Exchange of materials: dissolved substances Flashcards
What do sports drinks contain?
- water/mineral ions
- sugar
Why does drink contain water and mineral ions ?
to replace those lost during sweating as cells may become dehydrated so water rehydrates cells
Why does drink contain sugars?
to replace sugars used in energy release
What does it mean when a drink is isotonic?
when the concentration of the drink matches bodily fluid
What do the drinks balance?
concentration of bodily fluids and concentration inside cells
What happens if the balance is disturbed?
cells don’t work as efficiently
How do solutes enter the blood?
- via diffusion: high conc of food in digestive tract move to lower conc in blood
- via active transport: when conc in blood increases food still needs to be moved
Why do large organisms need exchange surfaces?
size/ complexity increases diffculty to exchange
- surfaces enable to obtain food and oxygen
How do you increase effectiveness of exchange surfaces?
- larger surgace area
- efficient blood supply
- thin walls - short diffusion path
- large capillary network
In humans how is surface area increased?
- lungs: alveoli
- intestine: villi with extensive capillar network
What is ventilation?
movement of air into and out of lungs
Why are the lungs ventilated?
to maintain steep diffusion gradient
