3.1.4 Ventilation in Mammals Flashcards
1
Q
Breathing in
A
- Diaphragm contracts and flattens
- External intercostal muscles contract (exercise)
- Ribcage goes upwards and outwards
- Pressure decreases in lungs
- Thorax volume increases
- Air is drawn in
2
Q
Breathing out
A
- While resting, mainly due to recoil of lungs
- External intercostal muscles relax
- Recoil of elastic fibres in alveoli forces air out
- Diaphragm relaxes and becomes dome shaped
- Internal intercostal muscles contract (exercise)
- Pulls ribs back and down
- Abs contract pushing organs up against diagphragm, expelling air quicker (exercse)
- Pressure increases
- Thorax volume decreases
- Air pusehd out
3
Q
Pathway of Air
A
- Nose / mouth
- trachea
- Bronchi
- Bronchioles
- Alveoli
4
Q
What is the purpose of ventilation
A
To ensure there is a higher concentration of oxygen in the alveoli than in the blood
