1. Filters blood, removes wastes, produces urine. 2. Formation of calcitriol. 3. Production and release of erythropoietin. 4. Regulation of ions, acids, and bases. 5. Help regulate blood pressure. 6. Gluconeogenesis.
Organs of the urinary system
kidneys, ureters, urinary bladder, urethra.
in renal corpuscle, forces fluid out with dissolved solutes.
Tubular reabsorption (General)
reclaim useful materials from fluid
Tubular secretion (general)
remove and concentrate unwanted materials in fluid becoming urine. Secretion leads to excretion
Which cavity are the kidneys in?
Retroperitoneal space, so no serous membrane
layers of CT around Kidney
1. Fibrous capsule: dense irreg CT, prevents infection 2. Perirenal fat pad: adipose insulates and protects from trauma 3. Renal fascia: Dense irregular CT anchors kidney to surrounding structures
What kind of tissue is the kidney made of?
Space between renal pyramids
Renal pyramids lead to
occur at the tip of the renal pyramid.
Major and mini calyces
merge to form renal pelvis
Site of filtration
1. Golmerulus: specialized capillary bed with afferent and efferent arterioles. 2. glomerulus capsule: surrounds golmerulus
layers of glomerulus capsule
1. visceral layer: contain podocytes 2. parietal layer: squamous cells joined by tight junctions
PCT, Nephron loop, DCT
thick cells: simple cuboidal. Thin cells: simple squamous
Types of nephrons
cortical nephrons: near peripheral edge: nephron loop barely penetrates medulla. juxtamedullary nephrons: corpuscles are adjacent to corticomedullary junction. Nephron loop deep in medulla
Flow of filtrate to urine
afferent arteriole --> gomerulus --> golmerulus capsule --> capsular space --> PCT --> nephron loop --> DCT --> collecting tubules -->collecting ducts --> papillary ducts --> renal papillae --> minor calyces --> major calyces -->renal pelvis --> ureter --> bladder --> urethra
peritubular capillaries: through cortical nephrons. vasa recta capillaries: through the nephron loop
Renal artery --> segmental artery--> interlobar artery -->arcuate arteries --> interlobular arteries --> afferent arteriols --> glomerulus --> efferent arteriole --> peritubular or vasa recta capillaries --> interlobular vein --> arcuate veins --> interlobar veins --> renal veins -->
What regulate filtrate formation and blood pressure?
modified smooth muscle afferent arterioles that 1. contract stimulated by stretch or sympathetic nervous system. 2. store, produce, and release renin.
modified epithelial cells in the DCT that sense NaCl.
1. endothelium of glomerulus (fenestrated) 2. Basement membrane of flomerulus 3. visceral layer of glomerular capsule with podocytes separated by filtration slits.
water, glucose, amino acids, hormones, vitamins and minerals
formed elements, large proteins
mid sized proteins
Glomerular hydrostatic pressure
pushes water and some dissolved solutes into capsular space
Blood Colloid osmotic pressure
osmotic pressure exerted by bolo due to dissolved solids
Capsular hydrostatic pressure
pressure in glomerular capsule due to amount of filtrate already in capsular space
Glomerular filtration rate
Rate at which the vole of filtrate is formed.
low blood pressure stimulates afferent arteriole to vasodialate. high BP stimulates afferent arteriole to constrct to maintain GFP.
Tubuloglomerular feedback mechanisms
macula dense cells of DCT are sensitive to NaCl levels. Increased NaCl (Too much GFR) sensed by MD, stimulate vasoconsticion of afferent arteries. Decrease HP(out) and lower GFR Decreased NaCl (Too little GFR) sensed by MD, stimulate vasodialation . Increase HP(out) and increase GFR.
Sympathetic stimulation of GA
1. Vasocontriction of afferent and efferent arterioles= decrease blood flow into glomerulus. -decreased GFR, decreased urine production, retains fluid and blood volume. 2. Contraction of mesangial cells=decrease filtration at flomerulus, lower GFR, lower urine production retains fluid and blood volume.
Atrial natriuretic peptide
Stimulus: high BP, atrial wall stretches. Control center: ANP released by heart. 1.vasodialation of afferent arteriole, increased blood flow to glomerulus, increase GFR, more urine, loss of additional fluid, decrease blood volume. 2. relaxation of mesangial cells= increased filtration surface area, increased GFR,
Tubular reabsorption in proximal convoluted tubule
100% glucose, amino acids, vitamins and minerals, water, hormones, urea and Uric acid, ions
Tubular secretion in