CVS physiology 3

Question 1

What 2 methods can be used to measure arterial pressure?

Answer 1

Sphygmomanometer and stethoscope oscillatory blood pressure measurement

Question 2

What is the systemic filling pressure?

Answer 2

Pressure difference that pushes blood back to the heart from the capillaries (from 20 to 5mmHg)

Question 3

What is velocity of blood flow related to?

Answer 3

Total cross section area (fastest in aorta and slowest in capillaries)

Question 4

What is the pressure of blood when they arrive at the capillaries?

Answer 4

40mmHg

Question 5

What is the drop in pressure of blood from the start of arterioles until they reach the capillaries?

Answer 5

90 to 40mmHg

Question 6

What is the values of pressure at the start of the arteries compared to the end?

Answer 6

95 to 90mmHg

Question 7

What can venous collapse in the neck be used to estimate?

Answer 7

Central venous pressure

Question 8

What effect does skeletal muscle pump have on blood flow?

Answer 8

Increases venous return and EDV

Question 9

What effect does respiratory pump have on blood flow?

Answer 9

Increased respiratory rate and depth increases venous return and EDV

Question 10

What is venomotor tone?

Answer 10

Smooth muscle tension in the veins

Question 11

Name 5 things that can impact venous return?

Answer 11

Gravity

Skeletal muscle pump

Respiratory pump

Venomotor tone

Systemic filling pressure

Question 12

What is the role of thrombin?

Answer 12

Converts fibrinogen to fibrin

Question 13

What is the role of prostacyclin?

Answer 13

Inhibits platelet aggregation

Question 14

What is the role of tissue factor pathway inhibitor (TFPI)?

Answer 14

Stops thrombin production

Question 15

What is the role of thrombomodulin?

Answer 15

Binds to thrombin and inactivates it

Question 16

What is the role of heparin?

Answer 16

Inactivates thrombin

Question 17

What is the role of plasminogen activator (t-PA)?

Answer 17

Converts plasminogen to plasmin which digests clots

Question 18

What are 3 types of capillary?

Answer 18

Continuous

Fenestrated

Sinusoid

Question 19

What feature of capillaries in the brain creates the blood brain barrier?

Answer 19

No clefts or pores

Question 20

On average, how much fluid is drained into the lymphatic system per day?

Answer 20

3L

Question 21

Name 4 causes of oedema

Answer 21

Lymphatic obstruction

Raised CVP due to ventricular failure

Hypoproteinemia

Increased membrane permeability due to inflammation

Question 22

What is mean arterial pressure equal to?

Answer 22

Cardiac output x total peripheral resistane

Question 23

What is the mechanism of active hyperaemia in blood flow?

Answer 23

Increase metabolite production stimulates the production of EDRF, Which causes arteriolar dilation - Increasing blood flow

Question 24

What is the mechanism of pressure autoregulation in blood flow?

Answer 24

A decrease in mean arterial pressure causes decrease in flow, this stimulates production of EDRF causing arteriolar dilation - increasing blood flow

Question 25

What effect does the sympathetic nervous system have on blood pressure?

Answer 25

Noradrenaline is released and binds to alpha 1 receptors, this causes arteriolar constriction which increases TPR - Increasing MAP

Question 26

What effect does the parasympathetic nervous system have on blood pressure?

Answer 26

Usually no effect (genitalia and salivary glands are an exception)

Question 27

What features of coronary blood flow allow the heart to have sufficient blood supply?

Answer 27

Shows excellent active hyperaemia expresses many beta 2 receptors

Question 28

What features of cerebal blood flow allow it to maintain stable conditions that is requires?

Answer 28

Shows excellent pressure autoregulation

Question 29

What features of renal blood flow allow it to maintain stable conditions that is requires?

Answer 29

Shows excellent pressure autoregulation

Question 30

What is the arterial baroreflex?

Answer 30

Short term blood pressure regulation