Brainscape's Knowledge GenomeTM

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


See full index

D1 Spring - Physiology Exam 6 > 4/29: Small Intestine and Colon: Motility, Digestion, Absorption > Flashcards

4/29: Small Intestine and Colon: Motility, Digestion, Absorption Flashcards

1
Q

What does the duodenum secrete?

A

CCK
Secretin
Gip, HCO3

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

What does the ileum secrete?

A

PYY
HCO3-

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

Rank the duodenum, jejunum, and ileum from high to low in function of intraluminal and surface digestion?

A

Duodenum > jejunum > Ileum

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

What does the duodenum absorb?

A

Fe

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

What does the ileum absorb?

A

Bile acids
Vitamin B12

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

What is the motility of the duodenum?

A

MMC
Segmentation
Peristalsis

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

What complex controls the fasting pattern of the small intestine?

A

Migrating motility complex

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

What hormone stimulates the fasting pattern of the small intestine?

A

Motilin

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

What does the fasting pattern do?

A

Sweep intestines of undigested material

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

How often does fasting pattern occur?

A

One every 90 min

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

Describe the waves of the feeding pattern?

A

BER Slow waves in small intestine

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

What cells control the feeding pattern of the small intestine?

A

Interstitial Cells of Cajal

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

What stimulates the feeding pattern?

A
  • Distention of duodenum
  • Nutrient content of chyme
  • Gastroenteric Reflex – short feedback loop from stomach to small intestine
  • Hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How often does feeding pattern occur?

A

3-12 waves/min

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

What is the primary control of the feeding pattern?

A

ENS

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

What is the small intestine stimulated by?

A

CCK
Gastrin
Insulin
Serotonin

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

What is the small intestine inhibited by?

A

Secretin
Glucagon

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

What are the two feeding patterns of the small intestine?

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

What is the mixing pattern of motility?

A
  • chyme with digestive enzymes
  • emulsifies fats
  • adjusts pH
  • exposes mucosa to chyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the function of peristalsis?

A
  • Propel chyme through small intestine at a velocity of 1 cm/min.
  • Spread chyme across mucosal surface as it enters from
    stomach
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where can peristalsis begin?

A

Anywhere in the small intestine
Normally weak and die out after traveling only 3-5cm

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

How long does peristalsis take?

A

3-5 hours from pyloric valve to ileocecal valve

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

What does duration of feeding pattern depend on?

A
  1. Caloric content of meal
  2. Nutrient composition of
    meal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Rank the duration of proteins, fats, and carbs

A

Fats > proteins > carbs
Ex. 450 kcal nutrient mixed
meal will disrupt MMC for ≈
3 hours

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

Net rate of movement of any
substance across the intestinal
epithelium is influenced by:

A
  • surface area
  • motility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the north-south vector influenced by?

A

Motility -> transit time

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

What is the east-west vector influenced by?

A

Surface area

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

What are substances presented for digestion and/or absorption?

A
  • Macronutrients – carbohydrate, protein, fat (Require “digestion”_
  • Electrolytes – Na+, K+, Ca++, Mg++, Fe++, Cl-, PO4—
  • Water
  • Bile salts
  • Vitamins – fat soluble, water soluble
  • Drugs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What factors influence digestion?

A
  • Motility
  • Large surface area
  • Appropriate pH
  • Hydrolytic enzymes
    (carbohydrates, protein, fat)
  • Emulsifying factors (Fat)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What factors influence absorption?

A
  • Large surface area
  • Specialized cells
  • Specific transport
    mechanisms – carriers,
    pumps, pores
  • Energy
  • Blood or lymph flow
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Where are most substances completely digested and abosrbed?

A

In proximal small intestine
- dietary fat is the (potential) exception

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

What does an increase intake produce?

A

Increase absorption, may produce increase storage and obesity
- diversion of chyme to distal gut is one treatment for obesity

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

What pH do digestive enzymes in the small intestine require?

A

Neutral pH to function

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

Where does the pH come from?

A

H+ from stomach
Bile HCO3-
Pancreatic HCO3-

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

What are the two sites for digestion of protein and carbohydrate?

A
  1. Intraluminal (stage I - pancreatic hydrolases)
  2. Mucosal surface (stage II - brush border hydrolases)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What does intraluminal site yield?

A

di- and tripeptides, amino acids, maltose, maltotriose, α-limit dextrins, glucose;
- Fat digestion completed in lumen

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

What are the end products of the mucosal surface?

A

amino acids and di- and tripeptides, glucose, galactose, fructose

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

What are examples of carbohydrates in the diet?

A

Polysaccharides/disaccharides

38
Q

What do carbohydrates need to be broken down into before being absorbed?

A

building blocks (Glucose,
Fructose, and Galactose)

39
Q

_____________ cannot be digested and is lost in feces

A

Fiber (cellulose)

40
Q

Where does carbohydrate digestion begin?

A

In mouth when exposed to salivary amylase
- not significant
- enzyme activated by acidic gastric juice

41
Q

What are carbohydrates digesting in the small intestine by?

A
  • Starch and Glycogen
    digestion by pancreatic amylase
  • Brush border
    hydrolases produce
    the monosaccharides
42
Q

What does amylase do?

A

Take polysaccharides and break them down to disaccharides

43
Q

How is protein added to the lumen?

A

In form of mucus and enzymes
- disintegration of epithelial cells

44
Q

What must polypeptides be digested into?

A

Small peptides or amino acids

45
Q

What does digestion begin in the stomach by?

A

Pepsin

46
Q

What is pepsin important for?

A

collagen digestion

47
Q

What is pepsin inactivated by?

A

Basic pH in small intestine

48
Q

80-90% digested in small intestine by?

A

Small peptides and amino acids

49
Q

What are small peptides and amino acids produced by?

A

Trypin, chymotrypsin, carboxypolypeptidases, elastase

50
Q

What do brush border peptidases produce?

A

Amino acids

51
Q

Describe peptide transporter 1 (PEPT1)

A
  • Extremely broad substrate availability
  • Pharmacological Significance – Can be used for drug delivery
52
Q

What is the most abundant dietary fat?

A

Triglycerides

53
Q

What do fats have smaller amounts of?

A

Cholesterol, cholesterol esters, and phospholipids

54
Q

Digestion of fat requires emulsification of what?

A

Bile salts
Lecithin (phospholipid)

55
Q

What does agitation of the fat (segmentation) break the fat globule down into?

A

Smaller fragments, increasing area for digestion

56
Q

Where does fat digestion begin?

A

In stomach
- lingual lipase

57
Q

Where does 90% of fat digestion occur?

A

In small intestine by pancreatic lipase (and colipase)

58
Q

Where do digestion products solubilize in?

A

Micelles

59
Q

What do micelles remove?

A

TG digestion products from fat
globules so fat digestion can continue

60
Q

What do micelles transport?

A

TG digestion products to brush border membrane

61
Q

What is digestion of cholesterol esters by?

A

Pancreatic colesterol ester hydrolase

62
Q

What is digestion of phospholipids by?

A

Pancreatic phospholipase A2

63
Q

What are fats packaged into?

A

Micelles with TG digestion products

64
Q

Micelle formation and breakdown are in _________

A

Equilibrium

65
Q

How do FA and MG cross apical membrane via?

A

Simple diffusion

66
Q

What happens to TG in smooth ER?

A

Resynthesized
- keeps [FA] and [MG] low inside cell
- maintains gradient for simple diffusion and absorption
- Fat-soluble vitamins (A, D, E, K),
phospholipids, and cholesterol
esters absorbed by same
mechanism

67
Q

TG and other hydrophobic
substances packaged into ________ and secreted across BL membrane via __________

A

chylomicrons; exocytosis

68
Q

How do chylomicrons enter lymphatic vessels via?

A

Lacteals and are transported to systemic veins and enters circulation

69
Q

What are surface cells?

A

Mature intestinal epithelial cells

70
Q

What do surface cells absorb?

A

Na, Cl, and H2O

71
Q

Where are crypt cells found?

A

Deep in the spaces between the circular folds

72
Q

What are crypt cells?

A

Immature intestinal epithelial cells

73
Q

What are crypt cells produced by?

A

Stem cells

74
Q

Where do crypt cells migrate to?

A

Surface

75
Q

What do crypt cells secrete?

A

Na, Cl, and H2O

76
Q

Where does fluid secreted by crypt cells flow?

A

To surface cells where reabsorbed

77
Q

What do crypt cells provide flowing H2O for?

A

Absorbing intestinal digestates

78
Q

What do crypt cells balance?

A

Absorption and secretion

79
Q

Describe the prandial state of surface cells?

A

Electrogenic
Anions and water follow

80
Q

Describe the post-prandial state of surface cells?

A

Electroneutral
H2O follows

81
Q

Describe the Na, Cl, and H2O secretion of crypt cells

A

Electrogenic
Na and H2O follow

82
Q

What do cholera and E.coli produce?

A

Enterotoxins that increase cAMP

83
Q

What is the function of cAMP?

A

Activates Cl- secretion via CVTR into gut lumen: massive diarrhea

84
Q

_________ do not affect sodiun-glucose cotransport

A

Enterotoxins

85
Q

What does vitamin B12 do in the stomach?

A
  • Binds to the R-binding protein
  • Stabilizes B12 in acidic environment
  • Intrinsic factor secreted by gastric parietal cells cannot interact with B12 at low pH
86
Q

What does vitamin B12 do in the duodenum?

A
  • Proteases digest R-binding protein
  • B12 binds to intrinsic factor (pH
    neutral)
87
Q

What does vitamin B12 do in the ileum?

A

Intrinsic factor binds to IFCR and
taken into cells via receptor-
mediated endocytosis

88
Q

What does vitamin B12 do inside cells?

A
  • Intrinsic factor degraded
  • B12 binds to TCII
  • Complex crosses BL via exocytosis
89
Q

How are Thiamin, riboflavin, niacin, pyridoxine, pantothenate, biotin, and ascorbic acid absorbed?

A
  • cotransport with Na
  • completed in upper small intestine
90
Q

What are other actively absorbed substances?

A
  • Ca++, PO4—
  • Mg++
  • Fe++
  • Bile salt
91
Q

What is maldigestion?

A
  • Pancreatic “insufficiency”
  • Liver disease
  • Biliary obstruction
    Steatorrhea occurs early
92
Q

What is malabsorption?

A
  • Achlorhydria
  • Short bowel
  • Mucosal disease (i.e. Celiac
    Disease – autoimmune destruction of intestinal
    cells)
  • Lactose intolerance
93
Q
A

D1 Spring - Physiology Exam 6 (6 decks)

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