Brainscape's Knowledge GenomeTM

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


See full index

GI exam 1 > Salivary and Gastric Secretory Functions (choudhury) > Flashcards

Salivary and Gastric Secretory Functions (choudhury) Flashcards

1
Q

under what control is saliva?

A

neuronal

hormones just modify

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

what are some functions of saliva

A 
taste
lubrication
protection
digestion
speech
not essential for life
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the composition of parotid salivary gland secretions

A

serous thin saliva

25 percent of saliva

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

what is the compostion of submandibular saliva

A

serous/mucous (thick)

70 percent

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

what is the composition of sublingual saliva

A

serous/mucous

5 %

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

what is the function of water in saliva

A

facilitates speech
dissolving and tasting food
swallowing

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

what is the function of kallikrein in saliva

A

activates bradykinin - dilates arterioles, constricts veins and increases flow to secretory glands

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

what is the function of bicarb in saliva

A

minimizes tooth decay

neutralizes refluxed gastric acid into lower esophagus (heartburn)

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

what tonicity is saliva and why

A

saliva is hypotonic so that food can dissolve into int and we can TASTE

cannot taste proteins

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

what is the function of myoepithelial cells

A

motile, contracts and expels saliva

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

what is the function of ductal cells

A

modifies secretion by modifying electrolytes

Na, Cl- reabsorbed
K and HCO3- are secreted

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

what is the function of striated duct epithelium tight junctions

A

H20 cannot leave duct

making it hypotonic

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

what do acini secrete

A

saliva (H20, Na, Cl, K, HCO3-, amylase)

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

what is the relationship between salivary rate of secretion and composition

A

at low rates of secretion –> saliva is hypotonic (high K+, low Na and Cl-)

at higher rates of secretion –> osmolality increases (High HCO3- conc and high pH = alkaline)

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

what is the major receptor for the sympathetic stimulation of saliva

minor?

A

Beta receptors –> leads to protein secretion

minor is alpha receptors –> leads to fluid secretion

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

which on (para or symp) exerts more control over salivary gland secretion?

A

parasympathetic

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

what receptor does the parasympathetic NS use and what is its effect

A

M3 receptors

fluid secretion

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

what hormones are involved in the hormonal control of saliva secretion

and what are there effects

A

ADH and aldosterone
- decrease Na conc and increase K + conc.

Kallikrein
-produces bradykinin which vasodilates
increases blood flow
increase salivary secretions

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

what is the effect of antidepressents on saliva

A

decreases salviary secretions and can lead to decreased bicarb –> rotting teeth

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

what occurs in drooling

what is the cause and treatment

A

excessive salivation due to increase nervous stimulation

treatment: anticholinergics and surgical removal of sublingual glands

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

what occurs in xerostomia and what are some causes

A

dry mouth due to absence of saliva production

(drugs, radiation treatment, autoimmune disease)

buccal infections/dental caries

Note lacrimal glands are fine

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

what is sjogren’s syndrome

what are the outcome s

A

autoimmune process-targets salivary and lacrimal glands

glandular atrophy and decreased saliva production (xerostomia)

difficulty in chewing, swallowing and speech.
dry oral mucosa, superficial ulceration, poor dentition
(dental caries, fractures, loss of teeth)

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

what is the problem with cystic fibrosis and saliva

A

elevated Na+, Ca2+ and protein in saliva, sweat, pancreatic fluid & bronchial secretion

CF patients lacks CFTR or chloride transporter

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

what is addison’s disease

A

increase Na+ in saliva (↓ Na+ reabsorbed), hypertonic saliva possibly

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

what happens to saliva with primary aldosteronism and cushing’s

A

decrease Na+ in saliva (↑ Na+ reabsorbed), salivary NaCl is zero, increase K+ levels

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

what occurs with digoxin therapy to saliva

A

increase Ca and K in saliva

27
Q

what occurs to saliva with parkinson’s or tumors of mouth/esophagus

A

increased saliva (drooling) production due to unusual local reflexes and increase neurological stimulation

28
Q

what is the composition of stomach secretion

A

isotonic

29
Q

what are the three cell types of the oxyntic glands in the body and fundus region of the setomach

A

The parietal (oxyntic) cells secrete
- HCl (protein breakdown, pepsinogen
activation, kills most microbes)
- intrinsic factor (IF) (necessary for
the absorption of vit. B12 by the ileum)

  1. Peptic (chief, zymogenic) cells secrete
    • Pepsinogen/zymogens- converted to pepsin
    • Chymosin, gastric lipase
  2. Mucous cells (mucus)
30
Q

what are the two cells of the pyloric glands in the pyloric and antrum region of the stomach

A

G cells
- Gastrin (hormone) – stimulates
parietal cells (HCl) & peptic cells
(pepsinogen) *cancer of antrum would mean too many G cells –>

  1. Mucous cells secrete
    - Mucous (thick/thin mucous)
31
Q

how often is the entire stomach mucosa replaced

A

every 3 days

32
Q

what do surface epithelial cells secrete

A

thick viscous alkaline mucous

33
Q

what do mucous neck cells secrete

A

thin water mucus

34
Q

what is the relationship between gastric secretion rate and composition

A

Non-parietal cells responsible for basal (low rate) secretion (between meals)

         - high in Na + and Cl -
         - low in H + and K +

 Parietal cells responsible for  stimulated (high rate) secretion (after a meal)
(stimulated by gastrin & histamine)

        - high in H + and Cl -
        - low in Na + and K +
35
Q

what is the alkaline tide

A

Secretion of H+ into the lumen is balanced by secretion of an equal amount of HCO3- into blood

Increased pH of venous blood leaving stomach following a meal is alkaline & referred to as alkaline tide

36
Q

what are the mechanisms of direct stimulation of parietal cells (3) and what is the result

A

ACh released from vagus nerve binds to M3 receptors

  • Histamine released from ECL cell binds to H2 receptors
  • Gastrin released from G cell binds to CCKB receptors

All three agonists synergistically stimulate and
potentiate acid secretion from parietal cell

37
Q

what are the mechanisms of indirect stimulation of parietal cells (3) and what is the results

A

ACh released from vagus nerve binds to M3
receptors on ECL cell and release histamine
-Gastrin released from G cells binds to CCKB
receptors on ECL cell to release histamine
-Histamine released from ECL cell (by the action of
Ach and gastrin) binds to H2 receptors on parietal cell

38
Q

what is the source of CCK

A

I cells of duodenum and jejunum

neurons in ileum and colon

39
Q

what is the source os secretin

A

s cells in small intestine

40
Q

what is the source of VIP

A

ENS neurons

41
Q

what is the source of GIP

A

K cells in duodenum and jejunum

42
Q

what is the source of neurotensin

A

endocrine cells in ileum

43
Q

what is the source of peptide YY

A

endocrine cells in ileum and colon

44
Q

what is the source of somatostatin

A

D cells of stomach and duodenum

cells of pancreatic islets

45
Q

what happens during the cephalic phase

A
  • conditioned reflexes (thought, smell, taste, hypoglycemia chewing, swallowing, hypoglycemia) send impulses to medulla oblangata which stimulates vagus nerve (parasympathetic): -ACh acts on parietal cells to release acid -ACh acts on ECL cells to release histamine H2 on parietal cells
    • ENS stimulate G cells to release gastrin -Chief cells release pepsinogen -Inhibits D cells, reduce release of somatostatin (somatostatin inhibits gastrin release)
46
Q

what happens during the gastric phase

A

-food distends gastric mucosa (inside the stomach!) -vagus & ENS reflexes activated -increase in acid and pepsinogen secretion –peptides (peptones) & a.a stimulate gastrin release

47
Q

what happens during the intestinal phase

A

peptides in duodenum stimulates gastrin secretion -chyme containing lipids or acid (pH 2) inhibits impulses from medulla oblangata and decrease vagal nerve stimulation, decrease acid secretion -duodenum releases 3 hormones-inhibits acid secretion -Secretin –released when too much acidic food , release a lot of bicarb from pancreas -GIP (gastric inhibitory peptide) -CCK (cholecystokinin)- fatty food comes along, CCK is released, causes lots of release of pancreas juice. CCK effects liver as well

48
Q

what is a vagotomy and what are the side effects

A

Vagotomy (cutting of vagus nerve):

- inhibits gastric acid secretion 
- used to treat peptic ulcers
- side effects: delay in gastric emptying, diarrhea
49
Q

what is a selective vagotomy

A

cutting only vagal nerves supplying parietal cells only

50
Q

what causes Pernicious anemia

A

absence of intrinsic factor
b/c IF is needed for Vitamin B12 absorption
and vit B12 absorption is needed for erythrocyte production

51
Q

what are 4 agents that cause mucosal damage

A

Alcohol

Salicylates (Aspirin)

H.pylori-
breaks down
bicarb layer

Bile acids-
Breaks down lipid bilayer

52
Q

what is the function of mucus secretion by surface cells

what happens if this layer is defected

A

acts as a diffusion barrier for H+ & pepsin
allows stomach to contain acid without injuring itself
-mucus layer traps HCO3- alkaline soln

HCO3- titrates H+ & inactivates pepsin
If H+ penetrates into gastric epithelium:
-it destroys mast cells-histamine released-inflammation
-severe damage-histamine, PAF, LTs, TXs, etc release
-tissue damage-H+ back diffusion

53
Q

what is the mechanism by which ulcer formation occurs?

A

Acid and pepsin break through mucosal barrier
Acid stimulates histamine release
Histamine stimulates parietal cells to release acid
Acid diffuses through broken barrier
Vicious cycle continues

54
Q

how does aspirin cause ulcers

A 
Aspirin (a weak acid) is easily
      absorbed in low pH of the 
      stomach
Once absorbed it acts by acid 
     stimulating histamine release 
     and disruption of local mucosa
Aspirin suppresses protective
     mucosal barrier production
55
Q

what occurs with a pentagastrin test with gastrinoma or zollinger-ellison syndrome

A

with gastrinoma there is already a large increase in gastrin secretion and subsequent gastric acid secretion both at rest and after a meal

so after a pentagstrin test the acid output doesn’t significantly increase because it is already elevated

56
Q

what happens with pernicocious anemia during pentagstrin testing and what are the serum gastrin levels

A

this is an autoimmune condition where antibodies against parietal cells and/or IF are produced

if there are attacks on parietal cells then both gastric acid secretions are low AND IF secretions are low

acid secretions are the stimulus for secretion of somatostatin so if there is no acid to stimulate there will be low/no somatostatin

if there is no somatostatin to inhibit gastrin, there is going to be a high serum gastrin level

however, there is going to be zero gastric acid secretion both before and after pentagastrin

without IF –> no Vitamin B12 absorption and this can lead to neurological disorders

57
Q

what are the lab values like for a duodenal ulcer compared to normal?

A

serum gastrin is elevated but not extremly high

basal acid output is similar (or slightly above) normal acid output before a meal

and acid output after pentagastrin stimulus, the acid out put is similar in values to normal

58
Q

what is atrophic gastritis

A

lack of parietal cells

crhonic inflammation of gastric mucosa due to h.pylori –> decrease in gastric acid

59
Q

what are examples of antacids

A

alka seltzer

Na HCO3 or KHCO3

60
Q

what are the H2 blockers used and what is there mechanism

A

rantidine (zantac)
cimetidine (tagamet)

Histamine potentiates effects of gastrin & ACh on parietal cells via H2 to release acid
Inhibiting H2 will decrease H+ release in the stomach

61
Q

what are the Proton Pump inhibtors

what is the mechanims

what are the long term side effects of PPI usage

A

omeprazole (prilosec) (H pump ATPase inhibitor)

PPIs inhibits proton pump and decreases H+ release, increases gastric pH (alkaline)

Long term side effects of PPIs usage are:
Pneumonia??
Clostridium difficle growth in gut
Osteoporosis

62
Q

what antibiotics are used for h pylori

A

clarithromycin

cymoxicillin (metronidazol)

63
Q

what are the surgical intervention in the stomach

A

vagotomy

antrectomy

64
Q

what is the muscarinic antagonist used in stomach problems and why is this not used often

A

dicyclomine

this is not used because there are many many locations for muscarinic receptors throughout the body and can cause harmful side effects

GI exam 1 (11 decks)

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