Genitourinary system Flashcards
(50 cards)
What are the four functions of the kidney?
Excretion : Metabolic products and foreign substances
Homeostasis : body fluids ,electrolytes and acid-base balance
Regulation : blood pressure
Secretion : hormones
Which Hormones do the kidneys secrete?
Erythropoietin and renin
Which metabolic products and foreign substances do kidneys excrete?
Urea, uric acid, creatinine
Drugs
Describe the supply of blood pathway from the renal artery to the renal vein?
Renal artery –> Segmental Artery –> Interlobar artery –> Arcuate Artery –> Interlobular artery –>
Afferent arteriole –> GLOMERULAR CAPILLARIES –> Efferent arteriole –> Peritibular capillaries –>
Interlobular vein –> Arcuate Vein –> Interlobar vein –> Renal Vein
Function of peritubualr capillairess
peritubular capillaries are tiny blood vessels
Travel alongside nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron
Which muscles lines the bladder and contracts during urination?
Detrusor muscle
What does the Trigone do?
Stretching of this triangular region to its limit signals the brain about the need for urination
What does the internal spincter do?
Involuntary control to prevent urination.
What does the external sphincter do?
Voluntary control to prevent urination.
What does the bulboutheral gland do?
Produces thick lubricant which is added to watery semen to promote sperm survival
What is a functional unit of the kidney?
The nephron
Why do the epithelial cells in the PCT have more mitochondria than the ones in the Descending loop of Henle?
Proximal convolated tubule : absorption of salt, glucose, bicarbonate etc,
Descending loop : passive reabsorption of salt and water
Why is the cortex of a kidney granular looking and medulla striated?
Loop of Henle and ducts go through medulla = striated
Whats the difference in the superficial nephron and Juxtamedullary nephron?
Superficial : have their glomeruli in the outer cortex. They have shorter loops of Henle, which dip only into the outer medulla
Juxtamedullary nephrons’ loops of Henle dip deeper into the inner medulla and papilla, and are vital in the concentration of urine.
What constitutes the juxtaglomerular apparatus?
Macula Densa (Distal convoluted tubule)
Extraglomerular mesangial cells
Juxtaglomerular cells (Afferent arteriole
What are the functions of the juxtaglomerular apparatus?
GFR regulation through tubulo-glomerular feedback mechanism.
Renin secretion for regulating blood pressure
What passive processes are happening in the glomerular?
Fluid is ‘driven’ through the semipermeable glomerular capillaries into the Bowman’s capsule space by the hydrostatic pressure of the heart.
What is the slit diaphragm?
Thin and porous, water and small solutes can pass
Why is the filtration barrier charge dependent?
The glomerular basement membrane is negatively charged to repel the majority of proteins which are also negatively charged
How to calculate the net ultrafiltration pressure happening in glomerular filtration?
Puf = HPgc – HPbw – πgc
HPgc = Hydrostatic pressure in glomerular capillaries
HPbw = Hydrostatic pressure in bowman’s capsule
πgc = Oncotic pressure of plasma proteins in glomerular capillaries
What is the glomerular filtration rate GFR?
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 across the two kidneys )
- a fall in GFR is the cardinal feature of renal disease
How to calculate GFR?
GFR = Puf x Kf
Where Kf is an ultrafiltration coefficient (membrane permeability and surface area available for filtration
Female : 90-140 mL/min
Male : 80-125 mL/min
What is the myogenic mechanism and how does it regulate GFR?
Arterial Pressure increases –> afferent arterioles stretch –> arteriole contracts –> vessel resistance rises –> blood flow reduces –> GFR stays the same
How does the Tubulo-glomerular feedback mechanism work to regulate GFR?
Increase in GFR –>
Increase in NaCl in loop of Henle –>
Change detected by macula densa –>
Increase ATP and Adenosine discharged –>
Afferent arteriole constricts –>
GFR stabalises
( For a decrease in DGR Nacl decreases, ATP and adenosine decreases and arterioles dilates.