2 Body Fluids And Membrane Transport Flashcards
Body fluid composition
42 litres - total body water
25 litres - intracellular fluid
17 litres - extracellular fluid
Extracellular fluid composition
Interstitial fluid - 13 litres
Plasma - 3 litres
Transcellular fluid - 1 litre
Blood: how man litres?
Composition?
6L
3L plasma
3L water
Where is interstitial fluid found?
The interstitium - between cells - it bathes cells
Which parts of phospholipids are charged?
The head. Not the tails.
Is the head of a phospholipid hydrophilic or hydrophobic?
Hydrophilic
Is the tail of a phospholipid hydrophilic or hydrophobic
Hydrophobic
Is the tail or head of the phospholipid on the outer surface of the membrane
The head
Name the four types of connective tissue
Collagen
Reticular
Elastic
blood and bone
Connective tissues
Consist of a few cells and an abundance of extracellular matrix
Include blood and bone
Connective tissues
Job is
To support and protect other body tissues
What is a transcellular fluid?
Something that has crossed a membrane in its production
E.g. Urine
Cerebrospinal fluid
Sweat
Synovial fluid
Gastrointestinal fluids
They all have specialised important functions
Balance between the ions in the plasma and which fluid are very similar?
The ISF (interstitial fluid)
The balance between the which two fluids is virtually opposite
ISF and ICF
What is osmolality
Attraction to water
True or false: all fluids in the body have the different osmolality
False. All the same.
Ions present in the fluids:
Na
Cl
K
Proteins
What is the difference between the ICF and the ECF
ICF rich in proteins and K
ECF rich in Na and lacking in proteins
4 properties of the plasma membrane
Selectively permeable
5nm thick
Contains lots of transport proteins
Vital for regulation of intracellular environment
6 functions of the plasma membrane
- selective transport of molecules
- enzymatic activity
- cell recognition
- cell communication via neurotransmitter and hormone receptors
- determination of cell shape because linked to cytoskeleton
- tissue organisation such as cell junctions
Major lipids in the plasma membrane are:
Phospholipids and phosphoglycerides
Which type of molecule can move across the plasma membrane without the help of transporter proteins
Lipids
Small non polar molecules
Types of transporters:
Channels
Carriers
Pumps
Types of carrier proteins
Uniport/facilitator
Symport/co-transporter
Antiport/exchanger
Composition of the human
Body
60% water (42 litres)
22% lean body mass
18% fat
Uniport/facilitator
-moves one molecule one way
Symport/co-transporter
-moves 3 different ions in the same direction (electrically neutral)
Antiport/exchanger
moves 2 ions opposite ways. Electrically balanced so both ions hold the same charge.
What happens in a cell that needs to grow
Na+, K+ and Cl- are moved into the cell (as usually the osmolality of the ECF and ICF is the same) and water follows, water is never actively transported
which active process moves water in or out of cells
none. its always passive osmosis
Conc in ICF: K+
High
Conc in ICF: Na+
Low
Conc in ICF: Cl-
Low
Conc in ICF: Ca2+
V. Low
Conc in ICF: Org-
High
Conc in ICF: Proteins
High
Con in ECF: K+
Low
Conc in ECF: Na+
High
Con in ECF: Ca2+
Low
Con in ECF: Cl-
High
Con in ECF: Org-
Low
Con in ECF: Proteins
Low
At rest, what charge does a cell have
negative due to the organic matter that cannot move out and the potential difference caused by the movement of K and Na ions
What is going on K+ wise in a cell at rest
High conc of K inside the cell means K is trickling out through ion channels. it is being pumped back in by K atpase pumps.
There is an equilibrium in the cell caused by the pull of the on gradient out but the pull of the negative interior of the cell on the k+
what causes the equilibrium of K+ in cells
the negative charge inside the cell pulling it back in and the conc gradient pull out of the cell.
osmolality is
attraction for water
3 qualities of endothelial membranes:
- very thin layer of cells lining blood vessels
- highly permeable in some organs (glomerulus) and not others (brain)
- important role in regulation of interstitial fluid
Describe the structure of an endothelial membrane
constitutes of very thin flat cells that warp around to form the membrane. there can be gaps between the cells depending how leaky/permeable you want the membrane to be
how do ions cross endothelial membranes
through the gaps (between cells not through them)
what is colloid osmotic pressure
attraction of proteins for other molecules
pressure in the capillary bed: beginning
- proteins can’t move out even though the conc in the blood is high causing a gradient.
- pressure at the beginning of the capillary bed is high coz of all the proteins so ions and water move out
- they are taken up by the cells
pressure in the capillary bed: end
-at the end of the capillary bed the pressure is low and the colloid osmotic pressure is high so the waste products and water move back into the bloodstream
epithelia are
cells that line structures
-can be layers or one cell thick
where are endothelial membranes found
blood vessels, kidney, brain
where are epithelial membranes found
in the gut
roles of epithelial membranes
- protection
- allowing things to be absorbed and secreted
what forms when ions move across epithelial membranes
trans epithelial fluid
structure of the epithelial membrane:
- can be one cell thick or layers
- cells meet at a tight junction which is essentially impermeable
- ions can’t move across except with a transporter
- the apical is the inside of the gut, the basolateral membrane is the outside
in the gut the basolateral membrane is located on the
outside
in the gut the apical membrane is located on the
inside
How does glucose get from the gut lumen to the blood
- a glucose-Na symporter on the apical membrane moves glucose and Na down the conc grad from the food and into the intestine cell
- glucose then diffuses into the blood through a uniporter in the basolateral membrane
- Na is pumped out through the Na/K+ atpase pump (exchanger) so the internal environment of the cell is maintained
water in the gut
Na, K and Cl all move into the gut from the blood and water follows. it then follows the cl- out of the cell through a channel on the apical membrane into the gut lumen and water follows
