urinary system Flashcards
important functions of kidneys
- maintain chemical consistency of blood
- filter many liters of fluid from blood
- send toxins, metabolic wastes and excess water out of body
main waster products are 3 nitrogenous compounds
- urea
- uric acid
- creatinine
organs of the urinary system
- kidneys
- ureters
- urinary bladder
- urethra
- kidneys are red-brown in color
- located retroperitoneally
- -behind the peritoneum
- lateral to T12-L3 vertebrae
location of kidneys
- average kidney is 12cm tall, 6cm wide, 3cm thick
- Hilum
- concave surface
- -vessels and nerves enter and exit
external anatomy of kidneys
- capsule of dense connective tissue that surrounds the kidney
- inhibits spread of infections
Fibrous capsule of the kidney
external to renal capsule
perirenal fat capsule of the kidney
external to perirenal fat capsule
-contains fat
Renal fascia
- renal cortex
- renal medulla
- renal pelvis
frontal section through kidney
–superficial region, granular appearance
renal cortex
–cone-shaped renal pyramids
renal medulla
- -major calices
- -minor calices
renal pelvis
- renal arteries branch into segmental arteries
- segmental arteries branch into interloper arteries
- arcuate arteries branch form interloper arteries
gross vasculature of the kidney
- the functional unit of the kidney
- over 1 million ___ in each kidney
- composed of renal tubule and renal corpuscle
Nephron
filtrate of blood leaves kidney capillaries
filtration
most nutrients, water, and essential ions reclaimed
resorption
active process of removing undesirable molecules
secretion
three major renal processes
- filtration
- resorption
- secretion
- first part of nephron
- glomerulus nd glomerular capsule
renal corpuscle
tuft of capillaries
-fenestrated
glomerulus
- parietal layer- simple squamous epithelium
- visceral layer- consists of podocytes
Glomerular capsule
- filter that lies between blood in the glomerulus and capsular space
- consists of 3 layers
1. fenestrated endothelium of the capillary
2. filtration slits between foot processes of podocytes
3. basement memebrane
filtration membrane
-holds back most proteins
-allows passage of:
water, ions, glucose, amino acids, urea
basement membrane and slit diaphragm
- filtrate proceeds to renal tubules from glomerulus
- proximal convoluted tubule
- nephron loop
- -descending limb
- -descending thin limb
- -thick ascending limb
- distal convoluted tubule
renal tubule
- receive urine from several nephrons
- plays an important role in conserving body fluids
- posterior pituitary secrets ADH
- -increases permeability of collecting ducts and distal convoluted tubules to water
collecting ducts of the renal tubule
classes of nephron
- cortical nephrons
2. juxtamedullary nephrons
85% of nephrons
cortical nephrons
15% of nephrons
-contribute to kidneys ability to concentrate urine
juxtamdeullary nephrons
- carry urine from the kidneys to the urinary bladder
- oblique entry into bladder prevents back flow of urine
ureters
muscular of ureters
- inner longitudinal layer
2, outer circular layer
adventitia of ureters
typical connective tissue
transitional epithelium of the ureters
mucosa
- a collapsible muscular sac
- stores and expels urine
- -full bladder- spherical
- –expands into abdominal cavity
- empty bladder
- lies entirely within the pelvis
urinary bladder
closed remnant of the allantois
urachus
- in males
- lies directly inferior to the bladder
- surrounds the urethra
prostate
urinary bladder composed of three layers
- mucosa - transitional epithelium
- thick muscular layer - detrusor
- fibrous adventitia
epithelium of the urethra
- transitional epithelium
- -at proximal end (near bladder)
- stratified and pseudo stratified columnar
- mid urthra (in males)
- stratified squamous epithelium
- at the distal end (near urethral opening)
involuntary smooth muscle in ureathra
internal urethral sphincter
- voluntarily inhibits urination
- relaxes when one urinates
external urethral sphincter
in females -3-4 cm in males 20cm in length 3 regions 1. prostatic urethra 2. intermediate part of urethra 3. spongy urethra
urethra sizes
passes through the prostate gland in males
prostatic urethra
through the urogenital diaphragm in males
intermediate part of urethra
passes through the length of the penis
spongy urethra
- more common in females
- burning sensation during micturition
urinary tract infections
kidney stones
renal calculi
3% of cancers - more common in men
bladder cancer
arises from epithelial cells of uriniferous tubules
kidney cancer
