T8. RENAL PHYSIOLOGY Flashcards
(34 cards)
What are the major functions of the kidneys?
Filter blood plasma, separate waste from useful chemicals, return useful substances to blood, eliminate wastes.
How do the kidneys regulate blood volume and pressure?
By eliminating or conserving water.
How do the kidneys regulate the osmolarity of body fluids?
By controlling the relative amounts of water and solutes eliminated.
What enzyme do the kidneys secrete and what does it do?
Renin; activates hormonal mechanisms that control blood pressure and electrolyte balance.
What hormone do the kidneys secrete to stimulate RBC production?
Erythropoietin.
How do the kidneys help regulate acid-base balance?
They collaborate with the lungs to regulate PCO₂ and acid-base balance of body fluids.
What hormone do the kidneys help synthesize and what is its function?
Calcitriol; contributes to calcium homeostasis.
What metabolic process do kidneys perform during extreme starvation?
Gluconeogenesis from amino acids.
How many nephrons are in each kidney?
1.2 million.
What are the two main parts of a nephron?
Renal corpuscle and renal tubule.
What is the function of the renal corpuscle?
Filters the blood plasma.
What is the function of the renal tubule?
Converts the filtrate into urine.
What structures make up the renal corpuscle?
Glomerulus and Bowman (glomerular) capsule.
What type of epithelium lines the parietal layer of the Bowman capsule?
Simple squamous epithelium.
What are podocytes and where are they found?
Elaborate cells in the visceral layer of Bowman capsule that wrap around the glomerular capillaries.
Where does glomerular filtrate collect and flow after filtration?
In the capsular space, then into the proximal convoluted tubule.
Which arteriole is larger, afferent or efferent?
Afferent arteriole.
What is the renal tubule and where does it lead?
A duct that leads away from the glomerular capsule and ends at the tip of the medullary pyramid.
What are the four regions of the renal tubule?
Proximal convoluted tubule, nephron loop, distal convoluted tubule, collecting duct.
What is the proximal convoluted tubule (PCT) and what is its function?
Arises from the glomerular capsule, longest and most coiled region with microvilli for most absorption.
What is the nephron loop (loop of Henle)?
A long U-shaped portion of the renal tubule with thick and thin segments.
What is the function of thick segments of the nephron loop?
Active transport of salts.
What is the permeability of the thin segment of the nephron loop?
Very permeable to water.
What is the distal convoluted tubule (DCT)?
Begins after ascending limb reenters cortex, shorter and less coiled than PCT, end of nephron.
