Urinary 2 and urine production

constriction and dilation

the two additional mechanisms to change filtration rate are

afferent arteriole constriction

renal blood flow: decreases

glomerular filtration rate: decreases

afferent arteriole dilation

renal blood flow: increases

glomerular filtration rate: increases

Efferent arteriole constriction

renal blood flow: decreases

glomerular filtration rate: increases

efferent arteriole dilation

renal blood flow: increases

glomerular filtration rate: decreases

glomerulus

filtration ONLY occurs in the

increases

systemic: if blood pressure goes up, it goes up in entire body and filtration

increase

localized: if only piece of arteriole constricts, it will have a localized _____ in BP

intrinsic filtration regulation

they ONLY involve the kidney

myogenic mechanism of autoregulation

When there is low blood pressure, the afferent arteriole will dilate to allow more plasma to be filtered in the glomerulus (BP down = less stretch = dilate) which increases filtration

constriction

if blood pressure increases it will lead to_____ due to muscle in arteriole walls

tubuloglomerular mechanism of autoregulation

If the concentration of filtrate is low in the distal convoluted tubule, you get a dilute urine

tubuloglomerular mechanism of autoregulation

Macula densa cells (in walls of distal convoluted tubule and act as chemoreceptors) detect the low concentration of the filtrate (aka dilute so more water passing through)

Macula densa activate JG cells (secrete renin which is important for aldosterone)

Causes vasodilation of the afferent arteriole

extrinsic filtration regulation

involve more than just the kidney

neural control

can be linked to hormonal, acts as an override!

neural control (for low BP)

sympathetic nervous impulses cause release of norepinephrine to vasoconstriction --> increase blood pressure --> increase filtration

neural control

If we need to change the distribution of blood to the skeletal muscles during a fight or flight scenario, sympathetic nervous impulses constrict blood flow to the kidney and redirect blood flow to the skeletal muscles

JG cells

(mechanoreceptors) in the modified walls of the afferent arteriole function as baroreceptors (detect blood pressure)

low blood pressure

when JG cells detect _______, they release renin

aldosterone

causes an increase in sodium reabsorption, blood pressure increases, and increases filtration

prostaglandins

local signaling molecules that act as vasodilator in kidney, increases filtration

nitric oxide

acts as vasodilator, increases filtration

adenosine

in the KIDNEY is acts as a vasoconstrictor, in other body parts its opposite

endothelin

lining of afferent and efferent arterioles that causes vasoconstriction

tubular reabsorption

primarily a transepithelial process that has to cross 3 borders!!!

lumenal border

out of lumen into epithelial cells

basolateral border

out of epithelial cells into interstitial space

endothelial border

from interstitial space into bloodstream

tight junctions

cells that make up the renal tubule have

basolateral

ions can move across paracellular channels on ________ side, shortcut

sodium

most abundant ion in filtrate is

proximal convoluted tubule

100% of glucose, amino acids, and lactate reabsorbed here

descending loop of henle

permeable to water, impermeable to solutes, on proximal convoluted tubule side

ascending loop of henle

permeable to solutes, impermeable to water, on distal convoluted tubule side

ascending loop of Henle

aldosterone increases sodium reabsorption in the

distal convoluted tubule and collecting duct

aldosterone increases sodium reabsorption in the

ADH

Reabsorption in the distal convoluted tubule and the collecting duct are affected by

ADH

what opens aquaporins in the collecting duct to make it permeable to water

decreased

increased adipose tissue leads to what fluid composition

countercurrent mechanism

The descending and ascending loops of Henle run in opposite direction in order to increase efficiency in exchange

countercurrent multiplier

As you move deeper into the medulla (loop of Henle), the concentration gradient (renal gradient) increases

osmotic gradient

as we go deeper into medulla, the tissue is more concentrated due to higher

countercurrent exchange

flow of blood goes opposite direction

vasa recta

are freely permeable to water AND sodium

dilute urine

low ADH produces a

ADH

production of this increases water reabsorption from collecting ducts

trigone

triangular region made of two uretal orifice and the internal urethral orifice

bladder

passive flow of urine into the

micturition

act of emptying the bladder

ok

go over mechanism of micturition

parasympathetic

stimulation contracts the bladder muscle, and relaxes the internal and external sphincters