digestive y urinary

Main functions of digestive system

ingestion, propulsion, digestion, secretion, absorbtion, and defecation

ingestion

taking food into mouth

propulsion

movement of food through the tract via peristalsis

peristalsis

squish

digestion

to break food down into absorbable nutrients; mechanical and chemical

mechanical digestion

chewing and grinding food to break it into smaller pieces, aiding in the digestive process.

chemical digestion

the process of breaking down food at the molecular level using enzymes and acids, allowing nutrients to be absorbed.

proteins, carbs, and lipids chemically digest into

amino acids, simple sugars, and fatty acids

secretion

the process of releasing substances, such as enzymes or hormones, from cells or glands into the digestive tract or bloodstream.

approx. how much digestiove secretions are produced each day?

5 liters

absorption

to bring the nutrients into the digestive system & the blood

defecation

removal of indigestible substance & wastes from the body

Gastrointestinal (GI) Tract (alimentary canal) - digestive organ

the continuous tube that runs from the mouth to the anus, responsible for digestion and absorption, all hollow

mouth, pharync, espohagus, stomack, small intestine, large intestine, rectum, anusand accessory organs such as the liver, pancreas, and gallbladder.

asccesory digestive organs

all lie outside of GI tract

teeth, toungue, salivary glans, live, gallbladder, pancreas

structure of alimentary canal

mucosa, submucosa, muscularis, serosa

mucosa

epithelium

simple columnar or strtified squamous depending on locationsu

bmucosa

areolar & dense orregular ct

numerous blood & lymphatic vessels, autoimmune nerve fibers

musculeris externa

smooth muscle

performs peristalsiss

serosa

visceral peritoneim

lines portions of GI tract

nutruents track

eat - nutrients - liver - heart - cells

salivary glands

produce saliva

1 liter a day

salivary amylase

digests starch, first thing we do is break down carbs bc theyre the biggest polymers

lysozyme

antibacterial action, enzyme found in saliva that helps to break down bacterial cell walls.

Mucin

when mixed with water, formes mucus = slimy → lubrication

amylase track

starch - maltose - glucose

amylase

epiglottis in pharynx

prevents food from entering the trachea

esophagus

transports bolus from pharynx to stomach

involuntary movement of food by smooth muscle Peristalsisis

rugae in stomach

logitudinal folds that allow tremendous extensibility

how much can the stomach hold?

1.5-4 liters

what is secreted within the stomach? (1.5 L/day)

mucus, hydrochloric acid, pepsinogen (digests proteins to amino acids)

movement in stomach

mixiing waves and peristalsis

bolus becomes what?

chyme that is slowly release by the pyloric sphincter

small intestine

duodenum, jejunnum, ileum

function of small intestine

majority of digestion & absorption

takes straight from pancreas

has folds, villi, & micro villi for incr surface area

intestinal juice

water mucus & enzymes (abt 2 L/day)

secrettions form liver & pancreas cia the hepatopancreatic ampulla ,icrovilli on villi, villi, on folds, & folds in intesting liver

pancreatic enzymes

all are empties into the small intestine via the pancreatic duct

digestion of all the major classes of food

22 enzymes & bicarbinate

neautralizes the acidity (& spicy)

Islets of Langerhans

produce hormones that regulate blood sugar

liver

secretes bile into the gall bladder

gallbladder

empties bile into the ssmall intestine via the bile dict

bile

emulsifies fats

big globs of fat → small globs of fat, to absorb

gall stones

pigmented or calified gall stones, cholesterol stones

functions of liver

stores glycogen, lipids, vitamins, iron

synthesizes & interconverts nutrients

produces & releases cholesterol

detoxifies toxins, poisons, drugs

phagocytosis of old RBC & excretion of bilirubin

produces blood proteins & clotting factors

hepatic portal system

picks up digested nutrients from the stomacj & intestines & delivers directly to the liver for processing

blood enter via hepatic portal vein & leaves via the hepatic vein

primary organ that regulates blood composition

cirrhosis

progressive inflmamation & scarring of the lover, excessive drinking

which enzyme in saliva breaks down carbs?

amalayse

why is the small intestine named that>

smaller in diameter

large intestine

ileocecal sphincter connects small intestine to large intestine, absorbs water and salt

ascending, transverse, descending, and sigmoid colon

undigested material converts to what>

feces for excretion

E Coli bacteria synthesizse what?

vitamin K

solid wastes are stored and released where?

in the rectum and anus.

hemorrhoids

burst blood vessel within anal sphincter, over exhertion

colonoscopy

drink liquid enema, look for abnormalities in the colon

main functions of urinary system

filter blood & remove wates (excretion)

homeostatic regulation of blood

filter blood & remove wates (excretion)

metabolic watstes (eg urea, uric acid, creatine)

excess water, ions & toxins processed by liver

homeostatic regulation of blood

keeps blood ion & pH levels balanced

regulates blood volume & blood pressure

kidneys

filter blood & produces urine

made of over 1 million nephrons

retroperitoneal - located behind the peritoneum

when they fail, life expectancy 1-2 days

ureters

carry urone to bladder

urinary bladder

stores urine

urethra

carries urine outside of body

gross anatomy of kidney

renal artery, renal vein, renal cortex, renal medulla, renal pelvis

renal artey

carries blood to the kidney

renal vein

carries filtered blood away from kidney

renal cortex

outer area of kidney

renal medulla

inner

6-8 pyramids

ends in papilla

renal pelvis

place where urine collects

nephrons (1 million per kidney)

functional unit that filters blood

glomerulus

cluster of capillaries

filtration

bowmanś capsule

hollow chamber that collects filtrate

tubule

extends from the Bowman’s capsule and participates in the processes of reabsorption and secretion in the nephron.

regions of tubule

PCT - proximal convoluted tubule; Loop of Henle; DCT - distal convoluted tubule.

capillaries

surround tubule

peritubular

around PCT, DCT

vasa recta

around loop of henle

collecting suct

leads to renal pelvis and ureter

important for the reabsorption of water

urine production

filtration

reabsorption

secretion

filtration

blood plasma is squeezes from the glomerulus into the capsule

filtrate

plasma without cells & proteins

reabsorption

most of the nutrients, water & essential ions are returned to blood

secretion

additional undesired chemicals can be added to urine

excretion rate od urine is 1-2 ml/min1

ADH - antidiuretic hormone

secreted by pituitary gland

stimulates water reabsorption grom the collecting ducts & dct

opens special water chanels (aquaporins)

alcohol inhibits …

the release of adh

no adh =

large volume of dilute urine

adh present =

small vilume of concentrated urine

juctaglomerular apparatus

a structure in the kidney that regulates blood pressure and the glomerular filtration rate. It consists of specialized cells in the distal convoluted tubule and afferent arteriole.

macula densa of dct

tall closely packed cells

chemmoreceptors that monitor solute concentrations

when concentrations drop, signal granular cells

granular cells

in walls of the afferent & efferent arterioles

mechanoreceptors that sense a fall in blood pressure

when granular cells secrete renin

activates renin-angiotensin mechanism (sequene of chemcal reactions in the blood)

eventually stimulates the adrenal cortex to secrete aldosteronewhich increases sodium and water reabsorption, and increases blood volume & pressure (caffeine & certain meds block reabsorption of Na+)

uretus

muscular tube transporting urine from the kidneys to the bladder.

peristaltic waves occure every 30 sec

urinary bladder

collapsible muscular sac that stores & expels urine

from the kidneys until excretion.

the bladder usually holds500 ml of urine but..

can stretch to hold over a liter

empty bladder

upside down pyramid

lies entirely within pelvis

full bladdder

spherical

expands superiorly into the abdominal cavity