Kidney Structure and Function Flashcards
What are some of the functions of the kidney?
water balance salt balance acid-base balance excretion of metabolic waste excretion of exogenous compounds conversion of VitD to active form secretion of renin secretion of erythropoietin
What does the urinary system consist of?
the kidneys
the structures that store and carry urine for elimination
What are the significant structures in the kidney?
the renal cortex the renal medulla the renal pyramid the renal pelvis the ureter
What is the nephron?
the functional unit of the kidney
What are the functional mechanisms of the nephron?
filtration
reabsorption
secretion
Where are the peritubular capillaries found?
the loop of henle
Where is the juxtaglomerular apparatus found?
around glomerulus, afferent and efferent arterioles
Where is the cortex of the nephron?
above the loop of henle
Where is the medulla of the nephron?
below the loop of henle
What are the two types of nephron?
juxtamedullary - 20%
cortical - 80%
What are the differences between the two nephrons?
there is a vasa recta on the juxtamedullary
juxtamedullary is much longer/ bigger
What is the afferent arteriole?
the artery taking blood into the glomerulus
What is the efferent arteriole?
the artery taking blood away from the glomerulus
What is the inner layer of the bowmans capsule called?
podocytes - surround glomerular capillaries
What is found on the distal tubule?
a layer of cells called macula densa
What is the function of the macula densa in response to lowered NaCl?
decreases resistance to blood flow from afferents
releases renin from juxtaglomerular cells
What is found next to the afferent arterioles?
granular cells - a.k.a juxtaglomerular cells
What is urine?
modified filtrate of the blood
What are the basic renal processes?
glomerular filtration
tubular reabsorption
tubular secretion
How much plasma that enters the glomerulus is filtered?
20%
What is rate of excretion equivalent to?
rate of filtration + rate of secretion - rate of absorption
What is the equation for calculating the rate of filtration of a freely filtered substance?
Rate = Xplasma x GFR
What is the equation for calculating the rate of excretion of a freely filtered substance?
Rate = Xurine x Vu
Where Vu = urine flow rate
What is the equation for calculating the rate of reabsorption of a freely filtered substance?
Rate of reabsorption = rate of filtration - rate of excretion
What is the case when rate of filtration> rate of excretion?
net reabsorption has occurred
How is rate of secretion calculated?
rate of secretion = excretion - filtration
What do rates of reabsorption and secretion reflect?
tubular modification of filtrate
