Chp 25 PP Flashcards
urinary system maintains what
fluid homeostasis
urinary system regulates what
regulation of volume and composition by eliminating certain wastes while conserving needed materials
regulation of blood pH
regulation of hydrostatic pressure of blood and, indirectly, of other body fluids
gluconeogenesis means
create new sugar
urinary system helps synthesize
calcitriol (active form of Vitamin D)
urinary system secretes
erythropoietin
what happens to the urinary system during starvation
performs gluconeogenesis
what does the urinary system deaminate
certain amino acids to eliminate ammonia
smallest fuctional unit of a kidney
hron
what are the three physiological processes of the nephron
1) filtration,
2) reabsorption 3) secretion
where are the kidneys located in the body
Retroperitoneal
nephrons are made up of what parts
renal corpuscle- where the glomerulus starts. Specifically afferent and efferent vessels.
nephrons are made up of what parts
renal corpuscle- where the glomerulus starts. Specifically afferent and efferent vessels.
why is the glomerulus pressurized
is meant to help filter things is pressurized because the afferent arterial is larger and efferent vessel is smaller
where is the glomerulus located
renal corpuscle
In the kidney the filtrate is carried by
the collecting duct system through the medulla
The urine is collected in the kidney where
at the papillae into the minor and major calyxes
Renal corpuscle
is what
site of plasma filtration
renal corpuscle is made up of
2 components
- glomerulus
- glomerular (Bowman’s) capsule
glomerulus is made up of
tuft of capillary loops
glomerulus is fed by
afferent arteriole
glomerulus is drained by
drained by efferent arteriole
glomerular (Bowman’s) capsule
is?
double walled cup lined by simple squamous epithelium
outer wall (parietal layer) separated from inner wall (visceral layer = podocytes) by capsular (Bowman’s) space
what happens as blood flow flows through the capillary tuft?
What does not cross?
filtration occurs
- water and most dissolved molecules pass into capsular space
- large proteins and formed elements in the blood do not cross
where filtered fluid passes from capsule in the nephron
renal tubule
pathway of fluid in the nephron
proximal convoluted tubule (PCT)
loop of Henle (nephron loop)
distal convoluted tubule (DCT)
short connecting tubules
collecting ducts
merge to papillary duct
- then to minor calyx
- 30 pap ducts/papillae
two different types of nephrons
Cortical vs. juxtamedullary nephrons
location of a nephron is related to
the length of loop of the nephron
15-20% of the nephrons have longer loops and increased
involvement in the reabsorption of water
Histology of the glomerular filtration membrane
- Three components to the filter
- From inside to out, the layers prevent movement of progressively smaller particles
what happens if you have a proteins, R/WBC, glucose inside of the glomerulus causing what
bursting kidneys, kidney failure
Endothelium of glomerulus
Single layer of capillary endothelium with fenestrations
Prevents RBC passage; WBCs use diapedesis to get out
Basement membrane of glomerulus
Between endothelium and visceral layer of glom. capsule
Prevents passage of large protein molecules
Filtration slits in podocytes in glomerulus
Podocytes
specialized epithelium of visceral layer
footlike extensions with filtration slits between extensions
Restricts passage of medium-sized proteins
Histology of Filtration Membrane of glomerulus
1) Endothelium (pores inside)
2) Basement membrane
3) Filtration slits in podocytes
Renal Blood supply flow of kidneys
1) Renal arteries
2) Segmental arteries
3) Interlobar arteries - through columns
4) Arcuate arteries
5) Interlobular arteries
vessel that long networks from the efferent arteriole around the Loop (juxtamedullary nephrons)
Vasa recta
Peritubular capillaries of kidneys are known as
Vasa recta
Renal veins - exit where
hilus
Renin-Angiotensin System is what kind of apparatus
Juxtaglomerular apparatus (JGA)
Juxtaglomerular apparatus (JGA) is found where
Distal tubule contacts afferent arteriole at renal corpuscle
Angiotensinogenase is
renin
an enzyme
Angiotensinogenase is released when
only three times
1) Blood pressure down
2) blood volume down
3) sympathetic nervous system on
what is released during a hemmorrage or dehydration
renin
Angiotensinogenase
Juxtaglomerular (JG) cells
modified smooth muscle cells in afferent arteriole wall detect changes in blood pressure (a stretch reflex)
Secrete enzyme renin to trigger Renin-Angiotensin System if blood pressure falls
Renin-Angiotensin System is secreted by
kidney
Angiotensinogenase when released creates
angiotensin I (inactive form) in lungs ACE (Angiotensin Converting Enzyme) is released then you release angiotensin II active form (very powerful vasoconstrictor)
why would someone be prescribed ACE inhibitor
to combat hypertension
what is Distal tubule contacts afferent arteriole at renal corpuscle
Juxtaglomerular apparatus (JGA)
what does the Juxtaglomerular apparatus (JGA)
do
cells that detect pressure in the glomerulus
Juxtaglomerular apparatus (JGA) tells the kidneys to do what when there is more pressure coming into the glomerulus
secrete more water
two cells at the efferent arterials Juxtaglomerular apparatus (JGA)
macula densa
and JG
cells work together to regulate blood pressure and blood volume
Both JG and MD
What does the D in VItamin D stand for
dicholecalciferol
dicholecalciferol is
vitamin d
kidneys can activate what in Vitamin D
calciferol
stimulate JG cells to
release renin if filtrate is too dilute, indicating insufficient filtration and/or low blood pressure/low blood volume
Macula Densa (MD) cells
special cells in the wall of the distal tubule in this area monitor the osmotic potential in the filtrate in the distal tubule
Juxtaglomerular (JG) cells are
modified smooth muscle cells in afferent arteriole wall detect changes in blood pressure (a stretch reflex)
Juxtaglomerular (JG) cells secrete
enzyme renin to trigger Renin-Angiotensin System if blood pressure falls
diabetes insipidis is
clear.
-lack of ADH (Anti diuretic hormone)
-happens if you are an alcoholic
not reabsorbing anything, causes you to be dehydrated
-Can create more ADH but can hurt the kidneys permanently
What is the role of sympathetic stimulation on renal blood flow?
In “Fight or Flight” or muscular exertion:
- decrease renal arterial flow
- decrease urine production
- maintain blood volume
- increase systemic blood pressure
Glomerular filtration is the
first step in urine formation
Glomerular filtration
-forcing of fluids and dissolved solutes through membrane by hydrostatic pressure
-same process as in systemic capillaries
results in a filtrate
180 L/day, about 60 times plasma volume
lack of ADH causes
diabetes insipidis
acidosis
increased H ions
Cells of the renal tubule can elevate blood pH in 3 ways:
Secrete H+ ions into the filtrate
Reabsorb filtered HCO3-
Produce more HCO3
is a toxic waste absorbed from bacterial metabolism in the large intestine and ammonia is generated from the deamination of amino acids in the liver
Ammonia
Liver converts ammonia to
urea
cells can also deaminate certain amino acids and secrete additional NH4+ with a Na+/NH4+ antiporter when blood pH becomes acidic
PCT (proximal convoluted tubule)
PCT (proximal convoluted tubule) reabsorbs
nutrients, electrolytes, and water
