L08: Arterioles And Vascular Resistance Flashcards

1
Q

What are arteriole vessels also called

A

Resistance vessels

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2
Q

When there is an increase in flow what happens to the vessels diameter

A

Vasodilation

Diameter increases

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3
Q

What happens to the vessel diameter as the flow decreases

A

Vasoconstriction

Radius decreases

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4
Q

What is vasodilation and vasoconstriction controlled by

A

Endothelial factors
Local mechanism
Central neural mechanism
Hormonal mechanism

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5
Q

What do arterioles do

A

Change radius in a flexible manner

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6
Q

What do endothelial cells produce

A

Vasoactive substances

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7
Q

What does vasoactive substances affect

A

Smooth muscle cells

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8
Q

What causes the release of vasoactive substances

A

Sheer stress
Paracrine hormones
Circulating hormone
Hypoxia

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9
Q

What are the vasoactive substances that cause vasodilation

A

Nitrous oxide
Prostaglandins
Endothelium derive hyper polarisation factor

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10
Q

What are the vasoactive substances that cause vasoconstriction

A

Endothelins
Thromboxanes
PGF

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11
Q

What are local factors products of

A

Metabolism

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12
Q

What are the local factors released

A

Adenosine
Potassium
Carbon dioxide
H+

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13
Q

What are local factors involved in

A

Vasodilation

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14
Q

What is an increase in flow due to an increase in metabolic activity known as

A

Active hyperaemia

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15
Q

What is the build up of metabolite causing an increase in blood flow known as

A

Reactive hyperaemia

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16
Q

Which organs have autoregulation

A

Kidney
Cerebral
Coronary circulation

17
Q

What is the role of autoregulation

A

Maintain stable blood pressures

18
Q

Which nervous system innervates arterioles

A

Sympathetic NS

19
Q

What does a decrease in SNS lead to

A

Vasodilation

20
Q

What does an increase in SNS lead to in arterioles

A

Vasoconstriction

Vasodilation if noradrenaline binds weakly to b2 receptors

21
Q

What receptors does noradrenaline bind to on arterioles

A

Alpha 1

Beta 2

22
Q

When noradrenaline binds to alpha 1 receptors what does this cause

A

Vasoconstriction

23
Q

When noradrenaline binds to beta 2 receptors what does this cause

A

Vasodilation

24
Q

Which other hormones associated with the kidney cause vasoconstriction

A

ADH/vasopressin

Angiotensin 2

25
Q

What receptors do circulating adrenaline bind to

A

Beta 2 receptors

26
Q

Therefore what does circulating adrenaline cause to arterioles

A

Vasodilation