Genitourinary system Flashcards
What are the 3 major functions of the kidneys?
Excretion
-Of metabolic products e.g uric acid
-Of foreign substances e.g drugs
Homeostasis
-Body fluid, electrolytes, acid-base balance
-Blood pressure
Secretion
-Hormones e.g EPO, renin
Top>Bottom
Cortex, Major calyx, Minor calyx, Medulla
What is route of blood supply to, through and out of the kidneys(all 13 vessels)?
Renal artery
Segmental artery
Interlobar artery
Arcuate artery
Interlobular artery
Afferent arteriole
Glomerular capillaries
Efferent arteriole
Peritubular capillaries
Interlobular vein
Arcuate vein
Interlobar vein
Renal vein
Function of the detrusor muscle
Contracts to build up pressure around the bladder to support urination
Function of the trigone
Stretching of this triangular region to its limit signals the brain about the need for urination
Function of the internal sphincter
Involuntarily prevents urination
Function of the external sphincter
Voluntary control to prevent urination
Function of the bulbourethral gland
Produces thick lubricant to be added to watery semen to increase likelihood of sperm survival
Describe the difference in density of mitochondria in different epithelium within a nephron
Mitochondria are rich in all tubule epitheliums
except
Thin descending loop
Thin ascending loop
Collecting duct principal cells
-All have a low mitochondria density
How does thickness change as you move through the loop of henle?
Thin on descending end, ascending is thin first then thickens
What is the ratio of superficial to juxtamedullary nephrons?
~10:1
What is the difference between a superficial and a juxtamedullary nephron?
A superficial nephrons’ loop of henle only goes as deep as the outer medulla whereas a juxtamedullary nephrons’ LOH goes into the inner medulla
What are the components in the juxtaglomerular apparatus and where are they?
Macula densa-Distal CT
Extraglomerular mesangial cells
Juxtaglomerular cells (Afferent arteriole)
What is the function of the macula densa?
GFR regulation through tubulo-glomerular feedback mechanism(Na+/Cl-sensing in the DCT)
What is the function of the juxtaglomerular cells?
Renin secretion to regulat blood pressure
Glomerular filtration
Left>Right
Reabsorption, secretion
Excretion
What is the difference between oncotic pressure and hydrostatic pressure?
Oncotic->Pulling force
Hydrostatic->Pushing force
both are across a semipermeable membrane
What does HPgc denote?
Hydrostatic pressure in glomerular capillaries
What does HPbw denote?
Hydrostatic pressure in bowmans’ capsule
What does πgc denote
Oncotic pressure of plasma proteins in glomerular capillaries
How do you calculate net ultrafiltration pressure(Puf)?
Puf = HPgc - HPbw - πgc
Puf = Glomerular capillary hstatic pressure - Bowmans capusle hstatic pressure - plasma protein onc pressure
GFR def
Glomerular filtration rate-
It is the amount of fluid filtered from the glomeruli into the Bowman’s capsule per unit time (mL/min)
Sum of filtration rate of all functioning nephrons
How do you work out GFR?
GFR = Puf * Kf
Kf = Ultrafiltration constant(membrane permeability and surface area available for filtration)