Glomerulus Flashcards
Which adrenal gland is depressed + why?
Right adrenal gland: liver sits on it
Blood supply + drainage of kidneys
Blood supply from renal a. & drained via renal vein
What is the pubic symphysis?
Joint between the R & L pelvic bones
Bladder sits behind this
What is the renal capsule + purpose?
Holds in all the pressure (drinks from the aorta)
What is renal fascia?
Connective tissue that surrounds the kidney
Perirenal fat
Completely surrounds the kidney + goes inside (holds kidney up)
What is pararenal fat?
Outside of renal fascia
What is the renal hilum?
Where fat/arteries/veins go in & BS/ureter go out
Characteristics of the renal cortex
Found in the outer layer, glomeruli are found here (makes the filtrate)
Thin cortex = glomeruli are falling apart (normal as you age)
Renal columns
Extension of cortex into medulla
Renal medulla
Where all the renal pyramids are found (in between columns)
Pathway of urine
Nephrons –> collecting ducts –> renal papilla –> minor calyx –> major calyx –> renal pelvis –> ureter –> bladder –> urethra
What are polycystic kidneys?
Kidneys with round sacs with fluid (inherited)
Problems with kidneys
- Too many ureters
- Severe hydronephrosis (joint kidneys)
- Supernumerary renal arteries (too many renal a.)
What is the renal corpuscle?
Composed of glomerular capsule & glomerulus
Glomerulus = tuft of capillaries
What feeds the glomerulus & what spreads over the tubules?
Afferent arterioles = glomerulus
Efferent arterioles = tubules
Role of juxtaglomerular cells
Acts as a quality control mechanism of filtrate
What happens between the peritubular capillaries (bloodstream) and the renal tubules?
Reabsorption of material from the filtrate in the tubule to the blood
Secretion of material from the blood to the tubule
Layers of the renal corpuscle
Visceral layer: covers the capillaries of the glomerulus
Parietal layer: outside layer
Components of the juxtaglomerular apparatus
Macula densa: part of the D.C.T., tastes the filtrate + making sure there’s the right amount
Granular cells: makes renin, if MD senses something wrong = renin release
Mesangial cells: also found in-between capillary tufts (regulates filtration)
Function of the renal corpuscle
The capsular space (space between visceral & parietal layers) is where filtrate is formed (BVs –> capsular space)
With every heart beat, blood is pushed in here (filtrate slowly enters capsular space)
Podocytes
Found outside of the glomerulus
Pedicels come off the podocytes
In between these, there are filtration slits
Relationship between kidneys and CV system
CV system generates the pressure necessary for glomerular filtration
The kidneys maintain blood volume, regulate plasma osmolality + secrete mediators that affect both cardiac performance & vascular tone
Positive pressures (filtration)
Pressure pushing fluid out of the glomerular capillaries (the pressure of the blood in the glomerular capsule)
Determines the glomerular filtration rate
Negative pressures (filtration)
Pressures holding fluid in the glomerular capillaries (pressure of the fluid already in the capsule)
Ways to auto regulate GFR (x2)
Myogenic mechanism
Tubuloglomerular feedback
Myogenic mechanism
The smooth muscle of the afferent arteriole is stretched by the increased in blood pressure and afferent arteriole responds with constriction which decreases GFR
Tubuloglomerular feedback
The macula densa of the juxtaglomerular apparatus detects high amounts of filtrate flow (i.e. lots of water & Na+ and Cl- flowing past) inhibits NO release which inhibits afferent arteriole dilation which decreases GFR
Hormonal regulation of GFR (x2)
ANP and angiotensin II
Angiotensin II and GFR
Sympathetic stimulation or decrease in blood pressure causes juxtaglomerular apparatus activation
J.A. releases renin
Angiotensin is made –> increased BV constriction & increased blood pressure
J.A. is then turned off
Result = increased BP from angiotensin II and more Na+ reuptake in tubules
ANP and GFR
ANP is released when there is distention of the atrium
ANP causes relaxation of mesangial cells between glomerular capillaries (so they’re more spread out = more filtration)
ANP also relaxes the afferent arterioles of the glomerulus and increases Na+ loss
Neural regulation of the GFR
Sympathetic branch of ANS has inputs to muscular walls of the afferent arterioles
Receptors are alpha 1 adrenoceptors
With low blood flow, glomerular hydrostatic pressure goes down & filtration decreases
