1
Q
G cells in antrum(G17) and duodenum (G34) release ________.
what stimulates gastrin production?
what inhibits gastrin?
A
Gastrin
- protein digestion, nervous, physical distension, calcium, decaf coffee and win e
acid in the antrum
2
Q
the _______ activity of gastrin is responsible for growth of ______ mucosa of the stomach, duodenal mucosa and colon mucosa; gastrin secreting tumors have mucosal hyperplasia and hypertrophy
A
trophic
oxyntic
3
Q
a gastrinoma is aka _______-______ ________; a gastrin secreting tumor of pancreas accounts for _____% or G-cell tumors in the duodenum which accounts for _____-____% and continually secretes gastrin in to blood.
- the symptoms are ____ _____, diarrhea, steatorrhea and hypokalemia
A
Zollinger- Ellison Syndrome
80%
10-15%
duodenal ulcers
4
Q
hypergastrinemia causes hypersecretion of _____ which presents as an increased ______ cell mass and constant stimulation of hyperplastic mucosa
A
acid
parietal
5
Q
CCK is released from __-cells in the duodenum and jejunum. ______-____ or monoglycerides, peptides and single amino acids are the stimuli release
A
I cells
fatty- acids
6
Q
CCK causes ________ of the gallbladder due to contraction of GB and relaxation of the sphincter of ______.
A
emptying
oddi
7
Q
CCK inhibits gastric _______ and its pancreatic exocrine is an enzyme stimulator and weak stimulator of bicarbonate (but potentiates ______ effects)
A
emptying
secretin
8
Q
______ is a 27- amino acid peptide that has no active fragments and is released from ___ cells of the duodenum mucosa-Acid in the duodenum and _____-____ in the duodenum stimulate the release
A
secretin
S-cells
fatty- acids
9
Q
Secretin is aka ______’s ______; it inhibits enterogastrone, stimulates pancreatic and bile bicarbonate secretion, stimulates pepsin and has a trophic effect on exocrine pancreas
A
nature’s antacid
10
Q
_______- ______ __________ ______ (GLIP) is a member of the secretin family that stimulates insulin release (glucose- dependent insulinotrophic peptide i.e. GIP) and inhibits gastric acid secretion (enterogastrone) and is released by duodenum and proximal jejunum
A
glucose dependant insulinotropic peptide
11
Q
________ stimulates upper GI motility and is known as “housekeeping contractions,” released from the duodenum and proximal jejunum under neural control. It is UNRELATED to other hormones
A
Motilin
12
Q
_________ is a peptide
- Found in gastric/duodenal mucosa and pancreas
- Release-stimulated by acid, inhibited by Ach
- Inhibits release of all gut hormones
- Directly inhibits parietal cell acid secretion
- Mediates acid induced inhibition of gastrin release
A
Somatostatin
13
Q
________
- Gastrin and Ach cause release from cells in stomach
- Stimulates acid secretion
- Histamine H2 receptor blockers decrease Acid secretion
- Cimetidine(Tagamet), Ranitidine (Zantac)
A
Histamine
14
Q
_________ (hormones)
- All GI hormones are peptides
- Released into blood–> act on distant target cell
A
Endocrines
15
Q
___________
- Some are peptides, some are not
- Endocrine cells release –>diffuse to target cells
- Can act on endocrine cells (+ or-)
A
Paracrines
16
Q
_________ are (neurotransmitters)
- Some are peptides, some are not (Ach and NE)
- Nerves release–>diffuse to target cells
A
Neurocrines
17
Q
_____ is located in Gut mucosa and SM and Relaxes gut SM
A
VIP (vasoactive intestinal peptide)
18
Q
____ (Bombesin) is located in Gastric mucosa and it increases Gastrin Release
A
GRP (gastrin-releasing peptide)
19
Q
___________ are located in Gut mucosa and SM and it increases SM tone
A
Enkephalins
20
Q
saliva is Secreted by 3 major glands, what are they? and what percent is secreted by them?
–_______ (serous) ___%
–_______ (mixed)___%
–________ (mucous)___%
A
Parotid –26%
Submandibular–69%
Sublingual–5%
21
Q
All of the following are functons of \_\_\_\_\_\_\_\_\_: –Keeps mouth moist for speech –Dissolves food for tasting –Lubricates food for swallowing –Improves dental health •Promotes remineralization •Antibacterial (salivary lysozyme & thiocyanate ions) –Alpha-amylase digests starch –Neutralizes acid (HCO3-)
A
Saliva
22
Q
•Stimuli for \_\_\_\_\_\_ include: –Acid in mouth –Irritating foods that are swallowed –Nausea –Chewing –Taste sensation –Afferents in pharynx, mouth, and olfactory area
A
salivation
23
Q
- ______ is for Lubrication
- Ptyalin (a-amylase) is for___________ digestion
- ______ ______ is for Fat digestion
- Kallikrein Forms _________, a strong vasodilator
- NaHCO3 Increases pH for optimum function of ______
- Water (99%) is a ________
A
- Mucus
- Carbohydrate
- Lingual lipase
- bradykinin
- amylase
- Solvent
24
Q
Nervous system control of salivary glands
Parasympathetic: ________ flow rate (CN VII, IX)
__________: slightly increases secretion
A
increases
Sympathetic
25
```
Taste reflex CN ___, IX
______ reflex CN V
Olfactory reflex CN I
Auditory CN VIII
______ CN II
______ reflex Thinking of food
Hormonal control is because of Aldosterone
```
- VII
- Touch
- Visual
- Psychic
26
```
2 types of glands for gastric secretions are:
_______ (gastric) glands which hold:
–Mucous neck cells
–Peptic or chief cells
–Parietal cells
–HCl & IF
_______ glands which hold:
–Mucus
–Gastrin
```
- Oxyntic
| - Pyloric
27
-____ Activates zymogens, Protein digestion, Immunity,
Stimulates pancreatic secretion
-_________ Inactives protease
-Mucus is for _______and Protection
-Ions(Na+,Cl-,K+,SO4,-Mg+2,HPO4-) are for Digestion
(solvent) and Buffer
-_______ factor is for B12 absorption in terminal ileum
-______(hormone) is for Gastric secretion of HCl & pepsinogen
- HCl
- Pepsinogen
- Lubrication
- Intrinsic
- Gastrin
28
Pepsin (secreted as pepsinogen by ____ _____)
chief cells
29
Major stimuli for acid secretion:
-_____
•Gastrin
•_______
ACh
Histamine
30
```
Major inhibitors for acid secretion:
-Prostaglandins
•Acid
•___________
•Dietary fat
•_______
```
Hyperglycemia
Secretin
31
Phases of gastric secretions
________ (30%):extrinsic nervous
-Think about or see food
-Parasympathetic (CN X)
-increase in pepsinogen leads to increase in gastrin
________ (60%): extrinsic nervous (VAGUS)
-Vagovagal reflex by food distention (mechanical)
-increase in pepsinogen, increase in HCL
________ (10%): intrinsic humoral
-Food in intestine (products of protein digestion)
- increase in gastrin stimulates gastric secretion
- Cephalic
- Gastric
- Intestinal
32
Cephalic phase- “psychic phase;”
parasympathetic fibers in branches of the ______
nerve conduct stimulating efferent impulses to
the______; stimulate production of gastrin
- vagus
| - glands
33
```
Gastric phase–
food in stomach elicits increased secretion; greatest effects with protein and peptides (also alcohol and caffeine); these changes are mediated by:
–_____ nerve
–______ reflex
–Gastrin
```
Vagus
Stretch
34
Intestinal phase–
various mechanisms seem to adjust gastric secretion as
chyme passes through the intestinal tract; _______reflexes involving gastric inhibitory peptide (GIP), secretin, cholecystokinin-pancreozymin inhibit gastric secretions
endocrine
35
Proteases
______-->Proteins to peptides
chymotypsin-->Proteins to peptides
__________--> Peptides to amino acids
- trypsin
| - carboxypeptidase
36
Lipases
-phospholipases A & B -->Phospholipids to phospahtes
,FA, & glycerol
-_______-->Cholesterol esters to free cholesterol
-_______-->TGs to FA & glycerol
- esterases
| - lipases
37
Nucleases
- _________-->RNA to ribonucleotides
- deoxyribonuclease-->____ to deoxyribonucleotides
- ribonuclease
| - DNA
38
pancreatic secretions are controlled by ______ which evokes production of pancreatic fluid low in enzyme content but high in NaHCO 3 content; potent stimulation by the presence of acid in the duodenum
Secretin
39
other pancreatic controls are ______; and ___ which has several functions:
–Increase exocrine secretions high in enzyme content
–Opposes the influence of gastrin on gastric parietal
cells
–Stimulates contraction of the gallbladder
- Acetylcholine
| - CCK
40
phases of pancreatic secretions:
_______ phase
–Sight & smell via vagus nerve
–Low HCO3, high protein concentration
_______ phase
–Induced by gastric distension
–Low HCO3, high protein concentration
–Via vagal reflex or gastrin
_______ phase
–Secretin (S cells) is released due to acidic chyme
–CCK (I cells) is released due to presence of chyme, particularly proteoses, peptones, long
-chain FA
Cephalic
Gastric
Intestinal
41
Bile is composed of:
-_____ ____–major stimulus for enhanced bile secretion
•_____ _______–chief bile pigment is bilirubin
•Cholesterol
•Triglycerides
•__________, such as lecithin
•Water & electrolytes (except Ca+2) are reabsorbed
Only bile salts and phospholipids aid in digestion.
- Bile salts
- Bile pigments
- Phospholipids
42
_______ ______ are Synthesized from cholesterol
| and their Function is fat absorption
Bile Salts
43
all of the following contribute to the formation of _____ _______:
-Cholesterol dissolution is proportional to lecithin concentration
•Cholesterol stones–50-75% cholesterol
•Pigment stones–calcium bilirubinate; 48% cholesterol
Gall Stones
44
________ gland (duodenum)– secretes alkaline mucus in response to:
- Tactile or irritating stimuli on duodenal mucosa
- Vagal stimulation
- GI hormones, esp. secretin
** and are inhibited by SP stimulation
Brunner’s
45
Crypts of_______ hold:
-Goblet cells–mucus
-Enterocytes–water & electrolytes which are
reabsorbed by the villi along with end products
of digestion; these cells also contain digestive
enzymes:
Peptidases–small peptides into amino acids
-Sucrase, maltase,isomaltase, and lactase
-Intestinal lipase–neutral fats into glycerol and FAs
Lieberkuhn
46
Control of intestinal secretion
–_______: direct stimulation causes the
release of mucus and ions
–Pelvic splanchnic nerves: pΣ to distal half
causes mucous secretion & peristaltic motility
–Hormonal (________)
•Decreases Na+ and Cl- secretion
•________K+ secretion
- Tactile
- Aldosterone
- Increases
47
______digestion – consists of all the physical movements of the digestive tract breaking apart the food particles into smaller particles.
Mechanical
48
_______ digestion – consists of all the changes in chemical composition that foods undergo in their travel through the digestive tract
Chemical
49
Carbohydrates account for approx. __% of ingested calories, Present in straight and branched chains
50%
50
Three major sources of carbohydrates in the human diet are:
–_________
–_________
–Starches
- Sucrose
| - Lactose
51
Pancreatic ________ has its Highest concentration in the duodenal lumen and it Rapidly hydrolyzes starch to oligosaccharides, maltose, and maltotriose
amylase
52
_________ hydrolases
Present in the brush border w/ highest concentration in the mid-jejunum and proximal ileum. ________ is the rate-limiting step in digestion/absorption
- Oligosaccharide
| - Hydrolysis
53
carbohydrates are absorbed via _______ transport
- _______ is absorbed in the duodenum and proximal jejunum
- fructose is absorbed by ______ diffusion
- ______ follows movement of carbs
- some carbohydrate movement is by _______ drag
- active
- Glucose
- Facilitated
- water
- solvent
54
Protein is largely digested by _____ _____ monomers.
amino acid
55
during gastric digestioon of protein ____-___% of protein is broken down to amino acids
-10-20%
56
during gastric digestion ______ splits proteins into proteases, peptones, and large polypeptides
- it also has the ability to digest collagen
–Pepsin
57
during intestinal digestion (80-90%) protein digestion occurs in the upper small intestine (_______ and ______) due to ______ enzymes
duodenum
jejunum
pancreatic
58
Pancreatic enzymes that act on protein during intestinal digestion are:
•______ & Chymotrypsin which digest proteins into peptides
•___________which cleaves from C-terminus (carboxyl end of of polypeptides)
•_______ which convertes to elastase, digesting elastin fibers
Trypsin
Carboxypeptidase
Proelastase
59
Peptides are digested by ___________. aminopolypeptidase and dipeptidase can be found in the _____ border of enterocytes
peptidases
Brush
60
tripeptides and dipeptides are broken down to _____ _____ and 99% are absorbed Inside the ______.
- amino acids
| - cytosol.
61
Is Pepsin essential in protein digestion? if not, why?
Not essential
-its not essential because of the other enzymes further down the digestive tract that can break the protein down without the help of pepsin
62
during protein absorption Amino acid is absorbed which is a Rate-limiting step and is dependent on _____ ______sodium-linked carriers. Amino acids appear rapidly in the _____ _____ system
Active transport
hepatic portal
63
In the human diet Fat is mostly _________ (neutral fats) and then there is a small ammount of ________, ________, and cholesterol esters
triglycerides
phospholipids
cholesterol
64
During the gastric digestion of fat digestion normally occurs in the _______. Normally accounts for 10% of fat hydrolysis through ______ and _______ lipase and the emulsifies and slowly empties chyme into small intestine
stomach
gastric
lingual
65
during intestinal digestion fats are Solubilized in the duodenum by ______, bile salts, and ______ _____. Most fat absorbed by the time chyme reaches ___-_______.
lecithin
fatty acids
mid-jejunum
66
during intestinal digestion of fat pancreatic _____ causes luminal concentration peaking within the _____ hour after a meal and the emulsifying agents enhance contact.
lipase
first
67
Bile salts Enter duodenum with ________ contraction usually within 30 minutes of a meal and aggregate with monoglycerides to form _______.
Gallbladder
micelles
68
FAs and monoglycerides associated with micelles absorb in intestinal lumen through ________ and are used to synthesize ________ in the smooth endoplasmic reticulum
diffusion
triglycerides
69
Fatty globules are combined with proteins to form _________ within the______ apparatus and then migrate to the _______ membrane and enter a _______.
- chylomicrons
- Golgi
- Basal
- Lacteal
70
•Steatorrhea–Excessive fat in the stool.
what can cause this?
–______ tract disease decreases fat absorption by 50%
–______ deficiency decreases fat absorption by 66% (if lipase activity is decreased)
–_____ defect causes bile salt malabsorption
- Biliary
- Pancreatic
- IIleal
71
during nucleic acid digestion DNA and RNA are ________ to their nucleotide monomers by________ Nucleases. Nucleotides are then broken apart by intestinal______ _______enzymes (nucleosidases and phosphatases), releasing the free bases, pentose sugars, and phosphate ions
- hydrolyzed
- pancreatic
- brush border
72
during nucleic acid absorption _____ sugars, nitrogenous bases, and _______ ions are transported actively across the epithelium by special carriers in the _____epithelium, then entering the blood
Pentose
phosphate
villus
73
during electrolyte absorption (coming from ingested food and GI secretions) ions are absorbed along the entire length of the _____ _______. However,_____and______absorption is largely limited to the duodenum
small intestine
iron
calcium
74
during electrolyte absorption Active transport of Na+
out of cell (into blood) pulls Na+ in from______ border of
intestine. some ______ is absorbed with Na+
brush
chloride
75
during electrolyte absorption K+ move across intestinal mucosa by_______ diffusion (or via “______” tight
junctions) in response to changing osmotic gradients.K+
absorption decreases if water absorption is hindered, as in _________
facilitated
leaky
diarrhea
76
Iron and calcium absorption is intimately related to the body’s need for them; Ionic iron (____ ion is absorbed better than ferric ion) is actively transported into mucosal cells, binding to ferritin; The intracellular iron- ______complexes serve as local storehouses for iron
ferrous
ferritin
77
Calcium absorption is also intimately related to the body’s need for them; its Locally regulated by the active form of ______ __, which acts as a cofactor to
facilitate active calcium absorption; ____ stimulates activation of vitamin D by the kidneys
vitamin D
PTH
78
Approximately __ L of water, mostly derived from GI secretions, enter the small intestine daily; Absorbed mostly by _______ via transcellular and __________
pathways; Normal rate of water absorption is 300-400
ml/hour
9
osmosis
paracellular
79
Fat-soluble vitamins (A,D, E, K) are absorbed
in similar fashion as fat; Most water-soluble vitamins (B vitamins and vitamin C) are absorbed easily by _____ or via active or passive transporters, except B12
–B12 binds to R proteins produced by ______
–R protein -B12 complex hydrolyzed by __________
enzymes; B12 binds with IF
–B12–IF complex binds to receptor site triggering
endocytosis
diffusion
saliva
pancreatic
80
Regulation of Absorption/Secretion:
•__________ regulate small intestine, colonic fluid, and electrolyte transport
•Opiates stimulate Na absorption and inhibit secretion in ileum
•_______stimulates Na absorption and decreases motility
•________ increase Na and Cl absorption
Glucocorticoids
Somatostatin
Cholinergics
81
Regulation of Absorption/Secretion
•VIP stimulates fluid secretion via cAMP
•_______ reduces water absorption
•Secretin/____ decrease Na, K, & Cl absorption in jejunum
•Toxins stimulate cAMP and thereby ______ Na and water absorption
•Aldosterone
Gastrin
CCK
decrease
