LEC 2 (gastrointestinal blood flow))

Question 1

the blood flow is directly related to the level of local activity وضح

Answer 1

after a meal → ↑ B.F then decreases back to the resting level

Question 2

The time require for back b.f to the resting level

Answer 2

2 to 4 hours.

Question 3

the activity that ↑ after meal

Answer 3

1. motor activity,
2. secretory activity
3. absorptive activity

Question 4

↑absorptive activity

Answer 4

↑ B.F in

1. villi
2. submucosa > 8fold

Question 5

increased motor activity

Answer 5

↑ B.F in muscle layers

Question 6

causes of the ↑ b. f during gi activity.

Answer 6

1. vasodilator substances
2. gastrointestinal glands
3. ↓ oxygen concentration in the gut wall

Question 7

vasodilator substances

Answer 7

cholecystokinin,

VIP, gastrin, and secretin.

Question 8

gastrointestinal glands also release into the gut wall

Answer 8

two kinins, kallidin and bradykinin →increased mucosal vasodilation that occurs along with secretion

Question 9

Directly .↓ oxygen concentration in the gut wall

Answer 9

↑metabolic rate → ↓oxygen concentration
► vasodilation ►↑increase intestinal blood flow at least 50 to 100
percent

Question 10

Indirectly ↓ oxygen concentration in the gut wall

Answer 10

↑increase fourfold of adenosine, a wellknown vasodilator ► vasodilation ►↑ blood flow.

Question 11

Countercurrent means

Answer 11

The arterial flow into the villus and the venous flow out of the villus

Question 12

Countercurrent شروطه

Answer 12

1. in directions opposite to each other
2. lie in close apposition to each other.
3. parallel to each other

Question 13

Blood Flow in the Villi.

Answer 13

much of the blood oxygen diffuses out of the arterioles directly into the
adjacent venules/
without ever being carried in the blood
to the tips of the villi(80 percent of the oxygen may take this short-circuit route (
نسبة الدم المحمل بال oعند القمة قريب من الvlli 20

Question 14

circulatory shock,

Answer 14

villus undergoes ischemic death →seriously blunted مثلوم

خشن →,leading to greatly diminished intestinal absorptive capacity

Question 15

effect Stimulation of the parasympathetic on BF

Answer 15

ncreases local blood flow

increases glandular secretion

Question 16

effect Stimulation of the parasympathetic on BF sit e

Answer 16

stomach and lower colon:

Question 17

effect of Sympathetic stimulation, on BF

Answer 17

V.C → ↓ B.F

Question 18

effect of Sympathetic stimulation, on BF SITE

Answer 18

all GIT

Question 19

autoregulatory escape

Answer 19

local metabolic vasodilator mechanisms that are elicited by ischemia override
the sympathetic vasoconstriction, returning toward normal

Question 20

value of sympathetic vasoconstriction

Answer 20

1. عشان الدم يروح للعضلات في حالة لما نلعب رياضة
   2.↓ in circulatory shock (the brain and the heart)
2. ↓ hemorrhagic shock(V.C of the large-volume intestinal and mesenteric veins)
   →displacing large amounts of blood في المناطق يلي بتحتاج دم