Physiology - Integration of the Cardiovascular Mechanisms

Question 1

Contraction of vascular smooth muscles cause an increase or decrease in SVR and MAP?

Answer 1

Increase. Slide 8

Question 2

What are the extrinsic control of vascular smooth muscle?

Answer 2

Sympathetic nerve fibres not parasympathetic, Adrenaline, Angiotensin II and ADH. Slide 11-14

Question 3

What is the vasomotor tone?

Answer 3

The innervation on alpha receptors by sympathetic nerve fibres which cause partial constriction even at rest to maintain BP. Slide 11

Question 4

What are the intrinsic controls of vascular smooth muscle?

Answer 4

Chemical and physical. Slide 15

Question 5

What local metabolites cause vasodilation of arteriolar smooth muscles?

Answer 5

They are a chemical intrinsic control.
Decreased pO2
Increased pCO2
Decreased pH
Increased osmolarity of ECF. Slide 16

Question 6

What humoral agents can cause vasodilation?

Answer 6

Histamine
Bradykinin
NO. Slide 17

Question 7

What are the effects of Nitric oxide and how is it stimulated?

Answer 7

Vasodilation.
Stress on vasculature can cause its activation - flow dependent NO formation
Chemical stimuli - Receptor stimulated NO formation. Slide 18

Question 8

What humoral agents can cause vasoconstriction?

Answer 8

Serotonin
Thomboxane A2
Leukotrienes
Endothelin. Slide 20

Question 9

What are examples of vasoconstrictors produced by the endothelial lining?

Answer 9

Pro-thrombotic
Pro-inflammatory
Pro-oxidants. Slide 21

Question 10

What are physical controls of vascular smooth muscle?

Answer 10

Temperature
Myogenic response
Sheer stress on vessels after one has dilated. Slide 22

Question 11

Where is the exception that the sympathetic nervous system does not play the primary rol in controllign vessel radius and SVR?

Answer 11

The brain. Slide 24

Question 12

What are the 4 factors influencing venous return?

Answer 12

Venomotor tone
Blood volume
Skeletal muscle pump
Respiratory pump. Slide 27

Question 13

What does increased venomotor tone do?

Answer 13

Contriction of the veins allows an increased venous return, SV and MAP. Slide 28

Question 14

What is the skeletal muscle pump?

Answer 14

Contraction of the muscles helps venous return as the one way valves push the blood to the heart. Slide 29

Question 15

What acute CVS responses occur when someone exercises?

Answer 15

Increased sympathetic nerve activity:
So HR and SV increase
Vasoconstriction in kidneys and gut.
Vasodilation in skeletal and cardiac muscle.
Increase in systolic BP only. Slide 32

Question 16

What chronic CVS responses occur when someone exercises?

Answer 16

Reduces blood pressure
Increase parasympathetic tone to heart
Improved endothelial function
Decreased arterial stiffening. Slide 37