Physiology Test 4
Card Set Information
Physiology Test 4
Digestion and Secretion
Humans must get basic organic molecules from food for what three reason
1. make ATP
2. build tissues
3. serves as cofactors and coenzymes
carbohydrates, fats, and proteins broken down to building blocks during digestion
building blocks taken into the bloodstream by absorption
By what process does digestion break down polymers into monomers?
hydolysis reactions- adding water
Where is the digestive tract considered to be in relation to the body?
indigestible fiber- wood fiber
Six functions of the digestive tract
5. storage and elimination
6. immune barrier
taking food into the mouth
one way automatic rhythmic movement through the GI tract starting at the esophagus after swallowing
churning as in the stomach
digestive enzymes, acid, mucus released outside an organ or tract
hormones to regulate digestion released within an organ or tract
breaking food down into smaller units
passing broken down food into blood or lymph
simple columnar epithelium with tight junctions to prevent swallowed pathogens from entering the body
Parts of the GI tract
mouth- stomach- pharynx- esophagus- cardiac sphincter- stomach- pyloric sphincter- duodenum (SI)- jujenum (SI)- ileum (SI)- large intestines- rectum- anus
length of the gastrointestinal tract
other organs that help the digestive tract but are not considered directly part of the tract
6 accessory organs
how many adult teeth do most people have?
GI tract layers
inner secretory and absorptive layer that may be folded to increase surface area
layer that contains glands and is very vascular to pick up nutrients
smooth muscle layer responsible for peristalsis and segmentation
outer binding and protective layer
stimulates and speeds up esophagus, stomach, small intestine, pancreas, gallbladder, and first part of large intestine by using parasympathetic division of GI tract
stimulates and speeds up lower large intestine by using the parasympathetic division of the GI tract
spinal nerves in sacral region
slows down and inhibits peristalsis and secretion by stimulating contraction of sphincters
sympathetic division of GI tract
paracrine signals and sensory neurons in gut wall
contains mucus and amylase to start digestion of starch and carbs
antimicrobial agen in saliva
How many muscles coordinatedly contract in deglutination?
Three parts of deglutination
voluntary part of deglutination where the muscles of mouth and tongue mix food with saliva
initiated by receptors in the posterior oral cavity and oropharynx
covers the nasopharynx
covers the vocal cord
What relaxes in order to allow deglutination?
upper esophageal sphincter
automatic part of deglutination regulated by the controlled byswallowing center of the brain stem
lump of food moving down the esophagus after swallowing
Mouth, pharynx, and upper esophagus are lined with ___ ____ and innervated by ___ ____ ___.
skeletal muscles; somatic motor neurons
Lower esophagus is lined with ___ ___ controlled by the ___ ____ ____.
smooth muscle; autonomic nervous system
length of the esophagus
the esophagus passes through the diaphragm through what structure?
esophagus is lined with what type of cells?
nonkeratinized stratified squamous epithelium
What sphincter allows food to pass into the stomach but not out
lower esophageal/ cardiac
5 functions of the stomach
churns food to mix with gastric secretions
begins protein digestion
kills bacteria in food with stomach acid
moves food into small intestine
food passing into the small intestines after going through the stomach
Food is delivered to the ___ region of the stomach.
upper region of the stomach
lower region of the stomach
distal region of the stomach
end of the pyloris and start of the small intestine
stomach folds in lining
stomach ulcers most occur in what region?
caused by overloading acids on barriers by burning, carbonation, and acidic foods
Located at the base of rugae to make secretory cells
secrete mucus to help protect stomach lining from acid
mucus neck cells
secrete HCl acid and intrinsic factor to help small intestine absorb vitamin B12
secrete histamine and serotonin as paracrine signals
enterochromaffin-like (ECL) cells
secrete gastrin hormone
descrete somatostatin hormone
primary active transport of H+ takes place through ____
H+/ K+ ATPase pumps
Cl- is transported through what process?
made in G cells and carried to parietal cells in blood to stimulate secretion of HCl
Gastrin stimulates ECL cells to secrete ___.
stimulates parietal cells via H2 receptors
stimulate parietal and ECL cells
Main functin of HCl
drops pH to 2
Describe the process by which HCl drops pH level
-Proteins denatured allowing enzyme access.
-Pepsinogen converted to active pepsin digests proteins.
-Drops pH level
Optimum pH for pepsin activity
Two things that could eat the stomach lining
acid and pepsin
Three defenses prevent eroding of the stomach lining
-adherent layer of mucus with
between epithelial cells
that replaces epithelium every
Stomach is the site of beginning digestion for which molecule?
Starches begin digestion in __
Starch digestion ends in the ___. Why?
stomach because salivary amylase is not active at pH 2
Only common substances absorbed in the stomach
alcohol and NSAIDs
erosions of the mucosa of the stomach or duodenum
bacterium that reduces mucosal barriers to acid
treatment for ulcers is a combination of ___ and ___.
K+/H+ pump inhibitors and antibiotics
inflammation of the submucosa caused by erosion from acid
needed to stimulate protective alkaline mucus production
Tagamet and Zantac inhibit ___ receptors.
big folds of the small intestine's mucosa and submucosa
three sections of the small intestine in order from top to bottom
mucosa of the small intestine has smaller folds called __?
epithelial plasma membranes are folded into ___
Site of complete digestion of carbs, proteins, and fats
Part of the small intestine that absorbs sugars, lipids, amino acids, calcium, and iron
duodenum and jejunum
part of the small intestine that absorpbs bile salts, vitamin B12, water, and electrolytes
columnar epithelium with goblet cells
villi and microvilli
what absorbs sugars and amino acids?
absorbs fatty acids
Lacteal is part of the ___ system.
have microbial properties and secrete antibacterial molecules
Paneth cells and mitotic stem cells make up ___.
intestinal enzymes located on villi
brush border enzymes
Brush border enzymes break 2, 3, 4 carbs apart to make ___.
Monosaccharides are absorbed by ___.
Active sites of brush border enzymes are exposed to ___.
Intestinal peristalsis is week because of pressure where?
What upsets autonomic peristalic rhythms?
toxins in small intestine
Stronger function of small intestines and its purpose
segmentation- to mix the chyme
___ ___ contractions occur automatically.
graded depolarizations produced by pacemaker cells that cause action potentions in muscle cells
What causes smooth muscle to contract automatically?
pacemaker cells of the smooth muscles
interstitial cells of Cajal
Depolorization fromt he interstitial cells of Cajal opens ___ gated __ channels
___ ___ nervous system stimulates or inhibits cells of Cajal.
Two things of the parasympathetic system that combine to increase amplitude and duration of slow waves
Acetylcholine and muscarinic ACh receptors
Path of the Large Intestine
ileocecal valve- cecum- ascending colon- transverse colon- descending colon- sigmoid colon- rectum- anal canal- anus
Four functions of the large intestine
-absorptin of water, electrolytes, vitamin K, and some B vitamins
-production of vitamin K and B vitamins via microbial organisms
-storage of feces
-minimal break down of Beta 1, 4 (cellulose) linkages by bacteria
several hundred different species of bacteria that live in the large intestines
Two categories of intestinal bacteria
commensal and mutualistic
bacteria that benefit while not harming the host
bacteria that benefit while also benefiting the host
Four benefits of microbes
- make vitamin K and some B vitamins
-make fatty acids from cellulose for energy
-aid absorption of electrolytes and salts
-outcompete harmful bacteria
IBS is caused by disruption of normal ___.
How much water is excreted with feces per day?
Stimulates greater salt and water absorption
what secretes aldosterone?
Controls defecation voluntarily
external anal sphincter
contract to increase pressure as the anal sphincters relax
longitudinal rectal muscles
As material passes to the rectum, PRESSURE ___ and the internal sphincter ___.
largest abdominal organ
first stop for blood from intestines
regenerative liver cells
capillaries that separate hepatic plates
True or False: The liver is very permeable.
delivers products of digestion absorbed in intestines to the liver
hepatic portal vein
blood leaves the liver after circulating through its capillaries through the ___
formed by hepatocytes and arranged as liver lobules with hepatic arteries, hepatic portal veins, and a central vein
bile secreted by hepatocytes is released into the __ ___
Five functions of the liver
detox of blood
secretion of bile
Where are molecules in bile reabsorbed to be returned to the liver?
How much bile does the liver make per day
Five components of bile
bile pigments (bilirubin)
breaks large fat down into small beads of fat
what acts as an emulsifier
color of bilirubin
a not water-soluble component derived from hemoglobin and produced in spleen, liver, and bone marrow
Bilirubin IS OR IS NOT directly filtered by kidneys and secreted by bile?
conjugates with bilirubin to make the bilirubin water soluble
color of biliverdin
When can bilirubin be secreted in bile?
when it is water soluble and conjugated
component that makes feces brown and is converted from bilirubin by bacteria in the small intestine
percentage of urobilinogen absorbed and taken to liver
Some urobilinogen can be used in the blood and kidneys to make )).
made from bile acids conjugated with glycineortaurine
derived from cholesterol and contain four polar groups on each molecule
Two examples of bile acids
cholic acid and chenodeoxycholic acid
most bile acids is recycled through ___ ___.
How much cholesterol is broken down and lost in feces?
bile salts form ___ with polar groups toward water
functional bile salts contain __
Three ways for the liver to detox the blood
secreted into bile
phagocytized by Kupffer cells in sinusoids
chemically altered by hepatocytes
converted into urea
returned to the blood to be filtered by the kidneys
altered and secreted into bile
Two things the liver stores blood glucose as and the processes by which it is done
What happens to glucose that the liver breaks down to glycogen?
stored or release into blood
can be made by liver from glucose by process of ___.
amino acids; guconeogenesis
__ can be made from fatty acids by the liver by the process of ___.
stores and concentrates bile from the liver
tract of the gallbladder
liver- bile ducts- hepatic duct- cystic duct- gallbladder- cystic duct- common bile duct- duodenum
sphincter located in duodenum
sphincter of ampulla
make insulin and glucagon in pancreas
Islets of Langerhans cells
make pancreatic juice to be delivered to the duodenum
Endocrine or Exocrine? insulin and glucagon of the pancreas
Endocrine or Exocrine? pancreatic juice of pancreas
bicarbonate + 20 digestive enzymes
made from CO2 from the blood by cells lining ductules
Process by which bicarbonate is made
-carbonic acid made
-carbonic acid dissociates to form H+ and bicarbonate
Bicarbonate is ___ into ___, and H+ is ___ into ___.
secreted; pancreatic juice; absorbed; blood
Bicarbonate is countertransported with __.
condition in which a person has trouble secreting bicarbonate, thus destroying the pancreas
inactive until they reach the small intestine
activated enzyme to digest protein
primary stage of digestion
starch digestion continues in small intestines with ___ ___
Two components of brush border cells
tripsin and enzymes
Two ways monosaccharides are absorbed across the epithelium
- secondary active transport with sodium
- facilitated diffusion with high glucose
formed from pepsin in stomach during digestion of proteins
Five enzymes to finish protein digestion
Digestion of proteins end in the ...?
duodenum and jejunum
During the absorption of proteins, ____________ are cotransported with sodium
free amino acids
Dipeptides and tripeptides cross via what?
secondary active transport
Aids dipeptides and tripeptides in active transport
pH range needed for protein digestion
Fat digestion begins where?
breaks down or emulsifies fat
breaks fat down into fatty acids
stripped to have two molecules outside of the gradient and one inside
Fatty acids and monoglycerides are transported to ___
brush border cells
Fatty acids and monoglycerides in epithelial cells are turned into what three things?
Fatty acides combine with proteins to make __.
main source of muscle energy
Two components of fat molecules
free fatty acids and glycerol
___ ___ drops chylomicrons into the bloodstream at the ___ ___.
lymphatic system; thoracic duct
agent that allows chylomicrons to bind to receptors on the capillary epithelium within muscles and adipose tissue
releases free fatty acids for use by muscle cells or storage by fat cells
Formed from the combination of cholesterol and triglycerides with apolipoproteins
very-low-density lipoproteins (VLDLs)
removed triglycerides which transport cholesterol to organs
low-density lipoproteins (LDLs)
cholesterol is excess returned to the liver
high-density lipids (HDLs)
primary function of the kidneys
blood pressure regulation
Four functions of the kidney
plasma volume/ BP
waste products in blood
functional unit of the kidney responible for forming urine
how many nephrons per kidney?
> one million
Three functions of nephrons
Made up of the glomerulus and Bowman's capsule
What is and is not secreted from the Bowman's capsule?
plasma is and blood is not
Function of the renal corpuscle
filtration slits of the kidney
Volumes of filtrate produced by BP
connected to Bowman's capsule for reabsorption
proximal convoluted tubule (PCT)
returns most filtrate to peritubular capillaries
reabsorption of PCT
How much urine excreted in 24 hours maximum?
Minimum amount of urine that must be excreted per day
Sodium goes out of filtrate by
Two things that passively follow sodium out of PCT
chlorine and water
part of Loop of Henle that is permeable to water; impermeable to salt
part of Loop of Henle that is impermeable to water' permeable to salt
allow descending and ascending limbs of Loop to increase osmolality in medulla
countercurrent flow and proximity
An increase in osmolality in ___ ___ causes more filtrate to be delivered to ___ ___.
descending loop; ascending loop
Pumping sodium out of ascending loop __ osmolality causing increased ___ to diffuse out of ___ ___.
increases; water; descending loop
__ filtrate causes more sodium transport, which results in __ osmalality around ___ ___.
increased; increased; descending loop
covering of Loop of Henle for secretion
important component of countercurrent multiplier
Vasa recta recirculates salt trapping some in the ___.
what reabsorbs water coming from where on the loop of henle?
ascending loop; descending loop
hyperosmotic urine produced due to maintenance of solute gradients
contributes to osmolality in medulla
urea diffuses to __ __.
plays important role in water conservation because it is impermeable to salt in the medulla and permeable to urea
permeability of water in the collecting duct varies because of
antidiuretic hormone (ADH)
Three components of urine
urea and uric acid
trace amino acids
causes regulation and secretion of urine
creatine and urea
imparied ability to excrete wastes and regulate blood volume, pH, and electrolyes- resulting from atherosclerosis, inflammation of tubules, kidney ischemia, or NSAIDs
acute renal failure
inflammation of glomeruli caused by an autoimmune attack against glomerular capillary basemen membranes and leakge of protein into urine
nephrons destroyed causing salt and water retenion and uremia
condition with high plasma H+ and K+ levels
inability to regulate ammonia or urea flow
How to solve many urinary problems
How much fluid does the average person need per day?
men- 3 liters (13 cups)
women- 2.2 liters (9 cups)
procedure used to shatter simple stones in the kidney or upper urinary tract
extracorporeal shock wave lithotripsy (ESWL)
bacteria enters the bladder or kidneys
cystitis is more common in ___ because the urethra is shorter.
common name for cystitis
Symptoms of a urinary tract infection
frequent need to urinate
pain in abdomen
burning sensation during urination
cloudy, bad smelling urine
blood in urine
low back pain
A UTI can be an infection of what two things?
bladder or kidneys
tube that can be inserted into a body cavity (such as the bladder), duct, or vessel
process of inserting a catheter
sudden contractions of the bladder produce sensation of urgency, more common in women
inability to control urination or defecation
synthetically removing, cleansing, and putting blood back through tubing of various passage sizes
waste product of protein digestion
inadequate rate when kidneys fail to filter that causes an increase in creatine
glomerulus filtration rate (GFR)
feuls filtration rate
bacteria in urine could cause what appearance?