The Respiratory System

Question 1

The function of the respiratory system?

Answer 1

The system specialised to facilitate the intake of oxygen and the removal of carbon dioxide.

Question 2

What are the organs of the respiratory system?

Answer 2

The nose, the trachea, the bronchi, and the two lungs.

Question 3

The function of the nose?

Answer 3

Air enters the body through the mouth and the nose. The lining of the nose and nasal cavity is convoluted and lined by mucous membranes. As air passes over the membranes, it is warmed and humidified. There are also hairs and mucus lining the nose which trap debris, preventing it from reaching the lungs.

Question 4

The function of the pharynx?

Answer 4

The pharynx is the region from the nasal cavity to the top of the trachea and oesophagus. Air travels through it before being diverted into the trachea by the epiglottis.

Question 5

The function of the epiglottis?

Answer 5

During inhalation, the epiglottis covers the oesophagus, guiding the air into the trachea. When swallowing, the epiglottis covers the larynx, preventing food from entering it.

Question 6

The function of the larynx?

Cartlidge structure joining the … and the … Contains ……………. that are able to vibrate as air passes over them.

Answer 6

The larynx is a cartilage structure joining the pharynx and trachea. The larynx contains vocal cords, which are mucous membranes that are able to vibrate as air passes over them.

Question 7

The function of the trachea?

Carries air ….. and ….. the lungs

It is made up of …………………, ensuring that air can always pass through it.

At its base, the trachea splits into ……..

The …….. lining of the trachea produces mucus which …………… The cilia that line the trachea move in a …………………………… so that it can be swallowed and digested or coughed out

Answer 7

The trachea is the tube that carries air into and out of the lungs.

• It is made up of C-shaped cartilage rings that hold the structure open, ensuring that air can always pass through it.
• At its base, the trachea splits into two branches, one branch taking air into each lung.
• The epithelial lining of the trachea produces mucus which traps dust and debris. The cilia that line the trachea move in a wave-like motion to take this music and debris up to the pharynx so that it can be swallowed and digested or coughed out.

Question 8

The function of the bronchi?

Answer 8

Are divisions of the trachea that take air from the throat to the lungs, moistening and warming it.

• Has C-shaped cartilage rings. As the bronchi get smaller, the cartridge is more spread out, with smooth muscle and elastin forming more of the structure.
• Cilia and mucus work together to trap and expel debris from the airways.

Question 9

Explain the divisions of the bronchi.

Answer 9

The trachea splits into two primary bronchi, one for each lung. These then split further into secondary bronchi which take air into each lobe of the lung. The secondary bronchi continue to split, forming tertiary bronchi.

Question 10

The function of the bronchioles?

Answer 10

Are the very small divisions of the tertiary bronchi, which continue to split until they end in millions of terminal bronchioles.

• Bronchioles do not contain cartilage. They are made up of smooth muscle and elastin, allowing the bronchioles to control the flow of air into the lungs, expanding when the body needs more oxygen.
• Cilia and mucus protect the lungs from contaminants.

Question 11

The function of the lungs?

Answer 11

Take up the whole surface of the chest cavity except for the mediastinum, that is occupied by the heart and blood vessels.

• The left lung has two lobes and the right lung has three lobes.
• A membrane called the pleura covers the surface of the lungs (the visceral pleura) and lines the inside of the chest (the partial pleura). Between these two layers of the membrane is a thin layer of pleura fluid, which holds the lungs against the inside of the chest wall and allows them to slide along the wall when breathing.

Question 12

The function of the alveoli?

Answer 12

The smallest bronchioles open into clusters of tiny air sacs called alveoli.

• Each alveolus is only one cell thick and is surrounded by a network of blood capillaries, where gases move between the blood in the capillaries and the air in the alveoli.
• The alveoli are the functional units of the lungs. They are the surface for gaseous exchange, allowing a net flow of oxygen to pass from the airways into the blood and carbon dioxide to pass from the blood into the airways.

Question 13

Describe what happens to the pressure of air in the lungs during inspiration.

Answer 13

For air to flow into the lungs, the pressure of air in the lungs must be less than the atmospheric pressure outside of the body. This is achieved by increasing lung volume.

Question 14

Describe what happens to the pressure of air in the lungs during expiration.

Answer 14

For ait to flow out of the lungs, the pressure of the air in the lungs must be greater than the atmospheric pressure outside of the lungs. This is achieved by decreasing lung volume.

Question 15

List the steps that occur during inspiration.

Answer 15

1. The diaphragm contracts extending the chest cavity downwards.
2. The external intercostal muscles contract, extending the rib cage upwards and outwards. This increases the volume of the chest cavity.
3. As the pleura adheres to the internal wall of the chest cavity, the lungs expand with the expanding chest cavity.

• Increased lung volume means that the pressure of the air inside the lungs is less than the pressure outside.
• Air flows in through the nose and trachea until the pressure becomes equal.

Question 16

List the steps that occur during expiration.

Answer 16

1. The diaphragm relaxes, pushing up into the chest cavity.
2. The external intercostal muscles relax, moving the rib cage down and inwards.

• This reduces the volume of the chest cavity and that of the lungs.
• Decreased lung volume means that air pressure in the lungs is now greater than the pressure outside of the body.
• Air flows out throughout the trachea until the pressures are equal.

Question 17

Explain why the lungs are well suited to their gas exchange function.

Answer 17

1. The alveoli give the lungs a huge internal surface area so that large amounts of gases can be exchanged in a relatively short time.
2. Each alveolus is well supplied with blood vessels so that as much blood as possible is close to the air in the alveolus. This continuous flow of blood helps to maintain a difference in the concentration of oxygen and carbon dioxide between the blood and air in the lungs.
3. The membrane that forms the wall of the alveolus is very thin, so that gas molecules do not have far to travel when moving into or out of the blood. This wall has only one layer of cells and is only 1 micrometre thick.

Question 18

Explain the process of gas exchange of oxygen in the alveoli.

Answer 18

In the alveoli of the lungs, oxygen diffuses into the blood. The blood in the capillaries surrounding the alveoli is brought to the lungs by the pulmonary arteries. This blood has been through the capillaries of the body, where much of the oxygen has been taken up by the body cells. Therefore, the blood that comes into the capillaries around the alveoli has a low concentration of oxygen- lower than the concentration in the air in the alveolus. Due to this concentration gradient, oxygen dissolves in the moisture on the inside of the alveolus and diffuses through the membrane, the walls of the capillaries and into the blood.

Question 19

Explain the process of gas exchange of carbon dioxide in the alveoli.

Answer 19

In the alveoli of the lungs, carbon dioxide diffuses out of the blood and into the air in the alveolus. The blood arriving at the capillaries of the alveoli has come from the body circulation where it has picked up carbon dioxide produced by respiration in the cells. The concentration of carbon dioxide in the alveolar capillaries is higher than the concentration in the air in the alveolus Therefore, carbon dioxide diffuses out of the blood and into the air in the alveolus.

Question 20

What is the percentage of oxygen and carbon dioxide in inspired air?

Answer 20

Oxygen- 20.95%.
Carbon Dixoide- 0.04%
Note- The other 79% of the inspired air is made up mainly of nitrogen, with varying amounts of water vapour.

Question 21

What is the percentage of oxygen and carbon dioxide in expired air?

Answer 21

Oxygen- 15.80%.

Carbon Dioxide- 4.30%.

Question 22

Explain how the concentration gradient for oxygen and carbon dioxide in the lungs is maintained.

Answer 22

1. The constant flow of blood through the capillaries. As the blood flowing through the capillaries around each alveolus picks up oxygen and loses carbon dioxide, it is replaced by more blood being pumped into the capillaries. This ‘new’ blood is low in oxygen and high inc carbon dioxide, so the concentration gradient is maintained.
2. The movement of air into and out of the alveoli as we breathe in and out- The air that has picked up carbon dioxide from, and lost oxygen to, the blood is replaced by ‘new’ air with each breath. The ‘new’ air is low in carbon dioxide and high in oxygen.

Question 23

What is Emphysema?

Answer 23

Emphysema is a disease of the lungs that damages the alveoli. It is caused by long-term exposure to irritants. The irritating particles cause damage to the alveoli. They lose their elasticity, are often replaced with fibrous tissue, and may break down, reducing the internal surface area of the lung. Because of the loss of elasticity of the lung tissue, the lungs are constantly inflated and breathing out no longer occurs passively but requires voluntary effort. Thus emphysema sufferers have two problems, inadequate surface area for gas exchange and difficulty in ventilating the lungs.

Question 24

Causes, symptoms, and treatments of Emphysema.

Answer 24

Causes: Usually caused by long-term exposure to irritating particles in the air taken into the lungs. Smokers, people who work in situations where there is a lot of dust and people who live in cities with continually high air pollution are at a greater risk.

Symptoms: Frequent coughing or wheezing, shortness of breath and tightness in your chest.

Treatment: Emphysema cannot be cured.

Question 25

What is lung cancer?

Answer 25

Lung cancer is the growth of a tumour in the lungs. The most common form of lung cancer begins in the walls of the air passages, usually the bronchi. Inhaled smoke particles constantly irritate the mucous membrane that lines the air passages. This results in excessive production of mucus. Cells at the base of the membrane begin to divide more rapidly and the accumulating mass cannot be removed. This results in ‘smokers cough’. This trapped mucus causes rapture to the alveoli. Emphysema has then developed. Ultimately, a cancerous growth develops in an air passage and may spread to other parts of the body.

Question 26

Causes, symptoms, and treatments of lung cancer.

Answer 26

Causes: Exposure to asbestos fibres and other pollutants and tobacco smoking.

Symptoms: Coughing up blood, shortness of breath, feeling tired or weak.

Treatment: Chemotherapy, immunotherapy, radiation therapy.

Question 27

What is Pneumonia?

Answer 27

Pneumonia is an infection of the lungs caused by bacteria, viruses, fungi or other organisms. The inflammation resulting from the infection causes the secretion of fluid and mucus into the alveoli, thus reducing the amount of air that they can contain. The surface area available for the exchange of gases is also reduced.

Question 28

Causes, symptoms, and treatments of pneumonia.

Answer 28

Causes: Bacteria, viruses, fungi, or other organisms.

Symptoms: Breathing difficulty, cough, fever.

Treatments: Antibiotics, anti-fungal medication.

Question 29

What is tuberculosis?

Answer 29

Tuberculosis is an infection, usually of the lung, by the bacterium Mycobacterium tuberculosis. Most lung infections such as tuberculosis, are spread by droplets. When infected people cough, sneeze or spit, tiny droplets of moisture containing the bacteria, viruses or fungi may be inhaled by others, causing the spread of the infection. Good hygiene practices help to reduce the spread of lung infection.

Question 30

Causes, symptoms and treatments of tuberculosis.

Answer 30

Causes: The bacterium, mycobacterium tuberculosis.

Symptoms: Cough, blood-stained sputum, fevers.

Treatments: Antibiotics.

Question 31

What is asthma?

Answer 31

Asthma is a medical condition that causes difficulty breathing due to the narrowing of the airways. This occurs due to: the smooth muscles contracting, narrowing the airway, inflammation causing the lining of the airways to thicken, narrowing its diameter and mucus filling the airway, narrowing the tube.

Asthma can be an allergic response or a non-allergic. During an asthma attack, the muscles that surround the bronchioles go into spams, which is sudden involuntary contractions. This causes a narrowing of the air passages, and, therefore, difficulty breathing.

The irritation of the membranes lining the air passages also causes the secretion of excess mucus, which also restricts the movement of air. The reduced volume of air going into and out of the lungs means that the exchange of gases is impaired, and the blood does not carry the usual amount of oxygen.

Question 32

Causes, symptoms, and treatments of asthma.

Answer 32

Causes: Triggers for asthma flare-up include respiratory infections, cigarette smoke, and allergens such as dust mites, moulds, pollens and animals. Other triggers include exercise, cold weather, smoke, some medications, stress, and emotions.

Symptoms: Difficulty breathing, chest tightness or pain, and wheezing.

Treatments: Anti-inflammatories, bronchodilators, inhalers and puffers.