Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

physiology 2 > GIT physiology 1 > Flashcards

GIT physiology 1 Flashcards

1
Q

mechanical digestion

A

mixing waves - gentle, rippling peristaltic movements - creates chyme

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

chemical digestion

A

different enzymes require different environments
many molecules require stepwise digestion
all require specific conditions

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

3 types of chemical digestion

A

secreted enzymes
brush border enzymes
cytosolic enzymes

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

carbohydrases

A

chemically digest carbohydrates

  • pancreatic amylase
  • a-dextrinase, sucrase, lactase, maltase in brush border
  • ends with monosaccharides which can be absorbed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

proteases

A

chemically digest proteins

- trypsin, chymotryp[sin, carboxypeptidase, and elastase from pancreas

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

lipases

A

chemically digest lipids

  • pancreatic lipase most important in triglyceride digestion
  • emulsification by bile salts increases surface area
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

nucleases

A

chemically digest nucleic acids

  • ribonuclease and deoxyribonuclease in pancreatic juice
  • nucleosides and phosphates in brush border
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3 types of movement in the GI tract

A
  • interdigestive clearing
  • squishing
  • peristalsis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

interdigestive clearing

A

driven by a pacemaker

rhythm that sweeps the gut clean

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

squishing

A

stretch driven rhythmic contraction

for mechanically breaking up food

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

peristalsis

A

local stretch driven propulsion

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

mechanical aspects of digestion are modulated by

A

ANS/hormones/paracrines

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

basal electrical rhythm

A

cells opening and closing channels constantly

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

enteric smooth muscle

A

tonic/phasic

bundles electrically connected via gap junctions contraction stimulated by Ca

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

tonic/phasic

A

on/off or oscillating

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

bundles of enteric smooth muscle is connected via

A

gap junctions

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

contraction of enteric smooth muscle is stimulated by

A

calcium

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

Ca2+ channels in enteric smooth muscle are

A

slow to open/close

long AP duration/contraction

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

excitation of smooth muscle

A

lots of things can open smooth muscle Ca channels

  • ANS activity - acetyl choline
  • enteric nervous system activity
  • local chemistry
  • autorhythmicity - some GIT smooth muscle cells are pacemakers
  • hormones, lumocrines
  • stretch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how does stretch excite enteric smooth muscle

A

stretching smooth muscle opens mechanically gated channels;s and causes it tp contract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

stretch triggering enteric smooth muscle is called

A

myogenic stretch response

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

how does ANS open Ca channel;s

A

acetylcholine stimulates Gi tract smooth muscle

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

autorhymicity

A

some GIT smooth muscle cells are pacemakers

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

when there is no food to digest

A

phasic pacemaker dominates - continual slow intrinsic electrical activity - basal electrical rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

2 types of phasic pacemaker pattern

A
  • slow waves

- spikes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

when a slow pave passes the threshold

A

an AP is generated

this is a spike

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

migrating motor complex

A

rhythmic contraction event passing from cell to cell via gap junctions
lasts 90-120 minutes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

migrating motor complex stops when

A

feeding/eating occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

migrating motor complex restarts when

A

resumes automatically when there is no food

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

segmentation and grinding

A

stretch initiates local rhythmical circular muscle contraction and relaxation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

when there is food in the gut there is two stimuli

A

stretch and osmotic stimuli (hyperosmolar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

frequency and strength of segmentation and grinding and peristalsis is affected by

A

PNS - increased

SNS - decreased

33
Q

peristalsis

A

retrograde circular contraction and anterograde circular relaxation
moves

34
Q

2 signals regulating peristalsis

A

retrograde signal and anterograde signal

35
Q

retrograde signal results in

A

results in contraction

36
Q

anterograde signal results in

A

results in relaxation

37
Q

retrograde signal molecule

A

acetyl choline

38
Q

anterograde signal molecule

A

NO and ATP

39
Q

during absorption

A

segmentation and mixing

40
Q

after completion of absorption

A

peristalsis to move food onto next section of the gut

41
Q

colon motility

A

a reservoir for the undigested

slow to absorb sodium

42
Q

ileocaecal valve

A

restricts colon bugs from leaving the colon

prevents back flow

43
Q

increase in ileum pressure

A

ileocaecal valve opens

44
Q

increase in colon pressure

A

ileocaecal valve shuts

45
Q

ileocaecal calve opens when

A

increase in ileum pressure

opens briefly with each peristaltic wave

46
Q

involuntary sphincters are controlled by

A

myogenic tone and relative pressures

47
Q

three states of pressure control

A

resting state - closed, inhibits movement between segments
relaxation - open, pressure infront of sphincter>after
constriction - very closed, pressure after sphincter»in front, prevents retrograde flow

48
Q

neural control of sphincters

A

indirect mechanism

  • excites interneurons
  • uses NO/ATP, facilitates flow
49
Q

neural control of defamation

A

parasympathetic stimulation causes internal anal sphincter relaxation
external anal sphincter is under voluntary control

50
Q

2 gut nerve plexuses

A
  • submucosal plexus - meissner’s

- myenteric plexus - aurbach’s

51
Q

submucosal plexus

A

between the mucosa and circular muscle layer

52
Q

myenteric plexus

A

between circular and longitudinal muscle layer

53
Q

myenteric plexus controls

A

GI tract motility - mechanical digestion

54
Q

submucosal plexus controls

A

coordinates local secretions and local blood flow

chemical digestion

55
Q

intrinsic reflexes

A

enteric nervous system only

control secretion, peristalsis, local effects

56
Q

extrinsic reflexes

A

prevertebral ganglia

transmission of long distance signals

57
Q

entero-gastric reflex

A

acidic duodenum contents promote colonic contractions

58
Q

gastrocolic reflex

A

stretched stomach increases colon motility causing evacuation - so stomach can empty into duodenum

59
Q

gastro-ileal reflex

A

stretch stomach causes ileocaecal valve to open

60
Q

long reflexes

A

uses the CNS
vago-vagal reflex
pain reflex defecation reflex

61
Q

3 things regulating hormonal control of motility

A

secretin
cholecystokinin
motilin

62
Q

motilin

A

starts migrating motor complex

63
Q

cholecystokinin (CCK) and secretin

A

produced by duodenum in response to food

once contents have left the stomach - they slow down the stomach to prevent overload of the duodenum

64
Q

secretin produced in response to

A

acid (food)

65
Q

cholecystokinin is produced in response to

A

FAs/peptides (food)

66
Q

motilin initiates

A

interdigestive clearing - promotes migrating motor complex

67
Q

motilin produced by

A

small intestine M cells

68
Q

motilin is surpassed by

A

feeding

69
Q

phases of digestion

A

cephalic phase
gastric phase
intestinal phase

70
Q

cephalic phase

A

largely neural control

smell, sight and thought of food

71
Q

gastric phase

A

neural and hormonal control

food enters stomach

72
Q

intestinal phase

A

largely hormonal control

begins when food enters small intestine

73
Q

inter digestive phase

A

when there is no food

74
Q

what does cephalic phase do

A

reflex from taste buds stimulates vagal centre in the CNS
cranial nerves from medulla stimulate secretion from salivary glands, stomach, pancreas
vagus also increases motility of stomach, intestine

75
Q

what does gastric phase do

A

food in the stomach stimulates vago-vagal reflexes and the release of hormones
stimulates gastric and pancreatic secretion, priming for digestion
hormones further stimulate gastric secretion

76
Q

what does intestinal phase do

A

food releases stimulatory hormones from the gut mucosa

  • hormones stimulate secretion of exocrine pancreases, contraction of gallbladder
  • inhibitory hormones acting on stomach
77
Q

what is excreted during the intestinal phase

A

HCO3- to nuetralise the acid, enzymes to further digest food,
gallbladder delivers bile salts into intestines

78
Q

why is the stomach inhibited during the intestinal phase

A

to prevent overloading the intestines

physiology 2 (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions