Lecture 24 Flashcards
What is the extracellular fluid?
protein-free plasma
What is the fluid entering the proximal tubule?
dilute urine
How much fluid is filtered at the renal corpuscle per day?
180 L
What are podocytes?
epithelium around the glomerular capillaries
What are in between eh foot processes of the podocytes? What is its function?
filtration slits = allows filtrate to pass through
What is the mechanism of filtrate movement from afferent arterioles into the lumen of the nephron?
passive | due to high pressure in the afferent arteriole
What does protein in the urine indicate?
issue with the kidney
What is the ENaC?
epithelial sodium channel/carrier | takes up sodium from lumen and into ECM
What is the SGLT?
sodium glucose transporter | glucose and sodium from lumen into ECM
What is GLUT?
passive glucose transporter | glucose into ECM
What is the NaDC?
sodium dicarboxylate cotransport
Where does the body want the organic anions and the aKG?
trade the organic anions for the aKG = excrete organic anions
What is the endpoint of the organic anions and aKG transport across the nephron lumen?
excrete organic anions into lumen
Which side has a high concentration of aKG and organic anions to begin with?
tubule lumen = high aKG | ECM = high organic anions
What is reabsorbed by the time fluid reaches the end of the nephron?
glucose, amino acids, water, ions, and useful emtabolites
What is renal clearance?
rate at which the solute disappears from the body by excretion or metabolism
What molecule has a 100% renal clearance?
inulin
What molecule has a 0% renal clearance?
glucose
What does the presence of glucose in urine indicate?
an issue
What is microurition?
urinate
What happens to smooth muscle when the bladder is empty?
smooth muscle not stretched = bladder continues to be filled
What happens to the smooth muscles when the bladder is getting full?
stretch receptors on smooth muscle bladder cells = send signal to CNS = contract bladder muscle = relax sphincter = pee
What part of the CNS controls urination?
spinal cord
What is reabsorbed in the descending limb? What kind of transport mechanism is used?
only water | passive transport
What is reabsorbed in the ascending limb? What kind of transport mechanism is used?
only solutes | active transport
What is the counter-current mechanism (multiplication)?
movement of filtrate in two opposite directions
What does the counter-current mechanism establish?
different concentration gradients within the medulla
What does the counter-current mechanism dictate?
how concentrated the urine will be when it is excreted out of the kidney
What happens if there is improper excretion of waste from the body? What can it cause?
build-up of uric acid = causes gout
What is an anti-diuretic?
body not allowed to excrete water
What is the effect of anti-diuretic hormones on the collecting duct epithelium?
more permeable to water
What happens when vasopressin binds to the receptor on the epithelial cells of the collecting duct?
second messenger system = insert more water channels on the apical membrane of epithelial cell
Which aquaporin (1 or 2) is dependent on vasopressin?
aquaporin-2
Which aquaporin is not controlled by vasopressin (1 or 2)?
aquaporin-1
What are the 3 stimuli that control the secretion of vasopressin?
plasma osmolarity | blood volume | BP
What is the function of osmoreceptors?
detects changes in water levels in the blood (not enough water = increase osmolarity = trigger vasopressin secretion)
