L8: Control of Blood Flow Flashcards

1
Q

What happens to the blood flow after a large meal?

A

Increased blood flow to stomach & intestines

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2
Q

What happens to blood flow at a localised inflammation?

A

Increased blood flow to affected areas only

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3
Q

What happens to blood flow during diving?

A

Reduced blood flow to skeletal muscle, skin, kidneys, GI tract

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4
Q

What happens to blood flow to brain & heart during diving?

A

Maintained

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5
Q

What happens to the blood flow during aerobic exercise?

A

Increased blood flow to skeletal & cardiac muscle

Decreased blood flow to kidneys, GI tract

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6
Q

What happens to blood flow to brain during aerobic exercise?

A

Maintained

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7
Q

How can blood flow in some tissues be increased while at the same time others are decreased?

A

Different organs use different mechanisms or a combination of mechanisms for control of blood flow

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8
Q

Equation for blood flow?

A

Flow = Pressure / Resistance

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9
Q

What happens to resistance & blood flow during VASOCONSTRICTION?

A

Resistance INCREASED
Blood flow DECREASED

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10
Q

What happens to resistance & blood flow during VASODILATION?

A

Resistance DECREASED
Blood flow INCREASED

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11
Q

4 mechanisms for blood flow control1

A

1) Sympathetic (neuronal) control
2) Endocrine control
3) Local metabolic control
4) Local myogenic vs metabolic control

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12
Q

Where is sympathetic control of blood flow important in the body?

A

Muscle, skin, kidney, GI tract

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13
Q

How are arterioles constricted at rest?

A

Partially constricted

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14
Q

What happens to arterioles & blood flow when MORE noradrenaline is released?

A

Arterioles constrict MORE
Blood flow REDUCED

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15
Q

What happens to arterioles & blood flow when LESS noradrenaline is released?

A

Arterioles constrict LESS
Blood flow INCREASED

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16
Q

Where are vasoactive hormones secreted into?

A

Blood

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17
Q

What are vasoactive hormones?

A

Hormone found in the pancreas, intestine & CNS

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18
Q

What is active hyperaemia?

A

Increased blood flow

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19
Q

Why is blood flow increased during active hyperaemia?

A

An organ/tissue requires more O2 because it is MORE METABOLICALLY ACTIVE

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20
Q

What are blood flow controlled by?

A

Metabolites

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21
Q

Define flow auto-regulation

A

When a tissue can regulate its own blood flow

22
Q

2 opposing mechanisms of flow auto-regulation

A

1) Metabolic Control
2) Myogenic control

23
Q

What is metabolic control in flow auto-regulation?

A

Increases flow in response to metabolite accumulation

24
Q

What is myogenic control in flow auto-regulation?

A

Reduces flow in response to increased pressure

25
Q

What happens to muscle arterioles at rest?

A

Partially constricted by noradrenaline from sympathetic nerves

26
Q

What are adrenergic receptors?

A

Proteins found on the surface of cells that respond to hormone adrenaline

27
Q

What happens to sympathetic control when metabolic demand of the muscle increases?

A

Over-ridden by local metabolites & adrenaline, both causing vasodilation

28
Q

Is adrenaline both a vasoconstrictor & vasodilator?

A

Yes

29
Q

What must happen to cardiac output to support increased blood flow to skeletal muscle?

A

Be doubled

30
Q

What happens to cardiac muscle & coronary blood flow when cardiac output is doubled?

A

Both doubled

31
Q

Why is blood supply more extensive in left ventricle than right?

A

Left ventricle is more thicker

32
Q

What happens when blood flow is during early DIASTOLE?

A

At its peak

33
Q

What happens when blood flow is during SYSTOLE?

A

Blood flows STOPS

34
Q

What is diastole?

A

Time between heart beats

35
Q

Does blood flow to the brain always have to remain constant?

A

Yes

36
Q

How is the blood flow staying constant in the brain achieved?

A

Flow Auto-regulation

37
Q

How does cerebral arterioles respond to changes in?

A

In perfusion pressure

38
Q

Define perfusion pressure

A

How much pressure it takes to push blood through all the blood vessels in a specific area

39
Q

What does increased CO & MAP increase?

A

Increase cerebral blood flow & cerebral perfusion pressure

40
Q

What is control of skin blood flow an essential component of?

A

Thermoregulation

41
Q

What are skin arterioles effectors in?

A

Thermoregulation Reflux

42
Q

What happens to skin arterioles at normal core body temp?

A

Partially constricted

43
Q

What nerves constrict skin arterioles that supply blood to the surface of the skin?

A

Sympathetic Nerves

44
Q

What detects changes in core temperature?

A

The Hypothalamus

45
Q

What reduces blood flow to the skin surface?

A

Constriction

46
Q

What increases blood flow to the skin surface?

A

Dilation

47
Q

What are the 2 types of circulation ?

A

Pulmonary & Systemic

48
Q

Are pulmonary & systemic circulation in series OR in parallel?

A

In series

49
Q

Equation for cardiac output for the right & left ventricle

A

RV CO = LV CO

50
Q
A