gastrointestinal

Question 1

describe the 4 process in digestive system

Answer 1

digestion: mechanical or chemical
secretion: endocrine (hmn enters blood) and exocrine (to lumen of organs)
absorption
motility: mastication in mouth (into bolus) ; ;peristalsis in esophagus

Question 2

describe what happened in mouth to esophagus

Answer 2

1. mastication in mouth -> into bolus
2. peristalsis occurs: coordinated contraction of esophageal muscle -> push bolus into stomach
   involuntary, 2nd peristalsis

Question 3

3 ____ glands in upper GI tract:

• parotid gland: secretes liquid that contains __ ___ & ____ ___
• _____ gland: less of those and more mucus
• sublingual gland: more ___ & almost no ____

Answer 3

exocrine

salivary amylase /. lingual lipase
submandibular
mucus / enzymes

Question 4

what is special abt G cells in mucosa?

Answer 4

only endocrine cells in mucosa, secretes gastrinl. the rest are exocrine: mucus cells , parietal cells & chief cells

Question 5

what is activated and what is not by HCl in the chemical digestion of stomch?

Answer 5

gastric lipase and lingual lipase activated by HCl (for carb digestion)

bt salivary amylase is inactivated (carb digestion stops)

Question 6

compare the parietal cells and chief cells

Answer 6

both exocrine cells of mucosa

bt parietal cells release intrinsic factors and HCL while chief cells release pepsinogen and gastric lipase

Question 7

using the pyloric sphincter as a focus, describe what happens in mechanical digestion in stomach

Answer 7

propulsion: pyloric sphincter closes, gentle mixing waves

grinding: still closed for vigorous mixing

retropulsion: pyloric sphincter slightly opens. most chyme pushed back into stomach for further mixing.

Question 8

compare the layers of stomach to small intestine: mucosa & submucosa

Answer 8

single layer of cel: endocrine & exocrine vs a mixed combo of epithelial cells, blood vessels & lymph vessels
rugae & pitt vs villi & crypt

same: contains neural network (submucosal plexus)
bt for stomach, has connective tissue tht adheres mucosa & smooth muscle

Question 9

compare the layers of stomach to small intestine: smooth muscle and serosa

Answer 9

smooth muscle same: layer of smooth muscle: circular and longitudinal
has a neural networK (myenteric plexus)

dense vs thin connective tissue

Question 10

compare segmentation vs peristalsis in SI

Answer 10

segmentation: localized contraction to mix chyme and digestive juices
< interaction btw chyme particles & absorptive cells

peristalsis: propels food into LI

Question 11

when does digestion occur in SI and when does absorption occur?

Answer 11

most digestion occurs in duodenum: can </> motility to optimize ch.diges

most absorption occurs in jejunum: villi to < SA for optimal absorption
some in illeum if needed

Question 12

describe a diagram of intestinal wall cell (@ SI): endocrin? exocrine?

note the available cells: CCK, paneth cells, goblet cells, K cells, internal gland cells and S cells, absorptive cells

Answer 12

absorptive cells: epithelial cells w/ villi

exocrine:
- goblet cells (secrete mucus)/ intesintal gland (also mucus) & paneth cells (lysozyme)

endocrine
- S cells (secretin
- CCK: cholecystokinine
- K cell: GIP (glucose depnedent insolunitrophic peptide)

Question 13

how can disacc be digested with villi?

Answer 13

via its brush border enzyme

lactase: glucose + galactose
sucrase: glucose + fructose
galacrtose+ glucose + glucose

Question 14

sketch the anatomy of Large Intestine and its function

Answer 14

ascending -> transverse -> descending colon -> rectum
ileocecal valve: only allows motion from small -> large intestine

function: to complete absorption (mainly H20 & ions) and bacteria to ferment

Question 15

describe function of ileocal valve, haustra, appendix in LI and its accompanied reaction

Answer 15

gastroileal reflex: food in stomach stimnulates opening from ileocecal valve
haustra: circular strucrtures that flip content in lumen
haustral churning: churning LI content from 1 haustra to next for optimal absorption
peristalsis pushes along
appendix: store bacteria; repopulate if neeced

Question 16

separate exocrine secretions of pancrease into 2 group

Answer 16

from ductal cells

from acinar cells

Question 17

how is the exocrine secretion of pancreas split into? name the 2 enzymes + 1 chemical

Answer 17

exocrine secretion of pancrease:
- from ductal cells: HCO- neutralize stomach acid
- from acinar cells:
pancreatic amylase: digest carb
pancreatic lipase: digest lipid

Question 18

how did the zymogen (inactivated protein) of pancreas becomes enzyme towards duodennum?

Answer 18

exocrine secretion enters pancreatic duct into lumen:
- trypsinogen is cut by enterokinase into trypsin
- activates its fellow zymogens into enzymes

chymotrypsinogen ->: chymotrypsin
procarboxypeptidase -> carboxypeptidase (protein)
prophospholipase -> phospholipase (phospholipid)
procolipase -> colipase (not ennzyme, bt lipid_

-> converges into common bile duct
-> into duodenum

Question 19

compare & contrast glucagon, insulin and somatostatin cells of pancreas

Answer 19

(+): all endocrine secretions from Islet of Langerhands

(-): respectively from alpha cells, from beta cells, crom delta celsl

Question 20

how to make bile?

Answer 20

= bile salt + cholesterol + bilirubin + water and ions

Question 21

bile caniculi collects bile made by leukocytes -> empty into the hepatic portal artery -> common liver duct

T or F? states what is wrong

Answer 21

F

made by hepatocytes -> hepatic duct -> common bile duct

Question 22

what is the relation btw bile solution and gallbladder?

Answer 22

gallbladder stores bile solution from liver -> becomes concentrated
muscular contracts (by CKK & neural activation) to secretes it
enters into duodenum through opening of Sphincter of Oddi

Question 23

GIP

Answer 23

glucose-dependent insulinotrophic peptide

endocrine cells of SI

Question 24

further compare glucagon vs insuylin

Answer 24

(-) from alpha cells vs beta cells
raises blood sugar by releasing storage glucose into blood
lower blood sugar by releasing it into cells

(+) both endocrine secretions of pancreas
both hmn

Question 25

function of liver

Answer 25

makes bile salt (lipid digestion) / excretes cholesterol & bilirubin / metabolizes carb, protein & lipid

Question 26

without the saliva, how will you be impacted?

Answer 26

cant lubricate and help chew the food
damage mouth & teeth
less aid in speech

Question 27

what is the stimulus for cephalic, gastric, intestinal phase?

Answer 27

cephalic: sight, smell, taste of food
gastric: presence of bolus in stomach, am.a
intestinal: presence of chyme in intestine

Question 28

effect of intestinal phase’s inhibition on gastic phase?

Answer 28

decreased secretion & motility of stomach
less gastric emptying

Question 29

hormonal control of intestinal phase

Answer 29

< secretion in:
intestine
pancrease:
HCO3- @ ductal cells - secretin cells
digested enzymes - @ acinar cells - CCK
insulin - @ beta cells - by GIP

Question 30

describe the cephalic phase:

Answer 30

stimulus: slight, smell & taste of food
neural: activate submucosal plexux & myenteric plexus

< secretion in salivary glands, stomach & intestine
< motility in stomach & SI

Question 31

why do we say for Gastric Phase, Gastrin?

Answer 31

part of hormonal control

< secretion of
stomach
intestine

< motility of
stomach, more gastric emptying

Question 32

outline the process of carb digestion

Answer 32

@ mouth: salivary annylase breaks starch -> maltose

@ stomach: HCl inactivates salivary amylase

@ SI, lactase breaks lactose / maltase breaks maltose / sucrase breaks sucrose
@ pancrease, release pancreatic amylase breaks startch -> maltose

Question 33

T or F? correct if F

with lactose: lactose -> glycogen + glucose
with maltose: maltase -> glucose _ glucose
with sucrase: sucrose -> galactose + fructose

Answer 33

all F

with lactase: lactose ->galactose + glucose
with maltase: maltose -> glucose + glucose
with sucrase: sucrose -> glucose + fructose

Question 34

essential am.a is made in the body and therefore, can be derived from food. is that T?

Answer 34

F

essential am.a cannot be made in the body; MUST be derived from food

Question 35

how does endopeptidase and exopeptidase work tgt?

Answer 35

endopeptidase has pepsin, trypsin and chymotrypsin to cut polypetides

exopeptidase has aminopeptidase to cut amino end of protein and carboxypeptidase to cut carboxy at the end

do this until reduced to ama, and di- tri- peptide

Question 36

what would the chemical composition of unsaturated fat be composed of?

Answer 36

it would be triglyceride: 3 fatty acids and glycerol

and there would be double bonds

Question 37

fat-soluble vs water-soluble vitamins?

Answer 37

fat-soluble: D, E, K, A
-> found within micelle

water-soluble: vit B & C
-> need protein carrier

Question 38

describe the protein absorption in intestinal cell

Answer 38

using Na gradient, symporter carries am.a across luminal
also carries di- tri- peptide -> with peptidase, breaks into am.a -

uniporter collects all am.a and transport into blood
there’s Na+/K+ ATPase at the basolateral

Question 39

describe the carb absorption in intestinal cell

Answer 39

uniporter carries fructose across the luminal
using Na+ gradient, symporter carries glucose & galactose across the luminal

uniporter collects all monosacc & transports into blood
there’s Na+/K+ ATPase at the basolateral

Question 40

outline the fat digestion

Answer 40

though present in the mouth, lingual lipase doesnt work
at the stomach, HCl activates the lingual lipase and gastric lipase
pancreas makes pancreatic lypase (+ coliipase) while liver provides bile salt

Question 41

how does bile salt aid in lipid digestion

Answer 41

since bile salt is both hydrophobic and hydrophilic, coats the micelle

micelle can now interact with they hydrophilic lipase -> colipase pushes bile salt apart as lipase enters

Question 42

micelle bring _____ & ___ ___ and difuse across [redacted’]

-> repackage into _____
-> enters lymphatic vessel via _____

Answer 42

monoglycerides / fatty acids / intestinal cell’s phospholipid bilayer

choloromicron
exocytosis

Question 43

fill in the blank

hepatic ___ carrying oxygenated blood and hepatic _____ _____ carrying ___-____ blood merge at [redacted] at [redacted]

drain into the _____

leave the liver towards art via _____

Answer 43

hepatic artery
portal vein
nutrient-rich
sinusoids
liver

ventral vein

hepatic vein

Question 44

list the steps invovled in fed state

Answer 44

1. glycolysis
2. glycogenesis
3. lipogenesis
4. protein anabolism

Question 45

list the steps involved in fasted state

Answer 45

1. glycogenolysis
2. gluconeogenesis
3. lipolysis
4. ketogenesis
5. in extreme fasted state, protein catabolism

Question 46

describe gluconeogenesis

Answer 46

liver forms glucose from non-carb sources: glycerol
lactic acid + am.a via pyruvic acid towards glucose

glucose -> glucose 6-PO4 -> glyceraldehyde 3-PO3 -> pyruvic acid

Question 47

what happens when once ATP is depleted?

Answer 47

glycogenolysis occurs

glycogen in liver storage breaks into glucose-6PO4 -> glucose for most tissues, including the brain
glycogen for muscle storage does the same for skelemtal muscle

Question 48

how can you create triglycerides w.o using lipid sources? how many sources are there?

Answer 48

via lipogenesis,

glucose -> glyceraldehyde 3-PO4 -> pyruvic acid -> ACoA
glycerol (links to glyceraldehyde 3-PO4) combines w/ f.a (links to ACoA) to make trig in liver & adipose tissue

extra am.a via ACoA triggers trig propduction too

Question 49

postive and negative abt ketogenesis?

Answer 49

heart and kidney cortext prefer ketone bodies to create ATP bt too much ketone bodies < blood acidity

Question 50

compare protein anabolism vs protein catabolism (include 1 special fact!)

Answer 50

fed state vs extreme fasted state
protein synthesis from am. a vs breakdown protein into am.a for aTP
in skeletal muscle vs liver can convert am.a into f.a / ketone bodies/ glucose

Question 51

what happens in lipolysis?

Answer 51

breakdown of trig into glycerol and f.t

glycerol enters gluconeogenesis: glycerol -> glucose 6-PO4 -> towards glucose
f.a VIA ACoa into ketone bodies for ATP

converts to ACoA to enter citric acid cyle for ATP

Question 52

some forms of protein?
1. enzymes
2. ____
3. structural components
4. ______

Answer 52

hmn/ transporter

Question 53

how does brush border enzyme help with protein digestion?

Answer 53

by creating

aminopeptidase, dipeptidase and enterokinase