Chapter 7 Vascular control Flashcards

1
Q

Are these vasodilator or vasoconstrictor substances?

  • Prostaglandins
  • Histamine
  • Bradykinin
A
  • Prostaglandins : certain are potent vasodilators: inflammation, other are vasoconstrictors: PG produced by platelets/endothelial cells, involved in hemostatic vasoconstriction
  • Histamine: vasodilator (+ increased vascular permeability)
  • Bradykinin: vasodilator (10 times more potent than histamine) (+ increased vascular permeability)
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2
Q

Define active hyperemia:

A

= when the blood flow closely follows the tissue’s metabolic rate. => skeletal muscle blood flow increases within seconds of the onset of muscle exercise and returns to control values shortly after exercise ceases

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3
Q

Define reactive hyperemia

A

Lower than normal blood flow transiently followed by a higher-than-normal blood flow - also known as postocclusion hyperemia
=> flow through an extremity is higher than normal for a period after a tourniquet is removed from the extremity

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4
Q

What is the sympathetic vasoconstrictor neurotransmitter?

A

Norepinephrine, through alpha 1 adrenergic receptor. Normal nasal tonic activity, increasing arteriolar tone in a continuous manner. If decreased tomic activity of sympathetic nerves, causes vasodilation.

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5
Q

What protein does Ca+ bind to in smooth muscles and initiate muscle contraction?

A

Calmodulin

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6
Q

T/F Once smooth muscles have contract, it is very cheap (low ATP cost) to maintain the contraction

A

True

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7
Q

What is the main molecule determining the resting membrane potential in a smooth muscle cell

A

Potassium

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8
Q

What is smooth muscle cells’ reaction to high vs low O2 concentration? (in most tissues)

A

High O2 -> vasoconstrict

Low O2 -> vasodilate

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9
Q

Nitric oxide is produced intracellular from which amino acid?

A

L-arginine

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