objective 7 pt 1 Flashcards
how do the kidneys maintain the body’s internal environment?
- Regulating total water volume and total solute
concentration in water - Regulating ion concentrations in extracellular
fluid (ECF) - Ensuring long-term acid-base balance
- Excreting metabolic wastes, toxins, drugs
- Producing erythropoietin (regulates RBC
Production) and renin (regulates Blood Pressure) - Converting Vitamin D to its active form
- Carrying out Gluconeogenesis during prolonged
fasting.
what does the urinary system include?
ureters
urinary bladder
urethra
transport urine from kidneys to urinary bladder
ureter
temporary storage reservoir for urine
urinary bladder
transports urine out of the body
urethra
bean shaped
retroperitoneal, in the superior lumbar region
convex lateral surface
concave medial surface with vertical renal hilum leads to internal space called renal sinus
kidney
sits atop each kidney
adrenal gland
what are the 3 layers of supportive tissue surrounding the kidneys?
renal fascia
peri-renal fat capsule
fibrous capsule
outer layer of dense fibrous connective tissue
anchors adrenal gland and kidney to surrounding structures
renal fascia
transparent capsule that prevents spread of infection in close regions from spreading to kidney
fibrous capsule
fatty cushion around kidney
protects it
holds it in position
peri-renal fat capsule
what are the 3 distinct regions of the internal kidney?
renal cortex
renal medulla
renal pelvis
superficial region
renal cortex
deep, composed of cone-shaped medullary pyramids
renal medulla
separated by renal columns
renal pyramids
tip of pyramid points internally
papilla
each medullary pyramid and its surrounding cortical tissue make up a lobe; about eight lobes per kidney
lobe
funnel-shaped tube continuous with ureter
renal pelvis
what do the branching extensions of the renal pelvis form?
minor calyces
major calyces
cup-shaped areas that collect urine draining from pyramidal palillae
minor calyces
areas that collect urine from minor calyces
empty urine into renal pelvis
major calyces
what is the flow of urine?
renal pyramid –> minor calyx –> major calyx –> renal pelvis –> ureter –> bladder
kidneys cleanse blood and adjust its composition, so it has a rich blood supply
blood
deliver about one-fourth of cardiac output to kidneys each min; branches in kidney until it reaches each nephron
renal arteries
sympathetic fibers from renal plexus
nerve supply
are the structural and functional units that form urine
nephrons
what are the 2 main parts of a nephron?
renal corpuscle
renal tubule
what are the 2 parts of renal corpuscle?
glomerulus
glomerular capsule
high pressure capillary bed
composed of fenestrated endothelium
highly porous
allows for efficient filtrate formation
glomerulus
plasma-derived fluid that renal tubules process to form urine
filtrate
cup-shaped, hollow structure surrounding glomerulus
glomerular capsule
bowman’s capsule
what are the 2 parts of glomerular capsule?
parietal layer
visceral layer
structural, doesnt play a role in forming filtrate
parietal layer
clings to glomerular capillaries; consists of branching epithelial cells
visceral layer
about 3cm long
consists of single layer of epithelial cells, but each region has its own unique histology and function
renal tubule
what are the 3 major parts of the renal tubule?
proximal convoluted tubule
nephron loop
distal convoluted tubule
cuboidal cells with dense microvilli that form brush border
functions in reabsorption of water and solutes from filtrate and secreting substances into it
found only in renal cortex
proximal convoluted tubule
U-shaped structure consisting of 2 limbs
nephron loop
proximal part of descending limb is continuous with proximal tubule;thin
descending limb
thick ascending limb
ascending limb
cuboidal cells with very few microvilli
function more in secretion than reabsorption
found only in cortex
distal convoluted tubule
maintain water and Na+ balance
help maintain acid-base balance of blood
recieve filtrate from many nephrons
run through the pyramids
ducts fuse together to deliver urine through papillae into minor calyces
collecting ducts
what are the 2 main groups of nephrons?
cortical nephrons
juxtamedullary nephrons
make up 85% of nephrons in kidney
almost entirely in cortex except small parts of nephron looks that dip into the outer medulla
cortical nephrons
long nephron loops deeply invade medulla
ascending limbs have thick and thin segments
important role in production of concentrated urine
juxtamedullary nephrons
what are cortical nephrons associated with?
glomerulus
peritubular capillaries
what are juxtamedullary nephrons associated with?
glomerulus
vasa recta
capillaries are specialized for filtration
different from other capillary beds bcuz they are fed and drained by arteriole
glomerulus
why is BP high in glomerulus?
- Afferent arterioles are larger in diameter than efferent
arterioles - Arterioles are high-resistance vessels
low-pressure, porous capillaries adapted for absorption of water and solutes
arise from efferent arterioles
cling to adjacent renal tubules in cortex
empty into venules
peritubular capillaries
long, thin-walled vessels in juxtamedullary nephrons
arise from efferent arterioles serving juxtamedullary nephrons
function in formation of concentrated urine
supply oxygen and nutrients to the tissue through which they pass
vasa recta
what are the 3 cell populations that are seen in JGC?
macula densa
granular cells
extraglomerular mesangial cells
tall, closely packed cells of ascending limb
contain chemoreceptors that NaCl concentration in the filtrate
macula dense
enlarged smooth muscle cells
act as mechanoreceptors to sense blood pressure in afferent arteriole
synthesize, store and secrete renin
granular cells
found between the arteriole and tubule cells
interconnected with gap junctions
may pass signals between macula densa and granular cells
play a role in renal autoregulation of blood flow to the kidney and regulation of blood pressure through the renin-angiotensin system
extraglomerular mesangial cells
