9. Body Fluids Flashcards
What is the difference between intracelluar fluid (ICF) and extracelluar fluid (ECF)?
intracelluar fluid in contained within cells
extracelluar fluid is split into two compartments:
- plasma - the fluid portion in blood
- interstital fluid - spaces between cells
What is the difference in composition between intercellular fluid and the two compartments of extracelluar fluid?
Intracelluar fluid makes up 40% of body weight
extracelluar fluids makes up 20% of body weight
of that 20%, 80% of it is intersitial fluid and 20% is blood plasma
How are body fluids regulated and what type of exchange do they have?
They are regulated by selectivley permeable membranes in endothelial cells and cell membranes. However there is an equilibrium between intercellular and extracelluar and the fluids exchange continuously
What are electrolytes?
they are a substance that can dissociate into ions in a solution and is able to conduct electricity. Eg sodium, potassium, chloride, phosphate, magnesium and calcium
How is a homeostasis in electrolyte balance achieved?
There is a regulation of solute and electrolytes in the selectively permeable membranes. This means solutes and electrolytes don’t move freely and the distribution is regulated.
The osmolarity between ICF and ECF are identical, there is water movement to according to electrolyte osmotic gradients
What is important about the body water intake and loss?
the volume of fluid intake and loss is kept at a constant. this is because of electrolyte balance
How does overhydration occur?
if there is excessive fluid loss along with intake of water, this reduces the electrolytes and dilutes the ones still present
this causes a decreased osmolarity of intestinal fluid and plasma.
Cells in a hypotonic cell (cell expands)
What are the two classifications of solutes and give two examples of each
electrolytes - inorganic slts, acids and bases, proteins
non-electrolytes - glucose, lipids, creatine, urea
What is the distinct pattern of electrolytes in intracelluar and extracelluar fluids?
intracelluar:
low sodium and chloride.
Potassium main cation, phosphate main anion
extracelluar:
sodium is the main cation
chloride is the main anion
How does the sodium potassium pump work in terms of what’s getting pumped in and out?
3 NA+ ions get pumped out and 2 K+ ions get pumped into the cell
What is the composition of non-electrolytes (proteins, phospholipids etc) in the plasma (extracelluar) intersitial fluid (extracelluar) and the intracelluar compartment
90% of mass of the mass of solutes in plasma
60% of the mass of solutes in intersitial fluid
97% of the mass of solutes in the intracelluar compartment
Ion fluxes are restricted and move selectivley by active transport. What direction do nutrients, respiratory gases and waste move? What direction does plasma move?
nutrients, respiratory gases and waste move unidirectionaly
plasma is the only fluid that circulates the body and links externa land internal envionrments
What does antidiuretic hormone (ADH) do and where is it located?
it tells the kidney how much water to take up and how much water to excrete.
its located in the posterior pituitary
What is the function of ADH? antidiuretic hormone Name 4
water resabosbtion in kidney collecting ducts
low ADH dilute urine and reduced volume of body fluids
High ADH concentrated urine
What are aqua porins? What is their function in relation to ADH?
They facilitate the transport of water between intercellular and extracelluar. They diffuse through the phospholipid bilayer.
