breathing

Question 1

vo2 max

Answer 1

the maximum consumption of oxygen per minute
dependent on the efficiency of uptake and delivery of oxygen by the lungs and cardiovascular system
and the efficient use of oxygen in the muscle fibres

Question 2

cardiac output

Answer 2

volume of blood pumped by the heart in a minute
depends on volume of blood ejected from the left ventricle and HR
CO= SV X HR

Question 3

stroke volume

Answer 3

volume of blood pumped out of the left ventricle each time the ventricle contracts

Question 4

venous return

Answer 4

blood returning to the heart

Question 5

changes to breathing during exercise

Answer 5

Increased cardiac output
faster rate of breathing
deeper breathing

Question 6

vital capacity

Answer 6

the maximum volume of air we can inhale and exhale

Question 7

tidal volume

Answer 7

the volume of air we breathe in/ out with each breath
assumed to be 0.5 dm3 at rest

Question 8

minute ventilation

Answer 8

tidal volume x breathing rate
spirometer trace can be used to work out these two things

Question 9

inhalation

Answer 9

ventilation centre sends nerve impulses to external intercostal muscles and diaphragm muscles
contraction of both of these causes inhalation
volume change in chest cavity allows lungs to expand

Question 10

exhalation

Answer 10

as lungs inflate, stretch receptors in bronchioles are stimulated
stretch receptors send inhibitory impulses back to the ventilation centre
causes muscles to relax
weight of ribcage and elastic recoil of the lung help force air out of lungs

Question 11

breathing rate stimulus

Answer 11

concentration of dissolved carbon dioxide in arterial blood
affects pH
small increase in blood CO2 conc causes a large increase in ventilation