GI Physiology - Exam 1 Flashcards
Endocrine is related to _ release and exocrine secretes _ and requires _.
hormone
enzymes
ducts
T/F All endocrine GI hormones (gastrin, secretin, CCK, GIP, GIP, and motilin) are peptides and sent into bloodstream
true
Some hormones of the paracrine system are _ (somatostatin) and some are not (_)
peptides
histamine
T/F Paracrine hormones such as somatostatin and histamine enter the blood stream to act on endocrine cells.
False,
These are NOT sent into the bloodstream, they DIFFUSE to target cells, same with neurocrines
Histamine helps _ acid secretion and aids in _ digestion
increase
protein
T/F Neurocrines are released from nerves to blood stream and sent to target cells.
False
These, like paracrines, DIFFUSE to target cells, not via bloodstream
Neurocrines such as VIP are _ and some are not (_ and _)
peptides
ACh
NE
Amylase aids in _ break down via ATP _.
carb
hydrolysis
-polysach-disach-monosach
Which 2 areas does amylase come from?
Salivary glands (parotid and submand glands)
-alpha amylase (ptyalin) stimulate carb break down
Pancreas
-more abundant, finishes digestion in the small intestine
Gastrin hormone
-chemical class
-where it’s made
peptide
antrum of stomach
Gastrin hormone
-trigger for release
-inhibiting factor
Trigger: protein intake (AA/ peptides in stomach) , PNS nerves
Inhibitors: stomach acid, somatostatin
Gastrin hormone
-target sites
-action
Stomach
-stimulates acid secretion and motility
Sm Int.
-stimulates ileum
Lrg Int.
-stimulates mass movement
CCK hormone
-chem class
-where it’s made
peptide
Sm Intestine
CCK
-trigger for release
-inhibiting factor
Trigger: AA, FA in stomach
Inhibitors: -
CCK
-target site
-action
Stomach
-inhibits acid secretion and motility
Pancreas
-potentiates secretin increasing bicarb
-stimulates enzyme secretion into Sm. Int.
Liver
-potentiates secretin’s increase of bicarb
Gallbladder
-CONTRACTS gallbladder
-RELAXES sphincter of oddi
Secretin
-chem class
-where it’s made
peptide
Sm. Intestine
Secretin
-trigger for release
-inhibiting factors
Trigger: acid in sm. int.
Inhibitors: -
Secretin
-target sites
-action
Stomach
-inhibits acid secretion and motility
Pancreas
-stimulates Bicarb secretion, potentiates CCK
Liver
-stimulates Bicarb secretion
The most abundant enzyme:
pancreatic lipase
Pancreatic lipase is made in the _ and acts on the _ _
pancreas
Sm. intestine
Trypsin and Chymotrypsin are made in the _ in their inactive forms (_ and _) which are activated in the _ _
pancreas
chymotrypsinogen
trypsinogen
sm. intestine
Trypsin and Chymotrypsin both break down _ in the _ _
dipeptides
sm intestine
Pepsin is made in the _ as its inactive form (_) which is activated by _
stomach
pespinogen
HCl and gastrin (increases HCl secretion)
CCK and secretin are both made in the _ _and are stimulated by _
sm intestine
food
Pepsin breaks down _ in the stomach
proteins (polypeptides)
Disaccharides are broken down in to monosaccharides from _ _ and _
ATP hydrolysis
amylase
Which hormone is responsible for the release of bile salts from the gall bladder and enzyme (trypsin, amylase, pancreatic lipase) release from the pancreas?
CCK
-Secretin assists in pancreas
Which hormone is responsible for Bicarb release from pancreas and liver?
Secretin
-CCK assists both
2 components of the enteric (intrinsic) nervous system:
-Myenteric (Auerbach’s) Plexus
-Submucosal (Meissner’s) Plexus
2 components of the autonomic(Extrinsic) nervous system
PNS
-triggers via ACh (histamine stimulates gastrin and ACh to release from cells in stomach)/ atropine does the opposite
SNS
-inhibits via NE
Basis for digestion is _
hydrolysis
Carb’s smallest units are _
Protein’s smallest units are _ and _
Fat (triglyceride)’s smallest units are _ and _
monosaccharides
small peptides and AAs
FFAs and glycerol (monoglyceride)
5 cells of the stomach(oxyntic gland)
-mucous neck cells
-peptic cells (Chief cells)
-parietal cells
-G cells
-Entero-chromaffin-like (ECL) cells
Stomach cells
Mucous neck cells secrete
mucus and bicarb
-protect stomach lining
Stomach cells
Peptic/ Chief Cells secrete
pepsinogen and rennin (found in cows too?)
Stomach cells
Parietal cells secrete
HCl
Intrinsic factor for vitamin B12 absorption
Stomach Cells
G Cells secrete
gastrin
Stomach cells
Enterochromaffinlike (ECL) cells secrete
histamine
-increases HCl
Which hormones(4) can increase parietal cell acid production?
-gastrin
-secretin
-histamine
-ACh (PNS)
Which hormone can decrease parietal cell acid production?
somatostatin
Pancreatic ENZYMES (4):
trypsin
lipase
amylase
bicarb
The enzyme Trypsin breaks down _ and comes from the _
proteins
pancreas
-released as trypsinogen then upon entering the sm. int., becomes trypsin to not break down pancreas
The enzyme, Lipase breaks down _ and comes from the _
fat
pancreas
-makes FFA and monoglycerides
The enzyme, amylase breaks down _ and comes from the _
polysacch (carbs)
pancreas
“Nature’s Antacid”=
secretin
-releases bicarb into sm. intestine and decreases HCl release into stomach
The liver secretes which 2 things?
bile and bicarb
The primary site of bile production is the:
liver
Function of bile
-emulsify fat into smaller globs that lipase can act on or body can absorb
Process of bile release:
1. _ is released from sm. intestine in response to _ from food
2. _ travels thru _ to the gallbladder
3. Gallbladder _ , increasing bile flow to the _ _ _ and the sphincter of oddi _
4. Bile is then released into the _ _
- CCK, Fatty Acids
- CCK, blood
- contracts, common bile duct, relaxes
- small intestine
Liver functions:
-produces and secretes bile and bicarb
-filters and removes old RBCs, forming bilirubin
-processes and stores nutrients
-makes important plasma proteins (albumin, clotting proteins, angiotensinogen, steroid binding proteins)
-synth of cholesterol (VLDL)
-Apoprotein B synth
Liver cells (3)
Hepatocytes
Endothelial cells
Large Kupffer cells (reticuloendothelial)
-macrophages that eat bacteria and foreign matter
Endocrine Pancreatic cells and their hormone secretions:
Alpha Cells - glucagon
Beta Cells- insulin
Kinase does what to a molecule?
adds a phosphate group and activates it
Phosphatase does what to a molecule?
removes a phosphate group and deactivates it
Phosphorylase does what to a compound?
splits a compound by adding phosphate ( similar to hydrolysis but uses phosphate and not water)
Glycogenesis:
forming glycogen (stored polysacch) from sugar
-stores it for energy for body
Glycolysis:
breakdown of glucose by enzymes to make ATP and pyruvic acid
-can occur with or without O2
-makes 2 pyruvates, 2 ATP, 2 NADH, and 2 H2O
-occurs in cytoplasm
Gluconeogenesis:
forming glucose from non-carb substances
Lipogenesis:
forming lipids/fats
Lipolysis:
breaking down of fats/lipids
Ketogenesis:
synth of ketone bodies
Increased plasma insulin will cause:
-muscles
-increase glucose uptake/use
-net glycogen synth
-net AA uptake
-net protein synth
Increased plasma insulin will cause:
-fat/adipocytes
-increased glucose uptake and use
-net TG(triglyceride) synth
Increased plasma insulin will cause:
-liver
-decreased gluconeogenesis
-net glycogen synth
-net TG synth
-NO ketone synth
Decreased plasma insulin will cause:
-muscle
-decreased glucose uptake/use
-net glycogen catabolism
-net protein catabolism
-net AA release
-FA uptake and use
Decreased plasma insulin will cause:
-fat/adipocytes
-decrease glucose uptake/use
-net TG catabolism
-release of glycerol and FA
Decreased plasma insulin will cause:
-liver
-increased glucose release due to removing inhibitory effects on glycogen catabolism and gluconeogenesis
-increased ketone synth and release
Glucagon response to low glucose:
1.When plasma glucose decreases, pancreatic _ cells increase glucagon secretion.
2. This causes the liver to increase processes of _, _, and _ synth.
3. Plasma glucose and _ are increased.
- alpha
- gluconeogenesis, glycogenolysis, ketone
- ketones
SNS/ Epi response to low glucose:
Epi released from the _ _ impacts the _ _, liver, and adipose tissue
SNS activity impacts the liver and adipose tissue
Skeletal musc increases _
The liver increases _ and _
The adipose tissue increases _
Adrenal medulla->epi-> skeletal musc, liver, and fat
SNS -> increased activity of liver and fat tissue
Skeletal muscle- glycogenolysis
Liver- Glycogenolysis and gluconeogenesis
Adipose- lipolysis
_, _, and _ increase serum glucose when it’s low.
Cortisol, epi, glucagon
Cortisol’s response to low serum glucose:
1. Increases enzymes needed to make glucose from _ in liver cells(muscle mainly)
2. Antagonizes _’s effects of inhibiting gluconeogenesis in liver
3. Causes a moderate decrease in glucose utilization by cells in the body leading to _ resistance
- AA
- insulin
- insulin
