Chapter Five - Breathing and The Respiratory System Flashcards
Explain the process of breathing
Physical process ensuring gas exchange can take place at the alveoli. At the alveoli oxygen needed for respiration is absorbed by blood and waste C02 is removed from blood. Movement of both gases occurs by diffusion and the process of breathing maintains the concentration gradients required.
Label bell jar lung model
- glass tube A
- bell jar
- glass tubes B
- balloons
- rubber sheet
Explain modelling inhaling
- rubber sheet (representing diaphragm) in its raised position
- volume of bell jar decreased
- results in fall in air pressure compared to externally
- air therefore rushed I’m via the glass tubes (representing trachea and bronchi) to fill the balloons (lungs) and balance the pressure.
Modelling exhaling
- when rubber sheet is released it returns to its flatter position
- the volume in the bell jar thus decreased
- this means air pressure inside hair is increased above surrounding air pressure
- air is therefore forced out through the tubes and the balloons deflate
Comparing model lung to respiratory system
- Model lung uses rigid glass bell jar but respiratory system has a ribcage with intercostal muscles that raise and lower the ribcage
- The balloons are composed of one large air space but human lungs have millions of tiny alveoli
- Model lung does not represent the nasal cavity or bronchioles
- Glass tubes of model are inflexible unlike the trachea and bronchi. Doesn’t represent c-shaped rings of cartilage
- Human lungs are surrounded by pleural membrane containing pleural fluid. Neither represented on model.
Label diagram of inhaling
- intercostal muscles contract causing ribs to move up and out
- diaphragm contracts and moves down
- the volume of the chest cavity (thorax) increases causing the pressure to decrease. Air enters the lungs because the lung pressure falls below the atmospheric pressure.
Label diagram of exhaling
- intercostal muscles relax causing ribs to move down and in
- diaphragm relaxes and returns to its domed shape
- the volume of the thorax decreases raising the pressure inside the thorax which forces air out of the lungs.
Summary of inhaling
Diaphragm - contracts and flattens Intercostal muscles - contract Ribcage position - raised up and out Volume - increased Pressure - decreased Result - air rushed in
Summary of exhaling
Diaphragm - relaxes and returns to domed position Intercostal muscles - relax Ribcage position - lowered down and in Volume - decreased Pressure - increased Result - air is forced out
Comparison of inhaled and exhaled air
Inhaled air
Oxygen - 21%
Carbon dioxide - 0.04%
Nitrogen - 78%
Exhaled air
Oxygen - 16%
Carbon dioxide - 4%
Nitrogen - 78%
Why the change?
Oxygen - oxygen diffuses from alveoli into blood and is used in respiration
Carbon dioxide - carbon dioxide from respiration diffuses from blood into alveoli
Nitrogen - not used in respiration
What is respiration?
- a chemical process
- release of energy for use in living organisms
- not breathing - all living things respire but not all breathe e.g plants respire but don’t breathe
Energy released in respiration can be used for;
- movement
- growth and repair
- heat
- reproduction
- active transport
Word equation & balanced chemical equation for aerobic respiration
Glucose + oxygen –> carbon dioxide + water + energy
C6H12O6 + 6O2 –> 6CO2 + 6H2O + energy (ATP)
Adaptions of respiratory surfaces
Adaption and reason
Large surface area - more opportunities for gases to be exchanged
Thin and permeable walls - minimise diffusion distance and allow gases through
Moist - allow gases to dissolve easily
Have features to maintain the concentration gradient e.g. A diffusion gradient and (in mammals) a good blood supply - ensure that gas exchange proceeds continuously
What is aerobic and anaerobic respiration?
Respiration with oxygen is called aerobic respiration and respiration without oxygen is called anaerobic respiration.
