Brainscape's Knowledge GenomeTM

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


See full index

Upper GI > Physiology > Flashcards

Physiology Flashcards

1
Q

Layers of GI wall?

A
  1. Mucosa (lamina propia, muscularis mucosa)
  2. Submucosa (Meissners plexus)
  3. Muscularis externa (inner circular, outer longitudinal)
    - Auerbacks plexus (myenteric)
  4. Serosa/Adventitia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Why do SM fibers of GI tract contract in rhythmic cycles?

A

syncytium of gap junctions

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

Slow waves?

A

not action potentials

-cyclic opening of calcium channels that increases probability of AP as it gets closer to threshold

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

Spike potentials?

A
  • true action potentials

- large influx of calcium

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

Factors that depolarize smooth muscle?

A
  1. stretching
  2. ACh from parasympathetics
  3. hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Factors that hyper polarize smooth muscle?

A
  1. NE/EPI

2. sympathetics

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

Role of myenteric plexus (auerbachs)?

A

motility

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

Role of submucosal plexus (meissners)?

A

secretion and blood flow

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

Vasodilators released from GI mucosa?

A
  • CCK
  • VIP
  • Gastrin
  • Secretin
  • Kinins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sympathetic effect on blood flow?

A

vasoconstrictor to decrease blood flow

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

Jaw muscles innervated by?

A

Trigeminal III branch

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

Salivary gland secretion?

A
  1. Amylase (serous)

2. Mucin (not parotid)

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

Composition of saliva relative to plasma?

A
  • hypotonic

- high bicarbonate

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

Innervation to salivary glands?

A

Parasympathetic

  • Glossopharyngeal to parotid
  • Facial (chorda tympani) to submand/sublingual
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

T/F

Sympathetic stimulation increases salivation.

A

True

-but less than parasympathetic

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

How does salivation dilate blood vessels?

A

Kallikrein splits alpha2 globulin to form bradykinin

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

Swallowing reflex?

A
  1. Sensory from vagus and glossopharyngeal to medulla
  2. medulla sends motor to striated muscle to voluntarily swallow
  3. then involuntary reflex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What regulates entrance of food into stomach?

A

LES

  • normally tonically constricted
  • relaxes as peristaltic wave passes down esophagus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Vomiting reflex?

A
  1. vagus and sympathetic afferent to brainstem
  2. motor through spinal nerves to diaphragm and abdominals
  3. strong duodenum and stomach contractions
  4. LES relaxation
  5. deep breath and raise hyoid bone
  6. close glottis
  7. lift soft palate
  8. downward contraction of diaphragm builds pressure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does the stomach empty?

A

intense antral peristaltic contractions

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

Factors that promote gastric emptying?

A
  • food volume
  • stomach stretch
  • Gastrin
  • Ghrelin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Factors that inhibit gastric emptying?

A
  • duodenum distention
  • duodenal irritation
  • acidity
  • osmolarity
  • proteins and fats
  • CCK
  • GIP
  • Secretin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

CCK?

A
  • most potent block on stomach motility (pyloric constriction)
  • pancreatic enzyme secretion from acinar cells
  • GB contraction
  • relaxes sphincter of oddi
  • secreted by I cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Role of mucous secreting cells in stomach?

A
  • mucous

- alkaline environment

25
Q

Cells of tubular gastric glands (oxyntic) and function?

A
  1. mucous neck secrete mucous
  2. chief cells secrete pepsinogen
  3. parietal cells secrete HCl and Intrinsic factor
26
Q

Cells of pyloric glands and functions?

A
  1. mucous cells
  2. G cells secrete Gastrin
  3. D cells secrete somatostatin
27
Q

Pepsinogen function?

A

activated by HCl to degrade proteins into peptides

28
Q

Intrinsic factor function?

A

absorption of Vitamins B12 which helps stimulate bone marrow

29
Q

Role of acetylcholine in stomach?

A
  1. pepsinogen secretion
  2. HCl secretion
  3. mucous
30
Q

Role of Gastrin?

A
  1. Stimulates ECL to release histamine
  2. H binds H2 on parietal cells
  3. increases cAMP
  4. stimulates H/K ATPase and secretes HCl
  5. bicarbonate secreted into plasma
    - Gastrin also directly stimulates parietal cells at CCKb receptor
31
Q

Role of somatostatin in stomach?

A

responds to acid to inhibit parietal cells, G cells, and ECL cells

32
Q

What determines amount of HCl secreted?

A

amount of histamine from ECL

-gastrin and ACh (M3) plays smaller role

33
Q

Phases of gastric secretion?

A
  1. Cephalic
    - dorsal motor nuclei of vagus by sight, smell
    - 30% of secretion
  2. Gastrin
    - 60% of secretion
  3. Intestinal
    - presence of food in duodenum
    - 10%
    - secretion is then inhibited by reverse enterogastric reflex
34
Q

Secretin function?

A
  • inhibits parietal cells
  • bicarbonate
  • adds Na/bicarb to bile
  • secreted by S cells, activated at low pH
35
Q

GIP?

A
  • increase insulin

- inhibit gastric secretion (also VIP and somatostatin)

36
Q

Brunners glands?

A
  • located in duodenum
  • stimulated by secretin
  • release bicarbonate
37
Q

Crypts of lieberkuhn cells?

A
  1. goblet cells
    - mucous
  2. enterocytes
    - water and electrolytes
38
Q

Paneth cells functions?

A
  1. lysozyme

2. defensins

39
Q

Active secretions of small intestines?

A
  1. chloride
  2. bicarbonate

Others:

  • peptidases
  • lactases and other ases
  • lipase
40
Q

Substances absorbed by stomach?

A
  • OH
  • Aspirin
  • highly lipid soluble
41
Q

How does SI absorb water?

A

osmosis through paracellular and transcellular

  • enhanced by aldosterone
  • reverse if hyper osmotic chyme
42
Q

Transport of Na and glucose?

A
  1. Na actively transported into ISF from basolateral Na/K ATPase
  2. creates a gradient for Na to transport from lumen as secondary active
  3. Na/glucose cotransport
  4. Na/AA cotransport
  5. Na/H exchanger
43
Q

Where is bicarbonate reabsorbed? secreted?

A
  • actively reabsorbed in duodenum and jejunum

- secreted in ileum and colon to neutralize bacterial acid

44
Q

Reabsorption of calcium?

A
  • actively reabsorbed from duodenum
  • enhanced by Vit D which is activated by PTH
  • calbindin enhances
45
Q

Absorption of fatty acids?

A

directly into portal blood

46
Q

What mixes chyme with digestive juices in SI?

A

segmentation contractions propelling it

-gastroileal reflex

47
Q

How long to get from pylorus to ileocecal valve?

A

3-5 hours

48
Q

Hormonal increase in intestinal motility?

A
  • Gastrin
  • CCK
  • Insulin
  • Motilin
  • Serotonin
49
Q

Hormonal inhibition of intestinal motility?

A
  • Secretin

- Glucagon

50
Q

What sweeps inside of intestines clean between meals?

A

Migrating motility complex regulated by Motilin

-inhibited by feeding

51
Q

Function of ileocecal sphincter?

A

prevents contamination of SI by bacteria

52
Q

Function of acinar cells of pancreas?

A

secrete digestive enzymes

53
Q

Function of duct cells of pancreas?

A

secrete Na, Bicarb, H2O

  • protects duodenum
  • higher pH needed to activate enzymes
54
Q

Activation of Trypsin?

A
  1. secreted as zymogen
  2. cleaved by enteropeptidase
  3. Trypsin activates other enzymes
    - trypsin inhibitor made in acini
55
Q

Phases of pancreatic secretion of bicarb?

A
  1. Cephalic (ACh-20%)
  2. Gastric (5-10%)
  3. Intestinal (secretin)
56
Q

What forms bile?

A

Liver (600-1000 mL/day)

57
Q

Precursor to bile salts?

A

Cholesterol

-7a-hydroxylase

58
Q

Where does 95% of bile salts come from?

A

reabsorbed by enterohepatic circulation

59
Q

Cause of cholesterol gallstones?

A

bile salts combine with cholesterol to form micelles

  • obesity
  • estrogen
  • too thin
  • female

Upper GI (5 decks)

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