Physiology of the human circulatory system - Cardovascular system PP

Question 1

The microcirculation:

Answer 1

The microcirculation is the portion of the vascular system comprising arterioles, apillaries, and venules.

Question 2

What happens in the microcirculation (and lymphatic system(?))?

Answer 2

It is a part of the circulation where nutrients, water, gases, hormones, and waste products are exchanged between the blood and cells

Question 3

What determines the net direction of fluid exchange across the capillaries?

Answer 3

Interplay between net hydrostatic and oncotic forces determines the net direction of fluid exchange across the capillaries.

Question 4

How does the sympathetic nervous system regulates blood pressure and flow?

Answer 4

Sympathetic nervous system regulates blood pressure and flow by constricting the microvessels

Question 5

Autoregulation:

Answer 5

• Certain organs control their blood flow via local autoregulation mechanisms. It may also serve as a form of compensatory mechanism.
• A phenomen related to autoregulation is reactive
  hyperemia.

Question 6

How does resistance to flow change with Radius of the Vessel?

Answer 6

• If a vessel has a smaller radius, at constant flow the velocity will be higher.
• If a vessel has a smaller radius, at constant pressure the velocity will be lower (and the flow will be lower still).

Question 7

Hagen–Poiseuille equation (known also as Poiseuille’s Law):

Answer 7

Applies to non-turbulent flow of liquids through pipes, such as blood flow in the circulatory system

Question 8

How is the velocity at laminar flow?

Answer 8

Laminar flow will mean that velocity is at its lowest – essentially stationary – at the edges and at its highest at the centre of a tube where the edge effect is weakest

Question 9

True or false: Laminar flow will mean that the width of the tube greatly affects its resistance?

Answer 9

True

Question 10

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Answer 10

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