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Digestive & Urinary System - Coggle Diagram
Digestive & Urinary System
Major Functions Digestive
rake in food
break down food into nutrient molecules
absorb molecules into the blood stream
rid body of any indigestible remains
food processing requires 6 essentials
ingestion:
eating
propulsion:
movement of food through the alimentary canal, which includes swallowing & peristalsis
mechanical breakdown:
includes chewing, mixing food w/ saliva, churning food in stomach & segmentation (local constriction of intestine that mixes food w/ digestive juices)
digestion:
series of catabolic steps that involves enzymes that break down complex food molecules into chemical building blocks
absorption:
passage of digested fragments from lumen of GI tract into blood or lymph
defecation:
elimination of indigestible substances via anus in form of feces
Major Functions Urinary
micturition:
aka urination or voiding
step 1:
glomerular filtration:
a passive process & no metabolic energy required
step 2:
tubular reabsorption:
quickly reclaims most of tubular contents & returns them to blood
step 3
tubular secretion:
reabsorption in reverse
Major Organs Digestive
mouth:
where food is chewed & mixed w/ enzyme-containing saliva that begins process of digestion, & swallowing process is initiated
tongue
grips, repositions, & mixes food during chewing
lingual frenulum:
attachment to floor of mouth
forms
bolus:
mixture of food & saliva
initiates swallowing, speech, & taste
salivary glands
2 secretory cells
serous cells:
produce watery secretion, enzymes, ions, & some mucin
mucous cells:
produce mucous
functions of saliva include:
cleansing mouth, dissolving food chemicals for taste, moistening food & compacting it into bolus, & beginning breakdown of starch w/ amylase
pharynx:
allows passage of food, fluids, & air
esophagus
is a flat muscular tube that runs from laryngopharynx to stomach
gastroesophageal (cardiac) sphincter:
surrounds cardial orifice & keeps orifice closed when food is not being swallowed & protect esophagus from acid reflux
major function:
propulsion that starts w/
diglution:
swallowing
stomach
is a temporary storage that starts chemical breakdown of protein digest
converts bolus of food to paste-like chyme and delivers it to small intestine
cardinal part:
(cardia) surrounds cardial orifice
fundus:
dome-shaped region beneath diaphragm
pyloric part:
wider & more superior portion of pyloric region, antrum, narrows into pyloric canal that terminates in pylorus
pyloric valve:
sphincter controlling stomach emptying
pancreas
exocrine function:
produce pancreatic juice
endocrine function:
secretion of insulin & glucagon by pancreatic islet cells
supplies most of enzymes needed to digest chyme, & bicarbonate to neutralize stomach acid
liver
digestive function:
production of bile
bile:
yellow-green, alkaline solution containing bile salts & bilirubin
largest gland in body
gallbladder
function:
store & concentrate bile by absorbing water & ions
a thin-walled sac on ventral surface of liver
small intestine
is major organ of digestion & absorption
has 3 subdivisions
duodenum:
mostly retroperitoneal; curves around head of pancreas
jejunum:
attached posteriorly by mesentery
ileum:
attached posteriorly by mesentery; joins large intestine @ ileocecal
villi:
fingerlike projections of mucosa w/ a core that has dense capillary called a lacteal for absorption
chyme:
contains partially digested carbs & proteins, & undigested fats
segmentation:
most common motion of small intestine; mixes & moves contents to the ileocecal valve
peristalsis:
increases between meals & is initiated by rise in hormone motilin in late intestinal phase; meal remnants move towards large intestine
large intestine
has 5 subdivisions
cecum:
1st part of large intestine
appendix:
masses of lymphoid tissue; bacterial storehouse
colon
ascending colon:
travels up right side of abdominal cavity to level of right kidney
transverse colon:
travels across abdominal cavity
descending colon:
travels down left side of ascending cavity
sigmoid colon:
s-shaped portion that travels through pelvis
rectum:
3 rectal valves stop feces from being passed w/ gas (flatus)
anal canal:
last segment of large intestine that opens body exterior @ anus
teniae coli:
3 bands of longitudinal smooth muscle in muscularis
haustra:
pocketlike sacs caused by tone of teniae coli
epiploic appendages:
fat-filled pouches of visceral peritoneum
metabolic functions:
fermentation (ferment indigestible carbs & mucin), & vitamin synthesis (synthesize B complex & some vitamin K needed by liver to produce clotting factors)
*major functions:
propulsion of feces to anus & defecation, reabsorption of vitamins (made by bacterial flora), water, & electrolytes (especially Na+ & Cl-)
Major Organs Urinary
kidneys
major excretory organ
regulate total water vol. & total solute concentration in water
ensure long-term acid-base balance
produce erythropoietin, regulates blood pressure & renin, which regulates RBC production
regulate ion concentrations in extracellular fluid
excrete metabolic wastes, toxins, & drugs
activates vitamin D
has 3 regions
renal cortex:
granular-appearing superficial region
renal medulla:
deep to cortex, composed of cone-shaped medullary (renal) pyramids
renal pelvis:
funnel-shaped tube continuous w/ ureter
filtrate:
produced by glomerular filtration & is basically blood plasma minus proteins; urine is produced from filtrate
urinary bladder
muscular sac for temporary storage of urine
males:
prostate inferior to bladder neck
females:
anterior to vagina & uterus
collapses when empty
full bladder can hold ~1 pint; can hold twice that amount if necessary but can burst if overdistended
ureters
slender tubes that transport urine from kidneys to bladder
bladder pressure increases = distal ends of ureters close, preventing backflow of urine
urethra:
muscular tube that drains urinary bladder; transports urine out of body
Digestive Enzymes
hydrochloric acid (HCl):
denatures protein, activates pepsin, breaks down plant cell walls, & kills bacteria
trypsin:
produced in pancreas & helps break down protein
chief cells:
secrete pepsinogen & lipases
pepsin:
produced in stomach & helps break down protein
rennin:
breaks down milk protein (casein)
pancreatic juice:
watery, alkaline solution to neutralize acidic chyme from stomach
bile salts:
cholesterol derivatives that function in fat emulsification & absorption
renin:
regulates RBC production
erythropoietin:
regulates BP & renin
Macromolecule Digestion & Absorption
carbohydrates
broken down by amylase
digested in mouth, stomach, & small intestine
absorbed in the jejunum of the small intestine
lipids
broken down by lipases
digested in the small intestine w/ help of bile
absorbed throughout the small intestine
protein
broken down by proteases
digested in stomach & small intestine
absorbed in the jejunum of the small intestine
nucleic acids
broken down by nucleases
digested in the stomach
absorbed in the small intestine
Layers of GI Tract
mucosa
tunic layer, lines lumen
functions:
different layers perform 1 or all 3
secrete mucus, digestive enzymes, & hormones
absorb end products of digestion
protect against infectious diseases
submucosa
consists of areolar connective tissue
contains:
blood & lymphatic vessels, lymphoid follicles, & submucosal nerve plexus that supply surrounding GI tract tissue
help organs regain shape after storing large meal
muscularis externa
muscle layer responsible for segmentation & peristalsis
contains inner circular muscle layer & outer longitudinal layers
circular layer thickens in some areas to form sphincters
segmentation:
local constriction pf intestine that mixes food w/ digestive juices
peristalsis:
major means of propulsion of food that involves alternating waves of contraction & relaxation
serosa
outermost layer
made up of visceral peritoneum
visceral peritoneum:
membrane on external surface of most digestive organs
Nephron Anatomy/Physiology
nephron:
structural & functional units that
form urine in kidneys
has 2 main parts
renal corpsule
glomerulus
tuft of capillaries composed of fenestrated epithelium
allow efficient filtrate formation
filtrate:
plasma-derived fluid that renal tubules process to form urine
glomerular capsule
parietal layer:
simple squmaous epithelium
aka
Bowman's capsule:
cup-shaped, hollow structure surrounding glomerulus
visceral layer:
clings to glomerular capillaries; branching epithelial podocytes
renal tubule
proximal convoluted tubule
functions in reabsorption & secretion
closest to renal corpuscle
cuboidal cells w/ dense microvilli that form brush boarder
consists of single layer of epithelial cells
nephron loop
u shaped structure with 2 limbs
descending limb:
proximal part is continuous w/ proximal tubule & distal portion is simple squamous epithelium
ascending limb:
thick ascending limb but thin in some nephrons; cuboidal or columnar cells
distal convoluted tubule
cuboidal cells w/ few microvilli
functions in secretion & some reabsorption
farthest from renal corpuscle
Disorders
urinalysis:
urine is examined for signs of disease, along w/ illegal substances
gut bacteria can influence body weight, susceptibility to disease, & mood
urinary tract infection:
cloudy & smelling urine
GERD:
bloating, stomach pain & cramps; treatment: lifestyle changes & medication
cystitis (bladder infection):
usually caused by bacteria
kidney infection:
backed up ureters