L14 - Control of Circulation Flashcards Preview

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Flashcards in L14 - Control of Circulation Deck (46)
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1

What are the two key targets for control
How many layers?

Ateriole resitance and the stored blood in veins as well as the vascular smooth muscle
Multiple layers of control

2

What are two key differences between and artery and a vein

In the artery there is more elastic tissue and more smooth muscle

3

What does resting tension mean
What vessels possess it

The balance between the contraction of the smooth muscle and the elastic recoil
All vessels

4

What is myogenic regulation

When an artery is stretched it evokes a contraction of the smooth muscle causing the artery to return to its original shape

5

What is meant my metaboite regulation

Several metabolites are able to cause dilation/constriciton of the vessesl

6

What is this low level of designed to give, what can this be called

Constant level of flow
Also known as autoregulation

7

What are most vessels tonicallt innervated by

Sympathetic adrenoreceptor input (alpha receptors)

8

What is the effect of sympathetic stimulation of blood vessels supplying skeletal muscle, heart, lung and kidney
What NT is involved in this

Vasodilation
ACh involved

9

What is the effect of parasympathetic stimulation of blood vessels supplying erectile tissue / glands
What NT is involved in this

Vasodialtion
Ach involved

10

What can be said about the innervation density of sympathetic constrictors
Give examples

It varies
E.g. high in cutaneous tissue
low in cerebral tissue

11

What is the adrenal medullary hormone most involved in the control of circulation

Adrenaline

12

What is the effect of adrenaline at the skin and other viscera

Vasoconstriction

13

What is the effect of adrenaline at the skeltal muscle and liver

Vasodilation

14

Why would adrenaline cause vasodilation at the liver

Because liver stores glycogen ==> increased blood supply to increase glycogenolysis in the liveer to provide the skeltal muscle cells with glucose

15

What reaction is adrenaline responsible for;
Summarise

Defence reaction
Blood diverted to heart, skeletal muscle and the liver

16

Give an example of a kinin

Bradykinin

17

What is the effect of bradykinin

It is a vasodilatory peptide

18

What is the effect of angiotensin 2 on the blood vessels

Vasoconstriction leading to an increase in blood pressure

19

How is angiotensin II formed

Formed by enzymes e.g. renin acting on precurrsors when the blood pressure falls

20

What is the effect of ACE inhibitors

Reduce the ammount of angiotensin II in the blood so reduced blood pressure

21

What are ACE inhibitors used to treat

Hypertension

22

What are extrinsic humoural controls of circulation

1) Adrenal medullary hormones
2) Kinins
3) Angiotensin II

23

What are the local agents which are involved in the extrinsic control

Prostaglandins
Serotonin
Histamine
Endothellium derived relaxing factors
Endothellium derived hyperpolarising factors

24

What is the effect of prostaglandins

Act as vasodilators

25

What is the effect of serotonin release
When is it released

Platelets release 5-Ht causing vasoconstriction to aid in the formation of clots

26

What is the effect of histamine
When is it released

Released by mast cells in response to an allergen
Causes vasodilation

27

What is the effect of endothelium derived relaxing factors

Released after stimulation - by Ach
NO from endothelial cells
Stimulated cGMP in muscles
Causes relaxation

28

Describe how nitroglycerin can be used clinically

Is converted to NO (increased NO)
Vasodilation
Increased flow
Increased oxygen supply

29

Describe how slidenafil citrate works - what is its trade name

Inhibits the cGMP breakdown
Causes dilation of the blood vessels

30

Describe a endothellium derived hyperpolarising factors

Release after stimulations (again by Ach)
Complex pathways