Respiratory system

Question 1

Tidal volume

Answer 1

amount of oxygen breathed in or out per breath

Question 2

Minute ventilation

Answer 2

amount of oxygen breathed in and out per minute

Question 3

Mechanics of inspiration at rest

Answer 3

• thoracic cavity expands
  -external intercostals muscles contract, lifting sternum up.
• increases volume inside thoracic cavity.

Question 4

Mechanics of expiration at rest

Answer 4

• intercostals relax lowering rib cage
• diaphragm returns to dome shape.

Question 5

Mechanics of inspiration during exercise

Answer 5

• sternacleidamastoid lifts sternum further up and out
• scalenes and pectorals contract and lift rib cage further out.
• volume of oxygen in the lungs increases.

Question 6

Mechanics of expiration during exercise

Answer 6

• this now becomes an active process.
• further muscles are recruited to (internal intercostal muscles and abdominals).
• this creates a greater down and inward movement pf the rib cage and sternum
• decreases volume and increases the pressure.

Question 7

Question - Explain the role of the sternocleidomastoid muscle in respiration during exercise (4)

Answer 7

1. contraction of sternocleidomastoid during inspiration
2. causes ribcage to move up and out
3. causes a greater volume inside thoracic cavity
4. greater drop in pressure
5. more air to enter the lungs

Question 8

Minute ventilation = tidal volume x breathing frequency