the urinary system Flashcards
what is the primary function of the kidneys?
cleanse the blood (filter it)
kidney maintain the body’s internal environment by:
- 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 blood pressure and renin (regulates RBC production)
- Activating vitamin D
- Carrying out gluconeogenesis, if needed
upper parts of both kidneys are protected by what?
thoracic cage
perirenal fat provides what?
cushioning
lower parts of the kidneys are susceptible to what?
blunt trauma
(especially right kidney)
renal artery is especially vulnerable to injury from what?
rapid deceleration during car crashes, lead to laceration or thrombosis
what is hematuria and what is it an important sign of?
blood in urine and is an important sign of such trauma
internal kidney has three distinct regions, what are they?
- renal cortex
- renal medulla
- renal pelvis
where is the renal cortex?
granular-appearing superficial
where is the renal medulla?
deep to cortex, composed of cone-shaped medullary (renal) pyramids
what does the renal pelvis do?
urine flow
the order of urine flow:
renal pyramid
minor calyx
major calyx
renal pelvis
ureter
what is the major unit in the kidneys that produce urine?
nephrons
what are the 2 main parts of the nephrons?
renal corpuscle
renal tubule and collecting ducts
what is in the renal corpuscle?
glomerulus
glomerulus capsule (bowsman capsule)
what is the glomerulus?
tuft of capillaries composed of fenestrated endothelium
the renal tubule is about _____________ long
3 cm (1.2 in)
three major parts of the renal tubule:
- proximal convoluted tubule
- nephron loop
- distal convoluted tubule
where is the proximal convoluted tubule and what does it do?
proximal, closest to renal corpuscle
functions in reabsorption and secretion
the nephron loop was formerly called what?
loop of henle
what does the nephron loop look like? what two limbs does it have?
U-shaped structure
descending limb
ascending limb
where are the distal convoluted tubule? and what does it do?
distal, farthest from renal corpuscle
function more in secretion than reabsorption
distal convoluted tubule drains into a . . .
collecting duct
collecting ducts receive what?
filtrate from many nephrons
where does the collecting duct run through?
medullary pyramids
why do the ducts fuse together?
to deliver urine through papillae into minor calyces
2 major groups of nephrons:
- cortical nephrons
- juxtamedullary nephrons
cortical nephrons make up _____of nephrons and are almost entirely in _________.
85%
cortex
what are the juxtamedullary nephrons?
long nephron loops that deeply invade medulla
juxtamedullary nephrons ascending limbs have _______ and ______ segments
thick and thin
juxtamedullary nephrons are important in production of what?
concentrated urine
blood pressure is high where?
in glomerulus
blood pressure is low where?
peritubular capillaries
the 3 nephron capillary beds:
glomerulus
peritubular capillaries
vasa recta
the capillary beds in the renal tubule:
glomerulus
peritubular capillaries
glomerulus capillaries are specialized for what?
filtration
glomerulus are fed and drained by what?
arterioles
why is blood pressure high in glomerulus?
arterioles are high-resistance vessels
what are peritubular capillaries?
porous capillaries adapted for absorption of water and solutes
where do peritubular capillaries arise from?
efferent arterioles
peritubular capillaries empty into where?
venules
whart are vasa recta?
long, thin-walled vessels parallel to long nephron loops of juxtamedullary