Green - Stomach Flashcards Preview

S&F 4 test 1 > Green - Stomach > Flashcards

Flashcards in Green - Stomach Deck (81)
Loading flashcards...
1
Q

Distal region of stomach that contracts to mix food and propel it into duodenum

A

Caudad stomach

2
Q

Semifluid mass of partially digested food passed from the stomach to small intestine

A

Chyme

3
Q

Impaired/delayed gastric emptying

A

Gastroparesis

4
Q

Protein produced by the parietal cell that is required for the absorption of vitamin B12

A

Intrinsic factor

5
Q

Peristaltic contractions that occur in the stomach every 90 minutes during fasting; mediated by motilin

A

Migrating myoelectric complex

6
Q

Proximal region of stomach that receives ingested meal

A

Orad stomach

7
Q

Stomach cell that produces acid and intrinsic factor

A

Parietal cell

8
Q

What does the parietal cell produce ?

A

Acid

Intrinsic factor (B12 absorption)

9
Q

Disorder caused by lack of intrinsic factor, patient has decreased RBC”s due to lack of vitamin B12

A

Pernicious anemia

10
Q

Relaxation of the proximal stomach when food enters it

A

Receptive relaxation

11
Q

Closure of the pyloric sphincter that forces food back into the stomach

A

Retropulsion

12
Q

Receptive relaxation is mediated by _____ which is initiated by distention of the stomach and abolished by vagotomy

A

Vagovagal reflex

13
Q

________ causes the distal stomach to increase contractions, which mixes food w/ gastric secretions and reduces size of particles

A

Presence of food

14
Q

Peristaltic contractions of the stomach begin in the _______ and proceed distally . As they move distally towards pylorus, both velocity and force of contractions increase

A

Midstomach

15
Q

This part of the stomach is responsible for the regulation of intragastric pressure

A

Fundus

16
Q

Hunger pangs start _____ hours after last meal and continue for 3-4 days before subsiding

A

12-24 hours

17
Q

When does gastric emptying occur ?

A

When chyme is decomposed into small enough pieces to fit thru pyloric sphincter

(Following normal mixed meal this may take about 3 hours )

18
Q

What is the order of gastric emptying for protein-rich food
Fat-rich food
Carbohydrate rich food

A

Carbohydrate rich food leaves faster than protein rich food which leaves faster than fat rich food

(Will feel full longer on fat rich diet)

19
Q

The rate of gastric emptying is _______ to the pressure in the proximal stomach ?

A

Inversely proportional

20
Q

The rate of gastric emptying is controlled Mostly by >

A

Signals from the duodenum

21
Q

What are some things that can inhibit gastric emptying ?

A

High [H+] concentration, high protein or fats, non-isotonic solutions

Increased distention of proximal stomach

Increased pressure of the proximal small intestine

22
Q

Impaired/delayed emptying

S/s: fullness, loss of appetite, nausea, vomiting

most common cause DM but can be 2ndry to meds that slow contractions in intestine (anticholinergics), neuro disorders

A

Gastroparesis

23
Q

Why can increased gastric emptying cause diarrhea?

A

Because there is an increased osmotic load in the small intestine

24
Q

What can increased gastric emptying cause?

A

Diarrhea - increased osmotic load in small intestine

Duodenal ulcers - stomach acids reach the duodenum bc they aren’t equalized in stomach and cause ulcers

25
Q

Explain dumping syndrome

A

Lower end of small intestine fills to quickly w/ undigested food from stomach

Common after stomach sx

Early phase (during or right after meal); nausea, vomiting, diarrhea

Late phase (1-3 hours after meal)- sweating, weakness, dizziness

Symptoms are due to too much fluid in intestine and hypoglycemia

26
Q

What are the two regions of the stomach in regards to secretory function ?

A

Oxyntic gland mucosa

Pyloric gland mucosa

27
Q

Functional secretory area of the stomach

Secretes mostly gastrin
Secretes some pepsinogen and mucous

A

Pyloric gland mucosa

28
Q

Functional secretory area of the stomach.

Secretes pepsinogen, acid, intrinsic factor, and mucous

A

Oxyntic gland mucosa

29
Q

Parietal cells secrete

A

Acid and intrinsic factor

30
Q

Chief cells secrete ?

A

Pepsinogen

31
Q

Stem cells of the oxyntic gland are located in the mucous neck (some of these also secrete mucous) and can proliferate and differentiate into: (x4)

A

Mucous cells - mucous

Parietal cells - acid and intrinsic factor

Chief cells - pepsinogen

Endocrine cells - regulatory products

32
Q

What are the four components of the gastric juice with physiological function ?

A

HCl

Mucous

Intrinsic factor

Pepsin

33
Q

Begins digestion of dietary proteins

Converts pepsinogen to pepsin (for further protein degredation)

Kills most bacteria that enter stomach

Secreted from parietal cells

A

HCl

34
Q

Activated by gastric acid and itself

Begins digestion of proteins by breaking internal peptide bonds in the proteins

Vagal stimulation causes the greatest increase in secretion

A

Pepsin

Stored and secreted as pepsinogen

35
Q

______ stimulation causes the greatest increase in the secretion of pepsinogen

A

Vagal

36
Q

Secreted by stomach

Serves as a protective coating for stomach and lubricant and barrier between cells and ingested material

A

Mucus

37
Q

Is soluble mucous present in resting stomach?

A

No

38
Q

What type of stomach mucous is secreted by mucous neck cells ?

A

Soluble form

39
Q

What type of stomach mucous is secreted by surface mucous cells

A

Insoluble/visible form

40
Q

Is insoluble mucous secreted in the resting stomach ?

A

Yes.

In response to chemical or physical irritation

41
Q

Receptive relaxation is controlled by _______ signaling

A

Vagovagal

42
Q

Parietal cells secrete ____ into lumen of stomach and _______ into the bloodstream

A

HCL

HCO3-

43
Q

At low basal rates, gastric juice is primarily _____ from nonparietal secretion

A

NaCl

44
Q

At high stimulated gastric rates, gastric juice is primarily _______ from parietal secretion

A

HCl

45
Q

[K] in gastric juice are always _______ than in plasma

A

Higher

46
Q

The blood near the stomach having high pH due to the high activity of the Cl - HCO3- pumps is called

A

The alkaline tide

47
Q

During production of. Acid, H+ enters the lumen in exchange for which ion?

A

K+

48
Q

Acid secretion initiated by though, sight, taste, or smell of food

A

Cephalic phase

49
Q

Region in the fourth ventricle of the brain that initiates vomiting

A

Chemoreceptor trigger zone

50
Q

Substance that causes vomiting

A

Emetic

51
Q

Acid secretion initiated by entry of food into the stomach

A

Gastric phase

52
Q

Acid secretion initiated by the presence of protein digestion products in the duodenum

A

Intestinal phase

53
Q

Release of acid by the parietal cell after initiation by multiple stimulants;

The amount is greater than the sum of release by each individual stimulant

A

Potentiation

54
Q

What are stimulants of acid secretion?

A

ACh

Histamine

Gastrin

Ca and cAMP (by increasing concentration of H, K atpases and Cl channels)

55
Q

How does Acetylcholine (ACh) cause stimulation of acid secretion ?

A

Acetylcholine binds to muscarinic receptors on the membrane of parietal cells; this activates phospholipase C which catalyzes the formation of IP3 which releases Ca++. Ca++ causes secretion of H+ by. Increasing concentration of H/K atpases and Cl- channels

56
Q

How do Ca and cAMP cause stimulation of H+ secretion ?

A

By increased the concentration of H-K atpases and Cl- channels in the apical membrane

57
Q

How does histamine cause stimulation of H+ secretion ?

A

Histamine binds to H2 receptors on the parietal cell membrane. H2 then activates adenylate cyclase to form cAMP

58
Q

How does gastrin cause an increase of H+ secretion in parietal cells?

A

Gastrin binds to gastrin/CCK-B receptors in the parietal cell membrane. This causes the activation of phospholipase C which then catalyzes the formation of IP3

IP3 then causes the release of Ca++ ions

59
Q

________ potentiates the actions of gastrin and ACh

A

Histamine

60
Q

_______ potentiates the actions of histamine and gastrin

A

ACh

61
Q

_______ stimulates the release and synthesis of histamine and the proliferation of enterochromaffin-like cells

A

Gastrin

62
Q

______ stimulates the release and synthesis of histamine but not as much as gastrin

A

ACh

63
Q

ECL cells has receptors for ____- and _____

A

Gastrin and acetylcholine

64
Q

Explain how acid production and stomach pH cycles in relation to meals

A

At baseline, stomach acidic. You eat food, pH rises, causing release of gastric acid. Food is digested and leaves the stomach. Then pH drops in stomach. When it drops to below 3.0 gastrin release is inhibitted by the release of somatostatin which inhibits acid secretion by parietal cells and gastrin secretion by G cells. Maintaining baseline pH

65
Q

What are inhibitors of acid secretion ?

A

Chyme in duodenum

Low pH in stomach

66
Q

How does chyme in the duodenum affect acid secretion in the stomach ?

A

Chyme in the duodenum inhibits acid secretion in the stomach by both hormonal and neural methods. There are responses to acidity, osmolarity, and fat content in the chyme that trigger these responses. The responses mechanism is to inhibit gastrin release by G cells and/or acid secretion by the parietal cells

67
Q

When are the basal rates of acid secretion the highest ?

A

The evening

68
Q

What are 2 ways in which the vagus nerve stimulates acid secretion in the cephalic phase of acid secretion ?

A

ACh directly acts on muscarinic receptors of parietal cells

ACh causes release of GRP

69
Q

________ is the only major nutrient that stimulates gastric secretion. And works by causing direct chemical release of gastrin from G cells

A

Proteins (must be broken down to peptides and amino acids)

70
Q

Caffeine causes a ______ in acid secretion by the stomach

A

Increase

71
Q

What are stimulants of acid production in the gastric phase?

A

Stomach distention

PH increased

Proteins

72
Q

Caused when protective barrier of stomach breaks down, leading to injury of gastric mucosa by acid and pepsin.

Most commonly in distal stomach

H+ secretion into stomach reduced because some acid leaks into gastric mucosa

A

Gastric ulcers

73
Q

3 major causes of peptic ulcers

A

Infections (helicobacter pylori)

NSAID’s

Alcohol

74
Q

How does helicobacter pylori contribute to peptic ulcers ?

A

In stomach, breaks down gastric epithelial barrier

In duodenum, inhibits secretion of somatostatin, allowing increased gastrin release and acid produciton

75
Q

What are treatments for peptic ulcer disease

A

Antibiotics

Proton pump inhibitor (blocks H-K-ATPase)

76
Q

What leads to increased salivation, sweating, rapid breathing, and irregular heartbeat that occurs before and during emesis

A

General discharge of the autonomic nervous system

77
Q

The vomiting center is located in the ?

A

Medulla

78
Q

What are some afferent stimulations that can cause vomiting (from the vomiting center in the medulla)

A

Sight/smells

Intense pain

Motion sickness

Tickling back of throat (pulling the trigger)

Distention of the stomach/duodenu

79
Q

Direct activation of the vomiting center causes what ?

A

Vomiting w/o nausea or retching

80
Q

What are 3 places of vomiting control

A

Medulla (vomiting center)

Chemoreceptor trigger zone (area postrema)

Receptors present in stomach and duodenum

81
Q

What are the effects of prolonged vomiting ?

A

Metabolic alkalosis

Hypokalemia (loss of K and decreased reuptake)

Hyponatremia (lost Na in vomit)

Dehydration