Brainscape's Knowledge GenomeTM

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


See full index

Physiology > GI - Small Intestine > Flashcards

GI - Small Intestine Flashcards

1
Q

SI section length/time

A

2 - 4 hrs in total, 3/4 length GI

duodenum: 8 inches
jejunum: 8 ft
ileum: 12 ft

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

ways to increase SA in SI

A

circular folds (x3)
villi (x10)
microvilli (x20)
total = 250 sq m

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

crypts of lieberkuhn fxns

A

secrete water and electrolytes

nurseries - high mitotic activity makes cells that migrate up to replace old villi cells (100 million shed/min)

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

cells migrating from crypts to villi

A

[ ] of brush border enzymes goes up and absorptive capacity goes up as they get higher

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

segmentation description

A

circular contractions @ alternate sites

main mvmt in SI

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

segmental contraction rates by area

A

duodenum: 12/min
jejunum: 10 - 11/min
ileum: 8 - 9/min

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

peristalsis location

A

occur for only short length of intestine

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

types of SI motility

A

segmentation*
peristalsis
migrating motor complex

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

ileocecal juncture structure

A

valve-like folds of ileum protrude into cecum

SM of last few cm is thickened

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

ileocecal juncture regulation

A

neural and hormonal

ex: gastroileal reflex - gastrin stim extrinsic nerves relax sphincter

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

ileocecal juncture fxn

A

prevent contamination of SI by LI bacteria

makes for one way transit

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

places food can be digested

A

in GI secretions
on luminal surface of GI
inside epithelial cells

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

CHO digestion (main)

A

duodenum + jejunum

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

kinds of CHO we eat

A

amylopectin**
amylose*
cellulose
animal glycogen

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

amylopectin

A

plant starch
major source of CHO in most humans
glucose polymer
alpha-1,4 glycosidic bonds w. branch points at alpha-1,6

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

salivary amylase actions

A

catalyze the hydrolysis of internal alpha-1,4 bonds

not terminal alpha-1,4 or alpha-1,6

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

main products of starch digestion

A

maltose, maltotriose, branched oligosaccharides (alpha-dextrins?)

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

actions of maltase

A

cleaves terminal alpha-1,4 bonds

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

starch digestion

A

starch + salivary amylase –>
partially converted starch + pancreatic amylase –>
maltose, maltotriose, alpha-dextrins + maltase, maltase, isomaltase (brush border) –> GLUCOSE (in lumen)

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

how to absorb monosaccharides

A 
Into epi from lumen:
glucose: use SGLT1 w/ Na
galactose: use SGLT1 w/ Na
fructose: use GLUT5
out of epi into cap:
all use GLUT2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

lactose intolerance

A

low levels of lactase
lactose isnt broken down
lactose is osmotically active
brings water into lumen –> diarrhea

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

protein digestion location

A

stomach

upper GI

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

is all CHO absorbed in SI?

A

5 - 15% CHO goes to colon

CHO metabolized by bacteria to make SCFA (important fuel for colon epi cells)

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

protein digestion in stomach

A

max 15% protein digested by pepsin in stomach

not totally necessary

25
Q

intestinal protein digestion

A

proteins + pancreatic –> oligopeptides + brush border peptidases –> AAs, dipeptides, tripeptides

26
Q

pancreatic enzymes that digest protein

A

trypsin
chymotrypsin
carboxypeptidase (A/B)
elastase

27
Q

brush border peptidases

A

amino-oligopeptidase
amino peptidase
dipeptidyl aminopeptidase

28
Q

absorption of small peptides

A

single membrane transporter
high affinity for di and tri peptides
low affinity for larger peptides

29
Q

absorption of AAs

A

7 diff AA transporters

some Na dependent, some independent

30
Q

main locations of lipid digestion

A

duodenum

jejunum

31
Q

digestion of fats

A

dietary fat + bile salts –> lipid emulsification + pancreatic lipase –> monoglyceride, FAs + bile salts –> micelles

32
Q

where are bile salts reabsorbed

A

terminal ileum

33
Q

absorption of fat

A

micelles absorbed passively

34
Q

processing recycled bile salts

A

hepatocytes extract bile salts
unconjugated bile salts reconjugated in hepatocytes
secondary bile salts rehydroxylated

35
Q

water in and out of GI system

A

GI absorb ~ 9 L /day
2 L water ingested
7 L GI secretions
only 100 ml of water in feces

36
Q

chyme tonicity

A

hypertonic in stomach

isotonic in duodenum

37
Q

Na absorption

A

*cotransport w/ glucose and AAs (D/J)

cotransport w/ bile salts (I)

38
Q

NaCl secreting cell actions

A

Cl into lumen via CFTR (when open)
Na into lumen paracellularly
need Na in lumen for Na-nutrient reabsorption
(Na/K/Cl into cell from blood by cotransporter)

39
Q

NaCl secreting cells and pathogens

A

cholera ups cAMP
opens CFTR
much Cl out
much water follows

40
Q

oral rehydration therapy

A

give glucose and Na
actively pumped in together
changes dire`ction of Na mvmt

41
Q

cholera and CF

A

CF patients dont get diarrhea from cholera – abnormal CFTR

carriers do – sufficiently normal

42
Q

Ca absorption locations

A

all portions of intestines

esp. duodenum and jejunum

43
Q

things that make you Ca deficient

A

Ca deficient diet
growth
pregnancy
lactation

44
Q

Ca absorption based on Ca need

A

need for Ca up
up synth of vit D precursor
up Ca absorption

45
Q

how vit D changes Ca absorption

A
  1. rapid open Ca channels
  2. increase calbindin synthesis (maintain Ca gradient so Ca can come in)
  3. increase # of Ca ATPase (gradient)
46
Q

excessive iron

A

toxic (mammals don’t have excretion path)

47
Q

iron absorption location (+cell)

A

proximal duodenum

enterocytes

48
Q

iron adsorption and pH

A

need acidic environment

antacids/gastric acid secretion issues interfere w/ Fe absorption

49
Q

iron absorption in enterocyte

A

leave enterocyte via ferroportin transporter

bind to ferritin and get sloughed off

50
Q

how metals get into enterocytes

A

divalent metal transporter-1 (DMT-1)

zinc, lead, copper

51
Q

iron absorption when iron stores full in liver

A 
liver secretes hepcidin
hepcidin binds to ferroportin
ferroportin degraded
all iron bind to ferritin instead
limit iron intake
52
Q

absorption in duodenum

A

CHO, PRT, FAT (high)
Ca, Fe, folate (moderate)
bile acids (very low)

53
Q

absorption in jejnunum

A

CHO, PRT, FAT (moderate)

Ca, bile acids (low)

54
Q

absorption in the ileum

A

CHO, PRT, FAT, Ca (low)
cobalamin (B12) (moderate)
bile acids (high)

55
Q

results of intestinal inflammation

A

increase motility
move too fast for proper absorption
diarrhea, dehydration and pH imbalance

56
Q

order of hormones during a meal

A

gastrin
secretin/CCK
motilin

57
Q

colon fxns

A

absorption: Na, SCFAs, water
secretion: K, mucus

58
Q

colon motility

A

mix: haustrations - like segmentation but less frequent
propulsion: mass mvmts - propel distances, gastrocolic reflex

Physiology (22 decks)

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