The respiratory cycle

Question 1

What are the three major steps of the respiratory cycle?

Answer 1

inspiration
expiration
pause

Question 2

describe inspiration

Answer 2

simultaneous contraction of the intercostal muscles and diaphragm

volume of inter thoracic cavity increases

parietal pleura moves with walls of thorax and diaphragm

active process as energy required for muscle contraction

Question 3

describe expiration

Answer 3

intercostal muscles and diaphragm relax,

pressure inside lungs increases and air is expelled from respiratory tract

passive process, no energy needed

Question 4

pause

Answer 4

there is a pause and the next cycle begins