Gastrointestinal system Flashcards

Rebecca

1
Q

what is the primary function of the GI tract

A

absorption of dietary nutrients maximised by secretions added to convert large molecules to smaller ones

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

what are the other GI functions

A

storage and secretion

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

what is the mucosa made up of and where is it found

A

epithelium, lamina propria, muscularis mucosa

nearest the lumen, inside

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

what is lamina propria

A

CT , has nerves, blood and lymph vessels

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

what is the muscularis mucosa

A

thin layer of smooth muscle

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

what is the submucosa layer and where

A

thicker layer with similar composition to lamina propria (CT)
contains submucosal plexus
middle

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

what is the muscularis externa

A

circular muscle, myenteric plexus and longitudinal muscle

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

what does the ENS do

A

coordinates contractions to mix and move contents between compartments

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

what is the serosa layer

A

outmost layer of CT and squamous cells

some tract sections dont have this layer

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

what 3 divisions of the ANS regulate the Gi function

A

parasympthetic
sympathetic
enteric

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

what does the PNS do

A

signals stimulate GI secretions and motility facilitating digestion and absorption of nutrients

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

what does the SNS do

A

decreases GI secretions and motility

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

how does the ENS work

A

can operate independenly and is involved with reflexes and majority of GI functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the main plexuses in the ENS

A

myenteric

submucosal

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

what does the myenteric plexus do

A

motility

regulates intestinal smooth muscle , contractions of muscles

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

what is motility

A

coordinated contraction and relaxtion of muscles in the Gi tract

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

what does the submucosal plexus do

A

secretions, regulates secretions and local absoptive environment

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

what do reflexes in the ENS do

A

If one thing is going onn in one place then it can influence whats happening in another part

19
Q

how do they reflexes in the ENS communicate?

A

they are neural circuits with mechanoreceptors or chemoreceptors that then causes nerves to signal to regulate endocrine or secretory cells

20
Q

what are some GI neurotransmitter examples

A

enkephalins (contrict circular muscle around sphincters), ACh, serotonin

21
Q

what are some GI hormones (endocrine)

A

gastrin, cholecystokinnin, motilin, secretin

22
Q

what are paracrines

A

hormones released that act locally

23
Q

examples of paracrines

A

histamine, prostaglandins , somastostatin

24
Q

what are the 3 digestive phases

A

cephalic phase, gastric phase and intestinal phase

25
Q

what is the cephalic phase

A

triggered by thought of food , primarily neural, stimulates secretion

26
Q

what is the gastric phase

A

begins when food and oral secretions enter the stomach, coincides with distension (expansion of stomach). hormonal, neural and paracrine

27
Q

what is the intestinal phase

A

when stomach contents recah the duodenum

primarily hormonal but also other 2

28
Q

what is the role of the upper GI tract

A

minimal role in nutrient absorptionm transports and prepares food to be absorbed

29
Q

parts of the upper GI tract

A

mouth, salivary glands, oesophagus,stomach

30
Q

what does the mouth do

A

reduces food to optimal size, mixes food with secretions from 3 salivary glands (submandibular, parotid, sublingual)

31
Q

what is mastication

A

chewing

32
Q

swallowing (oesophagus)

A
  • intiated voluntarily, involuntary after
  • parasympathetic
  • from mouth to upper oesophageal sphincter
33
Q

peristalsis in the oesophagus

A

series of coordinated muscle contraction/relaxtion

commences after upper oesopheageal sphincter

34
Q

functions of the stomach

A

3 primary motility functions
mixing via slow wave-intiated contractions, retropulsion and gastric emptying

accept and store food
mix food with secretions
digest food
deleiver food to small intestine

35
Q

stomach secretions

A

dervived from gastric invaginations (pits) which contain multiple cell types to secrete different secretions

36
Q

how do salivary secretions get produced

A

controlled by sympathetic and parasympathetic
cl, na and water are transported to duct lumen
ductal cells modify by reabsorbing na and cl and secreting K and HCO3 -

37
Q

examples of gastric secretions

A

ions and water, mucus from mucous neck cells, pepsinogen from cheif cells , H+ from parietal cells

38
Q

what are the sections of the small intestine

A

duodenum
jejunum
illeum

39
Q

what is the role of the small intestine

A

most macronutrient , vitamin and mineral absorption occurs (big SA)

40
Q

what are the parts of the large intestine

A

caecum, ascending, transverse, descending and sigmoid colon
rectum
anus

41
Q

role of large intestine

A

significant water and ion absoprtion

motility of contents :mixing and propulsion

42
Q

waht does motility in the small intestine involve

A

mixing via segementation and propulsion via peristalsis

43
Q

what does motility in the large intestine involve

A

segementation, peristalsis and mass movement and reflexes that control sphincter contraction and relxation

44
Q

what does the ileocecal sphincter regulate

A

amount of chyme entering the large intestine