Topography and histology of the urinary system Flashcards
What is the gross anatomy of the kidney?
Retroperitoneal organ lateral to vertebral column T12-L3 Right kidney is lower than the left The left kidney is also slightly longer and closer to the midline
What is perinephric fat?
Surrounds the kidney for functions of protection and providing essential nutrients
What are the muscle located posteriorly to the kidneys?
Psoas major
Quadratus lumborum
which ribs do the kidneys sit in front of?
Ribs 11 and 12
What is the Hilum of the kidney?
The vasculature of the kidney made up of the mesenteric artery and IVC
Where are nephrons located?
within the renal medulla
What is the structure of the nephron?
Renal corpuscle:
glomerulus, bowmans capsule
Renal tubule:
PCT, loop of henle, DCT
Collecting duct
Papillary duct
What are the blood vessels entering into the kidney?
renal artery segmental artery interlobular artery arcuate artery interlobular artery afferent arteriole Glomerulus Efferent arteriole
What are the blood vessels leaving the kidney?
peritubular capillaries / vasa recta interlobular vein arcuate vein interlobular vein Renal vein
What are the 3 constriction points of the ureter?
uteropelvic junction
internal iliac artery Passover point
….
What are the blood supply to the ureter?
renal
gonadal
iliac
What is the blood supply of the bladder?
internal iliac artery:
superior vesical artery
inferior vesical artery (male)
Uterine artery (female)
Where is the internal and external urethral sphincter?
Internal - above prostate
External
how is urine formed?
Blood flows into the nephron
selective removal of substances
controlled reabsorption of water, ions, salts, sugars carbs, small proteins.
1% forms urine
What is the process of urine formation?
filtration
reabsorption
secretion
excretion
Where does filtration of urine occur?
glomerular
where does reabsorption and secretion of urine formation occur?
Peritubular network
Where does excretion of urine occur?
collecting duct
What makes up the renal corpuscle?
Glomerulus:
leaky endothelium
basement membrane
Bowman’s capsule:
visceral podocytes
parietal simple squamous epithelium
What are podocytes?
cells that cover the capillaries in the visceral layer of the glomerulus
What is the juxtaglomerular apparatus composed of?
mesangial cells
pericytes
granular juxtaglomerular cells - constrict like smooth muscle
macula densa - sensing cells
What does the juxtaglomerular apparatus do?
control the flow of blood to the kidney by increasing or decreasing pressure in the arterioles
what is the function of the PCT?
lined with a brush border and absorbs most of the filtrate (95%)
absorbs ALL glucose, proteins and amino acids
absorbs ALMOST all carbs, and 75-85% water
Secretion of metabolic waste
Why are there mitochondria on the basal infoldings of the PCT?
Contain mitochondria and sodium pumps supplying energy for ionic transport across cell membranes into the interstitium.
what is the function of the loop of henle?
High interstitial osmolarity draws water from the filtrate
Vasa recta capillaries take up water from interstitium and return it to systemic circulation
What is the function of the DCT?
shorter than proximal and lack a brush border.
peritubular capillaries return ions to systemic circulation to maintain vital acid-base balance.
What is aldosterone?
hormone which enables the active absorption of sodium ions from the filtrate
What is the histology of the ureter?
Transitional epithelium Lamina propria Smooth muscle Adventitia
What is the sympathetic innervation of the urinary system?
reduction of blood flow to the kidney increase renin peristalsis in ureters distension of the bladder contraction of the sphincters
What is the parasympathetic innervation of the urinary system?
peristalsis in ureters
contraction of the bladder
relaxation of the sphincters
