Control breathing

Question 1

Describe inhalation

Answer 1

Ventilation centre sends impulses every 2-3 seconds
External intercostal and diaphragm muscles contract causing inhalation
Deep - neck and check muscles involved

Question 2

Describe control at rest

Answer 2

CO2 dissolves into carbonic acid which dissociates reducing pH and increasing H+ conc
This is detected by chemoreceptors in the ventilation centre
Sends impulses to the rest of the centre and to the muscles involved in breathing

Question 3

Describe exhalation

Answer 3

Lungs inflate and stretch receptors are stimulated

Sends inhibitory impulses back to the centre so impulses to the muscles stop and they relax

Question 4

What causes exhalation

Answer 4

elastic recoil of longs and gravity lowering the ribs
Residual air(air left in lungs) mix with air inhaled
Deep - Internal intercostal muscles

Question 5

Describe breathing during exercise

Answer 5

Impulses from motor cortex directly affect VC increasing ventilation
Also increased by impulses reaching VC from stretch receptors in tendons and muscles in movement
Chemoreceptors sensitive to CO” and changes in blood temp increases depth and rate of breathing