Chapter 17 - Guyton Flashcards

1
Q

Factors affecting tissue needs?

A

delivery of oxygen to tissues; delivery of nutrients such as glucose, amino acids, etc.; removal of carbon dioxide, hydrogen, and other metabolites from tissue; transport various hormones and other substances to different tissues (flow is closely related to metabolic rate of tissues)

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2
Q

Which tissue receives the most blood flow?

A

liver (liver>kidneys>muscles>brain)

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3
Q

Decreases in oxygen availability to tissues _________ tissue blood flow.

A

increases

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4
Q

Two major theories for local blood flow.

A

vasodilator theory (greater metabolism or decreased availability of oxygen increases vasodilation), oxygen demand theory (absence of oxygen due to it being used causes vasodilation as vessels relax)

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5
Q

Explain Q=deltaP/R

A

Flow (Q) through a blood vessel is determined by the pressure difference (deltaP) between the two ends of the vessel and the resistance (R) of the vessel.

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6
Q

Explain the Vasodilator Theory.

A

increase tissue metabolism–>increase release of vasodilators–>decrease arteriole resistance–>increase blood flow

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7
Q

Name some vasodilators.

A

adenosine, CO2, lactic acid, ADP compounds, histamine, K ions, H ions

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8
Q

Explain the Oxygen Demand Theory.

A

increase tissue metabolism or decrease oxygen delivery to tissues–>decrease tissue oxygen concentration–>decrease arteriole resistance–>increase blood flow

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9
Q

Autoregulation

A

ability of a tissue to maintain blood flow relatively constant over a wide range of arterial pressures

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10
Q

Metabolic Theory

A

as arterial pressure is decreased, oxygen or nutrient delivery is decreased resulting in a release of vasodilator

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11
Q

Myogenic Theory

A

as arterial pressure falls, the arterioles have an intrinsic property to dilate in response to decreases in wall tension

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12
Q

Blood flow autoregulation in the kidneys.

A

feedback system between the tubules and the arterioles

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13
Q

Brain blood flow autoregulation.

A

controlled by carbon dioxide and hydrogen ion concentrations

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14
Q

Laplace’s Law

A

tension=pressure x radius

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15
Q

How is long-term local blood flow regulated?

A

changing the degree of vascularity of the tissues (size and number of vessels)

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16
Q

Important stimulus for regulating tissue vascularity.

A

oxygen

17
Q

Angiogenesis

A

growth of new blood vessels

18
Q

Angiogenic factors?

A

small peptides such as vascular endothelial cell growth factors (VEGF), fibroblast growth factor (FGF), and angiogen

19
Q

Angiogenic factors released from?

A

ischemic tissue, rapidly growing tissue, tissue with high metabolic rates

20
Q

Humoral regulation of blood flow vasoconstrictors.

A

norepinephrine, epinephrine, angiotensin, vasopressin, endothelin

21
Q

Humoral regulation of blood flow vasodilators.

A

bradykinin, serotonin, histamine, prostaglandins, nitric oxide