Urinary System

H20 balance (osmolarity affects cell volume, and plasma volume affects blood pressure)
Regulates electrolyte concentration in ECF
Regulate Acid-Base Balance
Excrete waste product
Produces Erythropoietin
Produces Renin

A glycoprotein hormone produced by peritubular cells, stimulates production of red blood cells

Enzyme that is made by the kidneys and aids in salt conservation

Vascular and Tubular component

Functional unit of the kidney that filters blood

Renal artery
Afferent arteriole
Glomerulus
Efferent arteriole
Peritubular capillaries
Venules
Renal vein

Bowmans capsule
Proximal tubule
Loop of Henle
Distal tubule
Collecting duct

JGA (Juxtaglomerular apparatus)
Distal tubule, contains macula densa cells
Afferent and efferent arterioles, contain granular cells

Ball-like tuft of capillaries
Water and solutes are filtered through the glomerulus as blood passes through it

Surround the tubular part of the nephron, involved with tubular exchanges

Encapsulates the glomerulus and collects filtrate from glomerulus.

Lies entirely in the cortex
Where most reabsorption occurs
Reabsorption of water, Na+, glucose, and amino acids

Descending and ascending limb
Reabsorption of Na+(ascending)
Reabsorption of water (descending)

Na+ and water

Na+, water, urea

Glomerular filtration, Tubular reabsorption, Tubular secretion

Fluid from blood goes into the lumen of nephron
Nonspecific protein free plasma is filtered from the glomerulus into the bowman's capsule

Filtrate moves from inside of tubular part of nephron into the blood of peritubular capillaries.

Specific process by which substances from the peritubular capillaries enter the nephron tubule.

Endothelium of glomerular capillaries, basement membrane, inner layer of bowman's capsule

More permeable, fenestrated, blood cells and plasma proteins are not filtered

Gelatinous layer composed of collagen and glycoproteins, negative charge of glycoproteins repel small filtered proteins.

Contains podocytes that encircle the glomerulus tuft, filtration slits

Hydrostatic pressure of capillaries,
The capillaries have high permeability
Hydrostatic pressure continues along the entire length of the capillary.
Hydrostatic pressure is determined by blood pressure

Filtration pressure * filtration coefficient

Plasma colloid osmotic pressure and bowmans capsule hydrostatic pressure.

Afferent arteriole radius

Intrinsic autoregulation prevents spontaneous changes
Extrinsic sympathetic is used for long term regulation

Myogenic control - smooth muscle response to stretch
Tubuloglomerular feedback mechanisms - juxtaglomerular apparatus

Macula densa cells will secrete paracrine signals (adenosine).
Adenosine = Vasoconstriction = Decrease in GFR

Secrete renin to increase sodium reabsorption

Hormones and autonomic neurons also influence GFR.
Changes resistance in arterioles, altering the filtration coefficient.
Sympathetic nervous system, causes vasoconstriction, overrides intrinsic mechanisms.

Constant - Proximal tubule and ascending loop of henle
Variable - Distal tubule and collecting duct

Thirst, Vasoconstriction, Aldosterone release, ADH (vasopressin) release

Increases H2O reabsorption
Adds more aquaporins to the Distal tubule and Collecting duct

Stimulates reabsorption of Na+ in DT and CD
Adds Na+/K+ pumps on the basolateral membrane of the DT and CD cells.
Adds Na+ channels to the apical membrane of the DT and CD cells.

Lowers blood pressure
Inhibits Na+ reabsorption and promotes water loss.
Inhibits renin and aldosterone release