digestive and urinary system Flashcards
What are the tissue layers that make up the digestive tract?
mucosa
submucosa
muscularis
serosa
mucosa
innermost layer of digestive tract
submucosa
middle layer of digestive tract layers
muscularis
outermost muscular layer with 2 types of muscle:
longitudinal and circular
serosa
the outermost layer of the digestive tract, houses the other three layers inside it
peritoneum
serous membrane that forms the lining of the abdominal cavity
mesenteries
2 layers of peritoneum fused together that anchor organs to the cavity wall
mouth
ingestion, tasting, and chewing
pharynx
muscular funnel which connects mouth to esophagus
esophagus
used for swallowing, no digestive purposes
stomach
mechanical and chemical breakdown of food
small intestine
nearly all chemical digestion and nutrient absorption
3 segments of the small intestine
duodenum
jejunum
ileum
large intestine
absorbs water and salts and eliminates feces
liver
secretes bile that contributes to digestion
pancreas
produces most of the digestive enzymes in their zymogen form
gallbladder
stores bile for future use
amylase
produced in mouth
breaks down starch
enzyme
trypsin
produced by pancreas
digests protein
enzyme
gastrin
produced in stomach
stimulates acid production
hormone
cholecystokinin (CCK)
produced in duodenum in response to fat
stimulates gallbladder to release bile
secretin
produced by small intestine in response to chyme
stimulate liver and pancreas to secrete bicarbonate
buffers HCL
pepsin
secreted by chief cells in the stomach
digests protein
enzyme
carboxypeptidase
produced by pancreas
removes amino acids from end of chain
enzyme
Dipeptidase
produced in pancreas
splits dipeptides to release 2 peptides
Enzyme
Lysozyme
produced in salivary glands
kills bacteria
enzyme
pancreatic juice
produced by pancreas
mix of zymogens released into duodenum
HCL
produced in stomach
breaks down food particles in the stomach
acid
bicarbonate
produced in stomach
maintains ph in body
hormone
bile salts
produced in liver
aids in fat digestion
steroid
disaccharidase
produced in pancreas
breaks down disaccharides
enzyme
somatostatin
produced in stomach
inhibits acid production
hormone
what controls/contributes to HCL production?
stimulation by ACh, histamine, and gastrin
high if all three ligands bind, low if it is only one
enteric NS
located between layers of the digestive system
short reflexes
stretching or chemical stimulation triggers contraction of smooth muscle
long reflexes
autonomic nerves trigger contraction of smooth muscle
mechanical breakdown
physical breakdown of food, chewing and swallowing
chemical breakdown
use of chemicals, enzyme, and hormones to break down food
what are proteins broken down into?
broken down into shorter peptide chains
what are fats broken down into?
2 free fatty acids and a monoglyceride by lipase’s
what are carbohydrates broken down into?
eventually broken down into glucose
components of saliva
mainly water + mucus, lysozymes, amylase, and lingual lipase
zymogens
inactive enzymes
segmentation
movement of haustra in the intestine
peristalsis
muscular contraction that pushed food through a tube
cephalic phase of gastric function
stomach responds to smell, sight, taste, or thought of food
gastric phase of gastric function
swallowed food activates gastric activity
intestinal phase of gastric function
duodenum responds to chyme and moderates gastric activity through hormones and nervous reflexes
three phases that control gastric function
cephalic
gastric
intestinal
how are carbohydrates absorbed
turned into glucose and used as energy
how are lipid’s absorbed
broken down and reformed over and over again until it cant be anymore
how are proteins absorbed
broken down into free amino acids, then taken away by hepatic portal circulation
Lacteals
absorb fat from the digestive system in the small intestine
sphincters
esophageal
pyloric
ileocecal
anal
functions of bacterial flora in the colon
extract the nutrients we cant
digest things we cant like pectin
2 reflexes that control defecation
- intrinsic defecation reflex
2. parasympathetic defecation reflex
intrinsic defecation reflex
involuntary but also relatively weak
drives feces towards the anus
parasympathetic defecation reflex
stretching signal sends signal to spinal cord which sends back signal to intensify peristalsis in descending and sigmoid colon and relax internal anal sphincter
functions of the urinary system
excretion of waste
regulation of blood volume and pressure
regulation of solutes in the blood
nephron
regulates water and solutes by filtration of the blood
renal corpuscle
houses bowman’s capsule and glomerulus
bowman’s capsule
houses filtrate, surrounds glomerulus
glomerulus
place where blood comes to the kidney for filtration
renal tubule
duct that leads away from the glomerulus
separated into 4 parts
proximal tubule
majority of absorption
nephron loop
releases water in descending tube and releases solutes in ascending tube
distal tubule
active transportation of sodium
collecting tube
one for many nephrons
collects almost finished product and finished final filtration
kidney
filters blood contents and forms urine
ureter
tubes connecting kidneys to bladder
bladder
holds final urine product for excretion
urethra
tube leading from bladder to the outside of body for expulsion
3 stages of urine formation
filtration
reabsorption
secretion
filtration
movement of materials across filtration membrane
reabsorption
solute reabsorbed across wall of nephron
secretion
solute secreted from peritubular capillary into filtrate
hydrostatic pressure
glomerular capillary BP, very high
colloid osmotic pressure
pulls water back into capillary
hydrostatic pressure
fluid inside bowman’s capsule opposing fluid movement into capsule
glomerular filtration rate (GFR)
the rate the kidneys filter blood
depends on pressure in and around glomerulus
renal autoregulation
ability of nephrons to adjust their own blood flow and GFR without external help
2 methods of renal autoregulation
Myogenic mechanism
tubuloglomerular feedback
myogenic mechanism
tendency of smooth muscle to contract when stretched
tubuloglomerular feedback
circle of nerves wrapped around distal tubules that cause contraction when stretched
renin
increases BP
ADH
increases BP
ANH
lowers BP
renal clearance
volume of blood plasma from which a particular waste is completely removed in 1 minute
countercurrent multiplier
ascending tubule of nephron loop
countercurrent exchange system
descending tubule of nephron loop
micturition reflex
peeing
transport maximum
the highest rate of transfer in and out of the nephron loop
what affects tubular reabsorption
hydration, functionality of kidney’s, saltiness of ones diet
what maintains the concentration gradient of the renal medulla?
a constant exchange of salts and water
diuretics
any chemical that increases urine volume
acts on nephron loop to inhibit ascending tubules ability by making medulla less salt
PTH
increases phosphate content and decreases Ca content of urine
responds to Ca deficiency in blood