GI: Key Information > Physiology > Flashcards

Physiology Flashcards

(60 cards)

Study These Flashcards
1
Q

four layers of the GI tract

A

mucosa
submucosa
muscularis externa
serosa/adventitia

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

where is the muscularis mucosae located?

A

mucosa

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

where is the submucous plexus located?

A

submucosa

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

where is the myenteric plexus located

A

muscularis externa

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

which layer is made up of the circular and longitudinal muscle layers?

A

muscularis externa

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

function of the circular muscle layer?

A

makes the lumen longer and narrower

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

function of the longitudinal muscle layer

A

makes the lumen shorter and fatter

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

what initiates slow wave activity in the GI tract?

A

interstitial cells of Cajal (pacemaker cells between the two muscle layers)

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

major patterns of motility in the stomach and small intestine

A
  1. peristalsis
  2. segmentation
  3. colonic mass movement (faeces into rectum)
  4. migrating motor complex (stomach to terminal ileum)
  5. tonic contractions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

gastric factors affecting stomach emptying

A

volume and consistency of chyme

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

patterns of motility in the large intestine

A
  • haustration (slow wave)
  • peristalsis propulsion
  • defecation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

two areas of secretion in the stomach

A
  • oxyntic gland area

- pyloric gland area

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

cells in the oxyntic gland area

A
  • chief cells (pepsinogen)
  • parietal cells (HCl, intrinsic factor and gastroferrin)
  • enterochromaffin (histamine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

cells in the pyloric gland area

A
  • D cells (somatostatin)

- G cells (gastrin)

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

role of intrinsic factor and gastroferrin

A

bind B12 and Fe2+

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

role of somatostatin

A

inhibit HCl secretion

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

how does the mucosa protect itself from being digested?

A

secretes PGE2 and PGI2

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

two motility regions in the stomach

A
  • orad: tonic contractions- vagus

- caudad: slow wave (retropulsion)

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

two types of secretions in the pancreas

A
  1. endocrine: islets of Langerhans

2. exocrine: acinar cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

five pancreatic enzymes (precursors)

A
  1. trypsinogen
  2. chymotrypsinogen
  3. carboxypeptidase
  4. pancreatic amylase
  5. pancreatic lipase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how is Cl- secreted

A

through CFTR on apical membranes (overstimulated causes secretory diarrhoea- loss of K+)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

describe luminal digestion

A

pancreatic enzymes secreted into the duodenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

describe membrane digestion

A

mediated by enzymes at the brush border of epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

in carbohydrate digestion what is the role of alpha-amylase

A

breaks alpha-1,4-links

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
in carbohydrate digestion what is the role of isomaltase?
breaks alpha-1,6 links
26
what are oligosaccharidases
integral membrane proteins with a catalytic domain that faces the lumens
27
examples of oligosaccharidases
lactase, maltase, sucrase and isomaltase
28
substances involved in protein digestion
- HCl and pepsin in stomach | - pancreatic enzymes function as either endopeptidases or exopeptidases in the small intestine
29
describe lipid digestion
converted to an emulsion by lipases which is reduced by pancreatic lipase
30
what does failure to secrete bile salts result in?
lipid malabsorption (steatorrhoea and vitamin deficiency- A, D, E and K)
31
how are glucose and galactose absorbed?
secondary active transport mediated by SGLT1 (Na+)
32
how is fructose absorbed
facilitated diffusion mediated by GLUT5
33
how do all monosaccharides exit enterocytes
facilitated diffusion by GLUT2
34
how are peptides absorbed at the brush border?
by PepT1 (co-transport with H+)
35
how is cholesterol absorbed
NPC1L1 (ezetimibe)
36
what is the taeniae coli
longitudinal smooth muscle in the colon is divided into three strands to cause the production of haustra
37
how is the appendix connected to the caecum?
appendiceal orifice
38
three major functions of the large intestine
- secretion of K+, HCO3- and mucus - absorption of Na+, Cl- and H2O (& short chain fatty acids) - reservoir for periodic elimination
39
what enhances Na+ absorption and K+ secretion
aldosterone
40
is the absorption of water a passive process?
yes, it follows solutes (usually Na+)
41
three mechanisms of water absorption in the jejunum
- Na+/glucose co-transport - Na+/amino acid co-transport - Na+/H+ exchange
42
mechanism of water absorption in the ileum and proximal colon
Na+/H+ and Cl-/HCO3- exchange (reduced NaCl absorption causes diarrhoea)
43
mechanism of water absorption in the distal colon
epithelial Na+ channels (enhanced by aldosterone)
44
define assimilation
overall process of digestion and absorption
45
major functions of the liver
- metabolism - deactivation of hormones (insulin, glucagon, ADH, steroids) - storage of A, D, E, K vitamins, iron, copper and glycogen - synthesis of protein (acute phase proteins, coagulation, albumin, etc.) - protection: Kupffer cells - detoxification - secretion of bile
46
describe the secretion of bile by the liver
secreted by hepatocytes into canaliculi which drains into bile ducts, neutralising chyme an forms micelles
47
two phases of drug metabolism in the liver
Phase 1: oxidation (CYP450s), reduction and hydrolysis. | phase 2: conjugation e.g. glucuronidation
48
what is the enteric nervous system
it is the autonomic nervous system that supplies the GI tract
49
parasympathetic neurotransmitter in the ENS
both preganglionic and postganglionic synapse with ACh
50
role of the parasympathetic in the ENS
'rest and digest' - increases blood flow, secretion and smooth muscle contraction - relaxation of sphincters
51
neurotransmitters in the sympathetic of the ENS
preganglionic release ACh and postganglionic release NA
52
role of the sympathetic in the ENS
- increased sphincter tone | - decreased motility, secretion and blood flow
53
define retching
rhythmic reverse peristalsis with forceful contraction of abdominal muscles and the diaphragm
54
define emesis
forceful expulsion of gastric-intestinal contents out of the mouth
55
what stimuli act directly on the VC
- pain, repulsive sights, smells and emotional factors | - motion (signals via the vestibular nucleus)
56
what stimuli act on the NTS
pharyngeal stimulation, gastric/duodenal distension or irritation
57
what stimuli act on the CTZ (no BBB)
- pharyngeal stimulation, gastric/duodenal distension or irritation - toxins, drugs and vagal afferents
58
consequences of severe vomiting
- dehydration - metabolic alkalosis - hypokalaemia - oesophageal damage e.g. Mallory-Weiss tear
59
which area of the brain 'causes' obesity
lesioning ventromedial hypothalamus (leptin and insulin report fat status)
60
define satiety
period of time between termination of one meal and the next (gherlin is the hunger signal)
GI: Key Information
flashcards
Decks in class (24)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions