Urinary System Flashcards
major excretory organs
kidneys
also lungs and skin participate
main functions of the kidney
- filter 180-200L of blood daily to allow toxins, wastes, and excess ions to leave the body as urine
- regulate blood volume and chemical make up
- water and salt balance, and acid base balance
other renal functions
- gluconeogenesis- during prolonged fasting glucose is made from glycerol and amino acids; happens in kidney cortex
- rennin production- help regulate bp and erythropoietin to stimulate RBC production
- Activation of vitamin D
urinary bladder
provides a temporary storage reservoir for urine
paired ureters
transport urine from the kidneys to the bladder
urethra
transports urine from bladder to outside the body
external anatomy of the kidney
- right kidney is lower than the left because it is crowded by the liver
- lateral surface is convex, medial surface is concave
- the renal hilum leads to the renal sinus cont calyces and renal pelvis
- ureters, renal bv, lymphatics, and nerves enter/exit at the hilum
renal/fibrous capsule
fibrous capsule that prevents kidney infection
perirenal fat/adipose capsule
fatty mass that cushions the kidney and helps it attach to the body wall
also for energy
if kidneys lose this fat they can fall and compress the ureter backing up urine causing ptosis
renal fascia
outer layer of dense fibrous CT that anchors the kidney
internal kidney anatomy
cortex
light colored granule superficial region
most vascularized region of the kidney
internal kidney anatomy
medulla
exhibits cone shaped medullary (renal) pyramids separated by columns
the medullary pyramid and its surrounding capsule constitute a lobe
internal kidney anatomy
major calyces
large branches of the renal pelvis
collect urine draining from the renal papillae
empty urine into renal pelvis
internal kidney anatomy
renal pelvis
flat funnel shaped tube lateral to the hilum within the renal sinus
internal kidney anatomy
minor calyces
branches of the major calyces that collect urine formed in the papilla draining from the medullary pyramid
amount of the cardiac output that flows through the kidneys each minute
1/4 (1200mL) of systemic cardiac output
nerve supply to the kidney
renal plexus-sympathetic nerves
renal vascular pathway
aorta—renal artery—segmental artery—interlobar artery—arcuate artery—cortical radiate artery—afferent arteriole—glomerulus capillaries—efferent arteriole—peritubular capillaries and vasa recta—cortical radiate vein—arcuate vein—interlobar vein—renal vein—inferior vena cava
nephron
structural and functional units that form urine
consist of a glomerulus and renal tubules
glomerulus
tuft of capillaries associated with a renal tubule
renal tubules
made of the glomerular capsule, PCT, DCT, and loop of henle
renal corpuscle
the glomerulus and its bowmans capsule
anatomy of the renal corpuscle
glomerular epithelium
fenestrated epi
allows solute rich virtually protein free filtrate to pass from the blood into the glomerular capsule
anatomy of the renal corpuscle
glomerular/bowmans capsule
blind cup shaped end of a renal tubule that completely surrounds the glomerulus
glomerular/bowmans capsule
external parietal layer
simple squamous epithelium
is a structural layer
glomerular/bowmans capsule
visceral layer
modified, branching epithelial podocytes
extensions terminate in foot processes
glomerular/bowmans capsule
filtration slits
openings between the foot processes that allow filtrate to pass into the capsular space
whatever is made in the renal corpuscle goes to the
renal tubules because they are a continuation of eachother
renal tubule
PCT
composed of cuboidal cells with numerous microvilli and mitochondria
reabsorbs water and solutes from filtrate and secretes substances into it
renal tubule
loop of henle
a hairpin shaped loop of the renal tubule
proximal part is similar to the PCT and then is followed by thin segment of simple squamous cells (water) and the thick segment of cuboidal/columnar cells (salt)
renal tubule
DCT
cuboidal cells without microvilli that function more in secretion that reabsorption
less mitochondria-no villi
less reabsorbtion
connecting tubules
the distal portion of the DCT that is nearer to the collecting ducts
important cell types in the collecting tubules
intercalated cells- cuboidal cells with microvilli that funct in maintaining the acid base balance of the body
principal cells- cuboidal cells without microvilli that help maintain the bodies water and salt balance
cortical nephrons
85% of the nephrons
located in the cortex
juxtamedullary nephrons
15%
located at the cortex medulla junction
have loops of henle that deeply invade the medulla
have extensive thin segments (hold more H20 when dehydrated)
involved in the production of concentrated urine
every nephron has 2 capillary beds
glomerulus
peritubular capillaries
glomerular capillary bed
each glomerulus is fed by an afferent arteriole and drained by an efferent arteriole
fluids are forced out of the blood throughout the entire length of the glomerulus
blood pressure is high in the glomerulus because
arterioles are high resistance vessels
afferent arterioles have larger diameters than efferent arterioles
blood is coming in at a faster rate than leaving
peritubular beds are low pressure, porous capillaries adapted for absorption that
arise from efferent arterioles
cling to adjacent renal tubules
and empty into the renal venous system
absorb 99% of the filtrate
cortical nephrons
vasa recta
long straight efferent arterioles of juxtamedullary nephrons that play a role in forming concentrated urine
juxtaglomerular apparatus of the nephron
where the distal tubule lies against the afferent (sometimes efferent) arteriole