Renal 1: Overview of kidney function Flashcards
List the main functions of the kidney
Regulation of water and electrolyte balance. Regulation of arterial pressure. \+ Regulation of: -blood pH, -excretion of metabolic waste products -RBC production -hormone production (eg vit D+ Ca2+ regulation) -blood glucose levels
What body system is kidney part of
cardiovascular as it filters the blood, not the food. It helps regulating blood pressure, water and electrolyte balance, pH and waste product removal.
What are the physiological consequences of kidney failure
- Swelling as kidneys are not filtering any fluid out
- Increase blood pressure
- Short of breath due to oedema in lungs
- Fatigue : heart has to pump harder, less O2 exchange
- pH and K+ levels rise and cause nausea
What is osmolarity
Assuming that all the osmotic solute cannot permeate the cell membrane, Osmolarity is the number of dissolved particles in a set volume.
therefore = molarity (moles) x dissociation (ie 2 particles per 1 NaCl
What is osmotic pressure. What osmotic pressure swells the cell vs collapse
The pressure required to prevent net water movement
High osmotic pressure : swell
Low osmotic pressure : collapse
What is tonicity
Measuring the tone of the cell when put into a solution.It takes into account the concentration of the solute and its ability to cross the semipermeable membrane
what will happen to a cell in an isoosmotic solution of urea (to its cytosol osmolarity)
It will swell and burst because there is a concentration gradient for urea to move into the cell and this will make a concentration gradient for water to follow
Compare Hypotonic, Isotonic and Hypertonic solution by their effect on the cell
Hypertonic solution causes cells to shrink as water wants to move out of the cell.
Isotonic solution causes no net movement of water in or out of the cell
Hypotonic solution causes cells to swell as water wants to move inside the cell.
Compare Isoosmotic, Hyperosmotic and Hypoosmotic solution
Iso osmotic solution has same solute concentration.
Hyperosmotic soln has higher solute conc
Hypoosmotic soln has lower solute conc
Compare the osmotic pressure of the extracellular fluid and thus movement of water in cells during dehydration and Hydration
In Dehydration water is lost from the ECF, so the ECF osmotic pressure rises. This causes water to move out the of the cells to ECF.
However in Hydration, water is gained in the ECF, so osmotic pressure decrease and water moves into the cells.
How is the body fluid divided between the Intracellular fluid and Extracellular fluid and what are these two divisions
ICF have 2/3 of the body’s fluid. It is the fluid inside the cell
ECF have 1/3 of body’s fluid. 20% is blood plasma and 80% is interstitial fluid.
Why is it important to maintain osmolarity
The assymetric distribution of ions in the ICF and ECF set up ion gradients which set up membrane potentials. These allow important cell processes such as electrical nerve activity, active transport, intracellular signalling and muscle contraction to take place.
What ions have a higher concentration in the ECF than the ICF
Na+ (145: 10), Ca2+ and Cl- (110:4) , HCO3-
What ions have a higher concentration in the ICF than the ECF
K+ (140:5),
Mg2+, HPO42-, SO42-, protein anions
How much fluids in the body compared to solids
in females 55% and males 60%
