Chapter 17 - Guyton

Question 1

Factors affecting tissue needs?

Answer 1

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)

Question 2

Which tissue receives the most blood flow?

Answer 2

liver (liver>kidneys>muscles>brain)

Question 3

Decreases in oxygen availability to tissues _________ tissue blood flow.

Answer 3

increases

Question 4

Two major theories for local blood flow.

Answer 4

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)

Question 5

Explain Q=deltaP/R

Answer 5

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.

Question 6

Explain the Vasodilator Theory.

Answer 6

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

Question 7

Name some vasodilators.

Answer 7

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

Question 8

Explain the Oxygen Demand Theory.

Answer 8

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

Question 9

Autoregulation

Answer 9

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

Question 10

Metabolic Theory

Answer 10

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

Question 11

Myogenic Theory

Answer 11

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

Question 12

Blood flow autoregulation in the kidneys.

Answer 12

feedback system between the tubules and the arterioles

Question 13

Brain blood flow autoregulation.

Answer 13

controlled by carbon dioxide and hydrogen ion concentrations

Question 14

Laplace’s Law

Answer 14

tension=pressure x radius

Question 15

How is long-term local blood flow regulated?

Answer 15

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

Question 16

Important stimulus for regulating tissue vascularity.

Answer 16

oxygen

Question 17

Angiogenesis

Answer 17

growth of new blood vessels

Question 18

Angiogenic factors?

Answer 18

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

Question 19

Angiogenic factors released from?

Answer 19

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

Question 20

Humoral regulation of blood flow vasoconstrictors.

Answer 20

norepinephrine, epinephrine, angiotensin, vasopressin, endothelin

Question 21

Humoral regulation of blood flow vasodilators.

Answer 21

bradykinin, serotonin, histamine, prostaglandins, nitric oxide