Brainscape's Knowledge GenomeTM

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


See full index

GIR Test 1 > B5.010 - Small and Large Intestine > Flashcards

B5.010 - Small and Large Intestine Flashcards

1
Q

what is sucrose digested to

A

glucose and fructose

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

how does fructose enter the cell

A

GLUT 5 transporter

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

what is lactose digested into

A

glucose and galactose

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

uptake of glucose and galactose is depended on what

A

SGLT1 transporter in the apical membrane

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

what is the energy source for the SGLT1 transporter

A

its secondary active transport

gets energy from electrochemical gradient produced from Na/K ATPase in the basolateral membrane

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

how do monosaccharides leave the cell

A

through basolateral membrane via specific protein channels (GLUT2), sodium independent facilitated diffusion

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

describe Na absorption

A

Na traverses the apical membrane of the enterocytes through nutrient coupled Na transparent, Na/H exchange, Na channels

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

what generates the electrochemical gradient that provides the driving force for Na absorption

A

Na/K ATPase

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

what possible additional mechanisms are involved with Na absorption in small and large intestine

A

chloride/bicarb exchanger DRA or putative anion transporter 1 PAT1

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

what does DRA do

A

exchanges Cl/Bicarb

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

what dose KCC1 do

A

pottasium/2Cl cotransporter

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

what is ENaC

A

apical epithelial sodium channels allows sodium to enter epithelial cells

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

how does sodium exit the eipthelial cell

A

Na/K ATPase

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

describe water absorption in the stomach

A

Na pumps increase Na concentration in the intercellular space which increases the osmotic pressure, water flows across the brush border and out the sides of the intestinal epithelial cell to the paracellular space, this increase in hydrostatic pressure pushes fluid into capillaries

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

how much water is ingested/day

A

2 L

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

how much gastric secretions are released each day

A

7 L

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

where in the GI is water added to chyme

A

duodenum

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

where is the major site for water absorption

A

jejunum

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

how much water / day is absorbed in the colon

A

1.4 L

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

how much water is lost in feces

A

.1 L

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

describe chyme

A

hypertonic

osmolarity increases as digestion begins

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

what does the hypertonicity of chyme do

A

draws water into the intestine

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

what does Cl- do in the lumen of the intestine

A

draws Na and water into the lumen

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

describe bacterias effect leading to diarrhea

A

bacterial toxins can activate adenylate cyclase resulting in prolonged state of open CFTR leading to diarrhea

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

describe the electrolyte secretion by epithelial cells of intestinal crypts

A

Na is pumped out of cell
Cl-, Na+ and K+ are cotransported into cell by Na/K/2Cl cotransporter
K+ leaves by KCNQ1 potassium channels

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

what do activated mast cells do in intestine

A

release histamine, which either directly acts on epithelial cells or acts on submucosal neurons to stimulate release of ACh which then acts on epithelial cells

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

Ca absorption in small intestine

A

calcium enters intestinal epithelial cells via a calcium channel driven by ec gradient.

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

describe the movement of Ca within the cell

A

calcium bound to calbindin; calcium within the membrane bound vesicles. A Ca-ATPase moves caclum across basolateral membraen. A Na-Ca antiporter also moves calcium

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

in what state does iron have to be to be transported into the cell

A

ferrous (2+)

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

what is DMT1

A

transports Ferrous iron into the enterocyte

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

what is Dcytb

A

on enterocyte, converts Fe3+ into Fe2+

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

what happens with haem in the small intestine

A

the haem transporter takes up haem and then haem oxygenase converts it to Fe2+ for intracellular iron pool (ferritin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

what is hephaestin

A

converts Fe2+ to Fe3+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

what is ferroportin

A

the channel that allows Fe2+ to exit the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

where do you find vitamin B12

A

animal products like meat, eggs, milk, fish, bacteria in gut also make it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is R protein

A

made by salivary gland protects vitamin B12 from acid degradation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

what is IF

A

intrinsic factor made by parietal cells int eh dtoma hc but is outcompeted for vitamin B12 by R proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

what happens to R proteins in the small intestine

A

get digested by pancreatic enzymes and IF and Vit. B12 associate and are resistant to degradation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

where in the SI are there receptors for IF-Vit B12

A

distal ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

what is transcobalmin 2

A

moves B12 into the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

where is water absorbed

A

jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

where is Na absorbed

A

can be absorbed on any part of intestine, net rate highest in jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

where is HCO3+ absorbed/secreted

A

jejunum - absorbed

secreted - everywhere else

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

where is Cl- absorbed

A

all of SI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

where is K+ absorbed

A

jejunum

ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

where is Ca2+ absorbed

A

all segments of SI especially in duodenum and jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

where is iron absorbed

A

duodenum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

where is Mg2+ absorbed

A

along entire length of intestine

most in ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

where is phosphate absorbed

A

along entire length of intestine

duodenum > jejunum > ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

where is copper absorbed

A

jejunum

51
Q

what are the 3 .phases of interdigestive motility

A

1 - motor quiescence of stomach and duodenum
2 - sporatic peristaltic waves, segmenting contractions and peristaltic waves
3 - contraction of resivoir, forceful peristaltic waves

52
Q

what do phase 3 peristaltic waves do

A

clean the intestinal segment from chyme and bacteria which accumulates aborally. Because of the successive waves tart and end further aborally het phase 3 slowly migrates distally

53
Q

what is the migrating motor complex

A

starts 2-3 hr after digestion of a meal
triggered by hormone motilin
aborally clears small intestine of undigested debris
consists of 3 motility phases

54
Q

when does a new MMC begin

A

when a MMC reaches the ileum

55
Q

where does MMC start

A

antrum

56
Q

when is the time between MMC cycles longer

A

during the day

57
Q

when does the MMC terminate

A

when food enters the SI

58
Q

will IV nutrition terminate MMC?

A

no

59
Q

what hormones/chemicals terminate MMC

A

gastrin and CCK except in ileum

60
Q

what happens to digestive activity in the small intestine during sleep

A

reduces phase 2 activity and increases duration of phase 1

61
Q

what does ingestion of a meal do to interdigestive motility

A

suppresses it and induces fed motor patter

62
Q

describe postprandial motility

A

characterized by a lower amplitude of the antral waves occurring at maximal frequency, rhythmic pyloric opening and closure and coordinated duodenal contractions occurring in sequence with the antral waves

63
Q

what NTs and neurohormones alter GI motility

A 
ACh
Serotonin
Gastrin
CCK (gall bladder, SI)
Enkephalin
PP - colon 
Substance P
motilin
64
Q

what NTs and neurohormones decrease motility

A 
NE
Somatostatin
Secretin
CCK (stomach)
Enteroglucagon
GLP1
Adenosine
NO
VIP
GIP
PP
65
Q

what is motilin

A

produced in duodenal mucosa by M cells in response to stimulation via vagus nerve

66
Q

what does motilin do during fasting

A

may initiate phase 3 of MMC but the trigger is unknown

67
Q

when is MMC terminated

A

when food enters the small intestine

68
Q

what hormones can germinate the MMC

A

gastrin and CCK

69
Q

describe regulation of chyme into the cecum

A

chemoreceptors and mechanoreceptors and mechanoreceptors in cecum feedback into ileum and ileocecal sphincter to regulate chyme entry

70
Q

what does the cecum do to allow entry of chyme

A

undergoes receptive relaxation similar to proximal stomach

71
Q

what prevents backflow to SI from cecum

A

ileocecal sphincter, releases with jejunum distended, contracts when colon distended

72
Q

efficiency of large intestine in reabsorbing water

A

> 90%

73
Q

what does the large intestine do

A

reabsorbs water
absorbs electrolytes
stores fecal matter
evacuate 200-300 ml solid stool/day

74
Q

what does the ascending colon do

A

receives chyme from ileum
receptive relaxation
short transit time
resevoir for transverse colon

75
Q

what does the transverse colon do

A

primary region for absorption

long transit time (like 24 hrs)

76
Q

where is the splenic flexure

A

between the transverse and descending colon

77
Q

what does the descending colon do

A

completion of absorption
long transit time
sigmoid colon highly distensible for collection of feces

78
Q

what is segmented motility

A

similar to mixing patter of SI but less dynamic and slower moving
circular and longitudinal muscle contractions; net movement is aboral

79
Q

what are haustra

A

unstimulated areas of the small intestine, disappear and reappear with contractions and reform at other loci

80
Q

what are power propulsions

A

mass movement 1-3x/day

movement along large segment of colon occurs in transverse to sigmoid colon or rectum

81
Q

what triggers power propulsinos

A

arrival of large volume of chyme into cecum and transverse colon, also in response to gastrocolic reflex, response to stretch in stomach or digestion products in small intestine

82
Q

what happens to haustra in power propulsions

A

they disappear

83
Q

describe the internal anal spincter

A

smooth muscle that is tonically contracted, principle responsible for maintaining continence during the resting state

84
Q

why is the rectum so compliant

A

bc it needs to distend when theres a bunch of stool that you cant evacuate yet

85
Q

what happens when the rectum becomes distended

A

triggers rectoanal reflex which results in relaxation of the internal anal sphincter so that sampling of contents can be made

86
Q

what other than the sphincter helps contribute to the closure of the anus

A

mucosal folds and anal endovascular cushions

87
Q

describe the external spincter

A

skeletal muscle

contracts during voluntary squeeze and is responsible for maintaining continence when feces enter the rectum

88
Q

filling of the rectum with stool causes what

A

initial decrease in internal sphincter tone, which is counterbalanced by a reflex contraction of external anal sphincter

89
Q

describe the holding phase of defecation

A

rectal distension
sensory perception of stool
contracted puborectalis
contracted external anal sphincter

90
Q

describe the neuronal pathways for defecation reflex and fecal continence

A

when the rectum is distended neural pathways from chemo and mechanoreceptors send inhibitory motor signal to internal sphincter
mechano/chemo receptors in anal canal determine consitency of contents

91
Q

what does the conscious cortex do in the context of fecal continence

A

makes appropriate decision to control external anal and puborectalis muscles

92
Q

when does the puborectalis contract and relax

A

contracts to maintain continence, causesa nd acute rectoanal angle which helps maintain continence
relaxes to allow for defecation - allows widening of the rectoanal angle for defecation

93
Q

describe the muscular actions for defecation

A

relaxation of external anal sphincter and puborectalis muscle
contraction of abdominal muslces and diaphragm
power propulsions in sigmoid colon and rectum

94
Q

which muscles in the actions for defecation are under voluntary control

A

external anal sphincter and puborectalis

95
Q

what is intestinal obstruction

A

partial or complete blockage of the bowel resulting in failure of contents to move through intestine

96
Q

what causes intestinal obstruction

A

mechanical

bowel doesnt work correctly (ileus)

97
Q

causes of mechanical intestinal obstruction

A 
abnormal tissue grwoth
adhesions or scar tissue
foreign bodies
gallstones
hernias
impacted feces
itussusception
volvulus
98
Q

what is a pseudo obstruction

A

impairment to intestinal motility resembles mechanical obstruction but no blockage is present
underlying symptoms due to nerve, muslce, ICC issues

99
Q

chronic pseudo obstruction causes

A

neuropathic - DM, dysautonomia, CNS, panneoplastic, chagas

myopathic - scleroderman, amyloid, polymysitis

100
Q

secondary pseudo obstruction

A

chemical, electrolyte, mineral disturbances
complications of intra abdominal surgery
decreased blood supply
injury, infection, kidney disease

101
Q

what is bloat

A

sensation is common in women
most often due to abdominal distension (not increased gas)
associated with diminished propulsion of small and large bowel
if gas the cause then due to incomplete digestion and absorption of carbs in SI and bacteria in colon

102
Q

what is dyssynergic defecation

A

prolonged colonic transit time, discoordination of abdominal rectoanal and pelvic floor muscles, rectal hyposensitivity paradoxical increase in sphincter pressure, inadequate propulsion forces

103
Q

what does dyssynergic defecation resultin

A

chronic constipation due to pelvic floor dysfunction i.e. muscles and nerves are not functioning properly

104
Q

what is fecal incontinence

A

involuntary passage of fecal material

105
Q

causes of fecal incontincence

A 
weakness of anal sphincter
loss of sensation of rectal fullness
constipation
stiff rectum due to scarring
diarrhea
106
Q

Dx of hirschsprungs disease

A

newborns fail to have their first bowel movement within 48 hrs of birth
rectal biopsy; absense of ganglion cells in submucosal and myenteric plexuses
failure of normal peristalsis and relaxation of internal anal sphincter

107
Q

what is hirschprungs disease

A

loss of intrinsic nerves to sort segment HD (80% aganglionosis in rectosigmoid)
or long segment HD (15-20% up to splenic fixture and beyond)
neural crest cells stop growing along intestine towards anus

108
Q

genetic contribution to hirshsprungs disease

A

a chromosome abnormality present in 12%

most common down syndrome

109
Q

most common gene associated with HD

A

RET - proto oncogene, tyrosine kinase receptor

110
Q

what does RET stimulate

A

survival, proliferation, migration, differentiation of neural crest cells

111
Q

cephalic phase of digestion

A

stimuli include sight, taste, sound, or thought of food which are processed by brain

112
Q

describe the gastric phase of digestion

A

stomach is notified by brain that it should prepare for arrival of food. Stomach leaves interdigestiive phase and starts a low level of motor and secretory activity. 30% before food arrives

113
Q

what mediates the gastric phase

A

vagus to the DMN of vagus in the medulla, PARA efferents target direct and indirect pathways

114
Q

what does the pancreas do

A

ACh from vagus stimulates pancreatic secretions

short lived dissipates rapidly

115
Q

what does the gall baldder do

A

contracts (vagal efferents ACh)

Sphincter of Oddi (vagal efferents act on intrinsic neurons that release NO and VIP)

116
Q

describe the esophageal phase

A

mechanical stimulation of pharynx and esophagus initiates reflex pathways via the brainstem or intrinsic pathways via the ENS
peristalsis
relaxation of UES
relaxation of proximal stomahc transfer of bolus
protection of distal esophageal mucosa

117
Q

what is the vasovagal gastropancreatic reflex

A

detects presence of food in stomach and stimulates secretions from pancreas

118
Q

how does the sphincter of Oddi relax

A

vagal efferents act on intrinsic neurons that release NO and VIP

119
Q

what are enterogastrones

A

hormones that inhibit stomach processes like aid secretion released when intestinal duodenal phase starts

120
Q

describe the role of I cells in duodenal phase

A

factors like lipids stimulate I cells to release CCK which activates vagus resulting in stimulation pancreatic acinar cell production of enzymes

121
Q

what do S cells do in duodenal phase

A

lipids and other factors also stimulate release of secretin from S cells which increases bicarb and water secretion by ducts of pancreas and gallbladder
gastric acid better at stimulating HCO3- production than enzymes

122
Q

what is the major site for digestion and absorption of nutrients in small intestine

A

jejunum

123
Q

what is peptide YY

A

released by ileum to inhibit gastric functions

GIR Test 1 (15 decks)

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