Tract 

The respiratory system's organs are arranged geographically. From the nose to the beginning of the windpipe is the upper respiratory tract. From the windpipe to the lungs is the lower respiratory tract. 

The nasal cavity is the space between the roof of the mouth and the floor of the brain cavity. The nasal cavity serves as the body's air entry point. Air enters your nose via your nostrils as you breathe in. Mucous membrane lines the nasal cavity, including the nostrils. The tissue known as the mucous membrane aids in rehydrating and warming the air before it enters the lungs. Additionally, the mucous membrane eliminates bacteria to aid in preventing infection of the lungs. Most airborne particles are captured by mucus and cilia in the nose before they can infect lung tissue. Cilia, which resemble hair-like structures in the mucous membrane, capture dust and other foreign objects to keep the lungs clean.

There are reddish lymphatic tumour masses in the rear of the mouth. The tonsils was dubbed by suit. Bacteria that enter the mouth and throat are captured and eliminated by the tonsils. Air enters the top region of your throat through the mouth and nasal cavities. Your throat connects to your oesophagus and windpipe. Through a hole that connects to the windpipe, air travels down the throat. Food and liquids pass down the throat through another opening into the esophagus. Normally, it is impossible to breathe and swallow simultaneously. The soft palate is elevated when swallowing to prevent food or liquids from entering your nasal cavities. The epiglottis covers the windpipe's opening concurrently. When food enters the incorrect pipe, it accidentally enters your windpipe, causing you to choke or cough.

Key Points:

The respiratory system can be divided into two sections: the upper respiratory tract and the lower respiratory tract.

• The upper respiratory tract runs from the nose to the opening of the windpipe.
• The lower respiratory tract runs from the windpipe to the lungs.

The nasal cavity is the area between the roof of the mouth and the floor of the brain cavity.

• Air enters the body through the nasal cavity, which is lined with mucous membrane.
• The mucous membrane helps warm and moisten the air before it enters the lungs.
• It also filters out bacteria to protect the lungs from infection.
• Mucus and cilia in the nose trap most particles from the air before they can infect the lung tissue.

The tonsils are reddish masses of lymphatic tissue located at the back of the mouth.

• They trap and destroy bacteria that enter the throat and mouth.

From the mouth and nasal cavity, air passes into the upper part of the throat.

• The throat then opens into the windpipe and esophagus.
• Air passes down the throat through an opening that leads to the windpipe.
• Food and liquids pass down the throat through another opening into the esophagus.

Normally, breathing and swallowing cannot occur at the same time.

• When you swallow, the soft palate is raised to keep food or liquids from entering your nasal cavities.
• At the same time, the epiglottis covers the entrance to the windpipe.
• When food goes down the wrong pipe, it goes into your windpipe by mistake, and you gag or cough.

The Lower Respiratory Tract 

Figure 12-13 The chest expands during inhalation, when the diaphragm contracts and the ribs spread apart.

The larynx is the name for the entrance of the windpipe. The larynx is located directly below and in front of the lowest portion of the neck, near the base of the tongue. Because it serves as the voice organ, the larynx is frequently referred to as the "voice box." The larynx's mucous membrane aids in filtering out dangerous contaminants from the incoming air. To filter out these particles, it works similarly to the mucous membrane in the nasal cavity. The air is also warmed and made more humid.

The larynx and the windpipe are comprised of muscle and cartilage rings. The term "trachea" (TRAY kee uh) refers to the portion of the windpipe that is below the larynx. The cartilage rings maintain the trachea's stability and openness for airflow to and from the lungs.

The windpipe's bottom portion separates into two air tubes, known as bronchi [BRAHNG ky]. The bronchi are each tubes. Each lung has one bronchus. Smaller branches form as the bronchi split. These branches in turn split into tubes that get smaller and smaller. The tiniest tubes exit the lungs as collections of tiny air sacs. Before entering the lungs during inhalation, air travels through the bronchi and upper respiratory tract. The lungs are a pair of organs that play a key role in breathing. In the upper chest cavity, they are located. Lung cilia protect the airways from dust particles.

Due to variations in air pressure, air enters and exits the lungs. Simply explained, air flows from high-pressure regions to low-pressure regions. You may observe the impact of air flowing out of a high pressure region if you puncture an air balloon. As the diaphragm contracts and relaxes, the pressure in the lungs fluctuates continuously. The broad muscle that spans across the bottom of the chest cavity and divides the chest from the abdomen is called the diaphragm (DY uh fram). It is the primary breathing muscle. The diaphragm descends when you inhale. Then, the chest cavity enlarges. The air pressure inside the chest cavity decreases as it expands. There is more pressure outdoors. Air enters the lungs to balance the pressure.

The procedure is switched around when you exhale. The diaphragm relaxes and bends upward to expel air from the lungs. The chest cavity shrinks as a result. The chest cavity's internal air pressure then rises. Lungs lose air as a result. This procedure is demonstrated in Figure 12–13.

Alveoli are little air sacs that are found inside the lungs. These air sacs extend into the lungs from the tiniest air tubes. The lungs contain roughly 300 million alveoli. There are capillaries all around these small air sacs. The only barriers separating the air in the lungs from the blood in the capillaries are the air sacs' thin walls and the capillaries themselves. These air sacs receive oxygen as you breathe in.

These thin walls subsequently allow oxygen from the air sacs to enter the red blood cells. Carbon dioxide travels from the capillaries into the air sacs at the same moment. Therefore, carbon dioxide is exhaled into the atmosphere. As carbon dioxide is expelled from the cells, oxygen is passed into the cells.

Key Points:

• Larynx is the opening to the windpipe located below the throat, known as the voice box.
• Mucous membrane in the larynx filters out harmful particles and warms/moistens the air.
• Windpipe consists of muscle and rings of cartilage, keeping it firm and open for air passage.
• Trachea is the section of the windpipe below the larynx, leading to the lungs.
• Bronchi are two air tubes, each entering a lung and branching into smaller tubes leading to tiny air sacs inside the lungs.
• The lungs are the main breathing organs, containing about 300 million alveoli.
• The diaphragm, a large muscle separating the chest and abdomen, is the chief muscle used in breathing.
• Air moves in and out of the lungs due to differences in air pressure caused by the diaphragm's contraction and relaxation.
• Alveoli are surrounded by capillaries, allowing for gas exchange between air in the lungs and blood in the capillaries.
• Oxygen enters the air sacs during inhalation, passing through the thin walls into red blood cells, while carbon dioxide moves from the capillaries into the air sacs to be breathed out during exhalation.

Respiratory Disorders

Figure 12-14 Oxygen and Carbon Dioxide Levels in inhaled and exhaled air.

A half-quart of air, or around 500 millilitres, of air is exchanged with each breath when you are at rest. When you exercise, this amount could rise by up to five or six times. Therefore, it's critical that your respiratory system is in good condition in order to handle the increased gas exchange that occurs during exercise. Diseases of the respiratory system can affect the lungs, throat, or nose. You may be able to keep some of these common respiratory conditions at bay with regular exercise, a healthy diet, enough sleep, and excellent cleanliness.

Pneumonia 

The term "pneumonia" refers to a number of various lung infections. An illness called pneumonia results in lung tissue inflammation. Bacteria or viruses may be the source of the infection. Breathing may be challenging due to fluid accumulation in the lungs caused by pneumonia. The most frequent symptoms of pneumonia are fever and coughing. The appropriate course of action depends on the illness kind. Typically, doctors advise patients to stay hydrated, rest, and take any prescribed antibiotics.

Particularly in older adults, bacterial pneumonia can be fatal. It has to be handled with care. Some bacterial pneumonias are preventable with a vaccine. Although viral pneumonia is a serious condition as well, it usually does not pose a life-threatening threat.

Bronchitis 

Bronchitis is an inflammation of the bronchi's mucous membrane. It's possible for bacteria, viruses, or irritants to cause bronchitis. The bronchi get clogged with thick mucus as a result of fluid buildup. The disease may become worse if dust particles, new germs, or viruses are present. Initially, bronchitis may resemble a cold. Coughing and hoarseness are typical symptoms of the illness. Only a few days or a week may pass before bronchitis returns.

Antibiotics can be used to treat bacterial bronchitis. The infection may cause the body to become significantly more vulnerable to other illnesses. The illness may linger for a year or more if it is not appropriately managed. Once the infection has spread widely throughout the bronchitis, it is very challenging to treat. Bronchitis is more likely to strike those who smoke or are exposed to airborne contaminants.

Asthma 

Some respiratory illnesses last a long time or are chronic. They require ongoing therapy since they frequently reoccur. Asthma is one of these conditions. A respiratory condition known as asthma is characterised by coughing, wheezing, and shortness of breath. Usually. A chemical that is ingested or breathed in causes asthma. As a result, the smooth muscle in the bronchial tubes narrows or spasms. Additionally, the mucous membrane swells. Drugs that relax the bronchial muscles and open the airways can ease asthma episodes.

Figure 12-15 Asthma attacks are often triggered by these four common factors.

Emphysema 

Emphysema is a different chronic respiratory condition that is more prevalent in middle-aged or older adults. Emphysema is a respiratory condition that weakens the lungs and is characterised by severe breathlessness. Emphysema typically takes years to develop. Lung tissue becomes less elastic when the air sacs get increasingly thin and progressively eliminated. A person with emphysema finds it extremely difficult to exhale as a result of this. The exchange of gases is hampered by this. Because the lung damage is irreversible, there are very few treatment options for this illness. Smokers are more likely to get this illness. This lung condition has two possible outcomes: disability and death.

Key Points:

• Resting breathing exchanges about 500 milliliters of air, while exercise may increase it up to five or six times.
• Respiratory diseases may affect the nose, throat, or lungs, and a healthy respiratory system is important for handling increased gas exchange during exercise.
• Pneumonia is an infection that causes lung tissue inflammation, and the signs are usually fever and coughing. Treatment depends on the type of infection and may include antibiotics, rest, and fluids. A vaccine protects against some bacterial pneumonias.
• Bronchitis is an inflammation of the bronchi caused by bacteria, viruses, or irritants, and the signs are coughing and hoarseness. Treatment depends on the cause and may include antibiotics, rest, and avoiding irritants. Smoking and exposure to harmful substances increase the risk of developing bronchitis.
• Asthma is a chronic respiratory disorder characterized by shortness of breath, wheezing, and coughing, usually triggered by a substance that is breathed in or eaten. Treatment includes drugs that relax the bronchial muscles and open up air passages.
• Emphysema is a chronic respiratory disease caused by a weakening of lung tissue and characterized by serious shortness of breath. The lung damage is permanent, and treatment is limited. Smoking is the most common cause of this disease, and it may lead to disability or death.

The Air You Breathe

Air pollution can damage the respiratory system. Air pollution is the term used to describe the tainting of the air you breathe. Substances in polluted air have the potential to inflame the respiratory tract. Pollutants that might harm your health include chemicals in spray cans and smoke from factories. The lining of the bronchial airways can get damaged by some contaminants. They hinder or halt the cilia that line the airways from performing their function, which prevents the removal of mucus that is contaminated with dust or germs. The air passages may then get clogged with irritants, leading to edoema. Possible outcome: a respiratory infection. Many respiratory diseases and disorders may deteriorate due to air pollution.

Smokers typically have more respiratory issues and illnesses than non-smokers. Smokers continuously contaminate the air they breathe with their own cigarette smoke. The short-term side effects of smoking frequently include bronchitis, a persistent cough, a scratchy throat, and hoarseness of voice. Prolonged cigarette smoking has also been related to emphysema and several cancers. Fortunately, more and more individuals are learning via education that smoking may lead to major health issues and that they have a choice whether or not to smoke.

Key Points:

• Air pollution can harm the respiratory system by causing inflammation in the respiratory tract.
• Polluted air can contain substances such as smoke from factories and chemicals from spray cans that can harm the body.
• Certain pollutants can harm the linings of the bronchial airways and slow down or stop the action of the cilia lining the airways.
• When cilia are not functioning properly, mucus filled with dust or bacteria cannot be removed from the airways, which can lead to irritation and swelling.
• Respiratory infections may result from clogged air passages caused by irritants.
• Air pollution can worsen many respiratory disorders and diseases.
• Smokers tend to suffer more respiratory problems and diseases than non-smokers due to continuously inhaling tobacco smoke.
• Short-term effects of smoking include bronchitis, chronic cough, scratchy throat, and hoarse voice.
• Prolonged cigarette smoking can lead to emphysema and different forms of cancer.
• Education is helping people understand that smoking can cause serious health problems, and they can choose not to smoke.

Lesson Review

Every cell in your body receives oxygen thanks to your respiratory system. It also eliminates carbon dioxide waste from your body. Your body's respiratory system aids in infection prevention. However, infections themselves can harm the respiratory system. The lungs can suffer serious harm from smoking. By giving up smoking, you may assist safeguard your respiratory system.

1. Where is the upper respiratory tract located? 
2. What are the bronchi?
3. What is the chief muscle used in breathing?
4. List two chronic respiratory diseases?
5. Explain why smokers are more likely to suffer from respiratory List two chronic respiratory disease than nonsmokers.