Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

GI Physiology > lecture 14 - splanchnic and hepatic circulations in health > Flashcards

lecture 14 - splanchnic and hepatic circulations in health Flashcards

1
Q

what are the exceptions to the strictly in parallel systemic circulation?

A
  • splanchnic circulation

- renal system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the cardiac output distribution at rest?

A 
GI tract and liver - 25 %
skeletal muscle - 20 % 
kidneys - 20 %
brain - 13 %
skin - 8 %
heart - 4 %
others - 10 %
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

waht percentage of cardiac output goes to the GI tract and liver?

A

25 % of CO and oxygen consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what percentage of cardiac output goes to the celiac artery and what is its blood flow?

A

10 % and 700 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what percentage of cardiac output goes to the superior mesenteric artery and what is its blood flow?

A

10 % and 700 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what percentage of cardiac output goes to the inferior mesenteric artery and what is its blood flow?

A

5 % and 400 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what does the celiac trunk supply?

A

stomach, spleen, and pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what does the superior mesenteric artery supply ?

A

intestine and pancreas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the inferior mesenteric artery supply?

A

intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the blood flow in the hepatic artery?

A

500 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the blood flow in the portal vein?

A

1300 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is the blood flow in the hepatic veins?

A

1800 ml/min

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the general structure of the gut wall? list the order

A
  1. ) mucosa - epithelium
  2. ) mucosa - lamina propria
  3. ) mucosa - muscularis mucosae
  4. ) lumen
  5. ) lymphatic tissue
  6. ) duct of gland outside tract
  7. ) gland in mucosa
  8. ) submucosa
  9. ) glands in submucosa
  10. ) meissner’s submucosal plexus
  11. ) vein
  12. ) muscularis: circular muscle
  13. ) muscularis: longitudinal muscle
  14. ) serosa: areolar CT
  15. ) serosa: epithelium
  16. ) auerbach’s myenteric plexus
  17. ) nerve
  18. ) artery
  19. ) mesentry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

where do blood vessels enter and leave the gut wall?

A

enter - at 18: the artery

leave - at 11: the vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what does the microcirculation in the GI tract consist of?

A

artery, arteriole, precapilllary sphincter, capillary, venule, vein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

blood flow to each layer (mucosa, submucosa, muscularis) is organised in ……

A

parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

since blood flow is parallel, this allow blood flow to ?

A

adjust to metabolic requirments of each layer by shunting blood from one layer to another without changing the overall GI blood flow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

over 65 % of the GI blood flwo is to the ….

A

mucosa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

where does autoregulation of the GI tract occur?

A

-stomach, small intestine and colon

20
Q

when is autoregulation of the GI tract more prominent?

A

in the fed rather than the fasting state and in the mucosa which is metabolically more active

21
Q

blood vessels in the GI tract are heavily innervated by the …..

A

sympathetic nervous system

22
Q

what does activation of the sympathetic nervous system cause and what does this do to the body?

A

causes alpha adrenoreceptor mediated vasoconstriction which diverts blood from the GIT to the vital organs during reduction in MAP.

23
Q

during a haemorrhage, GI blood flow can be reduced to ,,,,, of resting glow follow ….. activation

A
  • 25 %

- SNS

24
Q

what does vasoconstriction of the arterioles and veins in the GI cause?

A
  • blood is pushed back from veins in GI to IVC increasing circulating blood volume
  • vasoconstriction of arterioles in GI increases blood pressure (TPR)
25
the liver is an ...... organ in which .... quantities of blood can be stored in its blood vessels
- expandable/compressable | - large
26
what is normal liver blood volume?
500 ml or 10 % of total blood volume
27
the liver is capable of acting as a ..... in times of excess blood and is capable of supply extra blood in times of ......
- blood reservoir | - reduced blood volume (hypovolaemia)
28
in cardiac failure, the blood volume in the liver can rise to?
1 L when right atrial pressure rises
29
in times of circualtory stress, the SNS causes ........ of ..... and a large volume of blood is discharged into the systemic circualtion within .....
- vasoconstriction of the hepatic veins | - 1-4 mins
30
in normal humans the volume of blood mobilised can be as much as ....
350 ml
31
what is hypoperfusion?
- arterial flow flows into the villus in an opposite direction to venous flow that goes out the villus. - Sometiems blood O2 is transported from arteriole to venule via capillaries, without the help of being carried by the tip of the villus. - Usually this wouldn't effect the villus but in circualtory shock, cells in the tip of the villus can become ishaemic and die.
32
as much as ..... of O2 can take a short circuit (countercurrent blood flow)
80 %
33
what can happen in severe hypoperfusion of the GI tract?
it is not tolerated for long because there is a disruption of the mucosa which reduces barrier function; - endotoxin (lipopolysaccharide) can enter sytemic circulation - endotoxin can induce multiorgan failure and circualtory shock (septic)
34
what happens after the ingestion of a meal to GI blood flow?
it can increase 6 fold
35
what are the mechanisms that are involved in gastric mucosal blood flow?
1. ) metabolic vasodialtion ( adenosine) | 2. ) dilator action of GI hormones and neurotransmitters (CCK, vasoactive intestinal peptide, gastrin, secretin)
36
what does vasoactive intestinal peptide do and where is it released from?
- it is a neurotransmitter released from parasympathetic, cholinergic nerves - acts on smooth muscle and glands - relaxes sphincters and increases pancreatic and intestinal secretion
37
what does CCK do?
- it is a hormone that acts on pancreas, gallbladder and stomach - increases enzyme secretion, contracts gallbladder, increases gastric emptying
38
what does gastrin do?
- it is a hormone that acts on the stoamch and increases gastric acid secretion
39
what doe secretin do?
- it is a hormone that acts on the stomach and pancreas | - it releases bicarbonate and pepsin
40
total liver blood flow?
1.5 L/min (1-2)
41
portal venous blood is partly ....
de oxygenated
42
portal venous blood flow is ..... of total liver blood flow
70-80 %
43
what is portal venous pressure?
5-10
44
where do hepatic arterial and portal venous blood flow meet?
in the hepatic sinusoid
45
sinusoids are lined with a layer of ...... whihc are clusters of ..... . This makes it ..... and allows .... to pass through it
- endothelial cells - fenestrae - leaky and allows plasma proteins

GI Physiology (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions