Respiratory System

Question 1

Respiration (breathing) is a vital process to sustain human life. It is concerned with supplying ______ to the cells and removing toxic ______ _______ from the body.

Answer 1

Respiration (breathing) is a vital process to sustain human life. It is concerned with supplying oxygen to the cells and removing toxic carbon dioxide from the body.

Question 2

During the respiratory process: list the process…(9)

Answer 2

During the respiratory process:

• oxygen is inhaled into the lungs
• the oxygen diffuses from the lungs into the blood
• oxygen is transported in the blood to the cells
• oxygen diffuses from the blood into the cells for use in metabolic reactions
• the metabolic reactions create energy and carbon dioxide
• the carbon dioxide diffuses from the cells into the blood
• the blood transports the carbon dioxide back to the lungs
• the carbon dioxide diffuses from the blood into the lungs
• the carbon dioxide is exhaled from the lungs

Question 3

As well as carbon dioxide being exhaled from the body, the process of exhalation also expels ____ and some _________.

Respiration therefore contributes to the body’s ________ processes.

Answer 3

As well as carbon dioxide being exhaled from the body, the process of exhalation also expels heat and some moisture.

Respiration therefore contributes to the body’s excretory processes.

Question 4

What are the three phases of respiration?

Answer 4

1. Pulmonary Ventilation - The inhalation (inspiration) and exhalation (expiration) of air between the atmosphere and the lungs is called pulmonary ventilation.
2. External Respiration - The diffusion of gases between the lungs and the blood is called external respiration. (Memory Hint: Think of the description ‘external’ to mean ‘outside the cells’.)
3. Internal Respiration - The diffusion of gases between the blood and the cells is called internal respiration.

Question 5

What 2 major systems is respiration dependant on?

Answer 5

As we have seen, respiration is dependent on two major systems:

1. The respiratory system - provides the mechanics for pulmonary ventilation and the site for external respiration.
2. The cardiovascular system - transports the gases between the lungs and the cells to facilitate internal respiration.

Question 6

The upper respiratory system starts at the ____, through which air is taken into the __a__ _______. The _____ and the ____ (tiny hairs that line the nasal passages) trap ____ __________. As the air passes through the ___a__ _____, it is ___b___ and ____c____ by mucus droplets.

This ___b___, _____c_____ air then travels from the __a___ ______ into the ___d____ (throat). The ____d____ connects the mouth and the nasal passage to the ___________ and the _______.

Answer 6

The upper respiratory system starts at the nose, through which air is taken into the nasal cavity. The mucus and the cilia (tiny hairs that line the nasal passages) trap dust particles. As the air passes through the nasal cavity, it is warmed and moistened by mucus droplets.

The warmed, moistened air then travels from the nasal cavity into the pharynx (throat). The pharynx connects the mouth and the nasal passage to the oesophagus and the trachea.

Question 7

Fill in the Upper Respiratory Tract diagram below:

Answer 7

Question 8

At the top of the trachea is the __a____, or voice box. The vocal cords are folds in its lining. The ____a___ contains _________ which keeps the trachea open to air. The trachea is closed off by the __________ during swallowing. This ensures that any food travels down the _____________ and not into the trachea.

Answer 8

At the top of the trachea is the larynx, or voice box. The vocal cords are folds in its lining. The larynx contains cartilage which keeps the trachea open to air. The trachea is closed off by the epiglottis during swallowing. This ensures that any food travels down the oesophagus and not into the trachea.

Question 9

Fill in the diagram below:

Answer 9

Question 10

The trachea extends down to the level of the ____ thoracic vertebra.

The trachea then divides into the left _______ ________ and right _______ _________, which descend into the left ___ and right ____ respectively.

The bronchi continue to divide until, after branching into secondary and tertiary bronchi, they become ___________.

Answer 10

The trachea extends down to the level of the 5th thoracic vertebra.

The trachea then divides into the left primary bronchus and right primary bronchus, which descend into the left lung and right lung respectively.

The bronchi continue to divide until, after branching into secondary and tertiarybronchi, they become bronchioles.

Question 11

The finest bronchioles terminate in little air sacs called ___a___. It has been estimated that there are about ___ _______ of them in the lungs.

These ___a___ are moist and surrounded by a network of _________.

It is here that _______ _________ takes place. Oxygen diffuses from the ___a___ into the ___b___ and carbon dioxide diffuses from the ___b___ into the ___a____.

Answer 11

The finest bronchioles terminate in little air sacs called alveoli. It has been estimated that there are about 300 million of them in the lungs.

Alveoli are moist and surrounded by a network of capillaries.

It is here that external respiration takes place. Oxygen diffuses from the alveoli into the blood and carbon dioxide diffuses from the blood into the alveoli.

Question 12

The lungs are located in the _____ _______. The right lung has ______ main lobes and the left lung has ___. A double _______ membrane covers each lung, and the lungs are further protected by the _______.

The __________ muscles and the _________ provide a muscular setting in which the lungs can expand and relax - a vital feature of respiration.

Answer 12

The lungs are located in the upper thorax. The right lung has three main lobes and the left lung has two. A double pleural membrane covers each lung, and the lungs are further protected by the ribcage.

The intercostal muscles and the diaphragm provide a muscular setting in which the lungs can expand and relax - a vital feature of respiration.

Question 13

Name the features of the diagram below:

Answer 13

Question 14

For air to be taken into the lungs, the air pressure in the lungs has to be ____ than the external air pressure. This is achieved by making the lungs ______.

For air to be expelled from the lungs, the air pressure in the lungs has to be _______ than the external air pressure. This is achieved by making the lungs _______.

The muscular movement of the diaphragm and the intercostal muscles is involved in increasing or decreasing the lung capacity.

Answer 14

For air to be taken into the lungs, the air pressure in the lungs has to be less than the external air pressure. This is achieved by making the lungs bigger.

For air to be expelled from the lungs, the air pressure in the lungs has to be greater than the external air pressure. This is achieved by making the lungs smaller.

The muscular movement of the diaphragm and the intercostal muscles is involved in increasing or decreasing the lung capacity.

Question 15

During inspiration, the diaphragm _______, causing it to ______. This _______ the chest, drawing the lungs out, so _________ the size of the lungs. The _______ intercostal muscles also _______ to ________ the ribs so __________ the size of the thorax. These actions decrease the pressure in the lungs and allow air to be inhaled.

Answer 15

During inspiration, the diaphragm contracts, causing it to flatten. This expands the chest, drawing the lungs out, so increasing the size of the lungs. The external intercostal muscles also contract to elevate the ribs so increasing the size of the thorax. These actions decrease the pressure in the lungs and allow air to be inhaled.

Question 16

During expiration, the diaphragm ______, causing it to ___, and the _______ intercostal muscles ____ causing the ribs to ___. This ________ the size of the chest, pulling the lungs in, so ________ the size of the lungs. These actions _______ the pressure in the lungs and allow the air to be exhaled. When expiration is forced, the _______ intercostals draw adjacent ribs together to decrease the size of the thorax even more.

Answer 16

During expiration, the diaphragm relaxes, causing it to rise, and the external intercostal muscles relax causing the ribs to fall. This decreases the size of the chest, pulling the lungs in, so reducing the size of the lungs. These actions increase the pressure in the lungs and allow the air to be exhaled. When expiration is forced, the internal intercostals draw adjacent ribs together to decrease the size of the thorax even more.

Question 17

1. What is the normal breathing rate?
2. What causes this to increase?
3. What causes this to decrease?
4. What is the approximate volume of Each breath?

Answer 17

1. The normal breathing rate is 10-12 breaths per minute,
2. This increases during exercise and stress, and
3. Decreases during sleep.
4. Each breath contains approximately 500ml of air.

Question 18

Pulmonary ventilation takes place rhythmically. Usually inspiration lasts for about _ _________ and expiration takes approximately _ ________. This is the basic rhythm.

Answer 18

Pulmonary ventilation takes place rhythmically. Usually inspiration lasts for about 2 seconds and expiration takes approximately 3 seconds. This is the basic rhythm.

Question 19

The rhythm of pulmonary ventilation is controlled by areas in the ____ and _______ ___________ of the _____. These respiratory control areas contain both inspiratory and expiratory _______ (nerve cells).

Answer 19

The rhythm of pulmonary ventilation is controlled by areas in the pons and medulla oblongata of the brain. These respiratory control areas contain both inspiratory and expiratory neurons (nerve cells).

Question 20

1. Describe time, and what happens on inspiration? Include the neural activity!
2. Describe time, and what happens on expiration?
3. Any exceptions?

Answer 20

1. After the 3 seconds of expiration, the inspiratory neurons become active. The inspiratory nerve impulses last for about 2 seconds. These impulses reach the diaphragm and the external intercostal muscles causing them to contract. This expands the chest and increases the size of the lungs. The pressure in the lungs therefore decreases and air is drawn in.
2. During normal, quiet respiration, expiration occurs passively. After the 2 seconds of inspiration, the inspiratory impulses cease. Then, in the absence of nervous stimulation, the diaphragm and external intercostal muscles relax. The chest naturally reduces in size, increasing the air pressure in the lungs, and the air is exhaled.
3. It is believed that the expiratory neurons function only during high levels of respiration. The expiratory neurons cause various muscles to decrease the size of the chest to force expiration.

Question 21

The basic rhythm of respiration adequately maintains optimum levels of carbon dioxide and oxygen in the blood during the normal resting state.

However, when the body is under stress, the metabolic rate ______ and ____ oxygen is required. The _________ metabolic rate also produces ____ carbon dioxide that has to be expelled from the body. Therefore, the rate of respiration has to _______.

Answer 21

The basic rhythm of respiration adequately maintains optimum levels of carbon dioxide and oxygen in the blood during the normal restingstate.

However, when the body is under stress, the metabolic rate increases and more oxygen is required. The increased metabolic rate also produces more carbon dioxide that has to be expelled from the body. To provide the necessary oxygen and to remove the excess carbon dioxide, the rate of respiration has to increase.

Question 22

The body is able to alter the rate of respiration according to the metabolic needs. When the metabolic rate increases (e.g. during exercise) the level of carbon dioxide in the blood rises. How are CO₂ levels detected in the body?

Answer 22

The body is able to alter the rate of respiration according to the metabolic needs. When the metabolic rate increases (e.g. during exercise) the level of carbon dioxide in the blood rises. This is detected by chemoreceptors.

Chemoreceptors transmit this information to strongly stimulate the inspiratory control areas. Consequently, nerve impulses are sent to contract the diaphragm and the external intercostal muscles. This results in faster and deeper breathing. The increased respiratory rate leads to more oxygen being supplied to the cells and the elimination of the excess carbon dioxide.

Question 23

It is not only the metabolic rate that can affect pulmonary ventilation. The rate of respiration is also affected by: (5)

Answer 23

• Blood pressure - An increase in blood pressure, detected by baroreceptors, causes a decrease in the respiratory rate. A decrease in blood pressure increases the respiratory rate.
• Temperature - An increase in body temperature, detected by thermoreceptors, increases the rate of respiration. A decrease in temperature results in a decrease in respiration.
• Pain - Sudden pain can bring about the temporary cessation of breathing. However, prolonged pain can increase the respiratory rate.
• Irritation of airways - Mechanical or chemical irritation of the airways causes breathing to cease, followed by coughing or sneezing.
• Stretching of the anal sphincter - This increases the respiratory rate.

Question 24

The _______ ______ has connections with the respiratory control centres. This allows the respiratory rhythm to be voluntarily altered. However, the ability to voluntarily alter respiration is limited…

Answer 24

The cerebral cortex has connections with the respiratory control centres. This allows the respiratory rhythm to be voluntarily altered. However, the ability to voluntarily alter respiration is limited…

When respiration is voluntarily reduced or stopped, the level of carbon dioxide in the blood builds up.

As we have seen, an increased level of carbon dioxide strongly stimulates the inspiratory control area. Inspiration is stimulated and breathing resumes. It is therefore impossible for people to kill themselves by holding their breath! The breathing rate would resume even upon fainting.

Question 25

So, to recap, the respiratory system provides the mechanics for pulmonary ventilation and the site for external respiration.

The cardiovascular system transports the gases in the blood between the lungs and the cells to facilitate internal respiration.

Describe the process in pulmonary circulation.

Answer 25

A major part in facilitating internal respiration is supplying the heart with newly oxygenated blood.

The heart can then pump it, via the vascular network, to all the body tissues.

Deoxygenated blood, received back in the heart from the tissues, is then returned to the lungs.

This process is called _________ ________?

Question 26

Lungs & Heart

A major part in facilitating internal respiration is supplying the heart with newly oxygenated blood.

The heart can then pump it, via the vascular network, to all the body tissues.

Deoxygenated blood, received back in the heart from the tissues, is then returned to the lungs.

This process is called _________ ________?

Answer 26

So, to recap, the respiratory system provides the mechanics for pulmonary ventilation and the site for external respiration.

The cardiovascular system transports the gases in the blood between the lungs and the cells to facilitate internal respiration.

Describe the process in pulmonary circulation.

Question 27

What are the blood vessels involved in transporting gases to & from the lungs?

Answer 27

• The pulmonary arteries supply blood to the lungs. - They run from the right ventricle of the heart and contain deoxygenated blood (without oxygen). The blood releases its carbon dioxide and becomes oxygenated in the lungs.
• The oxygenated blood is then carried away from the lungs in the pulmonary veins. - The pulmonary veins take the oxygenated blood to the left atrium of the heart. It passes into the left ventricle from which it is circulated around the body. During internal respiration the blood loses its oxygen and gains carbon dioxide. Deoxygenated blood then arrives back in the right atrium and is passed to the right ventricle for the cycle to repeat.