renal physiology 2 (incomplete)

glomerular filtration

-initial filtration (20%)

-non-specific process (allows passage and diffusion, just happens)

tubular reabsorption

-removal from the renal tubule outward

-selective process

-most filtered objects get reabsorbed

tubular secretion

-adding molecules into the renal tubules

-hasty/quick elimination but also selective

GF, TR, TB

all involved in manipulating and changing the urine concentration and production in renal tubules

whats in GF

glomerulus/renal capillaries and bowmans (glomerular) capsule

3

glomerular filtration has X layers

-G capillary wall

-basement membrane

-inners bowmans capsule

(helps filter things through body - water/solutes easy, blood/plasma can't)

glomerular capillary wall

contains PORES called fenestrae - allow molecules diffuse easily

basement membrane

GELatinous layer - help molecules diffuse that can

inner bowmans capsule

in renal tubule part, has filtration SLITS to allow molecules pass

energy with GF

-all passive transport/diffusion, no energy needed

glomerular (renal) capillaries

-higher level of permeability than other capillaries

-pressure forces are balanced throughout (even diffusion)

hydrostatic and oncotic pressure

renal capillaries are driven by

glomerular capillary pressure

-more hydrostatic pressure, more blood entering = more filtration

plasma-colloid osmotic pressure

-caused by protein concentration

-water enters into capillaries instead of tubules to oppose filtration

bowmans capsule pressure

-hydrostatic pressure coming from the renal tubles

perfect world of pressure

just GCP vs. BCP (no proteins) - blood coming in has higher pressure from renal tubules-> filtration outward

net filtration pressure

favors filtration (created an average GFR = 125 ml fluid in men, 115 ml in women

what change in pressure effects

changing any of 3 pressure changed GFR and kidney function (capillary pressre has greated impact/effect on actual filtration rate)

sympathetic

between sympathetic and parasympathetic, which nervous system would cause an increase in filtration

why sympathetic

vasoconstricts vessels - inc pressure to capillaries - more hydrostatic pressure - inc filtration rate bcs increasing pressure in capillaries

TR movement

from renal tubule and the peritubular capillaries/vase recta (happens right after renal capillaries)

TR explained

-highly selective process

-unimportant substances are eliminated

-important substances may be removed if theres too much of it

transepithelial transport

how reabsorption works, movement across multiple cell layers (tubule, to cells, to interstitial fluid, cells again, then peritubular caps)

passive reabsorption

no energy needed

-water

-chloride

-urea

active reabsorption

needs energy

-glucse

-amino acids

-sodium

(most kidney energy is spent on sodium)

tubular secretion movement

from capillaries into the renal tuble

TS explained

-2nd filtration method

-selective process

-speed method of eliminating substances that didn't get filtered

TS and transepithelial transport

-like reabsorption but in reverse

-secretion substance : H, K, organix anions/cations

reabsoprtion and secretion

can change depending on location

proximal tubules

majority of reabsorption and secretion

nephron loop/loop of henle

after the filtrate concentration (water and salt)

distal tubules/collecting ducts

-more secretion activity (finalizes the water, sodium, potassium and hydrogen concentrations)

-regulated by hormones

juxtaglomerular apparatus

intersection of renal tubules and glomerulus - quality control center

how JA works

last check reabsorption/secretion process

sodium in JA

senses sodium concentration in the blood and renal tubule - after plasma volume via water - leads to activation of the renin-angiotensin-aldosterone system

aldosterone

-released in response to increased in the K concentration

-sympathetic/adrenal cortex will secrete aldosterone

glomerular filtration summary

-between renal caps (glomerulus) and the bowmans capsule

-non-specific diffusion

reabsorption and secretion

-renal tubules and nephron loop (most in proximal tubule - later equals more changes)

-transepithelial transports ( reabsorption: active and passive) (secretion : active)

-specific process (depends on location in nephron and body needs) (changes in process)

water reabsorption

occurs in proximal tubule and nephron loop (400 ml minimum 1/8th gallon)

sodium

-filters at glomerulus (important for functionality)

-influences water and chloride movement

proximal tubule

reabsorption of:

-glucose

-amino acids

-h20

-chloride

-urea

ascending limb (loop of henle)

influences urine concentration/volume

distal tubule/collecting duct

-secretion (Na, K, H)

-hormonal regulation

descending limb

no sodium movement (manipulate Na concentration so can manipulate water movement as a whole)

salt and water: proximal tubule

-Na travels to the capillaries

-active energy transport is needed

-chloride and water will follow sodium (promotes water reabsorption)