2: Urinary System Flashcards
What are the organs in the urinary system?
2: kidneys, ureters
1: bladder, urethra
What are the general functions of the urinary system?
1) regulate water & electrolyte balance
2) excretion of nitrogenous wastes & some water & electrolytes
3) excretion of some other materials (drugs)
4) secrete renin
What are the 6 general parts of the kidney?
capsule, hilum, renal pelvis, major calyces, minor calyces, renal sinus
What is the kidney capsule?
thin & fiberous; made of dense irregular CT
What is the hilum of the kidney?
concave & medial; nerves enter, ureters exit; blood & lymph enter and exit
What is the renal pelvis?
widening of the ureter
What are the major calyces?
broad spaces w/i kidney to collect urine & direct to renal pelvis (2/3 kidney)
What are the minor calyces?
smaller collecting areas from each major calyx
contain renal papilla = tip of each renal pyramid
What is the renal sinus?
area surrounding renal pelvis, major calyces & minor caylces
contains adipose
What are the two general regions of parenchyma w/i the kidney?
Cortex & medulla
What does the cortex of the kidney contain?
renal corpuscles, tubles, medullary rays
What are the medullary rays of the kidney cortex?
extend from medulla into cortex
contains primarily portions of the loop of henle & collecting tubles
What are the parts of the medulla of the kidney?
renal pyramids: 8-12 per kidney
renal columns: areas separating the renal pyramids
How many nephrons are in each kidney?
~1 million
What are the parts a nephron?
renal corpuscle, proximal convoluted tubules (PCT), loop of henle, distal convoluted tuble (DCT), connecting tubles, collecting ducts
Where is the renal corpuscle found and the function?
always in cortex, blood filtration
What are the two major parts of the renal corpsule?
Bowman’s (glomerular) capsule, Glomerulus
What are the two layers of Bowman’s capsule?
parietal & visceral layer
What is the parietal layer of Bowman’s capsule made of?
simple squamous epithelium (bilayer)
What is the visceral layer of Bowman’s capsule?
an internal layer of podocytes
What are podocytes?
modified epithelial cells containing pedicles
What are pedicels?
secondary podocyte cell processes covering the glomerular capillaries creating filtration slits
What is the urinary (capsular) space?
space btwn parietal & visceral layer of Bowman’s capsule
recieves the filtered fluid from the capillaries
What is the glomerulus of the renal corpsule?
fenestrated capillary network inside the visceral layer of Bowman capsule
What is the unique location of the glomerulus?
btwn 2 arterioles so muscle in tunica media can create an increased capillary pressure to enhance filtration
increase/decrease pressure
What are the not so important part of the renal corpsule?
mesangial cells
What are mesangial cells?
special cells w/i the renal corpuscles; though to replace regular CT; many are pericyte-like (contractile filaments)
often present in areas lacking podocytes
What is the function of mesangial cells?
capillary support
adjust capillary pressure for good filtration
phagocytosis of interfering materials (proteins)
secrete various cytokines (immune defense & glomerulus repair)
What is the epithelium type in the proximal convoluted tubules (PCT)?
simple cuboidal w/ long microvilli (numerous)
What is the location of the proximal convoluted tubules?
cortex of kidney
What makes up the loop of henle?
thin limbs (descending & ascending) and thick ascending limbs
What epithelium type makes up the thin limbs of the loop of henle?
simple squamous
What is the location of the thin limbs of the loop of henle?
medulla
What is the epithelium type in the thick ascending limb of the loop of henle?
simple cuboidal (no microvilli)
What is the location of the thick ascending part of the loop of henle?
medulla & medullary rays
What type of epithelium makes up the distal convoluted tubule?
simple cuboidal (shorter cells w/ fewer & shorter microvilli)
Where are the distal convoluted tubules found?
cortex
What is the macula densa?
special part of the DCT at the vascular pole containing closely packed columnar cells @ begining
part of the juxtaglomerular apparatus (JGA)
- regulates glomerular BF & glomerular filtrate
What type of epithelium makes up the collecting tubule?
simple squamous to simple cuboidal
Shorter length
Are the collecting ducts part of the nephron?
NO
What type of epithelium makes up the collecting ducts?
simple cuboidal to simple columnar (in larger ducts)
What are the two principle cell types of the collecting ducts?
principle cells & intercalated cells
What are the principle cells of the collecting ducts?
light cells = collecting duct cells
MC cell type
in MEDULLARY RAYS & MEDULLA
What are the intercalated cells of the collecting ducts?
dark cells
fewer in #
found in_________????
NONE close to renal papilla
What are collecting ducts?
lead to a papillary duct which leads to a renal papillae and finally to a minor calyx
What are the ureters?
transport urine to urinary bladder
2 about ~24-34 cm long
What is the surface epithelium of the luminal wall of the ureters?
urothelium (4-5 cell layers thick)
What are the 3 basic layers of the luminal walls of the ureters?
1 layer of basal cells
1-several layers of intermediate cells
1 layer of large superficial cells UMBERELLA CELLS
What shape are the intermeiate cells of the luminal wallys of the ureters?
more columnar shape
What are umbrella cells?
can be bi-nucleate
have free-edge plasma membrane w/ plaque (allow folding @ thinner areas)
What are the functions of plaques in umbrella cells?
protection (cells & tissues beneath) & BLOCKS WATER passage
WHAT ARE THE MOST DEVELOPED CELLS IN THE URINARY BLADDER?
PLAQUE & UMBRELLA CELLS
What is the LP of the laminal wall of the ureter made of?
rather dense irregular CT
What is the muscle of the muscularis externa of the ureters?
smooth muscle mixed w/ CT
REVERSE PATTERN: inner longitudinal, outer circular layer
What are the 3 muscle layers of the muscularis externa of the ureter?
inner: longitudinal
middle: circular
outer: longitudinal
What motion of the muscularis externa helps move urine?
peristaltic motion
What is the adventitia of the ureter made of?
adipose, blood vessels, & nerves
How do the ureters connect into the bladder?
enters at angle to create a valve
as bladder fills, enterance to ureters closes
–> prevents backflow
IMPORTANT: stops the spread of infection to the kidneys
What is the epithelium of the bladder?
transitional/urothelium epithelium
What is the function of the urothelium of the bladder?
stretch & protect form hypertonic & toxic urine
~6 layers thick
PLAQUE: well developed to fold @ thinner regions when bladder collapses
What is the LP like in the bladder?
rather dense irregular CT
What is the submucosa of the bladder made of?
thin & blends w/ LP
What is the muscularis externa of the bladder made of?
3 distinct muscular layers DETRUSOR MUSCLE
1) inner longitudinal
2) middle circular
3) outer longitudinal
What is the internal urethral sphincter?
circle of muscle close to urethral opening
involuntary smooth muscle
part of the detrusor muscle
What do the sympathetic nerve of the bladder innervate?
blood vessels
What do the parasympathetics of the bladder innervate?
ME & adventitia = MICTURITION REFLEX
S2-S4 TRAVELING W/ SPLANCHNIC NERVE
What is the sensory innervation of the bladder?
urinary bladder & sacral spinal cord
AFFERENT FIBERS FOR MICTURITION REFLEX
What is the urethra?
fibromuscular tube
longitudinal folds in mucosa
What makes up the urethra in males?
urinary & reproductive system part
prostatic, membranous, spongy (penile) urethras
What is the prostatic urethra?
3-4 cm, in prostate, made of urothelium
What is the membranous urethra?
1 cm, passes through the external urethral sphincter: STRIATED MUSCLE,
STRATIFIED COLUMNAR &PSUEDOSTRATIFIED COLUMNAR EPI.
What is the spongy urethra (penile)?
15 cm, surrounded by erectile tissue (corpus spongiosum)
stratified & pseudostratified columnar and stratifed squamous distally)
What about the female urethra?
urinary only, 4-5 cm
What is the surface epithelium of the female urethra?
transitional, stratified columnar, pseudostratifed columnar (middle) & stratifed squamous distally
EXTERNAL URETHRAL SPHINCTER: around middle portion