Lecture 2- body fluids and membrane transport Flashcards
Whats the distribution across the plasma membrane for:
- K+
- Na+
- Ca2+
- Cl-
- Organic anions
- Proteins
- High in ICF. Low in ECF because potassium pumped into cell
- Na low in ICF. High in ECF because sodium potassium pump pumps sodium out
- Very low in cell, low in ECF. Actively transported out
- Chloride follows calcium. So Low in cell and high in ECF
- Proteins and organic ions high inside cell because they’re too big to pass
In the average male what is the total body water volume?
42 litres
How is the total body water distributed?
25 L intracellular fluid
then 17 L extracellular fluid made up of:
13 litres interstitial fluid
3 litres plasma
1litre transcellular fluid
What do the body fluids have to pass through?
- ICF to ISF
- ISF to Plasma
- ISF to transcellular fluid
- Plasma membrane
- Endothelium
- Epithelium
Which fluids have to cross a layer of epithelial cells?
Transcellular
Which transcellular fluid is produced by the kidneys?
Urine
Give 4 examples of transcellular fluids
- Bile- aids digestion
- Urine- made in kidneys
- Cerebrospinal
- Synovial - found in some joints
Which fluid accounts for most of the extracellular fluid?
Interstitial fluid
Name and explain the types of extracellular fluids in the body.
- Interstitial fluid- (13 L)- Not in the blood stream, outside cells, bathing cells.
- Transcellular fluid- Crosses a cell barrier. e.g sweat, urine.
- Plasma. in the blood
What determines water distribution between plasma and ISF?
Hydrostatic pressure pushing out of plasma. Colloid osmotic pressure pushing in to plasma. (out of ISF).
What generates the -70mV membrane potential?
The asymmetric distribution of K+ ions. SO -70mV outside the cell.
What are the 3 types of carrier across cell membranes?
- Uniport (also called facilitator)
- Symport (also called co-transporter, two things going the same way)
- Antiport (also called exchanger, 2 things going opposite ways)
