Physiology Exam 4 Flashcards
How do sphincters work
They are aones of resting pressure that relax with stimulus
Smooth muscle sphincters are closed when their inhibitory innervation is inactive.
Where does the vast majority of digestion and absorption take places
The small intestine
What does testosterone exert negative feedback loop on
LH
FSH
Main gastric enzyme in protein digestion
Pepsin
Liver blood supply
splanchnic circulation
25% form hepatic artery (oxy)
75% from portal vein (deoxy)
High flow, high compliance, low resistance system
What forms does CA2+ exist in plasma
45% free ionized Ca2+
45% bound to plasma proteins (ie albumin)
10% complexed with anions
most abundant female hormone
estradiol
Lipoproteins starting with more chloesterol and less protein
Chylomicrons
VLDL
LDL
HDL
PTH and Phosphate feed back
PTH causes excretion of phosphate
Vitamin D causes reabsorbtion of phosphate
Balances out
describe chloride shift in pancreas
As rate of secretion increases in pancreas the rate of bicarb increases as well
A chloride shift occurs to keep ionic balance
Bicarb goes out as chloride goes back in
Vitamin E
Acts as an antioxidant to protect cell membranes
Phases of gastric stimulation
cephalic
Cephalic (feed forward mechanism)
Stimulus = Thought of food
Pathway = Vagus nerve → parietal cells → G cells
Stimulate gastric secretions even before food is swallowed
What is precursor to glycogen
Uridine diphosphate glucose
5 enzymes that help control pancreatic secretion
Secretin Gastrin (GRP) ACh CCK Substance P
What induces the urge to defecate
Distention of rectum
Factors affecting gastric emptying
Type of food Temp of food Body position Stomach PH Emotional state Diseases
When does menses occur
day 28 around to day 4 ish
beginning and end of cycle
Menopause
Age 45-55
decline in estrogen
increase in LH and FSH
osteoporosis
why doesnt menstrual flow clot
fibrinolysin
Chemical digestion
Series of hydrolysis (break bonds) reactions that break dietary macromolecules (polymers) into their monomers (residues)
Carried out by digestive enzymes produced by salivary glands, stomach, pancreas, and small intestine
Polysaccharides → monosaccharides
Proteins → Amino Acids
Fats → Monoglycerides and fatty acids
Nucleic acids → Nucleotides
4 major receptor types
Ligand gated ion channels
g coupled protein receptors (secondary messengers)
catalytic recpetors
intrcellular receptors
Liver sinusoids
Very porous
Allow large flux of fluid and proteins into the perisinusoidal space
Sinusoidal epithelia form large quantities of lymph
Make up more than half of lymph
What inhibits insulin
Somatostatin
Nor epi
Epi
What is trypsinogen
it activates pancreatic enzymes once they are in the duodenum
What cells line bile ducts
Choliangiocytes
These secrete bicarbonate rich fluid into the billiary tree
What does the bulbourethral gland in males do
pre lubrication of urethra
neutralize the acidity of urethra
lingual lipase
Breaks down fat but does not get activated until it reaches the stomach
Describe process epi helps with in liver
Glycogenolyis
GnRH
Gonadotropin releasing hormone
phases of secretion after a meal in pancreas
Gastric
Gastric (feed forward)
Gastric distention release of gastrin and Ach cause increase secretion form pancreas
Describe compaction in the 5 stages of digestion
Absorption of water and consolidating the indigestible into feces
Types of nutrients that can be absorbed directly in their usable form
Vitamins Amino acids Minerals Cholesterols water
peristalsis contraction
Circular muscle contracts behind bolus
relaxation of cicular muscle in front of bolus
Describe Vitamin B12
Vitamin B12 is one of the eight water-soluble B vitamins.
The intestinal absorption of B12 depends on an intrinsic factor secreted from the stomach parietal cell.
Vitamins are water or fat soluble
Vitamin B12 comes from eggs, liver animal products (cobalamins)
Highly involved in helping us from healthy hemoglobin and red blood cells
B12 deficiency can result in anemia (pernicious anemia)
Must have intrinsic factor to absorb B12
Intrinsic factor comes from parietal cells in stomach
What effect does progesterone have on endometrium
as progesterone remains high, endometrial lining remains
As progesterone levels fall, you lose endometrial lining (menstruation)
What does insulin do in liver
Glycogen synthesis
Converts glucose to triglycerides
Protein synthesis
Where is majority of glycogen stored
Liver is the mainstorage site for glucose and glycogen
blood testes barrier
seperates sperm from immune system
sertoli cells form tight junctions
germ cells are differnet so immun system will attack them
What do RBC’s and the renal medulla depend on for energy
totallt dependant on blood glucose
Increased blood flow after a meal is called
postprandial hyperemeia
Sertoli cells (nurse cells)
in semineferous tubules
FSH binds to these cells
produce estradiol
regulate release of FSH through “inhibin” to stop sperm produciton but continue testosterone production
what happens in follicular phase
rise in FSH
follicle grows
Estradiol increases
ends in ovulation
Corpus cavernosa
2 columns of erectile tissue
What does insulin do in adipose tissue
Increases glucose uptake via (glut 4)
Storage of triglycerides
Allows the fatty acids into cell to become triglycerides
Ortho colic reflex
Urge to defecate upon standing
Describe Glucagon in liver
It is catabolic
Glycogenolysis
(also gluconeogenesis)
Primary vs secondary peristalsis in esophageal motility
Primary is act of swallowing
Secondary is involuntary peristalsis (food lodged)
What are gastric agonists
ACh
(Vagus nerve stimulation results in the release of Ach)
Histamine
(hormone)
Gastrin
(Hormone)
Works through secondary messenger system (Ca+, cAMP)
Granulosa cells
receptors for follicle stimulating hormone (FSH)
causes follicle to mature
produces estradiol with testosterone from theca cells
Produces progesterone
What does the enteric nervous system do
Gi tract own nervous system which is independent of the rest of the autonomic nervous system
Responsible for much of the moment-to-moment control of gut motility and secretion.
The myenteric plexus is mainly involved with control of gut motility and innervates the inner circular and outer longitudinal smooth muscle layers.
The submucosal plexus coordinates intestinal absorption and secretion through its innervation of the glandular epithelium, intestinal endocrine cells, and submucosal blood vessels.
What stimulate GnRH in females
kisspeptin (neurotransmitter)
Leptni simulates kisspeptin
GnRH stimulate FSH/LH
Estradiol
phases of secretion after a meal in pancreas
Cephalic
Cephalic (feed forward)
Increases secretion of pancreatic juice
Occurs through the release of Ach, gastrin and by vagal stimulation
Long term stress Response
Pituitary
Retention of sodium increase blood volume and pressure increased BGL Immune system suppression fatigue
What are Paneth Cells, where are they and what do they do
They are cells in the intestinal crypt
They function like neutrophils and produce antimicrobial substances that provide a protective barrier
Gastric enzymes
Pepsin
Gastric amylase
Gastric Lipase
Intrinsic factor
What is transferrin
Transferrin is the molecule that can move iron through the blood
What happens to the follicle
most go to atresia
the chosen one goes on to mature
After rupturing, the follicle becomes a corpus luteum.
What is motilin
GI hormone
Stimulates Motility of Gi tract
Sperm and mitochondria
Sperm has no mitochondria
all mitochondria comes from the mother
Describe insulin effect on potassium
action of insulin is increased cellular uptake of potassium
Also used to treat hyperkalemia
How are ketones formed
Beta oxidation
During prolonged starvation and in diabetes it is highly elevated (ketosis)
Long term fat metabolism
Cells of Gastric secretion G cells (enteroendocrine cells)
Secretes Gastrin
Gastrin secretion is a trigger for secretion from the parietal cells and the chief cells
Preferred substrate of brai
Glucose
• Brain and CNS rely on using glucose
What do H2 blockers do
H2 blockers are commonly used for the treatment of peptic ulcer disease and GERD
What happens in luteal phase
progesterone increases
corpus luteum matures
What happens in ovulatory phase
day 14 ish
LH surges causes ovulation
estradiol decreases
positive feedback
Egg stages
oogonia pirmary oocyte -------------(meiosis) secondary oocyte (& polar body) (meiosis II) if fertilized, If not it dies zygote embryo
Describe Parasympathetic salivation
Parasympathetic salivation
Rich in electrolytes
Rich in amylase
Increased salivation
Testosterone effect on hypothlamus and anterior pituitary
Inhibits
Secretion in which of the following tissues or glands is dependent mainly on parasympathetic nerve stimulation and not hormones?
A. Exocrine pancreas
B. Parotid gland
C. Small intestine
D. Stomach
B. Parotid gland
What forms does phosphate occur in the plsama
80% alkaline phosphate HPO4 2-
20% acid phosphateH2PO4-
Mechanical digestion
Physical break down of food
cutting, grinding, churning
teeth, small intestiners, stomach
exposes more surface area to digestive enzymes
What is ghrelin
GI hormone
Stomach grumbles, ghrelin is secreted
Hunger hormone
What is C peptide
Is a product of pro insulin
is a 1 to 1 ratio of insulin
can be used as a marker of insulin production
Ways the stomach inhibits Acid in stomach
If pH falls below 3, endocrine cells (D cells) in the antrum, secrete somatostatin
Somatostatin inhibits the release of gastrin and thus HCL
Acidification of the duodenal lumen
Acidification stimulates the release of secretin which in turn inhibits the release of gastrin
HCL secretion is important only during digestion of food
Excess HCL can damage mucosal surfaces
Process of pepsin secretion
Food ingested
pH of gastric acid changes (pH goes up, more basic)
The increase in pH stimulates G cells to produce gastrin
Gastrin then stimulates parietal and chief cells
Chief cells secrete pepsinogen
Pepsinogen then gets cleaved into Pepsin by HCL from parietal cell
Pepsin then can go break peptide bonds of amino acids in proteins
The short chain broken down amino acids can also activate the G cells
Sinusoidal epithelial cells (SEC) function
results in large drop in blood pressure and blood flow
what are 3 phases of secretion after a meal in pancreas
Cephalic (feed forward)
Increases secretion of pancreatic juice
Occurs through the release of Ach, gastrin and by vagal stimulation
Gastric (feed forward)
Gastric distention release of gastrin and Ach cause increase secretion form pancreas
Intestinal (feedback mechanism)
Secretin inhibits further movement of chyme from stomach
CCK causes increased secretion of pancreatic juice
Type 1 vs type 2 diabetes
Type 1 insulin dependant
pancreas does not produce insulin
Type 2 is desensitization of insulin receptors
No bonding, no glut transporters,
What do the intestinal crypts secrete
Mucous, H2O and electrolytes
How are Fats/Lipids digested and absorbed
Lipase that activates once in the stomach (gastric, lingual, pancreatic lipase)
Break down into micelles
Micelles then cross brush border
The micelles break down into chylomicrons
Then goes into the lymphatic system
Acid prodcution rate of gastric secretion
Acid production in the stomach parallels rates of gastric secretion
Sodium and Hydrogen ions are inverse
The faster the rate of secretion, the more H+ ions and less sodium ions and the more HCL
What are hydroxyapatite crystals
Components of bone
contain CA2+ and phosphate
Pancreatic enzymes
Enzymes are inactive in pancreas
Trypsin Chymotrypsin Lipase Carboxypeptidase Elastases Nucleases Pancreatic enzymes
Also secrets sodium bicarbonate which neutralizes the acidity of the chyme
scrotal mechanisms to regulat temp
cremaster muscle
retracts scrotum
Dartos fascia
sub cutaneaou smooth muscle
shrinks scrotum
Pampiniform plexus
network of veins and arteries to remove heat
What are inhibitory neurotransmitters of the enteric nervous system
ATP
Nitric oxide
Leydig cells
interstitum (between seminepherous tubules)
produce testosterone
LH bonds to these cells
Epi cascade
Tyrosine DOPA Dopamine Norepi Epi
How is the enteric nervous system linked to the CNS
The ENS is linked to the central nervous system (CNS) via the sensory and motor nerves of the parasympathetic nervous system (PNS) and the sympathetic nervous system (SNS).
In a study in which the volume of the gastric reservoir was recorded with an intragastric barostat in a normal subject, the volume of the reservoir increased and the wall compliance increased simultaneously at the onset of a swallow. This form of relaxation in the gastric reservoir is best described as
A. receptive relaxation.
B. gastric distension.
C. adaptive relaxation.
D. feedback relaxation.
A. receptive relaxation.
What is Haustration
Haustration is reminiscent of the mixing (segmentation) movements in the small intestine
How is sodium absorbed in the gut
Sodium absorption in the gut depends on the sodium potassium pump
2 layers of endometrium
funtional layer (sheds during menstruation)
basal layer (produces the new functional layer)
What causes splanchnic vasodilation
Hormones (high levels of cholecystokinin
Action of enteric nerves (VIPergic)
Gastro ileal reflex
Feed forward mechanism
Food in stomach
increases motility of ileum
Islets of langerhans cells
Have alpha, beta and delta cells
Alpha = glucagon Beta = insulin Delta = Somatostatin
What stimulates insulin
Hyperglycemia
AA
Fatty acids
GI hormones
ACh
What are the major regulated processes of the enteric nervous system
Gut motility
epithelial secretion
blood flow
What are the pacemaker cells of the enteric nervous system
Interstitual cells of Cajal (ICC)
enteric nervous systems own pacemaker cells
located in the myenteric plexus
Gastro colic reflex
Feed forward
Gastric distention increases colonic motility
Where is bile concentrated
the gallbladder
Stages of follicle
Primordial follicle Primary Secondary Early tertiary Graffian follicle
Ovulation
Egg is free from follicle
now corpus luteum
corpus albicans
Breaks down unless pregnancy (becomes placenta)
What does ovary produce
Mature ovum
progestins
androgens
estrogens
where does majority of semen come from
seminal vesicles
75%
fructose
coagulation of semen
How does penis dialate
Nitric oxide
pheochromocytoma
hypersecretion of catecholamines
epi / norepi
increased temp, sweating, HR RR BGL
What color is corpus albicans
white
What do goblet cells do
Secrete various mucins
Describe defecation in the 5 stages of digestion
Elimination of feces
Process of testosterone production
LH binds to Leydig cell receptors
g protein secondary messenger cascade (cAMP)
Cholesterol + STAR protein
make stestosterone
How is Iron absorbed
Must be ferrous iron to be absorbed
Fe2+
Enterocytes absorb iron in duodenum
Then gets transported across brush border and binds to transferrin
Transferrin is the molecule that can move iron through the blood
Ileo - gastric reflex
Feed back mechanism
Ileal distention
causes inhibition of gastric motility
Describe Muscularis externa
3rd layer from inside of 4
smooth muscle layer
2 types
inner circular layer
outer longitudinal layer
mechanically churns food
Most potent form of testosterone
DHT
Major functions of liver
Detoxification of hormones, drugs, waste products
Metabolism of carbs proteins and fats
Storage of iron and vitamins
Hormone production
Innate and adaptive immunity
What are inhibitory gastric hormones
Somastatin
secretin
What is glucagons pupose
break down adipose tissue, break downglycogen
to increase blood glucose levels
Secretion is stimulated by hypoglycemia, epi, vagal, AA
Inhibited by Hyperglycemia, insulin, somatostatin
Basic unit of salivary gland
Salivon
Define paracrine hormone
Hormone that is direct cell to cell
what are 2 secondary messengers for release of secretions
Ca+
cAMP
Calcitonin
Comes from the parafollicular cells (thyroid)
Has the opposite effect of PTH
if calcium levels go up, calcitonin trys to reduce the calcium levels
bone ca2+ reabsorption, urinary excretion of phosphate and calcium
Phosphate and calcium levels decrease
Adrenal Cortex GFR Medulla
G = Mineral corticoids = aldosterone F = Glucocorticoids = Cortisol R = Androgens = DHEA Medulla = EPI/NorEPI (chromaffin cells)
5 stages of digestion
Ingestion Digestion Absorption Compaction Defecation
When does GH peak
during sleep
during adolescence
Describe thyroid
rich blood supply
delivery of thyroid-stimulating hormone (TSH), iodide, and substrates to the thyroid gland.
adrenergic system have direct effects on cells
Follicular cells and colloid produce T3 and T4
Parafollicular cells produce calcitonin
What is the action of cortisol
anti insulin
pressor
anitinflammatory immune functions
moved via albumin
Is circadian, peaks during day, low at night
How are non essential amino acids formed
The liver can form nonessential amino acids from the essential amino acids.
The liver is the body’s only source of nonessential amino acids
Stellate cell function
Store fat in distinct cytoplasmic lipid droplets containing vitamin A
Vitamin A storage
Which of the following is not a physiologic effect of CCK?
A. Gallbladder contraction
B. Stimulation of bile acid synthesis
C. Stimulation of pancreatic enzyme secretion
D. Relaxation of the sphincter of Oddi
B. Stimulation of bile acid synthesis
How much of electrolytes are absorbed in the gut
Approximately 98% of the electrolytes in the gut are reabsorbed.
During an experiment elucidating control of gastric acid secretion, you determine that the stomach releases a paracrine substance that inhibits gastrin release whenever the pH of the gastric mucosa drops below 3. This peptide is most likely:
A. Histamine
B. ACh
C. Gastrin
D. somatostatin.
D. somatostatin.
What does the graffian follicle do
Mature graffian follicle contains the oocyte and is surrounded by granulosa cells
What is secretin
GI hormone
Comes from s cells in duodenum
Stimulus is increase in acid (H+) in small intestine
Increases pancreatic enzyme secretion
inhibts gastric acid secretion
What is the main neurotransmitter in stimulation of Enteric nervous system
ACh
for secretion and motility
phases of secretion after a meal in pancreas
Intestinal
Intestinal (feedback mechanism)
Secretin inhibits further movement of chyme from stomach
CCK causes increased secretion of pancreatic juice
How do nucleic acids breakdown
Nucleases of pancreatic juice hydrolyze DNA and RNA to nucleotides
Nucleosidases and phosphatases of brush border split them into phosphate ions, ribose or deoxyribose sugar, and nitrogenous bases
Membrane carriers allow absorption
Nucleotides can then cross into the blood stream
What anatomical features increase the surface area of small intestine
Cylindrical shape
Circular folds
Microvilli
Villi
Nutrient absorption does not occur without contacting the microvilli brush border
Average female cycle
28 days
What kind of control is gastric secretion under
neural
hormonal
What secrets leptin
Adipocytes
What happens if you lack iodide
this limits T3 and T4 synthesis
This causes chronic stimulation of TSH secretion
This produces goiter
Low iodine, low T3/T4, increased TSH, goiter
What are the regions sympthetic nerves influence
Thoracolumbar region
Celiac
superior and inferior mesenteric
Fight or flight, inhibits digestive functions
Two types of hormones (solubility)
water soluble (protein based)
Receptor is on plasma membrane (can’t cross)
secondary messenger process after that (ie insulin)
fat/lipid soluble (direct gene expression)
Needs proteins to transport it through blood (albumin)
can diffuse through plasma membrane
receptor is in nucleus, then affects gene expression
What hormones regulate CA2+ and phosphate
Parthyroid hormone (PTH) Vitamin D
DEscribe the islets of langerhans make up
Blood flows through the islets of Langerhans from the center toward the periphery so that the α-cells receive a high concentration of insulin;
insulin suppresses glucagon secretion
Alpha cells surround islets
Beta cells are in the center
Delta cells are mixed in randomly
Phases of gastric stimulation
intestinal
Stimulus = Protein digestion products in duodenum, distention
Amino acids in blood → intestinal endocrine cells
Gastrin briefly stimulate stomach, but then secretin,
CCK and enterogastric reflex inhibit gastric secretion and motility
Gives us a chance to digest what is already in the intestine
Sympathetic nervous system will also inhibit digestion
Parasympathetic activates digestion (rest and digest)
Sympathetic inhibits digestion (fight or flight)
What are the regions parasympthetic nerves influence
Cranio sacral
pelvic nerves
vagus nerve
Vagus is most of the gi tract
Sacral pelvic nerves i the latter half of large intestine
Rest and digest, stimulate digestion
Describe Submucosa layer
Connective tissue
second innermost layer of 4
Extensive vasculature and nerves
Lots of regulation and secretion
What is the main target organ of glucagon
the liver
What are Choliangiocytes
Cells that line the bile ducts
They secrete bicarbonate rich fluid into the billiary tree
What happens if the amount of secretions surpass the absorption rate of the small intestine
watery diarrhea
Where does most of lymph come from
Sinusoidal epithelia form large quantities of lymph
Make up more than half of lymph
Drug metabolism in liver
Hepatocytes are involved in metabolism of xenobiotics (foreign substances)
Hydrophobic substances are converted to hydrophilic to be eliminated
• Cytochrome p-450 breaks down drugs
What is the functional unit of the small intestine
The crypt villous unit
How does the body store glucose
Glycogen and triglycerides
Glycogen is short term storage
Corpus luteum vs Albicans
Corpus luteum (yellow)
becomes
Corpus albicans (white)
no more progesterone production
Cells of Gastric secretion
Chief Cells
Secretes pepsinogen and lipase
How are Proteins digested and absorbed
Protein breakdown does not start till stomach
Pepsin in stomach
Protease’s from pancreas (activated in small intestine)
Brush border enzymes breakdown into amino acids
Then absorbed into blood
Cells of Gastric secretion
Mucosa of stomach is lined by various cells
Surface mucous cells Mucous neck cells Parietal Cells Chief Cells G cells
Explain GI motility in relation to slow waves, contraciton and spike potential
Interstitual cells of cajal stimulate
Slow waves are smooth muscle oscillations
Must have spike potentials to push it past the threshold
Once at threshold, mucle contraction occurs
Ca2+ trigger excitation
K+ inhibits
What causes the secretion of secretin
Acidic Chyme in duodenum
Secretin also enchances the the flow of bile rich bicarb from the liver
what is the functional structure in which the oocyte develops
Follicle
The parents of a 5-year-old male received a diagnosis of hypertrophic pyloric stenosis, which is characterized by an absence of electrical slow waves at the gastroduodenal junction. In describing the pathophysiology, the pediatric gastroenterologist explained that a specialized population of cells is missing from the child’s intestine. Which of the following kind of cells is most likely missing?
A. Parietal cells
B. Interstitial cells of Cajal
C. Enteroendocrine cells
D. Kuffer cells
B. Interstitial cells of Cajal
What is somatostatin action on glucagon
inhibits glucagon
Glycogenlysis is
Breakdown of glycogen to release glucose
Down regulation
Cells decrese their receptors for a weaker response
What is albumin function
Albumin helps to preserve plasma volume and tissue fluid balance by maintaining the colloid osmotic pressure of plasma.
Choliangiocyte function
Modulate bile flow through the bile ducts
Disorders of defective bone mineralization
Rickets and osteomalacia
Paget disease is a chronic disorder leading to enlarged and deformed bones
Important plasma proteins synthesized in the liver
Albumin
Transferrin
Fibrinogen
Others
What are the main endocrine functions of the liver
Hormone degredations
Insulin degradation
Glucagon degradation
hGH degradation
GI hormone degradation
What is addisons disease
absence of cortisol
hypoglycemia weakness, fatigue aldosterone deficiency hypotension hypovolemia
hyperkalemia
How often is the epithelial lining of small intestine replaced
every 3 days
Colono gastric reflex
Feedback mechanism
Colonic distention decreases gastric motility
What helps prevent osteoporosis
testosterone
what is cut in vasectomy
vas deferens
2 methods of digestion
Chemical (enzymes)
mechanical
How is B12 absorbed
Intrinsic factor from parietal cells of stomach
GH disorders
Gigantism, tumor before plates close
acromegaly excess secretion after puberty
acondroplasia defect in FGF
Cretinism = hypothyroidism
Describe absorption in the 5 stages of digestion
uptake of nutrien moleculs into the epithelial cells of the digestive tract and then into the blood and lymph
What do the pancreatic duct cells secrete into the pancreatic fluid?
electrolytes
h20
Hyperthyroidism
increased thyroid hormones and decreased TSH
Primary is uncontrolled secretion of thyroid hormones from thyroid gland
secondary is uncontrolled secretion of TSH from Ant. Pituitary
Graves, goiter, autoimmune
Cells of Gastric secretion
Surface mucous cells
Secretes mucin in an alkaline fluid
Where are pancreatic enzymes created
Acinar cells of the exocrine pancreas
What kind of disorder is it in the anterior pituitary
secondary disorder
What does exercise do for Glut 4
GLUT4 is directly stimulated by increased muscle work via AMP kinase due to exercise
exercise is a mechanism to decrease blood sugar
What is detoxification pathway in liver
Toxins
phase 1
phase 2
elimination
What does the submucosal plexus of the enteric nervous system do
The submucosal plexus coordinates intestinal absorption and secretion through its innervation of the glandular epithelium, intestinal endocrine cells, and submucosal blood vessels.
in th submucosa layer
secretion, absorption, blood flow, and endocrine cell activity
Cells of Gastric secretion
Parietal Cells
Secretes HCL and intrinsic factor
How are bile and bilirubin related
Bile helps with bilirubin excretion
Prime temp fro sprem production
35 celsius
Five inhibitory motor neurons to the circular muscle of the colon are shown in association with the formation of haustra. Which of the five numbered neurons is/are most likely to be silent (inhibited)?
A. 2 B. 4 C. 2 and 4 D. 5 E. 1, 3, and 5
C. 2 and 4
the two depressions
What are the main endocrine functions of the liver
Hormone activations
VItamin D activation
T4 to T3 conversion
IGF modification
How are fatty acids transported through the blood
Albumin
What is ejaculation
Contraction of urethra
expulsion of semen
What is potentiation
Occurs when the effect of two stimulants is greater than the effect of either stimulant alone
The agonists potentiate one another
• Potentiation also occurs for pancreas
Describe Mucosa layer
inner layer
Epithelium
Lamina propria
Muscularis mucosae
What do intestinal secretions do
provide lubrication and protective functions
What does oxytocin do?
Contraction of uterus (smooth muscle)
Stimulates milk ejection/production (let down reflex)
Dialate cervix
social bond, climax, arousal
Frequency of slow waves
3 waves per minute in pylorum
12 waves per minute in duodenum
2-13 waves per minute in colon
Large intestine motility
Distention of the colon can also act as a strong stimulus.
Power propulsion is unique to the large intestine.
Gastro colic reflex (feed forward)
Chemoreceptors and mechanoreceptors in cecum provide feeback
Occasional giant migrating contractions (mass movements) propel fecal material into the rectum.
Amylase
Breask down carbs and starches
How does T4 convert to T3
deiodination reactions occur in tissues
Conversion from T4 to T3 in the peripheral tissues using enzymes
can be inactivated as well
salivary secretions
amylase
lingual lipase
Parasympathetic salivation
Sympathetic salivation
Antibodies as well as antimicrobial secretions in saliva
Describe digestion in the 5 stages of digestion
mechanical and chemical breakdown of food into a form usable by the body
Is insulin anabolic or catabolic
anabolic
What does the myenteric plexus of the enteric nervous system do
The myenteric plexus is mainly involved with control of gut motility and innervates the inner circular and outer longitudinal smooth muscle layers.
in the muscularis propria layer
controls sphincter activity.
regulates peristalisis
What are the 3 types of bile
Primary Bile acids
Secondary Bile Acids
Bile salts
What is unique about liver blood supply
It has a dual blood supply
How do the pancreatic enzymes get to the duodenum
through the duct of wirsung
through the sphincter of oddi
Male reproductive hormone cascade
Brain Hypothalamus (GnRH) Anterior pituitary FSH & LH Testes Testosterone (stimulated)
What does insulin do in skeletal muscle
Increases glucose uptake via (glut 4)
Glycogen & glycolysis synthesis
decreases fat breakdown
What do parietal cells secrete
HCL Intrinsic factor (for b12)
hypothyroidism
lower than normal thyroid hormone
1% of population
primary high TSH
Thyroid gland issue
secondary Low TSH
Ant pituitary issue (low TSH)
hashimoto, autoimmune
What is fibrinolysin
Prostate secretion
thin milky secretion
breaks down / liquifies coagulated sperm 15-30 minutes later
Food in duodenum is called
chyme
food before duodenum is bolus
Hepatocyte function
Metabolism
Main digestive gland of the body
Pancreas
What is the main carbohydrate stored in liver
Glycogen
What is the catcholamine response to hypoglycemia
inhibits insulin
gluconeogenysisglucose formation
glycogenolysis (glycogen breakdown for glucose)
triglyceride lipolysis for glucose
how are renein and aldosterone related
They are proportional
the more renin secretion results in more aldosterone secretion
Process of defecation and nervous system
Feces enters rectum stretch receptors activate signals sent to CNS s2-s4 parasympathetic nerve impulses are sent back (pelvic) smooth muscles relax in sphincter recto angle straightens out peristalsis forces feces out
What is cushings
Too much cortisol
hyperglycemia muscle wasting weakness obesity moon face hypertension
Precursor to testosterone
Cholesterol
Most potent female hormone
estradiol
Short term stress response
Hypothalamus
HR increase
BP increase
glycogenolysis (glycogen breakdown for glucose)
metabolic rate increases
What is ammonias role in liver
Ammonia, derived from protein and nucleic acid catabolism, plays a pivotal role in nitrogen metabolism, and is needed in the biosynthesis of nonessential amino acids and nucleic acids.
Which of the following will stimulate bile acid secretion by primary hepatocytes?
A. Fat in the duodenum
B. Gastric distension
C. Malabsorption of lipids by the ileum
D. Secretin
A. Fat in the duodenum
What do you need to begin with toe get Epi
Tyrosine
3 structures of defecation
Internal anal sphincter
external anal sphincter
pelvic diaphragm
What kind of disorder is it in the hypothalamus
Tertiary disorder
What class are epi and nor epi
Catchecholemines
come from chromaffin cells
- Insulin deficiency will cause
A. decreased hepatic glycogenolysis.
B. decreased hepatic glycogenesis.
C. decreased hepatic gluconeogenesis.
B. decreased hepatic glycogenesis.
What stimulates the release of pancreatic enzymes
Calcium released from intracellular stores
Works through secondary messenger system (Ca+, cAMP)
Is glucagon anabolic or catabolic
catabolic
What stimulates bile production
Bile is prodcued in the liver
It is stimulated by parasympathetic impulses from the vagus
Liver regeneration
The liver is the only organ capable of regenerating ist own tissue
Can fully regenerate with as little as 25%
Hepatocytes make this possible due to mitosis
What are inhibitory precursor hormones from hypothalamus
Dopamine
somatostatin
What is emulsification
Emulsifies or breaks down lipids into smaller parts or droplets
The lipases can then act on those smaller droplets
What is gastrin
GI hormone
Comes from G cells (stomach)
Increases stomach motility and H+ secretion
Stimulus is distention of stomach, vagus nerve or AA in stomach
2 segments of small intestine motility
propulsion
receiving
What are slow waves
They are smooth muscle oscillations
Must have spike potentials to push it past the threshold
Once at threshold, mucle contraction occurs
No slow waves in esophagus
What is first pass emtabolism
muspass through thte portal venous system and the liver before entering the systemic circulation
3 phases of gastric stimulation
cephalic
gastric
intestinal
What is a lack of contraction called in small intestine
physiological ileus
What does porinsulin become
Insulin and c peptide
What are 3 types of relaxation of stomach as food enters
Receptive
Adaptive
Feedback
up regulation
cells increase their receptors for a stronger response
What kind of disorder is it in the endocrine gland
Primary disorder
How does vitmain D increase calcium levels
The liver and kidneys convert vitamin D to the active hormone 1,25-dihydroxycholecalciferol.
Also need UV light to convert Vitamin D
This hormone stimulates intestinal calcium absorption .
3 phases of esophageal motility
Oral phase (voluntary) Pharyngeal phase (involuntary) Esophageal phase (involuntary)
Fat soluble vitamins stored in liver
A, D, E, K
Corpus spongiosum
one column that surrounds the urethra
What is emission
sperm moves into the urethra
bladder sphincter closes
what kind of receptors are on parietal cells
Histamine receptors
H2
What stimulates the secretion of CCK
Fatty acids and amino acids in chyme entering the duodenum stimulate secretion of CCK.
Glucose to glycogen is called
Glycogenesis
Phases of gastric stimulation
gastric
Gastric (feed forward)
Stimulus = Stomach distention
Local reflexes and vasovagal reflexes → parietal cells → G cells
Histamine and gastrin stimulate acid production
Kufpper cell function
Production of bilirubin
macrophages of liver
What is stress hormone
Cortisol
Blocking H2 histamine receptors in the stomach reduces gastric acid secretion during the cephalic phase of digestion because histamine:
A. directly stimulates pepsin secretion.
B. potentiates the actions of secretin in the stomach.
C. potentiates the acid-stimulating action of vagal stimulation on the stomach.
D. mimics the actions of Cholecystokinin (CCK).
C. potentiates the acid-stimulating action of vagal stimulation on the stomach.
Which bone cells are more active if there is a drop in blood calcium
Osteoclasts
breaks down bone to release more calcium into blood
What is the process of bilirubin breakdown and excretion
o Bilirubin is a byproduct of hemoglobin metabolism
o Macrophages break it down into biliverdin (green color)
o Biliverdin reductase converts biliverdin into bilirubin (yellow color)
o Bilirubin leaves the macrophage now called unconjugated bilirubin
o Albumin in blood binds unconjugated bilirubin and transports to hepatocytes.
o Hepatocytes convert it to conjugated bilirubin.
o This makes bilirubin more soluble so can it be secreted into bile
o In intestines, bacteria hydrolyze bilirubin into colorless urobilinogen.
o Normal urine contains urobilinogen.
o Most of the urobilinogen, becomes oxidized by gut bacteria to form stercobilin.
o Stercobilin is what makes feces brown in color.
o enterohepatic circulation Is another way bilirubin and bile acids get recycled
Hormone defenition
secreted into blood stream (endocrine)
distant target cell
some also do cell to cell communication
and diffusionin intersitual fluid
Hormones initiate a cell response by binding to specific receptors.
Goal of digestion
absorption
What does CCK do
CCK causes the contraction of the gall bladder
whcih causes the release of bile
as well as the relaxation of the sphincter of Oddi
Liver cell types
Hepatocytes Kupffer cells Choliangiocytes Sinusoidal epithelial cells (SEC) Stellate cells (Ito cells)
What is key organ in carbohydrate metabolism
Liver
What do delta cells do
in the islets of langerhans
of pancreas
produce somatostatin
5 steps to making tyroid hormone
Iodide trapping
Thyroglobulin is synthesized & secreted
Iodination and conjugation (T3/T4 created)
Endocytocis of thyroid colloid
Secretion by exocytosis (T3/T4 secreted into blood)
90% T4, 10% T3,
Spermatogenesis
1 - Germ cell 1 - spermatagonium 2 - spermatagonia 1 - primary spermatocyte 2 - secondary spermatocytes (2 per) 4 - spermatids (1 each) 4 - mature spermatozoa
Where does B12 come from
Vitamin B12 comes from eggs, liver animal products (cobalamins)
Define endocrine hormone
hormone that enters the blood stream
Describe Serosa
outer layer
connective tissue
Areolar tissue
Mesothelium
Reduces friction with other structures
Describe insulin in the liver
It is anabolic
Takes glucose and builds it into glycogen
regulates glycogenesis
Vitamin D
Builds strong bones and teeth
Cells of Gastric secretion
Mucous neck cells
Secrete mucin in an acidic fluid
What exerts control over CA2+ and phosphate homeostasis
PTH
Parathyroid hormone
Vitamin A
Healthy skin, mucous membranes, prevents night blindness, Promotes growth
How is water absorbed in the gut
osmosis
GI tract is extremely efficient in absorbing H2O
o Lots of water added, (i.e. 8900ml)
o lots of water then reabsorbed (i.e. 8900ml),
o small amount lost in feces (i.e. 100ml)
3 main salivary glands
submandibular
sublingual
parotid
Testosterone potency
DHT
Testosterone
Androstenedione
DHEA
What is CCK
Cholecystokinin
GI hormone
comes form I cells in duodenum
works on all GI organs
increases gastric secretion, contraction
inhibits gastric emptying
Where is bile produced
The liver
In hepatocytes
3 classes of hormones
amine based
peptide based
Steroids
What is a lacteal
Lymphatic capillary
Describe ingestion in the 5 stages of digestion
selective food intake
Where do gall stones occur
Can occur anywhere in biliary tree
Can cause pancreatitis and jaundice
Number of oocytes in female by age
birth - 1 million
puberty - 200,000
30 - 25,000
menopause - 0
What are pancreatic secretions rich in?
Bicarbonate ions
Happens through bicarbonate anhydrase reaction
PTH calcium feed back
decrease in blood calcium
induces the secretion of parthyroid hormone
PTH goes into blood stream
PTH causes bone to release CA2+, the kidneys to conserve and keep CA2+ Kidneys to activate Vitamin D Vitmamin D causes Intestines to absorb more CA2+ CA2+ increases PTH secretion is inhibited
How are carbohydrates digested and absorbed
Starts in mouth with saliva
Then pancreatic juices
Brush borders enzymes break the sugars down to simple sugars
Simple sugars go across brush border of small intestine
Then absorbed into blood
Where does bile origante
Bile canaliculus
What stimulates glucagon
Hypoglycemia
AA
ACh
Nor epi
epi
Where is bile stored
the gallbladder
Pancreas enzymes
Endocrine vs exocrine
Has both
endocrine (insulin)
exocrine (digestive enzymes) functions
Describe Sympathetic salivation
Sympathetic salivation
Rich in mucous
Reduced salivation
What stimulate prolactin porduciton
Dopamine
Intersitutal cells of cajal
pacemaker cells of GI tract
generate slow waves
Immune functions of liver cells
Ideal site for the clearance of blood-borne antigens and pathogens.
Hepatocytes, SECs, Kupper cells act as APCs
Stellate cells release interferons and cytokines
Other ways gluconeogenesis can occur
Through lactate
fats
amino acids
What inhibits glucagon
Fatty acids
somatostatin
insulin
What do T3 and T4 do
Regulate metabolism
T3 is more physiologically active
T3 affects transcription increases metabolic rate increases Na+ / K+ pump increases Beta adrenergic receptors
Migrating motor complex (MMC)
Bouts of contraction occur 2-3 hours after meal
used to flush the system
occurs about every 90 minutes between meals
intervals of strong then propulsive contractions
Under the influence of hormone motilin
salivon structure
All connected
Acinus
intercalated duct
striated duct
excretory duct
How are PTH, Vitamin D, and calcium related
Parathyroid hormone and vitamin D are required for calcium absorption
PTH activates vitamin D, makes gut more permeable to calcium
PTH = more calcium absorption
Vitamin K
Helps blood clotting
What must happen for nutrient absorption to occur
Nutrient absorption does not occur without contacting the microvilli brush border
What cells secrete CCK and secretin
I cells
or
enteroendocrine cells
What does AVP (ADH) do
Humoral stimulus
increases reabsorption of water by kidneys
What is bilirubin
Bilirubin is a waste product of hemoglobin breakdown
It is the end product of hemoglobin degradation
How do the parasympathetic and sympathetic nervous systems effect the enteric nervous system
PNS stimulates (rest/digest)
SNS inhibits (fight/flight)
where are sperm stored and matured
epidiymis
major secondary messengers
cAMP IP3/DAG Eicosanoids Guanylyl cylase Tyrosine kinase
Define autocrine hormone
Horomne that is secreted and works on itself
What color is corpus luteum
yellow
What does the adrenal cortex do
Synthesizes and secrets steroid hormones
Highly vascular
secretes on demand, not stored
What happens in stomach as food enters
Stomach relaxes
Folliculogenesis
production and maturation of follicle
What do theca cells do
LH binds to these cells
produce testosterone and is then sent to granulosa cell where it is converted into estradiol (FSH helps)
How do gall stones form
When cholesterol becomes too saturated
Can cause pancreatitis and jaundice
Things that effect drug metabolism in liver
Age Nutrition Genetics Sex Hormones
What role does liver play in iron tranpsort, storage, and metabolism
Kupffer cells breakdown damaged red blood cells through phagocytosis
Iron released from heme becomes part of free iron pool in blood
Transferrin is the molecule that can move iron through the blood
Must be ferrous iron Fe2+
What is the precursor molecule for all of the hormones and steroids of the adrenal cortex
ie. aldosterone, cortisol, DHEA
Cholesterol
Secondary messenger system (cAMP)
Star proteins move cholesterol into the mitochondria
What is atresia
follicles do not continue to develop
Hormones from the posterior pituitary
ADH
Oxytocin
Hormones form anterior pituitary
FLAT GP
FSH LH ACTH TSH GH Prolactin
ALl are tropic from hypothalamus
What is the role of the parasympathetic nerve activity after a meal
It stimulates GI secretion and motility, which also indirectly increases splanchnic blood flow as a result of increased local metabolism
(increase blood flow, parasympathetic, rest/digest)
What causes intestinal fluid hyper secretion
Toxins and other luminal stimuli
Transporter to bring glucose into liver
GLUT 2
facilitated transporter
4 layers of digestive system
Mucosa (inner layer)
Submucosa (connective tissue)
Muscularis externa (smooth muscle layer)
Serosa (outer layer)
What are fatty acids used for
Citric acid cycle
How are gametes transported within the female genital tract
Cilia and smooth muscle
how long is egg viable after ovulation
24 hours
how long is sperm viable for after ejaculation
48 hours
How long is fertilization window
2 days
fertilization process
sperm passes follicular cells (binds)
Acrosomal reaction occurs
acrosomal enzyme breaks down zona pellucida
sperm penetrates
causes rise in Ca2+ (cortical rxn)
this blocks off any other sperm from entering
this also triggers 2nd meiosis division
male sperm head then enlarges and fuses with female nucleus
Process of implantation
zygote (fertilized egg) 4 cell stage (day 2) morula (day 3) (16 cells) early blastocyte (day 4) Implanting blastocyte (day 7)
Amnion
Transparent sac filled with amniotic fluid
What is chorion
fetal portion of placenta
Encloses the embrionic body
provides gas and nutrient exchange
Yolk sac
forms part of digestive tube
earliest blood vessels
Allantois
small outpocket on yolk sac
umbilical cord
urinary bladder
intervillous space
acts like a big capillary
gas exchange
When does the placenta assume produciton of progesterone
week 9
What saves the corpus luteum from being brokendown
the early production of HCG in embryo
When is HCG detectable
Dectectable in urine 8-9 days after conception
What is hCS
human chorionic somatomammotropin (hCS)
hCS is the primary hormone in pregnancy that induces a state of insulin resistance in the mother
Causes gestational diabetes
Parturition
Process of delivery
Lactation
sucking inhibits GnRH
which suppresses FSH and LH
also suppresses the menstrual cycle (while breast feeding)
When does menstruation resume after breast feeding
Usually resume menstrual cycles about 2 months after giving end of breast-feeding.
Importatn hormones of birth delivery
Estrogen
induces oxytocin
Oxytocin
stimulates contractions and production of prostoglandins
Prostoglandins
help to soften the cervix
