Topic 16: Urinary System Flashcards
List the structures of the urinary system:
o2 kidneys
o2 ureters
o 1 urinary badder
- 1 urethra
What is the function of the urinary system
regulates: blood volume blood pressure pH ion concentrations
eliminate waste; nitrogenous waste
e.g. urea, uric acid, hormones, drugs
Describe the external anatomy of the kidney:
o retroperitoneal
o right lower than left
o supported & protected by 3 layers of CT
- renal hilus
list the 3 layers of CT that support the kidney
a) fibrous capsule
b) perirenal fat capsule
c) renal fascia
renal hilus (hilum):
medial indentation entry point of: o renal artery (superior) to o renal vein (inferior) o ureter o nerves
describe the internal anatomy of the kidney
o renal cortex (superficial)
o renal medulla (middle and deep to the cortex)
- CREATIG URINE OCCURS HERE
What does the renal medulla contain?
i. renal pyramids
apex of pyramid = renal papilla
ii. renal columns
separate pyramids
contain blood vessels
Nephron:
functional unit of kidney (microscopic)
What is the nephron composed of?
a) renal corpuscle
b) renal tubules
renal corpuscle
in cortex
site of blood filtration (first step in urine formation)
List the parts of the renal corpuscle
i. glomerulus
ii. Bowman’s capsule
iii. Filtration membrane
glomerulus
= capillary bed
Bowman’s capsule
surrounds glomerulus collects filtrate from glomerulus 2 layers: 1) outer = simple squamous epithelium 2) inner = podocytes wrapped around glomerular capillaries
Filtration Membrane
- glomerular endothelium (capillaries)
simple squamous with pores (= fenestrations) - basement membranes
- Podocytes (of Bowmans capsule)
simple epi- projections cling to glomerulus
List the parts of the renal tubules
i. Proximal Convoluted Tubule (PCT)
in cortex
ii. Loop of Henle
descending + ascending limbs
in medulla
iii. Distal Convoluted Tubule(DCT) in cortex
iv. Collecting Ducts
in cortex & medulla
connect nephron to ureter (via calyces/renal pelvis)
List the 2 types of nephrons and differences between the 2
a) Cortical (85%)
renal corpuscles near kidney surface in cortex
short Loop of Henle in outer medulla
b) Juxtamedullary (15%)
renal corpuscles in cortex near medulla
longs Loops
penetrate deep into medulla
o allow concentration of urine depending on need
Describe the kidney and nephron blood flow:
Aorta renal artery segmental artery interlobular artery arcuate artery cortical radiate artery afferent arteriole glomeruli efferent arteriole peritubular capillaries/ vasa recta cortical radiate vein arcuate vein interlobular veins renal vein inferior vena cava
Juxtaglomerular complex:
regulates filtrate formation
point of contact between end of ascending limb, afferent + efferent arterioles at renal corpuscle of same nephron
Describe the parts of the Juxtaglomerular complex:
a) Tubular Portion
modified (tall and narrow) ascending limb cells = macula densa
b) Arteriolar Portion
afferent and efferent arteriolar portion = granular (juxtaglomerular cells) o monitor blood pressure
o contain renin (enzyme + hormone)
Describe the histology of the ureters
a) Mucosa
transitional epithelium
b) NO Submucosa
lamina propria directly connected to muscularis externa
c) Muscularis externa
smooth muscle (~ 3 layers)
d) Adventitia/Serosa
retroperitoneal
Describe the histology of the urinary bladder
a) Mucosa
transitional epithelium with rugae
b) NO Submucosa
lamina propria directly connected to muscularis externa
c) Muscularis externa
= detrusor muscle - smooth muscle (~ 3 layers)
d) Adventitia/Serosa
adventitia = anterior, posterior, and inferior serosa = superior
internally: o triangleof2ureters(posterior)+urethraopenings=trigone mucosa of trigone lacks rugae (smooth) allows openings to remain in fixed position
Urethra histology
a) Mucosa
transitional to stratified squamous epithelium
b) Muscularis externa
smooth muscle
Urethra
2 sphincters (both surround proximal end of urethra): a) internal urethral sphincter (smooth muscle) thickening of detrusor muscle at base of bladder
b) external urethral sphincter (skeletal muscle)
in urogenital diaphragm
urethra in males vs females
in females
transports urine
in males
transports urine + semen
Describe the pathway of the filtrate
several DCT collecting ducts minor calyx major calyx renal pelvis ureters bladder urethra
