Hypertension- regulation of arterial resistance

Question 1

State Darcys law

Answer 1

Flow = pressure difference/ resistance

Question 2

What does poisuelles law about what factors affect resistance

Answer 2

Resistance is affected by, radius, viscosity and length of vessels

Question 3

What has the greatest effect on totally pulmonary resistance

Answer 3

varying the radius of the vessels

Question 4

What is the benefit of adjusting total pulmonary resistance by altering the radius

Answer 4

allows for re direction of blood flow

controling flow through individual vascular beds

Question 5

What is the equation for Mean arterial pressure

Answer 5

Cardiac output X total periphery resistance

Question 6

decreasing the radius of the arterioles increases the TPR, what affect does this have on the mean arterial pressure

Answer 6

therefore increases mean arterial pressure

Question 7

How is the flow rate maintained in the capillaries beds

Answer 7

By maintaining mean arterial pressure within the correct range by controlling the resistance of the vessels

Question 8

What is the two levels of control that maintain flow rate and Mean arterial pressure

Answer 8

Extrinsic control

Intrinsic control

Question 9

What is extrinsic control concerned about

Answer 9

maintaining the total periphery resistance of the body

and maintain adequate MAP

Question 10

What is intrinsic control concerned about

Answer 10

The needs of the individual tissue involved

Question 11

What is extrinsic control due to

Answer 11

Sympathetic NS

Hormones

Question 12

What is the affect of sympathetic NS on extrinsic control of the blood flow through vascular bed

Answer 12

release norepinephrine
binds to alpha1-receptors causing§ arteriolar constriction, decreasing the radius, therefore increasing the TPR, which reduces the flow rate of the blood

Question 13

What are the different hormones affecting the extrinsic control of the blood flow through the vascular bed

Answer 13

Epinephrine from the medulla
Angiotensin
Vasopressin
Atrial natriuretic peptide & Brain natriuretic peptide

Question 14

What is Epinephrine affect on extrinsic control on most muscles

Answer 14

binds to alpha1-receptors
causes arteriolar constriction
decreasing the radius, therefore increasing the TPR, which reduces the flow rate of the blood

Question 15

What is epinephrines affect on extrinsic control of skeletal and cardiac muscle

Answer 15

also activates beta2-receptors
- causes arteriolar dilation
Increasing the flow rate and decreasing TPR

Question 16

What do both Angiotensin and Vasopressin respond to, and what further affect does this have

Answer 16

Produced/released in response to low blood volume

causes arteriolar constriction therefore increasing the TPR, reducing the flow rate

Question 17

What kind of hormone is vasopressin

Answer 17

antidiuretic hormone - controls body water balance by reducing urination

Question 18

What is Atrial natriuretic peptide & Brain natriuretic peptide released in response to

Answer 18

released in response to high blood volume

causes arteriolar dilation decreasing TPR, increasing flow rate

Question 19

What effect does Parasympathetic NS have on extrinsic control

Answer 19

has no effect

Question 20

What is 4 examples which cause local intrinsic controls affecting the flow rate and TPR

Answer 20

Active metabolic hyperaemia
Pressure flow autoregulation
reactive hyperanemia
The injury response

Question 21

Active (metabolic) hyperaemia process is triggered by what

Answer 21

An increase in metabolic activity, causing an increase in concentration of metabolites

Question 22

The increase in metabolites in active hyperaemia and pressure flow regulation creates a negative feedback effect by triggering the release of what

Answer 22

EDFR

Question 23

What affect does the release of EDFR have on the vessels in active hyperaemia and pressure flow auto regulation

Answer 23

Makes the smooth muscle relax and dilate causing arterial dilation, increasing flow rate

Question 24

What is the purpose of active hyperaemia

Answer 24

To get rid of the metabolites concentration building up

and match blood supply to metabololic needs of the that tissue

Question 25

Pressure flow auto regulation process is triggered by what

Answer 25

Decrease in mean arterial pressure causes a decreases in flow causing an increased contraption of metabolites

Question 26

What is the purpose of the pressure flow auto regulation

Answer 26

an adaptation to ensure that a tissue maintains its blood supply despite changes in mean arterial pressure

Question 27

What Intrinsic control could be possibly myogenic

Answer 27

Pressure flow auto regulation

Question 28

What occurs in the Intrinsic control of reactive hyperanemia

Answer 28

Blockage of blood supply causes a subsequent increase in blood flow

Question 29

What is hyperanemia an extreme version of

Answer 29

Pressure flow auto regulation

Question 30

What occurs in the local intrinsic effect of an injury

Answer 30

Mast cells release histamine, this causes arterial dilation increasing blood flow as well as increasing permeability resulting in oedema

Question 31

What is the benefit of histamines indirectly increasing the blood flow

Answer 31

aids delivery of blood born leucocytes etc to injured area

Question 32

In coronary circulation how is the blood supply interrupted

Answer 32

As each time the heart contracts during systole it shuts of its blood supply as aortic valves open to expel blood but the valves opening shuts of the entry to the coronary arteries

Question 33

What kind of receptors do coronary circulation express a lot of

Answer 33

B2 receptors

Question 34

How does the coronary circulation cope with the increased demand caused by exercise

Answer 34

its hyperaemia - release EDFR | and has an abundance of B2 receptors which both dilates the BV so doesn't starve itself of oxygen

Question 35

What local intrinsic control allows stability to be maintained in the cerebral circulation

Answer 35

Pressure autoregulation

Question 36

How does pulmonary circulation differ to most tissues

Answer 36

as a decrease in oxygen causes arterial constriction

Question 37

What is the purpose of the pulmonary circulations opposing effect

Answer 37

this ensures the blood is directed to the best ventilated part of the lungs - shunt

Question 38

What is the main function of the renal circulation

Answer 38

Filtration

Question 39

What local intrinsic control does renal circulation portray to ensure the mean arterial pressure remains stable

Answer 39

shows excellent pressure autoregulation

Question 40

Why is it important to not vary Mean arterial pressure in the renal circulation

Answer 40

as would have a big effect on blood volume

Question 41

What are the four special areas that allow there specific properties to correlate to their function

Answer 41

Coronary Cerebral Renal Pulmonary