DUMS rugby physiology Flashcards
what are the functions of the kidney
- water/salt/electrolyte balance
- plasma volume + osmolarity
- acid base balance
- secrete metabolic waste
- excrete drugs/metabolites
- secrete EPO
- secrete renin
- active vit D conversion
what is the fluid homeostasis
input = output
what is osmolarity
concentration of active particles in a solution
what is tonicity
effect of solution of cell volume
what does water follow along osmotic gradient
salt
what are the tracers used to measure body fluid
TBW
ECF
plasma
main ions in the ICF
potassium and magnesium
main ions in ecf
Na+
Cl-
HCO3-
if you gain NaCl what does this mean in terms of fluid shift
increase ECF and decrease ICF
what does loss of NaCl do
decrease ECF and increase ICF
how much of the plasma that enters the glomerulus is filtered
20%
where does the plasma that enters the glomerulus and is not filtered go
the efferent arteriol
what are the three barriers to filtration
- glomerular capillary epithelium
- basal lamina basement membrane
- podocytes
what charge is the basal lamina
negative
what is GFR
rate at which protein-free plasma is filtered from the glomeruli into the Bowman’s capsule per unit time
what is the major determinant of GFR
glomerular capillary blood pressure
net filtration pressure
what are some intrinsic mechanisms that regulate renal blood flow
- myogenic mechanism
- tubulo-glomerular feedback mechanisms (involves juxtaglomerular apparatus)
what is plasma clearance
the volume of plasma completely cleared of a particular substance per minute
why can inulin clearance be used clinically to determine GFR
because inulin is freely filtered and not absorbed, secreted or metabolised
what is the plasma clearance of glucose and why
0
-glucose is filtered and fully reabsorbed and not secreted
PC of urea and why
PC
PC for H+ and why
PC>GFR
-H+ is filtered, secreted but not reabsorbed
what is renal plasma flow
the volume of blood plasma delivered to the kidneys per unit time
how is RPF (renal plasma flow) measured
using para-amino hippuric acid (PAH) a substance that is filtered freely and completely secreted (not reabsorbed)
what is the filtration fraction
GFR/RPF
-the fraction of plasma flowing through the glomeruli that is filtered into the tubules
what is sodium reabsorption driven by in the proximal convoluted tubule
the basolateral Na+-K+-ATPase
how do oxygen and carbon dioxide get in the proximal convoluted tubule
diffusion through lipid bilayer
how does Na get through proximal convoluted tubule
diffusion through channels
how does glucose get through the proximal convoluted tubule
facilitated diffusion
how do sodium and potassium enter and exit proximal convoluted tubule
primary active transport
how do sodium and glucose get into the proximal convoluted tubule
secondary active transport
what does it mean by the loop of henle generates cortico-medullary solute concentration gradient
it enables the formation of hypertonic urine
if the flow the same in both limbs of loop of Henle
no
what does the different flow in diff limbs of loop of Henle enable to happen
enables the kidney to produce urine with varying degrees of volume and concentration in response to circulating ADH levels
what are the different permeabilities of the limbs
Descending Limb: No active Na+Cl- reabsorbed but water permeable
Ascending limb: Water impermeable but active Na+Cl- reabsorbed
which side is iso-osmotic and which is hypo-osmotic
where is vasa recta found
travels alongside LOH in juxtamedullary nephrons
what type of fluid is the fluid leaving the LOH and entering the DT
hypo-osmotic to plasma
what happens to the fluid after it enters the DT
the DT empties fluid into the cortical collecting ducts
what is the DT permeability to water and urine
low
what happens in the early DT
NaCl reabsorption
what happens in the late DT
- Ca reabsorption
- H+ reabsorption
- Na+/K+ reabsorption
what does reduced atrial pressure result in in terms of ADH secretion
increase ADH
what does ADH do to water permeability in the collecting ducts
increases it
high ADH = high water permeability = hypertonic urine
nicotine effect on ADH release
stimulates AHD release
alcohol effect on ADH release
inhibits ADH release
-why you pee more when you drink
what causes nephrogenic diabetes insipidus
deficiency in ADH or insensitivity to ADH
what can cause the deficiency in ADH or insensitivity in ADH in nephrogenic diabetes
- genetic
- hypercalcaemia
- hypokalaemia
- drugs (lithium)
- tubulo-interstitial disease
treatment for nephrogenic diabetes
thiazides and low salt/protein diet
what does aldosterone do
causes distal tubules to resorb more sodium and water which increases blood volume
where is ANP (or ANH) released from
atrial muscle cells by mechanical stretch
what does ANP do
promotes sodium excretion and diuresis (lower plasma volume)
