Microcirculation

Question 1

nutrient and waste exchange occurs because of/by

Answer 1

diffusion–through/btwn capillary ENDOTHELIAL cells

Question 2

diffusion based on

Answer 2

pressure within/out

Question 3

proteins in vascular system generally

Answer 3

remain within system and contribute to oncotic pressure

Question 4

arterial capillary hydrostatic pressure tends to

Answer 4

promote FILTRATION across capillary wall

Question 5

oncotic pressure tends to promote

Answer 5

filtration from arterial side and

reabsorption by venous side

Question 6

interstitial fluid osmotic pressure is generally lower

Answer 6

than oncotic pressure

Question 7

lymphatic capillaries are formed by

Answer 7

single layer of endothelial cells with fenestrated basement membrane for movement of interstitial fluid and large particles

Question 8

stationed along the lymphatic vessels

Answer 8

lymph nodes

Question 9

immune system cells in lymphnodes

Answer 9

sample lymph gathered from tissues

Question 10

pathophysiology of lymph system

Answer 10

1. lymph edema–damage to normal lymph channels
2. lymphatic cancer spread–can spread locally (i.e melanoma) or globally
3. lymphadenitis
4. lymphoma

Question 11

knowing lymph drainage in relation to cancer will

Answer 11

instruct where to look for tumors around known tumor site–surgeons may remove surrounding lymph nodes when removing cancer

Question 12

most common cause of lymph edema worldwide

Answer 12

Filariasis–worm that infiltrates lymphnodes causing inflammation–>obstruction

Question 13

alarming for lymph cancer

Answer 13

large, very firm, NONTENDER nodes

Question 14

press deeply on swollen extremity with finger–stays depressed

Answer 14

pitting edema

Question 15

blood flow to capilaries relates to

Answer 15

precapillary sphincter status (contracted vs. relaxed)

Question 16

greatly controls capillary function

Answer 16

autonomic NS – Alpha 1 adrenergic receptors

Question 17

Ex. of vasoactive substances and hormonal control

Answer 17

1. epinephrine–may inject with lido to decrease blood flow
2. histamine–>bradykinins
3. serotonin–vascular spasm
4. prostaglandins–vasoconstriction or vasodilation
5. nitric oxide–vasodilator

Question 18

• substance made by endothelial cells for purpose of vasodialtion

Answer 18

nitric oxide

Question 19

decreased O2 to capillaries

Answer 19

dilates capillary beds–except in lungs

Question 20

lung capilaries _____ with decrease in O2

Answer 20

constrict–imp. increases blood flow to healthy or unobstructed (mucos/fluid buildup) lung spots–trouble with COPD pt’s (leads to RIGHT VENTRICULAR hypertrophy) (hypoxic pulmonary vasoconstriction)

Question 21

the maintenance of constant blood flow to an organ despite changing arterial pressure

Answer 21

AUTOREGULATION of organ blood flow

Question 22

autoregulation of organ blood flow may be due to_____________ or _____________

Answer 22

1. Myogenic hypothesis–smooth muscle contraction when stretched
2. metabolic hypothesis–vasodilation upon buildup of metabolic byproducts i.e. CO2, H+, lactate

decrease in flow will lead to vasodilation

Question 23

cerebral blood flow normal

Answer 23

50-150 mmHg – related to autoregulation or organ systems

Question 24

capillary dilation when

Answer 24

low pH, high CO2, histamine–except in lungs (opposite)