Renal 1 Glomerulus Flashcards
what are the functions of the kidney?
- regulate blood ionic composition
- regulate blood pH
- regulate blood vol. (water content)
- regulate BP (RAA pathway)
- maintain blood osmolarity (300Osm/L)
- prod. hormones (vit. D, EPO)
- regulate blood glucose (gluconeogenesis)
- excrete waste
where are the kidneys located?
in the superior portion of the posterior abdominal cavity; retroperitoneal
segmental arteries
as renal artery enters renal sinus it branches to 5 of these
how is a kink in the ureter formed?
by the iliopsoas muscle; kidney stones passing through the ureter can also get stuck in this region
renal fascia
dense layer of CT that helps hold kidney in place within posterior abdominal wall
perirenal fat
fatty tissue surrounding the renal capsule to cushion the kidney and protect it from trauma
renal capsule
the 3rd layer of stiff CT covering the external surface of the kidney and keeps it in one shape
renal hilum
where vessels and ureter enter/exit
renal cortex
outer layer of the kidney
renal medulla
inner portion of the kidney
renal columns
extensions of the cortex that project inward toward sinus; exist b/w triangular units in the medulla
renal pyramids
triangular-shaped areas of tissue in the medulla of the kidney
renal papillae
CT that collect the filtrate generated by the nephrons
nephron
filtering unit of the kidney that extracts waste from blood and sends it out to tip of renal pyramid to be collected via minor calyx
minor calyx
a cup-shaped extension of the pelvis that encircles the apex of a pyramid; at this point, filtrate becomes urine
major calyx
the cavity formed by the convergence of several minor calyces, which drain urine from the minor calyxes into the renal pelvis
renal pelvis
central collecting region in the kidney
structures in the renal cortex
renal corpuscle, Bowman’s capsule, renal tubules, juxtaglomerular apparatus, collecting duct
renal corpuscle
glomerulus and Bowman’s capsule, where blood filtering actually occurs; afferent arteriole brings blood toward glomerulus and efferent away
Bowman’s capsule
captures filtrate made by glomerulus, sending filtrate through renal tubules
renal tubules
small tubes in the kidney where reabsorption takes place
proximal convoluted tubule
first section of the renal tubule that the blood flows through; reabsorption of water, ions, and all organic nutrients
loop of Henle
section of the nephron tubule in renal pyramid that conserves water and minimizes the volume of urine
distal convoluted tubule
a portion of kidney nephron between the loop of Henle and the collecting duct system
juxtaglomerular apparatus
in the nephron, the complex of cells b/w distal tubule and glomerulus which fine-tune; constantly taste filtrate and alter rate of filtrate production
collecting duct
last 10% of water reabsorption, major site of action for ADH; at the tip of papilla will be collected by minor calyx
filtrate vs. urine
filtrate has no protein/formed elements/large molecules but lots of small molecules (glucose a.a.’s, HCO3-) while urine virtually has no small molecules
peritubular capillaries
tiny blood vessels that travel alongside nephrons allowing filtration between blood and the inner lumen of the nephron; there is reabsorption of material from filtrate and secretion of material into the tubule
what do renal tubules mostly contain?
plasma and dissolved substances
what is the glomerular capsule made of?
single layer of squamous epithelial cells (parietal layer), which gets projected onto the surface of blood vessels (visceral layer)
components of juxtaglomerular apparatus
macula densa (MD), granular cells (GC),, mesangial cells (MC)
macula densa
Tastes and try’s to see if filtrate is appropriate, secrete NO and works paracrine to talk to smooth muscle of afferent arteriole to relax (allows blood flow into glomerulus)
granular cells
responsible for releasing renin for RAA pathway
mesangial cells
modified smooth muscle cells; targets of action of ANP which tell these cells to relax to loosen glomerular tuft (lots of filtration, urine)
what is the function of the sympathetic nerve fiver on the afferent arteriole?
to help control vascular tone and constrict during fight or flight response
where is filtrate formed?
in the space b/w the visceral and parietal layer of the renal corpuscle (capsular space)
how is blood plasma forced out into the capsular space?
hydrostatic pressure
how are most proteins kept out of filtrate?
repelled due to -ve charge by basal lamina
pedicels
finger-like projections of podocytes surrounding glomerular capillaries; create filtration slits
podocytes
cells in the visceral layer of Bowman’s capsule that wrap around capillaries of the glomerulus
kidneys and the CV system
- the CV system generates BP necessary for glomerular filtration and drives high flow needed to maintain a stable cortical interstitial solute composition
- the kidneys maintain blood vol., regulate plasma osmolarity and secrete mediators that affect cardiac performance and vascular tone (products of kidney can affect preload and afterload)
net filtration pressure
the difference between net hydrostatic pressure and net osmotic pressure that pushes the filtrate into the capsular space, usually 10mmHg in kidneys
glomerular filtration rate (GFR)
the amount of filtrate formed per minute by the two kidneys combined
what pressure pushes fluid out of the glomerular capillaries
positive pressure..blood, hydrostatic pressure in capillaries
what pressures hold fluid in the glomerular capillaries
negative pressure..capsular hydrostatic pressure and blood osmotic pressure (attraction of dissolved materials in blood for water)
renal autoregulation
the ability of the nephrons to adjust their own blood flow and GFR without external (nervous or hormonal) control; easily altered by changing Bp in glomerulus or leakiness of capillaries
what are the 2 intrinsic mechanisms to change glomerular BP (and thus GFR)?
myogenic mechanism and tubuloglomerular feedback
myogenic mechanism
the smooth muscle of the afferent arteriole is stretched by an increase in BP and the afferent arteriole response w/ constriction which decreases GFR
tubuloglomerular feedback
the macula densa detect high amounts of filtrate flow (lots of water and Na+); this inhibits nitric oxide release which inhibits afferent arteriole dilation to decrease GFR
hormonal regulation of GFR
angiotensin II and atrial natriuretic peptide (ANP)
angiotensin II effect on GFR
decreases GFR b/c it constricts the afferent arterioles but increases BP b/c it also constricts systemic arterioles
angiotensin II
arises as a result of conversion of angiotensin I by ACE, which arose from the conversion of angiotensinogen (reaction calayzed be renin)
what is he effect of ACE inhibitors?
decrease BP and used to clinically treat hypertension
why does angiotensin II primary act on the afferent arteriole vs the efferent arteriole?
it will reduce blood flow to the glomerulus and hence reduce filtrate production rather than building up pressure in the glomerulus
ANP effect on GFR
increases GFR due to distension of the heart that triggers ANP release, it causes relaxation of mesangial cells which make the glomerular capillaries more spread out and relaxed for more filtration to occur (once blood vol. goes down, pressure in heart decreases and ANP is no longer secreted)
neural regulation of the GFR
via sympathetic branch of ANS to muscular walls of afferent arterioles
- a1-adrenoreceptors
- with low blood flow to glomerulus, hydrostatic pressure and filtration decreases
- there is little urine being made at this time
The left gonadal vein comes off of
Left renal vein
The right gonadal vein comes off the
Inferior vena cava
The gonadal arteries come off the
High on the aorta.. very long
Where does the bladder sit?
Behind pubic bone
What drains the kidneys and where to?
The renal veins and to the inferior vena cava
Where do the adrenal glands sit?
On top of both kidneys
Where do kidneys get blood from?
Renal arteries
What do the renal arteries turn into?
Segmental arteries.. five of them
Glugogenesis occurs
Half from liver and half from kidneys
Do the kidneys store significant levels of glycogen.
No
What is the right kidney depressed by?
Inferiorly by the liver
Ptosis is
Occurs when people are starving and kidney defends and kinks itself off
- last fat to be used when starvation occurs because once it starts to use the kidneys now fall and they drool which causes ureter to kink a bit which results in a lot of pressure and can create kidney damage
How can we crack the rib cage?
Part of kidney will peak below rib cage and if we get hit from behind we can crack rib
Renal arteries
Branching right away to give to segmental arteries, they further branch to give into interlobar arteries and then arcuate arteries
Where does urine come out of?
Out of collecting duct in the nephron
Where does collecting duct come out?
At the renal papilla
Where does the renal papillae drain into?
Drains into minor and major calyx
After minor and major calyx where does it go?
Enter renal pelvis and comes out ureter
The renal column is largely?
Interlobar arteries
The pyramids are
Tubules and collecting ducts
Poly cystic kidney
Kidney is filled with fluid filled sacs
Longer the loops..
More you can concentrate urine (less water)
From 20-25%of blood flow how much is made into filtrate?
180L
Out of 180L of filtrate how much is made into urine?
1-2 L so about 99% is reabsorbed
Filtrate has small molecules like glucose and amino acids but the urine
Does not contain any hardly
Reabsorption
Stuff we do want such as glucose, sodium and potassium
If filtration process within the nephron isn’t occurring it results in
Renal failure
Capsular space
Where filtrate is formed… between visceral and parietal layer
Osmotic pressure
All the things that are dissolved in the blood that attract water… does not allow water to enter capsular space
If GFR is too high
BP in glomerulus is too high
- afferent arterioles constrict so less blood flows to the glomerular capillaries under less pressure and the GFR goes down; opposite for gfr being too low
