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Advanced Patho UC > Exam #4 GI > Flashcards

Exam #4 GI Flashcards

1
Q

saliva composed of…

A

water w/mucus, sodium chloride, bicarb, K+, and salivary amylase (carb digestion) and is controlled by ANS

also contains IgA - prevents orally ingested microorganisms

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2
Q

What fibers stimulate the salivary glands? what meds inhibit?

A

cholinergic parasympathetic fibers stimulate salivation

anticholinergic meds inhibit salivation

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3
Q

stimulation of what decreases salivary secretion

A

sympathetic beta-adrenergic stimulation decreases salivary secretion - none, little, or little with rich protein content

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4
Q

normal pH of saliva

A

pH of 7.4 which neutralizes bacterial acids aiding to prevent infections

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5
Q

prevents air entry into the esophagus during respiration

A

upper esophageal sphincter

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6
Q

also called the cardiac sphincter - prevents acidic content regurgitation from the stomach

A

lower esophageal sphincter

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7
Q

what increases the tone of the lower esophageal sphincter? two things

A

cholinergic vagal stimulation and the digestive hormone gastrin

*Gastrin helps the pancreas produce enzymes for digestion and helps the liver produce bile. It also stimulates the intestines to help move food through the digestive tract.

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8
Q

what decreases the tone/relaxes the lower esophageal sphincter

A

non-adrenergic, non-cholinergic vagal impulse and the hormones progesterone, secretin, and glucagon

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9
Q

sphincters & chyme…

A

lower esophageal (chyme enters from esophagus into the stomach), pyloric (chyme exits stomach into duodenum of small intestines

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10
Q

the stomach can absorb very few substances, but can absorb?

A

alcohol, aspirin, NSAIDS

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11
Q

gastric hydrochloric acid does what? secreted by? converts what to what? stimulated by (what medication comes into play)? inhibited by?

A
  • secreted by parietal cells of the stomach
  • dissolves food fibers
  • acts as bactericidal agent
  • converts pepsinogen to pepsin (breakdown of proteins)
  • stimulated by: acetylcholine via vagus nerve, caffeine, calcium, gastrin (stimulates secretion of gastric acid by parietal cells), histamine
  • inhibited by: prostaglandins (mucus), gastric inhibitory peptide, somatostatin, secretin
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12
Q

two things that protect the mucosal barrier? mucus works to do what?

A

prostaglandins and nitric oxide: protect the mucosal barrier by stimulation of mucous and bicarbonate to inhibit acids

mucus protects against aspirin, NSAIDS, H.pylori, ethanol, regurgitated bile, and ischemia to prevent inflammation and ulceration

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13
Q

Gastric glands: primary secretory units contain what type(s) of cell(s)

A 
parietal cells 
chief cells 
G cells 
Enterochromaffin-like cells
D cells
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14
Q

parietal cells secrete?

A

secrete HCl acid and intrinsic factor, gastroferrin

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15
Q

chief cells secrete?

A

The primary function of gastric chief cells is the synthesis and release of the proenzyme pepsinogen, which subsequently, in an acid environment, is converted to the acid protease pepsin. Pepsin breaks down proteins in the stomach

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16
Q

g cells secrete?

A

gastrin (hormone) - *Gastrin helps the pancreas produce enzymes for digestion and helps the liver produce bile. It also stimulates the intestines to help move food through the digestive tract.

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17
Q

enterochromaffin-like cells produce

A

produce and secrete histamine

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18
Q

D cells

A

somatostatin

Somatostatin produces predominantly neuroendocrine inhibitory effects across multiple systems. It is known to inhibit GI, endocrine, exocrine, pancreatic, and pituitary secretions, as well as modify neurotransmission and memory formation in the CNS

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19
Q

phases of gastric secretion

A

celiac phase
gastric phase
intestinal phase

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20
Q

celiac phase of gastric secretion

where does it begin? what is secreted? mediated by? what is a strong stimulus to gastric secretion?

A

mouth

  • begins with smelling, seeing, tasting, chewing, swallowing
  • mediated by the vagus nerve
  • acid, pepsinogen, gastrin secreted
  • insulin secreted by pancreas to hyperglycemia and is strong stimulus to gastric secretion
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21
Q

gastric phase of gastric secretion

mediated by? blocked by?
2 major stimuli?

A

stomach

-begins with arrival of food to stomach
-2 major stimuli to secretory effect – distension of stomach and presence of digested protein
-vagus nerve stimulated by distension – contributes
to secretion stimulus
-mediated by acetylcholine and can blocked by
atropine

*distension causes PSNS activation of the vagus nerve which continues the signal to secrete HCl and pepsin

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22
Q

_____ levels higher in gastric secretions than in plasma

what is this important to note with?

A

potassium

important in vomiting, suctioning, etc.

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23
Q

______ allows for relaxation of lower esophageal sphincter during swallowing

A

vagus nerve

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24
Q

what two things enhance relaxation of the stomach. Remember that one of them normally increases tone of LES

A

gastrin and cholecystokinin

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25
Q

what three things increase peristalsis contractions of the stomach

A

gastrin, motilin, and low blood glucose enhance peristalsis

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26
Q

what three things inhibit peristalsis

A

sympathetic activity, secretin, and cholecystokinin inhibit peristalsis

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27
Q

the vagus nerve stimulates (parasympathetic) _____ and ______

A

stimulates gastric secretion and motility

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28
Q

gastric emptying is increased by? decreased by?

A

increased gastric emptying occurs d/t large volume consumption

delayed by solids, fats, and non-isotonic solutions

*slowed down by fats d/t cholecystokinin – inhibits intake, gastric motility, decreases gastric emptying so that fats do not exceed rate of bile and enzyme secretion

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29
Q

Intestinal phase - begins with? does what? what inhibits gastric secretions?

A
  • begins with movement of chyme from stomach to duodenum
  • decelerates gastric secretion – when chyme enters alkaline environment of duodenum – inhibitory vagal reflexes decrease gastric motility
  • secretin and cholecystokinin stimulate pancreatic secretions and inhibit gastric secretions
30
Q

• Peritoneum – serous membrane surrounding
the organs of the abd and pelvic cavity
• Visceral – lies over the organs
• Parietal – lines the wall of the abd cavity
• Inflammation of the peritoneum, peritonitis,
occurs with perforation of the intestine or after
surgery
• Peritoneal cavity: Space between the two layers of the
peritoneum

A

Know these

remember it’s visceral peritoneum and parietal peritoneum

31
Q

________ within the small intestine slow the passage of

food providing more time for digestion and absorption (more numerous in the jejunum and upper ileum)

A

Mucosal folds (plica) - part of the muscular layer of the small intestines

32
Q

Myenteric plexus and mucosal plexus of the small intestines

A

site of intrinsic motor innervation mediation
• Parasympathetic – secretion, motility, pain sensation, and intestinal reflexes mediation
• Sympathetic – inhibits motility and produces vasoconstriction

33
Q

Villi in the SI - what occurs here?

A

– cover the mucosal folds and are the functional units of the intestine
• Absorption occurs through the villi

34
Q

Villus composed of two things?

A

absorptive columnar cells (enterocytes) and mucus

secreting goblet cells of the mucosal epithelium

35
Q

Surface of each columnar epithelial cell contains ______

_____ with microvilli increase surface area for absorption

A

contains microvilli

remember there’s a villi and microvilli that cover it

villi and microvilli increase surface area for absorption

36
Q

All nutrients are absorbed in the _______ as well as 85% of the water and fluid intake

A

small intestines

37
Q

Carbohydrates digested into? What breaks it down? Sugars absorbed where?

A
  • digested into monosaccharides and disaccharides
  • salivary and pancreatic amylase break down starches
  • sugars are primary absorbed in the duodenum and in the upper jejunum (so first two parts of SI)
38
Q

Proteins digested into? Where are they broken down by hydrolysis? Carboxypeptidase?

A
  • digested into amino acids and peptides
  • pancreatic enzymes accomplish major protein hydrolysis in small intestines (trypsin and chymotrypsin hydrolyze the bonds or large molecules - endopeptidase)
  • carboxypeptidase: breaks away the end amino acids (exopeptidase)
39
Q

Fats digested into?

A

fatty acids and monoglycerides

40
Q

fat digestion step 1

A
  1. emulsification: emulsifying agents cover the small fat particles and prevent them from reforming into fat droplets - fats are then ready for lipolysis - LIPASE (from pancreas) breaks down triglycerides; PHOSPHOLIPASE cleaves fatty acids from phospholipids; CHOLESTEROL ESTERASE breaks down cholesterol esters
41
Q

fat digestion step 2 - 4 see notes, not bolded

A

…

42
Q

Most minerals are absorbed by _______ or ______

Most ________ vitamins are passively absorbed or by sodium-dependent active transport

A

most minerals are absorbed by passive diffusion or active transport (requires energy) or are actively transported with a carrier protein

most water-soluble vitamins are passively absorbed or by sodium-dependent active transport

43
Q

Large intestines do what?

A

Massages fecal mass; absorbs water and electrolytes

mucus secreting goblet cells are in the LI, but no villi

44
Q

Intestinal motility: Contractions of the circular muscles, called ________, mixes the chyme and promotes digestion

A

segmentation

45
Q

_______ inhibits gastric motility when the ileum is distended

A

Ileogastric reflex

46
Q

The _________ reflex inhibits intestinal motility when one intestinal segment is over distended

A

intestinointestinal

47
Q

_________ increases intestinal motility when gastric motility increases
• Initiates propulsion in the entire colon, usually during or immediately after
eating, when chyme enters from the ileum
• Causes fecal mass to pass rapidly into the sigmoid colon and rectum,
stimulating defecation
• Stimulates the reflex: Gastrin and cholecystokinin
• Inhibits the reflex: Epinephrine
• Increased intra abdominal pressure facilitates defecation

A

Gastroileal reflex

48
Q

Liver produces __________ necessary for fat digestion and
absorption
• Receives nutrients absorbed by the small intestine; which are metabolized and
synthesized into forms that can be used by the body’s cells
• Then releases them into the bloodstream or stores them for later use

A

bile, with salts

49
Q

Exocrine pancreas produces what?

A

enzymes needed for complete digestion of
carbohydrates, proteins, and fats
• Also produces an ALKALINE FLUID that neutralizes chyme and produces duodenal pH necessary for enzymatic function

*These enzymes include trypsin and chymotrypsin to digest proteins; amylase for the digestion of carbohydrates; and lipase to break down fats.

50
Q

Contractions of circular muscles (_______) mixes chyme and promotes digestion

A

segmentation

51
Q

Inhibits gastric motility when the ileum is distended

A

Ileogastric reflex

52
Q

Inhibits intestinal motility when one intestinal segment is over distended

A

intestinointestinal reflex

53
Q

Increases intestinal motility when gastric motility increases

A

gastroileal reflex

  • stimulates gastrin and cholecystokinin and decreases epinephrine
  • initiates propulsion in the entire colon, usually during or right after eating
54
Q

Liver lobules contain plates of hepatocytes that are the functional cells of the liver…what do they do?

A

hepatocytes synthesize 700-1200mL of bile per day and secrete into bile canaliculi – small channels b/w hepatocytes that can drain bile into the common bile duct and then into the duodenum through the sphincter of Oddi

55
Q

What are canaliculi

A

small channels b/w hepatocytes that can drain bile into the common bile duct and then into the duodenum through the sphincter of Oddi

56
Q

Star shaped cells that store lipids including vitamin A

A

lipocytes in the liver

57
Q

mononuclear phagocyte system in the liver central to innate immunity

A

Kupffer cells - phagocytic cells in the liver

58
Q

contain retinoids (vitamin A) - are contractile in liver injury, regulate sinusoidal blood flow, may proliferate into myofibroblasts, participate in liver fibrosis, remove foreign substances from the blood, and trap bacteria

A

stellate cells

59
Q

pit cells in the liver are what? why are they important?

A

Natural killer cells - important in tumor defense

60
Q

alkaline, bitter-tasting, yellowish green fluid that contains bile salts, cholesterol, bilirubin, electrolytes, and water

A

bile secretion

61
Q

conjugated bile acids that are required for the intestinal emulsification and absorption of fats

A

bile salts

62
Q

synthesized from cholesterol by the hepatocytes and are required for intestinal emulsification and absorption of fats

A

primary bile acids - primary acids are then conjugated to form bile salts

63
Q

product of bile salts deconjugation by bacteria in the intestinal lumen

A

secondary bile acids

64
Q

enterohepatic circulation

A

recycling of bile salts, also called choleresis

65
Q

choleretic agent

strong?

A

substance that stimulates the liver to secrete bile

strong stimulus: high concentration of bile salts

other cholerectic agents? secretin, cholecystokinin, vagal stimulation

66
Q

pigment which is the by-product of the destruction of aged red blood cells in the liver and spleen

A

bilirubin

*bilirubin gives bile a greenish black color and produces the yellow tinge of jaundice

67
Q

unconjugated bilirubin

A

is lipid soluble and can cross the cell membrane, present in the circulation, bound to plasma protein

68
Q

conjugated bilirubin

A

liver changes bilirubin to a water-soluble form that can now be excreted

primary method of bilirubin excretion is in the bile

69
Q

urobilinogen

A

in the ileum and colon, conjugated bilirubin is deconjugated by bacteria and then converted

gives feces its brown color

70
Q

higher percentage of unconjugated bilirubin = ?

A

heme breaking down, or inability of liver to conjugate

*ex. missing enzyme (congenital), hemolytic anemia

71
Q

higher percentage of conjugated bilirubin = ?

A

problem with secretion into bile

*ex. biliary obstruction, hepatitis

72
Q

liver functions

A
  • vascular and hematologic functions: stores bloods, removes bacteria or foreign particles, synthesizes clotting factors
  • metabolizes fats (bile)
  • synthesizes phospholipids and cholesterol
  • metabolizes proteins - deamination: the removal of ammonia (converted to urea and secreted in urine); converts amino acids into carbohydrates
  • metabolizes carbohydrates: liver releases glucose during hypoglycemia; takes up glucose during hyperglycemia; stores glucose as glycogen (glyconeogenesis) or converts it to fat
  • detoxification through biotransformation
  • storage of minerals and absorption of fat-soluble vitamins *vit K - essential for synthesis of clotting factors; absorption depends on adequate bile production

Advanced Patho UC (14 decks)

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