FoM:L2 - Body Fluids Flashcards
What is meant by the term ‘body fluids’?
- water (the solvent)
- all the solutes
NOT cells
What are the 3 types of extracellular fluid?
- blood plasma (not RBCs)
- Interstitial fluid
- transcellular; contained within spaces lined by epithelial cells, highly specialised
What do fluids moving in and out of Intracellular fluid cross?
cell membranes
What do substances moving between plasma and interstitial fluid have to cross?
epithelium of capillary wall
What electrolytes are in body fluids?
cations: Na+, Ca2+, K+, Mg2+
anions: Cl-, HCO3-, H2PO4-, SO42-
Proteins (P-)
Organic Anions (A-)
What non-electrolytes are in body fluids?
- glucose
- cholesterol
- phospholipids
- urea
Why are body fluids important?
- site of biological reactions
- transport (e.g. blood plasma transports RBCs)
- temperature regulation (e.g. sweat)
- lubricating (e.g. synovial fluid in joints)
- cushioning
What are the main ways body fluids are regulated?
- cardiovascular
- behavioural
- kidneys
What are 2 clinical effects of excess water?
- hyponatraemia
low [Na+] in blood (water diluting electrolytes) - oedema
pooling of fluid in interstitial space
Which tissue has a higher water content: muscle or fat?
muscle
Why are the young more susceptible to dehydration?
- cant obtain water independently
- cant communicate need
- SA:Vol ratio
- immature kidneys
Why are the old more susceptible to dehydration?
- cant obtain water independently
- cant communicate need
- ageing kidneys
What factors impact diffusion?
- temp
- conc. gradient
- size of molecules
- area
- solubility
- membrane properties
What is osmotic pressure?
opposing force that stops osmotic movement of water; because difference in concentrations is needed
What is osmolarity?
- osmolarity is the number of solute/osmotically active particles per a lire of water
- impacted by temperature
PARTICLES NOT MOLECULES
