Homeostasis
ability of the body to maintain its internal environment at a “steady rate” & within very narrow ranges of normal regardless of external changes
Functions of the kidneys
- regulates volume and chemical composition of blood
- regulates blood pressure
- produces erythropoietin
- metabolizes vitamin D to active form
- filters waste materials
- **fluids, electrolytes, acid/base balance
Excretory functions of the kidney
- plasma osmolarity (varying the excret. of water to maintain plasma osmolarity)
- plasma concentration of electrolytes
- plasma pH
- nitrogen end products of protein metabolism
Non-excretory functions of the kidney
- renin production
- erythropoietin production
- Vitamin D activation
- degrading insulin
Renal system & CV system
- delivers blood to be filtered
- sustains pressure needed for filtration
- provides specialized capillaries for filtration
Renal system & Nervous system
- regulates blood pressure via vessel tone (perfusion)
- controls the process of urination via sensory reflexs
Renal system & Endocrine system
- aldosterone (adrenal cortex) – Na reabsorption and K secretion
- ADH (posterior pituitary) – water conserver and released due low blood volume or low blood pressure
Renal system & urinary collecting system
- exit of urine from the body
- calyces, renal pelvis, ureters, bladder, urethra
Why is the right kidney lower than the left?
the liver pushes it down.
Hilum
entry/exit – renal artery, renal nerves. renal vein and ureter exit
Cortex
outer layer. directly underneath capsule, most nephrons and blood vessels located under the cortex (medulla)
Medulla
some nephrons and collecting system
pyramids
contain nephrons and blood vessels
Bertin’s columns
segment of cortex -> separate medulla pyramids
Collecting system
(papillae, calyces, renal pelvis)
transports urine out; no chemical modification
Papillae
(ducts of bellini)
collects urin, directs into minor–>major calyces–> renal pelvis –> ureter
Renal pelvis
can only hold 3-5 ml of urine
Nephron
- over 1 million in each kidney. 85% are located in the cortex and 15% are juxtamedullary nephrons (pass thru the medulla)
- all nephrons are active in forming urine
Bowman’s capsule
- surrounds the glomerulus
- contains everything filtered by the glomerulus
Bowman’s capsule/glomerulus AKA…
renal corpusule
Glomerulus
specialized cap. bed, important for filtration; very porous, filter by size (everything but RBCs and protein bc too big)
Proximal convoluted tubule
-connected to bowman’s capsule and loop of henle.
Distal convoluted tubule
into collecting duct (after loop)
Collecting duct
-each nephron may empty into same duct. not every nephron has its own
