1.2 The respiratory system

Question 1

Describe inspiration at rest

Answer 1

• Intercostal muscles contract, pulling the rib cage up and out, causing the chest cavity to expand.
• The diaphram contracts which pulls it down and flattens, making the chest cavity larger
• Thoracic cavity increases
• Chest cavity increasing causes the lungs to expand because the moist surface clings to the chest lining
• When the lungs expand, pressure inside decreases, so more air is sucked down the windpipe into the lungs

Question 2

Describe expiration at rest

Answer 2

• Passive as muscles just relax
• Intercostal muscles relax, lowering the rib cage, making the chest cavity smaller
• The diaphram relaxes so it bulges upwards and makes the chest cavity smaller
• When the chest cavity gets smaller the lungs are compressed so pressure in the lungs is high
• Therefore air is pushed out of the lungs and up the windpipe

Question 3

Describe inspiration during exercise

Answer 3

• The sternocleidomastoid, scalenes, pectorialis minor and external intercostals all contract
• The ribcage is therefore pulled upwards making the chest cavity expand, thoracic cavity increases and pressure decreases

Question 4

Describe expiration during exercise

Answer 4

• The internal intercostals and the rectus abdominus / obliques both contract
• The ribcage is lowered, causing the chest cavity to shrink , thoracic cavity decreases and pressure increases

Question 5

What is tidal volume

Answer 5

The volume of air breathed in or out in each breath

Question 6

What is inspiratory reserve volume

Answer 6

The volume of breath that can be forcibly inhaled after a normal breath

Question 7

What is expiratory reserve volume

Answer 7

The volume of air that can be forcibly expired after a normal breath

Question 8

What is residual volume

Answer 8

The volume of air that remains in your lungs after maximal expiration

Question 9

What is minute ventilation

Answer 9

The volume of air breathed in or out per minute

Question 10

What is vital capacity

Answer 10

The greatest volume of air that can be expired after taking the deepest possible breath

Question 11

What happens to tidal volume during exercise

Answer 11

Increases

Question 12

What happens to inspiratory reserve volume during exercise

Answer 12

Decreases

Question 13

What happens to expiratory reserve volume during exercise

Answer 13

Slight decrease

Question 14

What happens to residual volume during exercise

Answer 14

Stays the same

Question 15

What happens to minute ventilation during exercise

Answer 15

Big increase

Question 16

What is a spirometer

Answer 16

A device that is used to measure the volume of air inspired and expired by the lungs

Question 17

What is partial pressure

Answer 17

The pressure exerted by an individual gas when it exists within a mixture of gases

Question 18

What two movements of gas is gaseous exchanged with

Answer 18

• Getting oxygen in the air into the lungs so that it can diffuse into the blood and be transported to the cells of the body
• The removal of carbon dioxide from the blood

Question 19

What is a concentration / diffusion gradient

Answer 19

Explains how gases flow from an area of high concentration to an area of low concentration. The steeper this gradient (the difference in concentration between the high and low areas) the faster diffusion occurs

Question 20

What is the diffusion pathway of oxygen

Answer 20

Alveoli, blood, muscles

Question 21

What is the diffusion pathway of carbon dioxide

Answer 21

Muscle, blood, alveoli

Question 22

How does gaseous exchange of oxygen take place in the alveoli

Answer 22

The PP of oxygen (pO2) in the alveoli (100mmHg) is higher than the PP of oxygen in the capillaries (40mgHg). This is because oxygen has been removed from the capillaries to go to the working muscles so therefore oxygen will diffuse from the alveoli into the capillaries

Question 23

How does gaseous exchange at the muscles take place

Answer 23

The PP of oxygen surrounding the muscles is 40mmHg and the PP of oxygen in the blood is 100mmHg. Therefore as the PP is lower in the muscles oxygen diffuses down the concentration gradient into the muscles. Also the PP of CO2 in the muscles after respiration is 46mmHg whereas in the blood it is 40mmHg so its diffuses out of the muscles into the bloodstream.

Question 24

What are the 3 regulatory factors of pulmonary ventilation during exercise

Answer 24

Neural control
Chemical control
Hormonal control

Question 25

What are the other factors that affect neural control of breathing

Answer 25

Mechanical Factors
Baroreceptors
Stretch receptors

Question 26

What are the mechanical factors affecting neural control of breathing

Answer 26

Proprioceptors which are receptors that are located in joints and muscles which provide feedback to the respiratory centre to increase breathing during exercise

Question 27

How do baroreceptors affect neural control of breathing

Answer 27

If an decrease in blood pressure is detected by the baroreceptors in the aorta and carotid arteries breathing rate will be increased

Question 28

How do stretch receptors affect neural control of breathing

Answer 28

During exercise lungs are stretched more so stretch receptors prevent over-inflation of the lungs by sending impulses to the exploratory centre, down the intercostal nerve and to the expiratory muscles

Question 29

What are the expiratory muscles

Answer 29

Abdominals and internal intercostals

Question 30

What lifestyle choices can impact your respiratory system

Answer 30

Eating, drinking, smoking how much we exercise

Question 31

What are the effects of smoking smoking on the respiratory system

Answer 31

Reduces lung function
Damages cells on the lining of the bronchioles, bronchi and trachea
Causes cilia to not move mucus from the lungs - smokers cough
Damage alveoli
Increase risk of COPD