RENAL PHYSIOLOGY I Flashcards
what are the major functions of the kidneys? (7)
to control what is in our blood and how much blood we have
- endocrine function
- metabolic function
- pH regulation
- water homeostasis
- salt/ion homeostasis
- reabsorption of nutrients
- excretion of medications, toxins and metabolites
what is related to the endocrine function of kidney?
erythropoietin (EPO)
what happens if you have chronic kidney/renal failure?
not enough EPO —> anemia
what does it mean by saying kidneys have metabolic function
gluconeogenesis: durring fasting/under stress, the kidneys make glucose from lactate
what are the terms referred to blood with pH < 7.35 and blood with pH > 7.45
- acidosis
- alkalosis
what is the normal range for blood and urine pH
- blood: 7.35 - 7.45
- urine: 4.6 - 8
what are the 2 main sources of acid in your body?
- from metabolism, food, drink: direct source of H+
- carbon dioxide
CO2 + H2O <—> H2CO3 <—> HCO3- + H+
how does pH of blood controlled?
- lungs: exhalation of CO2
- kidneys: reabsorption and secretion of HCO3- and H+
why is K+ vital in body
resting membrane potential is based on K+ gradient in and outside of cells
—> related to action potential, rhythm generation in pacemaker cells, contractility and signaling
describe the difference of composition and charge of ECF and ICF?
- ECF: Na+ and Cl-
- ICF: protein (-) and K+
how does kidney maintain potassium balance
by secreting potassium
what happen if you suffer from kidney failure that is related to salt/ion homeostasis?
failure –> hyperkalemia –> death
where does lipophilic and hydrophilic drugs be filtered and excrete?
- lipopholic –> liver —–metabolised—–> kidneys –> excrete
- hydropholic —–directly—–> kidneys –> excrete
why is kidneys important function is balance body water?
to control the output and maintain the balance of intake and loss of water of the body to make sure the total body water remains relatively constant
define osmolarity of water?
water moves to where the osmolarity is highest
define osmolarity?
the total number of solute molecules in a solution
infine isosmotic, hyposmotic and hyperosmotic?
- isosmotic = same osmolarity
- hyposmotic = increase in water —> less solute molecules per L (e.g. decrease in ECF/plasma osmolarity)
- hyperosmotic = decrease in water (opposite to hyposmotic)
what happen if the water in each compartment of the body change?
- increase/decrease in plasma = increase/decrease in BP
- increase/decrease in ICF = swelling/shrinking of cells
what happen if there is loss in osmolarity of water in the ICF and ECF?
loss of water –> water loss from ECF –> ECF osmolarity increase –> water move from ICF to ECF to balance –> loss water from both –> cells shrink
what happen if there is gain in osmolarity of water in the ICF and ECF?
gain of water only –> water gain to ECF –> ECF osmolarity decrease –> water move from ECF to ICF to balance –> gain of water in both ECF and ICD –> cells swell
what happen to ICF and ECF if there is loss in isosmotic fluid?
loss both water and ions from ECF –> osmolarity between the 2 are the same –> no net water movement –> decrease in ECF volume only
what happen to ICF and ECF if there is gain in isosmotic fluid?
opposite to loss of isosmotic fluid –> increase in ECF volume only
what are the basic functions of the nephron?
filtration, secretion and reabsorption
where does filtration happen in the nephron?
renal corpuscles/glomerulus
what are the movement of substance within the filtration process at the renal corpuscles?
plasma from glomerular capillaries into glomerular capsule
what is the role of filtration?
create a plasma-like filtrate of the blood
what are filtered at the renal corpuscle and what is the exception?
- water and solutes are filtered at a constant rate at glomerulus
- exception = large proteins and substances bound to proteins
what are the movement of substance within the secretion process at the nephron?
movement of solutes from the peritubular capillaries into the tubular fluid
what is the role of secretion?
remove additional substances from the blood by secreting them into the tubular fluid
what is secreted into the PCT?
metabolites, medications and toxins
what are the movement of substance within the reabsorption process at the nephron?
movement of solutes from tubular fluid into peritubular capillaries
what is the role of reabsorption?
return useful substances to the blood so they are not excreted in the urine
what is reabsorbed in PCT?
bulk reabsorption of ions (Na), water and nutrients (glucose)
what is reabsorbed in nephron loop?
bulk reabsorption of ions (Na), water
what is reabsorbed in DCT and collecting duct?
fine-tuning (regulated by hormones) reabsorption of ions (Na), water
how is Na+ being dealt with in the nephron?
- freely filtered
- not secreted
- almost fully reabsorbed
- small amount excreted in urine
how is glucose being dealt with in the nephron?
- freely filtered
- not secreted
- fully reabsorbed in PCT
- no excretion in urine
how is medications and toxins being dealt with in the nephron?
- freely filtered
- entirely secreted
- not reabsored
- ALL in blood –> excretion in urine
how is creatinine and inulin being dealt with in the nephron?
- freely filtered
- not secreted
- not reabsorbed
- ALL filtered is excreted in urine
