7.2 Physiology of the Urinary System Part 2 Flashcards
What is the pressure with which the filtrate enters the PCT?
net filtration pressure
What forces solutes and fluids out of the membrane of the glomerular capillary?
high hydrostatic blood pressure inside of the glomerular capillary
What cannot pass through the fenestrations of the glomerular capillary?
blood cells
blood proteins
What is the glomerular filtration rate?
amount of blood filtered by the glomerulus over time
What is the normal GFR?
120-125 ml/min or 180 L/day
What contributes to the GFR?
huge surface area
large degree of filtration membrane permeability
moderate net filtration pressure
What can increase the GFR?
increase in the arterial blood pressure in kidneys
What can decrease the GFR?
increase in glomerular osmotic pressure caused by dehydration
What are the three mechanisms that regulate renal flow and GFR?
renal autoregulation
nervous system control
hormone control
How if the GFR controlled under normal conditions?
kidney/renal autoregulation
What is renal autoregulation?
when the kidney determines its own rate of blood flow by controlling the diameter of the afferent or efferent arterioles
When is renal autoregulation superceded by the nervous system and hormone control?
during emergencies when blood flow needs to be diverted away from the kidney
What does the sympathetic nervous system do to GFR?
narrows the afferent arteriole diameter
What releases epinephrine?
adrenal medulla
What does epinephrine do to GFR?
decreases renal blood flow and decreases GFR by constricting renal arteries
