Blood Vessels

Question 1

Is flow at capillary level pulsatile?

Answer 1

NO - continuous, slow flow

Question 2

What do endothelial cells release to stop blood sticking to vessel walls?

Answer 2

heparin

Question 3

What gas relaxes blood vessels?

Answer 3

nitric oxide

Question 4

Why is resistance to blood flow lower in pulmonary arterioles?

Answer 4

Less muscular

Question 5

What local metabolic control do pulmonary vessels have?

Answer 5

Constriction when there is low alveolar O2

Question 6

Is systemic capillary pressure higher or lower than pulmonary arterial pressure?

Answer 6

Higher

Question 7

How much ml is cerebral circulation per min? what % of cardiac output is this?

Answer 7

750ml

15%

Question 8

What is auto regulation of cerebral vessels?

Answer 8

They will try to keep the same pressure by dilating if pressure increases

Question 9

What can failure of autoregulation safeguards result in?

Answer 9

stroke

Question 10

What determines cerebral flow?

Answer 10

viscosity of blood and dilation of vessels

Question 11

What can happen if there is low pressure in cerebral vessels?

Answer 11

impaired dilation and artery collapse

Question 12

What can happen if there is high pressure in cerebral vessels?

Answer 12

Increased flow, vasogenic cerebral oedema (disruption of the BBB) –> high risk of haemorrhage stroke

Question 13

What organ has the highest basal oxygen consumption, and therefore the highest arterial/venous oxygen difference?

Answer 13

Heart

Question 14

Which hormone is an important mediator of increasing blood flow and auto regulation in the heart?

Answer 14

Adenosine

Question 15

What stimulates the release of NO

Answer 15

rubbing against the endothelium - occurs in hypertension

Question 16

Why is coronary flow reduced during systole?

Answer 16

Extravascular compression

Question 17

When does most coronary flow occur?

Answer 17

Diastole

Question 18

Which heart layer is must vulnerable to ischaemia and why?

Answer 18

Endocardial layer - pressure within the heart

Question 19

What does a white thrombus contain and when is it formed?

Answer 19

Lots of platelets

fast moving blood (damage to endothelium releases platelets)

Question 20

What does a red thrombus contain and where does it form?

Answer 20

Lots of RBCs

Slow moving blood

Question 21

What medication treats white and red thrombi?

Answer 21

white = antiplatelets
red = anticoagulants

Question 22

What does the sympathetic nervous system release that acts on the blood vessels?

Answer 22

Adrenaline and noradrenaline