4) Gaseous exchange occurs whilst a performer is at rest and during exercise.
Analyse how the body is designed for gaseous exchange to take place, how it adapts to allow this to happen more readily in the lungs and evaluate how breathing rate is controlled to meet the demands of changing levels of exercise.
Structures
Adaptations
Breathing for changing levels of exercise
D. Large surface area of the alveoli
C.Readiness of haemoglobin to combine with oxygen (oxyhaemoglobin)
E. Slow movement of blood through the narrow capillaries
B. Short distance from alveoli to capillary
F. Moist layer enhancing the uptake of oxygen
A. Permeability of the alveoli and capillary cell walls
I. More red blood cells/haemoglobin produced and enter blood
J. More myoglobin/mitochondria produced in muscles
H. Diffusion gradient caused by different partial pressures of gases
K. Due to process of diffusion / gases move from a high concentration to a low concentration
G. Capilliarisation
L. Differences establish diffusion gradients
Q. Nerve impulses to (respiratory centre) in medulla oblongata
R. Increased sympathetic / phrenic nerve impulses to respiratory muscles
P. Decrease in blood pressure detected by baroreceptors
S. Increased rate of contraction in diaphragm and intercostal muscles
O. Movements detected by proprioceptors / mechanoreceptors
T. Additional breathing muscles used during exercise (sternocleidomastoid/scalenes/abdominals/pectorals)
N. Exercise – Increased levels of carbon dioxide / acidity (in blood) detected by chemoreceptors
U. Expiration at rest is a passive process
M. Anticipation of exercise – adrenaline released - Increased depth and rate of breathing
V. Reference to repaying oxygen debt after anaerobic exercise
