Respiratory 1 Flashcards
1
Q
Increasing O2 uptake during exercise depends on …
A
Controlled increase in ventilation
- QO2 - oxygen uptake in the cell
- Oxygen to the blood and removing carbon dioxide
- Systems work together (muscle, circulation & ventilation)
2
Q
Functions of the lungs
A
- Gas exchange achieved by ventilating alveoli (oxygen & carbon dioxide via ventilation)
- Immune function - epithelial secretions, filters air, coughing, sneezing.
- Metabolic/hormonal functions.
- Speech
3
Q
Respiratory Airway
A
- Conducting airway
- Trachea -> Bronchi -> Bronchioles (nonrespiratory) - Terminal respiratory units
- Bronchioles (respiratory) -> Alveolar ducts
4
Q
Alveoli and blood-gas barrier
A
- 200 million to 600 million alveoli in the lungs
- Covered in pulmonary capillaries where gas exchange occurs
- Draining arterial blood from the alveoli are the pulmonary arterial vessels and draining oxygenated blood would be the pulmonary venous vessels
5
Q
Gas diffusion at the air-blood interface
A
- Lungs bring air to alveoli (ventilation) while pulmonary arteries bring blood to capillaries (perfusion).
- Gas diffusion occurs at the alveolar-capillary interface (~70 % of total alveolar surface).
- Total area and thickness of this ‘interface’ affect the rate of gas diffusion
6
Q
Gas exchange, ventilation and perfusion
- partial pressure
A
- Oxygen will move into the blood because the partial pressure in the lungs is higher than in the blood
- Carbon dioxide will move into the lungs because the partial pressure in the lungs in lower than in the blood
- Perfusion involves blood moving from the right side of the heart to the left side
7
Q
Ventilation during graded exercise
A
- Minute ventilation’ is the volume of air inspired or expired in one minute.
- Minute ventilation at rest is ~8-10 L/min.
- Ventilation increases in proportion to O2 uptake at lower intensities and disproportionately more as maximum VO2 is approached.
- Training – from ‘A’ to ‘C’ - increases the ‘ventilatory threshold’ (“Owles Point”) and the maximum ventilation. (REFER TO LECTURE)
- Owles point = describes the oxygen uptake (or intensity) beyond which ventilation increases much more than at lower workloads
- Maximum rates of ventilation can exceed 200 L/min in large endurance athletes.
- Alveolar ventilation and perfusion (i.e. cardiac output) rise during exercise.
8
Q
How do we breath at rest?
A
- Breathing in occurs because the diaphragm goes down (contracts) and opens up the volume inside the rib cage
- When the diaphragm relaxes we breath out
- Intercostals are also involves in breathing at rest
9
Q
The pleural cavity and breathing
- Boyles law
A
- Boyle’s Law - the pressure in an enclosed container is inversely proportional to the volume
- Expansion of thoracic or ‘chest’ volume increases the volume of the pleural cavity and reduces its pressure.
- This allows the lungs to expand and decrease lung pressure.
- Since lung pressure is now less than atmospheric pressure, air rushes into the lungs and results in inspiration.
- The opposite occurs during expiration.
- Pleural cavity - between the ribs and the soft tissue of the lungs. It is a lubricating fluid that prevents friction between the ribs and lungs
10
Q
How do we breath during exercise
A
- Inspiration: active and also involves ‘accessory’ muscles which increase the strength of inspiration.
- Expiration: becomes active and involves internal intercostals and, particularly, abdominal muscles.
11
Q
Lung volumes during rest and exercise
A
- Tidal volume is the volume of a breath (inspired or expired). Rest: 500ml, exercise: 2-4L
- Anatomic dead space is the volume of air which does not reach the respiratory zone. (stays in the conducting zone) 150 ml
- Alveolar volume is the total volume of air in all alveoli. 3L
- Pulmonary capillary volume is the total volume of blood in all pulmonary capillaries. Rest: 100ml, exercise: 130ml
12
Q
Volumes and flows during rest
A
- Flow is a volume per unit time.
- Minute ventilation = TV × fb. (7500ml/min)
- ml/min = ml/breath × breath/min.]
- Breathing frequency: 15 b/min
- Alveolar ventilation = (TV– dead space) × fb . (5250ml/min)
- Alveolar ventilation and pulmonary blood (5L/min) flows are very similar: 1 to 1 matching.
13
Q
Breath volumes during rest and exercise
A
During exercise there is an increase in tidal volume (2-4L)
14
Q
Ventilation, tidal volume and breathing frequency
A
During graded exercise, your minute ventilation increases and increases because your tidal volume and breathing frequency increase
- Tidal volume increases much more abruptly early on and then tends to plateau
- Breathing frequency increases more regularly and then takes off
- There is a disproportionate increase in breathing frequency at higher intensity
15
Q
Spirometric volumes and flows at rest
A
The women - asked to take a deep breath and forcefully expire the air
- FEV1 - forces expiratory volume in one second
- Someone with asthma would have a lower FEV1
- FVC (forced vital capacity) - the difference between the maximum air inhaled and what’s left after exhalation
(REFER TO LECTURE FOR GRAPH)
