4 - Applied basic science Flashcards
1
Q
Describe basic breathing mechanics.
A
- inspiratory muscles contract
- thoracic volume increases, thoracic pressure decreases
- air pushes in along pressure gradient
- expiration is passive
2
Q
What is the difference between quiet versus forced breathing?
A
- diaphragm contracts for quiet breathing
- intercostal and accessory muscles are used for forced breathing
3
Q
What is tidal volume?
A
- volume of air inspired during quiet breathing
- around 440ml
4
Q
What is IRV?
A
- inspiratory reserve volume
- maximal inspiratory level
5
Q
What is ERV?
A
- expiratory reserve volume
- resting expiratory level
6
Q
What is RV?
A
- residual volume
- maximal expiratory volume
- some air always remain within the lungs
7
Q
What is the dead space?
A
- also known as the conducting zone
- trachea, bronchi, terminal bronchiole
- not included in residual volume as no gas exchange occurs here
8
Q
What is the respiratory zone?
A
- region of gas exchange
- respiratory bronchiole, alveolar duct, alveolar sac
9
Q
What volume is the dead space?
A
150ml
10
Q
What is the normal alveolar ventilation volume?
A
300ml
11
Q
What is alveolar ventilation?
A
- volume of fresh air entering alveoli
- 150ml of air from dead space included from previous breath
12
Q
Describe pulmonary gas exchange.
A
- occurs between alveolar air and pulmonary capillary blood
- gases move across wall by diffusion determined by the partial pressure gradient
13
Q
Describe oxygen transport.
A
- 97% attached to haemoglobin
- 3% dissolved in plasma
14
Q
How is CO2 transported in the blood?
A
- erythrocytes
- plasma
15
Q
How is breathing controlled?
A
- breathing muscles are skeletal (voluntary)
- rhythm is generated from respiratory centres in brainstem and modified by sensory receptors
