B2.2 Flashcards
1
Q
What is surface area : volume ratio?
A
Surface area : volume ratio:
- Larger organism means lower surface area to volume ratio
- Alveoli increases SA : V ratio
- More area is exposed
2
Q
What are arteries?
A
Arteries:
- Small lumen
- Elastic fibre/ smooth muscle
3
Q
What is the role of an artery?
A
Artery:
- Narrow to keep high pressure to keep blood flowing everywhere
- Thick muscle
4
Q
What are veins?
A
Veins:
- Large lumen
- Pressure not sustained in veins, so there are valves
- Go through pairs of muscle that squeeze veins like tube of toothpaste
5
Q
What are capillaries?
A
Capillaries:
- Small lumen
- 1 cell thick
- Link arteries and veins
- Semi permeable walls
6
Q
What is the double circulatory system?
A
Double circulatory system:
- Blood pumped twice for each journey around body
7
Q
What is inside the blood?
A
Inside blood:
- Red blood cells
- White blood cells
- Platelets
- Plasma
8
Q
What are red blood cells?
A
Red blood cells:
- Biconcave shape for larger surface area
- Oxyhemoglobin
9
Q
How does the heart work?
A
Heart:
- Deoxygenated blood goes to right atrium and pumped to right ventricle
- Goes to lungs via pulmonary vein (oxyhaemoglobin)
- Enters left atrium through pulmonary artery and goes to left ventricle
10
Q
Where are xylem and phloem found in roots?
A
Xylem and phloem:
- Xylem in centre
- Phloem around outskirts
11
Q
Where are xylem and phloem found in stem?
A
Xylem and phloem:
- Xylem and phloem on outskirts for strength
12
Q
What is the xylem?
A
Xylem:
- Made of dead xylem cells
- Transports water and minerals from roots to leaves
- One way
- Lignin stiffens walls
13
Q
What is the phloem?
A
Phloem:
- Living phloem cells
- Carry sucrose and amino acids to where they are needed
14
Q
What is transpiration?
A
Transpiration:
- Loss of water vapour from stomata
15
Q
What factors affect transpiration?
A
Transpiration:
- Light intensity
- Temperature (evaporation)
- Humidity (humid air has water, so same water potential)
- Wind (blows water away
