intro to renal function, Lect 1 Flashcards
function of kidney
- regulates water and inorganic ions
- regulates osmolality and volume (via BP)
- excretes metabolic waste
- secretes hormones
- regulate bicarbonate levels
where is renin secreted
juxtaglomerular cells
what secretes erythropoietin
renal interstitial cells
how does kidney create a patient who is in a water steady state? negative water balance? positive water balance?
- steady state: water input - (water output (fecal, sweat, insensible) + urine) = 0
- negative water balance: water input - (water output (fecal, sweat, insensible) + more urine) = -X
- positive water balance: water input - (water output (fecal, sweat, insensible) + less urine) = + X
what are some conditions that can result in a negative sodium and water balance?
- less sodium and water in body than normal
- diarrhea
- diurectic medication
- insufficient aldosterone (adrenal dysfunction)
what are some conditions that can result in a positive sodium and water balance?
- excess steroids
- congestive heart failure
- salt-retaining disease (hyperaldosteronism)
renal calyces drain into?
renal pelvis
outer, granular portion of kidney? inner, striated portion of kidney?
- cortex
- medulla
what is the basic unit of the kidney
nephron
- there are millions in each kidney
renal corpuscle
- comprised of glomerulus and bowman’s capsule
basic function of proximal tubule
- drains Bowman’s capsule
60-80% of filtered solute and water is reabsorbed from what part of the nephron? (hint: isosmotic)
proximal tubule
- does not concentrate urine
basic function of loop of henle
- generate osmotic gradients in medulla that allow kidney to concentrate the urine
juxtaglomerular apparatus
where distal tubule passes between afferent and efferent arteriole
area in nephron where some reabsorption of water and ions occurs, fluid is isosmotic or hyposmotic
distal convoluted tubule
water permeability in the collecting duct is controlled by?
vasopressin
site where the final concentration of urine is adjusted (urine may be iso-, hypo-, or hyperosmotic)
collecting duct
differentiate between cortical nephrons and juxtamedually nephrons
- cortical nephrons
- glomeruli in outer cortex
- LOH short and does not extend into inner medulla
- juxtamedually nephrons
- glomeruli naer corticomedullary border
- LOH long and extends into inner medulla
ability to produce concentrated ruine is thought to be proportional to the number of
juxtamedullary nephrons
collecting ducts are shared by many nephrons which means that all nephrons function in ?
parallel
filtration barrier in nephron consists of what 3 layers
- capillary endothelium
- glomerular basement membrane (basal lamina)
- visceral epithelial cells (podocytes)
podocytes
visceral epithelial cells
pedicels
extensions of podocytes
through what does filtrate flow to get into bowman’s capsule
slits between podocytes
juxtaglomerular apparatus is composed of what 3 cell types
- macula densa
- extraglomerular mesangial cells
- granular cells (aka juxtaglomerular cells)
function of juxtaglomerular apparatus
- helps control GFR
- controls renin secretion (blood pressure and blood volume)
mesangial cells
cells between capillary loops that contract in response to angiotensin II
two arterioles of nephron
the afferent arteriole feeds the glomerular capillary bed while the efferent arteriole drains it.
peritubular capillary bed consists of what two sections
- cortical
- vasa recta
- supply blood to the nephron
vasa recta
- peritubular capillary bed that follows LOH
- supplies nutrients to medullary tissue and important for recovery of water
cortical arteries give off afferent arterioles, fluid not filtered goes into what arterioles?
efferent arteriole
how many afferent arterioles are there per one glomerulus
one
two capillary beds that supply blood to nephrone
- glomerular
- peritubular
the two arterioles (afferent and efferent) and two capillary beds (glomerular and peritubular) are connected in ?
series
renal nerves have what innervation?
sympathetic
- **parasympathetic innervation is absent
renal nerves release what neurotransmitters
- NE
- dopamine
what receptors are present on afferent and efferent arterioles
alpha 1 receptors
- *primarily on afferent arterioles
stimulation of the renal nerve via the sympathetic nervous system tends to have what effect on Renal blood flow and GFR?
Renal blood flow and GFR are reduced
simulataneous release of what prostaglandins with SNS stimulation keeps reductions of RBF and GFR minimized
- PGE2
- PGI2
granular cells (juxtaglomerular) cells are innervated by SNS, stimulation of what receptors on these cells releases renin?
beta receptors
normal GFR
120-125 ml/min
tubular reabsorption
from renal tubular lumen to peritubular capillary
tubular secretion
from peritubular capillary to tubular lumen
