Unit 3 Test Flashcards
1
Q
Sympathetic nerve activity
A
- Increase in HR
- Increase in SV
- Increase in CO
- Increase in flow for venous return
- Constrict arterioles, decrease conductance
2
Q
Parasympathetic nerve activity
A
- Decrease in HR
3
Q
Metaboreceptors
A
- Sense changes in metabolites (H+ and Pi)
- If metabolites increase, it increases
- Activates the medulla
4
Q
Feedback control
A
- Metaboreceptors
- Baroreceptors
5
Q
Feedforward control
A
- Mechanoreceptors
- Motor outflow/drive
- Both activate the medulla
6
Q
Baroreceptor
A
- Sense changes in MAP
- Increase with increasing blood pressure
- Inhibits the medulla
7
Q
Medulla
A
- Activates SNA
- Inhibits PNA
8
Q
What happens to arterioles with increasing intensity?
A
Dilation
9
Q
Blood flow and metabolism
A
- Blood flow increases in proportion to
metabolism
10
Q
Theory 1: The vasodilator hypothesis
A
- As metabolism increases so do the bi-
products
(vasodilators) such as extracellular K+,
adenosine, CO2, Lactate and H+ - These cause vasodilation which causes
increase in blood flow
11
Q
Theory 2: O2/ nutrient lack theory
A
- Decreased O2 availability causes there to be
less ATP in the arterioles causing smooth
muscle relaxation - This causes increased dilation and
conductance = Increased blood flow
12
Q
Sub-maximal exercise in hypoxic air
A
- DO2 can be restored due to a large enough
compensatory increase in dilation and then
blood flow
13
Q
Peak exercise in hypoxic air
A
- DO2 can not be fully compensated for an increase
in blood flow
14
Q
Ways to increase VO2 max
A
- Increase blood flow, increase CO, increase
DO2 - Increase O2 extraction by increasing CaO2
- Increase capillary density
15
Q
The impact of hypoxia on a-vO2 difference
A
- Decreases due to decreased CaO2
