1. Renal Corpusle (capsule +glomerulus)

2. Proximal convoluted tubule

3. Desending straight proximal limb of LOH

4. Loop Of Henle

5.  Acending straight distal limb of LOH

6. Distal convoluted tubule

-Very long loops of henle, extend deep into medulla

-Decending tubule has SHORT THICK region and LONG THIN region

-Acending tubule has LONG THIN and very important THICK region

-Decending tubules have VERY SHORT THIN regions

-Acending has NO THIN regions

-First, VERY coiled structure of uriniferous tubule

-Lined by Simple Low Column. Ep.

-Apical ends adjacent to filtrate

-Basal ends near capillaries

-Involved in select reabsorbtin of stuff from filtrate at apical end ->basal->capillaries

-Apical has Brush Border, long microvilli

-Contains many pinocytotic vesicles and lysosomes

-Involved in reabsorbtion and digestion of protein

-Normally gets all, but can be overwhelmed causing Proteinuria

-Lots of invaginations with other cells

-Lots of Na/K pumps form gradient (has lots of mitochondria to fuel them)

-Causes in flux of water and sodium from lumen

-Enters medullary ray, descends toward medulla

-First part lined with low columnar ep. like the PCT

-Changes from thick to thin after entering medullary pyramid and becomes simple squamous

-Loops around in medulla, makes its way back up towards cortex

-Simple squamous Ep

-Thin distal section of Simple SE

-Widens as it gets higher, becoming cubiodal

-Thick end leaves medulla and follows medullary rays into cortex

-Returns to same nepron it came from and becomes the Distal Convoluted Tubule

-Slightly smaller diameter than PCT

-Brush border less prominent

-Cells smaller, nuclei close together

-Large Lumen, well defined apical border

-Specialized region in the DCT

-Found between afferent and efferent arterioles, adjacent to vascular pole

-Epithelial cells are very tall and more closely packed than in the rest of the DCT

-Arise from DCT's

-Begin as arched connecting tubules ->medullary ray (straighten, pass down ray) ->medullary pyramid -> join similar tubules -> form papillary ducts ->open at apex of pyramid.

-Urine filtrate passes from ducts into the minor calyx ->major calyx->renal pelvis -> Pee pee

-Important for maintaing blood pressure

-Composed of juxtaglomerular cells that occupy the media of:

afferent glomerular arteriole

Macula densa

Extraglomerular mesangial cells (produce erythropoitin)

-Located in tunica media of Afferent glomerular arteriole

-Replaces internal elastic membrane of arteriole

-Epithelial cells that have granular cytoplasm and secrete Renin into arteriole lumen

-Low concentration of NaCL in the DCT detected by macular densa

-Decreased blood pressure in afferent areriole

-Sympathetic activity at the JG cells (NE binds to a1-adrenergic receptors ->vasoconstriction)

Renin Secretion

If you don't know this pathway, shame on you!

-JG cells stimulated, relase renin -> converts angiotensogen into AT I -> ACE converts AT I into active AT II

ACE found on surface of vascular endothelial cells

1. Constricts smooth muscle in arteriole walls

2. Stimulates zona glomerulosa in Adrenal cortex to release aldosterone

3. Stimulates ADH secretion and thirst

4. Enhances NaCL absorbtion by proximal tubule

-Renal artery enters at hilium, splits into 3

-These branch to form iinterlobular arteries that lie between adjacent pyramids

-Travel to cortex, reach cort-med border, become Arcuate arteries

-Branch off in cortical labyrinth, become interlobular arteries

-Enter lobules of cortex -> intralobular arteries

-Branch and form afferent glomerular arterioles (supply renal corpuscles)

-Afferent GA's give rise to glomerular capillary tuft

-Drained by efferent GA's

-Efferent GA's come from juxtamedullary glomeruli ->EGA's supply the medullary pyramids

-Vasa Recta, thin walled vessels descend from pyramids, make lots of turns and loops

-These vessels drains into arcuate veins at cort-med border

-Filtrate coming from corpuscle is similar to plasma

-Proximal tubule absorbes glucose, amino acids, phosphate, Ca and 85% NaCl and water. (secrete creatinine and forein crap)

-Distal tubule's ion exchange is influenced by aldosterone. Absorbs some NaCl and other ions

-Concentrate urine via Countercurrent Multiplier and exchange system in loop of henle, collecting tubules and vasa recta

-COncentration gradient increases towards medullary papillae

-Osmolarity is due to NaCl and urea

-Thick prtions of acending limb is impermable to water and urea ->actively absors NaCl from fluid

-Called the "diluting segment"

-NaCl outward pump here contributes to interstitial gradient

-Have high permeability to Urea

-Urea moves out as approached medullary papillae via outward urea transporters

-Water is removed from CT's are they pass through concentration gradient (under control of ADH)

-Arangement of VR allows for nutrients to be supplied to medulla and removes excess water while maintaining concentration gradient

-Responds to falling Na levels

-Increases Na absorbtion in Distal Convoluted Tubule and in salivary and sweat glands

-Water follows Na

-Responds to increased blood osmolarity, low blood volume, deydration

-Increases water absorbtion in Collecting tubules

-Both ureters and bladder lined with transitional epithelium

-Ureter wall contains some CT and smooth muscle layers with outr CT adventitia

-Bladder has thick T Ep. and thickened muscularis to form sphicters