urinary system

function

maintain homeostasis

methods of maintaining homeostasis

excretion, maintain water-salt balance, maintain acid-base balance, hormone function

excretion

removal of metabolic waste from the body; requires metabolism to create the waste

not the same as defecation, the release of undigested material

maintain water-salt balance

regulation of ions like NaCl (related to water regulation due to osmosis)

blood pressure regulation

maintain acid-base balance

control blood pH by excreting hydrogen ions and reabsorbing bicarbonate ions

hormone function

aldosterone (blood pressure) and erythropoietin (red blood cell production)

renal cortex

outside layer of kidney

renal medulla

inner layer of kidney

renal pelvis

central cavity where urine is collected

renal pyramid

collection of nephrons

span across the cortex and medulla

kidneys

blood filtration and urine production

ureter

transports urine from kidneys to bladder

bladder

storage of urine
stretch receptors that signal the need to urinate

urethra

transport urine from the bladder to the outside of the body

glomerular capsule (Bowman’s capsule)

cap-like structure where filtrate is pushed into nephron

efferent ateriole

brings blood out of glomerulus

afferent arteriole

brings blood into glomerulus

renal artery glomerulus

knot of capillaries in glomerular capsule

loop of henle

water-salt balance

proximal convoluted tubule (PCT)

part of nephron closest to beginning (Bowman’s capsule)

peritubular capillaries

capillaries surrounding nephron where material exchange occurs

distal convoluted tubule (DCT)

part of nephron further from capsule

tubular secretion

substances are removed from the blood using active transport and added to tubular fluid (filtrate)

for example creatinine, drugs like penicillin, hydrogen ions

collecting duct

reabsorption of water

descending loop

only permeable to water which will diffuse from tubular fluid into interstitial space

ascending loop

only permeable to NaCl and b/c tubular fluid is so concentrated from loss of water, salt will diffuse out of tubular fluid into interstitial space

lower portion of ascending loop

passive diffusion

upper portion of ascending loop

active transport

juxtaglomerular apparatus (JGA)

region where afferent arteriole comes in contact with DCT

anti pee hormone

antidiuretic hormone (ADH) or vasopressin

glomerular filtration

water and small molecules move from glomerulus into Bowman’s capsule due to blood pressure

filterable components of GF

water

nitrogenous waste (ex. urea)

small nutrients (amino acids, glucose, etc.)

salts (ions)

non filterable components of GF

formed elements (blood cells and platelets)

proteins

tubular reabsorption

salt is reabsorbed both actively and passively; due to osmosis, water will follow

glucose and amino acids are also selectively reabsorbed by specific carrier proteins

diabetes mellitus

due to high glucose conc, glucose will end up in the urine along with high water volume (osmosis)

diabetes insipidus

regular glucose levels, but frequent urination due to hormonal reasons

reabsorbed in TR

most water, nutrients, required salts, bicarbonate ions

not absorbed in TR

some water, much nitrogenous waste, excess salts

what does JGA secrete

enzymes called renin

what does JGA activate

plasma protein called angiotensinogen

angiotensin II

vasoconstrictor and signals the adrenal cortex to release aldosterone

vasoconstrictor

constricts blood vessel

what/where is the adrenal gland

related to adrenal cortex; on top of kidneys

what does aldosterone cause

reabsorption of sodium ions in DCT and collecting duct causing water to be reabsorbed due to osmosis

what is this anti pee hormone

protein hormone produced and release at the brain (produced at hypothalamus, stored and released at the posterior/pituitary gland)

what does adh stimulate

aquaporins (membrane channel proteins) production in collecting duct which increases water reabsorption and concentrates urine

what is adh inhibited by

alcohol