E5 Ch. 24 Flashcards
list the important functions of the kidneys
maintain chemical consistency of blood, filter fluid from blood, send toxins, metabolic wastes, and excess water out of body
list the 3 nitrogenous waste products that the kidney send out of the body
urea, uric acid, creatinine
list the organs of the urinary system
kidneys, ureters, urinary bladder, and urethra
where are the kidneys located
retroperitoneally (behind peritoneum), lateral to T12-L3 vertebrae
what is the hilum
concave surface where vessels and nerves enter and exit the kidney
what is the fibrous capsule of the kidney made of and its purpose
capsule of dense connective tissue surrounding kidney that inhibits spread of infections
where is the perirenal fat capsule located
external to renal capsule of the kidney
where is the renal fascia located and what does it contain
external to perirenal fat capsule; contains fat
describe the renal cortex
superficial region, granular appearance
what does the renal medulla consist of
cone-shaped renal pyramids
describe the renal plexus
network of autonomic fibers, offshoot of celiac plexus, supplied by sympathetic fibers from lowest thoracic splanchnic nerve and 1st lumbar splanchnic nerve
what is the functional unit of the kidney
nephron; over 1 million in each kidney
what are the mechanisms of urine production
filtration, resorption, and secretion
filtration
filtrate of blood leaves kidney capillaries
resorption
most nutrients, water, and essential ions reclaimed
secretion
active process of removing undesirable molecules
what is the nephron composed of
renal tubule and renal corpuscle
what is the renal corpuscle
first part of nephron
what is a glomerulus
tuft of fenestrated capillaries
what type of tissue is found in the parietal layer of the glomerular (Bowman’s) capsule
simple squamous epi.
what does the visceral layer of the glomerular (bowman’s) capsule consist of
podocytes
what is the filtration membrane
filter that lies b/t blood in the glomerulus and capsular space
what are the 3 layers that make up the filtration membrane
- fenestrated endothelium of the capillary
- filtration slits b/t foot processes of podocytes
- basement membrane
what do the basement membrane and slit diaphragm hold back and allow passage of
hold back most proteins, allow passage of water, ions, glucose, amino acids, and urea
function of collecting ducts
receive urine from several nephrons, play important role in conserving body fluids
where is ADH secreted and what does it do
secreted from posterior pituitary; increases permeability of collecting ducts and distal convoluted tubules to water
list the different classes of nephrons
cortical nephrons and juxtamedullary nephrons
what percentage of nephrons are cortical nephrons
85%
what percentage of nephrons are juxtamedullary nephrons and what do they contribute to
15%; contribute to kidney’s ability to concentrate urine
what 2 capillary beds are nephrons closely associated w/
glomeruli, peritubular capillaries in cortical nephrons or vasa recta in juxtamedullary nephrons
what does the glomeruli produce
filtrate that becomes urine
how much fluid is generated by glomeruli
1 liter of fluid every 8 minutes, 99% of which is resorbed by tubules
where do peritubular capillaries arise from
efferent arterioles draining cortical glomeruli
what are peritubular capillaries adapted for
absorption; low-pressure, porous capillaries, all molecules secreted by nephrons into urine are from peritubular capillaries
where does the vasa recta continue from
efferent arteriles of juxtamedullary nephrons
what is the vasa recta
thin-walled looping vessels descending into medulla, part of kidneys urine concentrating mechanism
what is the juxtaglomerular complex
an area of specialized contact b/t terminal end of the ascending limb and afferent arteriole that functions in regulating BP
what are granular cells
modified smooth muscle cells w/ secretory granules
what type of hormone do granular cells contain and what is that hormones function
the hormone renin; secreted in response to falling BP in afferent arteriole
what is the macula densa and its function
tall, closely packed epi cells adjacent to granular cells found at the end of nephron loop; monitor solute concentration in filtrate, signal granular cells to secrete renin, initiates renin-angiotensin mechanism
where are mesangial cell located and its function
located around base of glomerulus; regulate blood flow w/in glomerulus
function of extraglomerular mesangial cells
interact w/ macula densa and granular cells to help regulate BP
what type of tissue is found in the mucosa of the ureter
transitional epi
describe the muscularis found in the ureters
2 layers: inner longitudinal and outer circular layers
what is the outermost layer of the ureter
adventitia- typical connective tissue
where are does the urinary bladder occupy when its full and when its empty
full- spherical; expands into abdominal cavity
empty- lies entirely w/in pelvis
what is the urachus
closed remnant of the allantois
list and describe the 3 layers of the urinary bladder
- mucosa- transitional epi
- thick muscular layer-detrusor
- fibrous adventitia
what type of tissue is found in the urethra
Proximal end-transitional epi. near bladder mid urethra (in males)- stratified and pseudostratified columnar distal end (near urethral opening)- strarified squamous epi.
describe the internal and external urethral sphincters
internal- involuntary smooth muscle
external- voluntarily inhibits urination, relaxes when one urinates
what are the differences in urethra length b/t males and females
females- 3-4 cm
males- 20 cm
what are the 3 named regions of the male urethra
prostatic, intermediate part, and spongy (penile) urethra
where does the prostatic urethra pass though
prostate gland
where does the intermediate part of urethra pass though
urogenital diaphragm
where does the spongy (penile) urethra pass through
through the length of the penis
urinary tract infections
burning sensation during micturition; more common in females
renal calculi
kidney stones
what percentage of cancer are bladder cancer and who are the more common among
3%; more common in men
where does kidney cancer arise from
epithelial cells of uriniferous tubules
name the 3 pairs of kidneys the embryo develops
pronephros, mesonephros, and metanephros
which of the 3 paris of kidneys developed by the embryo goes on to become the adult kidneys
metanephros, produce urine by fetal month 3, contribute to volume of amniotic fluid
