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
what are three types of kidney transporters ?
glucose uniporter, sodium/hydrogen antiporter and sodium/glucose symporter
what is the primary active transporter of kidneys ?
sodium/potassium ATPase
what is the overall theme of the proximal tubule ?
reabsorbs almost everything
what is diabetes mellitus ?
glucose in the urine and increased urine volume
what does the descending loop of henle do ?
reabsorbs water
what does the ascending loop of henle do ?
absorbs ions (Na, K, Cl)
what does the distal convoluted tubule do ?
absorbs different things into our bloodstream (Na, Cl, HCO, H2O)
what does the collecting duct do ?
any additional wastes after the distal convoluted tubule gets absorbed (reabsorbs ions and water if necessary)
where does filtration occur ?
the corpuscle
what is another name for anti-diuretic hormone (ADH)
vasopressin
what does ADH do ?
decreases urine production
where is ADH made ?
hypothalmus
what is the hormone property of ADH ?
peptide hormone
what are osmoreceptors ?
detect changes to plasma osmolarity
what is hyperosmotic ?
increased plasma osmolarity
what is hypoosmotic ?
decreased plasma osmolarity
what are baroreceptors ?
sensors located in the blood vessels, type of mechanoreceptor (part of negative feedback system)
what is “dieresis” ?
make more urine (dehydrating themselves to a degree, removing water from body therefore dehydrating)
what is antidiuresis ?
less water, want to conserve it
where is ADH released by ?
posterior pituitary gland
what do the kidneys do when there is additional salt in the body ?
kidneys excrete the additional salt through the urine
what are sodium levels linked to ?
ECF volume and therefore blood pressure
what two hormones are responsible for sodium conotrol ?
RAAS (renin-angiotensin-adosterone system) and ANP (atrial natriuretic peptide)
what hormone is released when sodium levels are too high ?
ANP
what is ACE ?
angiotensin converting enzyme
what is angiotensin 2 ?
peptide hormone stimulated by renin release ; increases sodium reabsorption
what is aldosterone ?
steroid hormone made by the adrenal glands stimulated by angiotensin 2, levels of potassium ; increase sodium reabsorption
when is renin released ?
when sodium levels are low
what is ANP ?
peptide hormone made by cardiac atrial cells stimulated by high blood pressure ; decrease sodium reabsorption
what is hypertension ?
too much water = swelling
what is hypotension ?
not enough water = shriveling
which areas of the nephron absorb water when we have low water in our blood ?
descending loop of henle and collecting duct
which areas of the nephron absorb ions when we have low concentration of ions ?
ascending loop, proximal tubule and distal convoluted tubule
what are podocytes ?
make up the epithelial layer in Bowmans capsule
filtration happens through which cells ?
podocytes
which cells make and release the enzyme renin ?
juxtaglomerular (granular) cells
what activates RAAS ?
low blood pressure (hypotension)
once renin is released into the blood where does it head to ?
the bloodstream
if the kidneys do not have enough BP what is released ?
renin
angiotensinogen comes from ____
the liver
angiotensinogen acts in renin and turns it in ______
angiotensin 1
where is ACE (angiotensin converting enzyme) released from ?
the lungs
ACE turns angiotensin 1 into ________
angiotensin 2
angiotensin 2 works with the adrenal glands to create ________-
aldosterone
