The Respiratory System Flashcards
What happens during inhalation?
- The diaphragm contracts (flattens)
- External intercostal muscles contract
- Rib cage moves out and upwards
- Chest cavity enlarges
- Lungs expand
- Pressure inside decrease
- Air rushes into lungs to equalise pressure
What happens during exhalation?
- Diaphragm relaxes (moves upward)
- Internal intercostal muscles contract
- Rib cage moves down and inwards
- Volume of chest cage decreases
- Lung volume decreases
- Pressure inside lungs increases
- Air passively flows out of lungs due to pressure
Tidal volume
Volume of air breathed in and out in a single breathing cycle
Approximate tidal volume
0.5 litres
Inspiratory reserve volume
Volume when breathing in as deeply as possible
Approximate inspiratory reserve volume
2 litres
Exploratory reserve volume
Volume when breathing as forcibly as possible
Approx exploratory reserve volume
1.5 litres
Residual volume
Air remaining in lungs after maximal exhalation
Approximate residual volume
1.5 litres
Vital capacity
The maximum amount of air that can be moved into and out of the lungs in one breath
Approximate vital capacity
4 litres
Short term effects of exercise on ventilation
• Taking more breaths (increase in ventilation rate)
• Deeper breaths (increase in tidal volume)
-> respiration, more oxygen in
Long term effects of exercise on ventilation
• Increase in lung volume
-> respiration, more oxygen in
What effects does tar have on the human body?
• Lung cancer - tar contains carcinogens (substances that can cause cancer)
• Emphysema - chemicals in tar damage alveoli (decreased SA/V ratio)
• Lung infections, bronchitis
- cilia in bronchi(oles) get paralysed
- build up of mucus
- debris in lungs not removed
- build up of bacteria
What effects does nicotine have on the human body?
• Addictive substance in cigarettes - stimulates neurotransmitters in brain leading to heightened activity
• Strokes and heart attacks
- constricts arteries reducing blood flow
- fat deposited in blood vessels
- increased blood pressure
What effects does carbon monoxide have on the human body?
• Tiredness, dizziness, increased heart rate
- binds irreversibly to haemoglobin
- reduces oxygen-carrying ability of red blood cells
• reduced birth mass - foetus gets less oxygen
What is the function of the respiratory system?
Gas exchange
- intake of oxygen (for respiration)
- release of carbon dioxide (waste product)
Adaptations of the respiratory system for efficient gas exchange
- Large SA/V ratio - making diffusion efficient.
- Higher concentration gradient (breathing in makes the concentration of oxygen high and constant blood flow also does this).
- Short diffusion distance (walls of the alveoli are very thin, as are the walls of the capillary).
- Lots of moisture helps gases to dissolve.
- Surfactant keeps bubbles inflated and prevents the alveoli from collapsing.
