Exercise for Rehabilitation and Training Flashcards
(31 cards)
By how much can cardiac output increase during exercise?
From 1L/min to 22L/min.
List 3 points where the transport of oxygen from the lungs to the mitochondria can be limited.
1 - Oxygen uptake in the lungs (VO2 max).
2 - Cell perfusion.
3 - Diffusion into cells.
List 2 cardiovascular factors which limit oxygen uptake in the lungs (VO2 max).
1 - Maximum achievable cardiac output.
2 - Haematocrit.
What proportion of oxygen in the blood is carried by red blood cells?
98.5%.
What is the resting oxygen uptake in the lungs?
250ml/min.
Describe the types of cardiac hypertrophy.
1 - Concentric hypertrophy. Characterised by a thicker wall and smaller ventricular chamber.
2 - Eccentric hypertrophy. Characterised by a constant wall thickness but larger ventricular chamber.
How are sarcomeres arranged in concentric hypertrophy?
In parallel.
How are sarcomeres arranged in eccentric hypertrophy?
In series.
How does each type of cardiac hypertrophy affect stroke volume?
Why does this occur?
- Concentric hypertrophy decreases stroke volume.
- Eccentric hypertrophy increases stroke volume.
- This is due to changes in inotropy and EDV.
When might concentric hypertrophy occur?
Due to hypertension.
Which growth factor causes eccentric hypertrophy?
When is this growth factor released?
- Insulin-like growth factor.
- It is released during exercise.
How does an increase in inotropy affect the starling curve?
The curve is shifted upwards and maintains its shape.
What is Laplace’s law?
P = 2T / r
Where P = pressure, T = surface tension and r = radius.
What is the effect of Laplace’s law on stroke volume in hypertrophied hearts?
- The change in pressure due to changes in radius (Laplace’s law) is offset by changes in inotropy.
- In a concentric heart, although systolic pressure increases according to Laplace’s law, the decrease in inotropy means that the overall effect is a decrease systolic pressure.
- In an eccentric heart, although systolic pressure decreases according to laplace’s law, the increase in inotropy means that the overall effect is an increase in systolic pressure.
List 3 reasons that explain why EDV changes with cardiac hypertrophy.
1 - Chamber volume changes.
2 - Circulating blood volume increases with exercise training.
3 - Central venous pressure changes.
Other than increasing stroke volume, how does exercise training affect heart activity?
How does this come about?
- Heart rate is decreased (to maintain the same cardiac output as an individual with lower inotropy).
This comes about by:
1 - Increased vagal activity.
2 - Increased local ACh release from parasympathetic innervation.
3 - Decreased intrinsic pacemaker activity.
Which components of the heart receive sympathetic innervation?
Which components of the heart receive parasympathetic innervation?
- The SAN, AVN and ventricular muscle receive sympathetic innervation.
- The SAN and AVN receive parasympathetic innervation.
What is the capillary:cardiac myocyte ratio in a normal heart?
1
How does exercise training affect the capillary:cardiac myocyte ratio?
What might offset the effect of this?
- It increases.
- The increase in cardiac myocyte size offsets the effect of this increase.
Other than changes to the capillary:cardiac myocyte ratio, list the changes in vascular supply to the heart that occur with exercise training.
1 - Increased number of arterioles.
2 - Increased coronary artery diameter.
List the changes in vascular supply to skeletal muscle that occur with exercise training.
1 - Increased number of capillaries.
2 - Increased artery diameter.
Define conduit artery.
An elastic artery with many collagen and elastin filaments in the tunica media which give it the ability to stretch in response to each pulse.
Which growth factor causes angiogenesis?
When is this growth factor released?
- Vascular endothelial growth factor.
- It is released as a result of activation of hypoxic-inducible factor, which occurs in response to hypoxia.
List 4 changes in skeletal muscle that occur with exercise training.
1 - Increased mitochondria density in skeletal myocytes.
2 - Upregulation of endothelial nitric oxide synthase (eNOS) in the endothelium.
3 - Upregulation of antioxidant enzymes in the endothelium.
4 - Increased muscle myoglobin.
