Cardiorespiratory System

Question 1

Tidal volume

Answer 1

Volume of air breathed in or out with each normal breath

Question 2

Inspiratory reserve volume

Answer 2

The maximum amount of air that can be inhaled after a normal inhalation

Question 3

Expiratory reserve volume

Answer 3

The maximum amount of air that can be exhaled after a normal exhalation

Question 4

Residual volume

Answer 4

The volume of air remaining in the lungs after a maximal exhalation - prevents alveoli from collapsing/becoming damaged

Question 5

Name the apparatus used to measure the volume of air inspired and expired by the lungs

Answer 5

Spirometer

Question 6

Describe the pathway of air

Answer 6

Nasal cavity (air is warmed) –> Trachea –> Bronchi –> Bronchioles –> Alveoli

Question 7

Describe what happens in the body during inhalation (at rest)

Answer 7

• Diaphragm contracts and moves downwards
• Intercostal muscles contract and move the ribs upwards and outwards
• This increases the size of the chest, decreasing air pressure inside it which sucks air into the lungs

Question 8

Describe what happens in the body during inhalation (during exercise)

Answer 8

• Inspiration is assisted by pectoral muscles and the sternocleidomastoid which help to life the ribs up and out even further

Question 9

Describe what happens in the body during exhalation (at rest)

Answer 9

• Diaphragm relaxes and moves back into its dome shape
• Intercostal muscles relax, so the ribs move inwards and downwards under their own weight

Question 10

Describe what happens in the body during exhalation (during exercise)

Answer 10

• Abdominals pull the ribs downwards and inwards even further

Question 11

Explain the role of haemoglobin

Answer 11

Haemoglobin carries oxygen to be exchanged at the working muscle and carbon dioxide to be exchanged at the lung.

Question 12

Explain gaseous exchange

Answer 12

• High concentration of Oxygen in alveoli, low concentration of oxygen in capillary
• So, the oxygen diffuses from an area to high concentration to low concentration into the blood
• High concentration of carbon dioxide in the blood and low concentration in the alveoli
• So, carbon dioxide diffuses into the alveoli to be breathed out

Question 13

What factors help gaseous exchange?

Answer 13

• Alveoli has large surface area
• Alveoli has one cell thick moist walls (short distance for gas to diffuse)
• Semi permeable membranes
• Lots of capillaries

Question 14

Explain how oxygen and carbon dioxide are transported

Answer 14

• Oxygen diffuses into the blood from the alveolus and binds to haemoglobin (iron rich protein)
• This forms oxyhaemoglobin
• It is then transported to the working muscle to be exchanged
• Haemoglobin carries carbon dioxide to be exchanged at the lung

Question 15

What’s the equation for Cardiac Output? - and define all the parts to it

Answer 15

Cardiac output L/m = Heart Rate bpm x Stroke Volume L

Cardiac output: amount of blood pumped from the heart every minute
Heart rate: number of times the heart beats in one minute
Stroke volume: volume of blood pumped out of the heart with every beat

Question 16

Explain the structure and function of the body’s blood vessels.

Answer 16

Arteries:
- Carry blood away from the heart
- This requires high pressure, so they have thick muscle and outer wall with narrow lumen to force blood around the body

Veins:
- Carry blood to the heart
- Carries it at low pressure due to wide lumen and thin muscle and outer wall
- Have valves to prevent backflow of blood

Capillaries:
- Carry blood to and from the body’s cells + site of gaseous exchange
- Narrow lumen, one cell thick walls
- Medium blood pressure