3a.1 - Osmosis, Gas and Solute Exchange and The Breathing System Flashcards
Define osmosis
The movement of water molecules across a partially permeable membrane from a region of high water concentration to an area of low water concentration
What is a partially permeable membrane?
A membrane with very small holes in it
How do water cells move in and out of cells?
Osmosis
How do substances move to where they want to go in the body?
Diffusion, osmosis and active transport
What is diffusion?
Where particles move from a high concentration to a low concentration
Which forms of transport involves substances moving from high concentration to low concentration?
Diffusion and osmosis
Which form of transport involves substances moving from low concentration to high concentration?
Active transport
How are exchange surfaces adapted to maximise effectiveness? (4)
- Thin
- Large surface area
- Blood supply
- Ventilation
Which part of the leaf is the exchange surface?
The underleaf
Why is the underleaf the exchange surface in the leaf?
It is covered in small holes called stomata
What substances diffuse out through the stomata?
Oxygen and water vapour
What is the size of the stomata controlled by?
Guard cells
Why are there air spaces inside the leaf?
Increase the surface area
What conditions is evaporation of water vapour leaving a leaf best at?
Hot, dry and windy
What is the thorax?
The top of the body
Explain how gas gets to the lungs (4)
- Goes through the trachea
- Splits into two bronchi
- Splits into smaller bronchioles
- Ends at the alvioli
What happens when you breath in? (4)
- Intercostal muscle contarcts
- Diaphragm contracts
- Volume increases
- Pressure decreases
What happens when you breath out? (4)
- Intercostal muscle relaxes
- Diaphragm relaxes
- Volume decreases
- Pressure increases
What is ventilation?
The movement of air into and out of the lungs
What are advantages of the shell as a breathing aid? (3)
- Mimics what the body would normally do
- Stops the person from dying
- Not entirely restrictive
What are the disadvantages of the shell as a breathing aid? (3)
- Heavy
- Has to stay in hospital
- Have to wear
What are the advantages of the iron lung as a breathing aid? (3)
- Keeps the person from dying
- Simulates actual breathing
- Efficient
What are the disadvantages of the iron lung as a breathing aid? (3)
- Bed sores from lying down a lot
- Restrictive
- Has to stay in hospital
What are the advantages of the positive pressure systems as a breathing aid? (3)
- Keeps people who have no control over their lungs
- Can increase the levels of oxygen
- Can hook up different machines to test different thing
What are the disadvantages of the positive pressure system as a breathing aid? (3)
- Invasive
- Has to be sedated
- Doesn’t stimulate actual breathing
