Renal Physiology Flashcards
what are the 7 functions of the kidney ?
- regulation of ECF & blood pressure
- regulation of osmolarity
- maintenance of ion balance
- maintenance of body pH
- excretions of waste
- production of hormones
- gluconeogenesis
what is the functional unit of the kidney ?
the nephron
what two structures is the nephron composed of ?
renal corpuscle and tubule
what is the renal corpuscle ?
where filtration of blood occurs
what is the tubule ?
where the filtered fluid is processed
what are the 6 parts of the nephron ?
renal corpuscle, proximal tubule, descending limb of loop of hence, ascending limb of the loop of hence, distal convoluted tubule and collecting duct
what are the two types of nephrons ?
cortical and juxtamedullary
difference between cortex and medulla ?
jux. is closer to medulla (longer) while cortical is near cortex (shorter)
what is the bowman’s capsule ?
where fluid filters into
what does the glomerulus contain ?
leaky capillary beds
what do podocytes do ?
wrap around the leaky glomerulus and prevents some filtration
what are the three barriers to filtration ?
podocytes, basal lamina and slit spaces
what is GFR ?
the amount of fluid filtered in a day
what are the two auto regulatory mechanisms that function to keep GFR mostly constant throughout the day
myogenic response and tubuloglomerular feedback
what happens during the myogenic response ?
- afferent arteriole stretches
- increase in blood pressure
- ion channels open
- blood flow decreases in the glomerulus (smaller diameter & less blood in glomerulus)
what happens during tubuloglomerular feedback ?
- GFR increases
- flow through tubule increases
- afferent arteriole constricts
what happens when the afferent arteriole constricts ?
GFR decreases
what happens when the efferent arteriole constricts ?
GFR decreases
how to measure GFR ?
(substance X)urine x urine volume / (substance X)plasma
how does filtration process occur in the nephron ?
from the blood in the glomerulus into bowman’s space
how does reabsorption process occur in the nephron ?
from the filtrate in the tubule to the surrounding capillaries
how does secretion process occur in the nephron ?
from the surrounding capillaries into the filtrate in the tubule
what is hydrostatics pressures of glomerular capillaries (P GC) ?
pressure caused by blood flowing into the glomerulus and promotes filtration
what is colloid osmotic pressure of glomerular capillaries (π GC) ?
pressure caused by the presence of proteins in the glomerulus and inhibits filtration
what is hydrostatic pressure of bowman’s capsule (P BC) ?
pressure caused by filtrate remaining in bowman’s space and inhibits filtration
what is colloid osmotic pressure of bowman’s capsule (π BC) ?
pressure caused by the presence of proteins in bowman’s capsule and promotes filtration
how do you calculate net filtration pressure ?
(P GC + π BC) - (P BC + π GC)
what are two types of channels within kidneys ?
sodium channels and aquaporins