Gas Exchange In Mammals Flashcards
Outline the path in which air moves from outside to inside the body.
Mouth Trachea Bronchi Bronchioles Alveoli
What is the gas exchange organ in mammals?
The lungs
Why are there lots of alveoli in the lungs?
To provide a large surface area for diffusion.
What works together to move air in and out of the lungs?
Ribcage, intercostal muscles and diaphragm.
What do the goblet cells do to help exchange gases efficiently?
Hey secrete mucus which traps microorganism and dust particles and stops them entering the alveoli.
How does cilia help exchange gases efficiently?
They beat the mucus upwards and away from the alveoli towards the throat. This prevents lung infection.
Where are the goblet cells and cilia found?
Lining the airways.
How do elastic fibres contribute to effective gas exchange?
Elastic fibres in the trachea, bronchi, bronchioles and alveoli help the process of breathing out by elastic recoil.
How does smooth muscle help with effective gas exchange?
The muscles in the trachea, bronchi and bronchioles relax which makes the tubes wider which lets air move in and out easily.
How does cartilage help with effective gas exchange?
C-shaped rings in the trachea and bronchi provide support and stop them collapsing.
Why are the cartilage rings C-shaped?
To allow room for the oesophagus so we can swallow.
What is ventilation?
It consists of inspiration (breathing in) and expiration (breathing out).
What muscles contract during inspiration?
The external intercostal muscles and diaphragm contract.
What happens to the ribcage during inspiration?
It moves upwards and outwards.
What happens to the diaphragm during inspiration?
Contracts and flattens so it moves down.
What is increased and decreased in the thorax during inspiration?
What does this cause?
Volume inside the thorax increases.
Pressure inside the thorax decreases.
This causes air to enter into the lungs.
Inspiration is an active process. What does this mean?
It requires energy to happen.
What muscles relax during expiration?
External intercostal muscles and diaphragm relax
What happens to the ribcage during expiration?
Moves down and inwards.
What happens to the diaphragm during expiration?
Relaxes and moves up. Becomes curved again.
What increases and what decreases during expiration?
What does this cause?
Volume decreases inside the thorax.
Pressure increases inside the thorax.
Air is forced out of the lungs.
Normal expiration is passive. What does this mean?
It doesn’t require energy to happen.
What happens during forced expiration?
The internal intercostal muscles contract which pulls the ribcage down and in. This decreases the volume and increases the pressure in the thorax, forcing air out.
What is a spirometer?
A machine that can be used to investigate breathing.
How does a spirometer work (step by step)?
1) Person breathes through a tube connected to the oxygen chamber
2) As person breathes in and out, the lid of the chamber moves up and down
3) Soda lime in the tube absorbs carbon dioxide when the person breathes out.
4) Movements are recorded by a pen attached to the lid and a rotating drum
5) A spirometer trace is made
What is tidal volume?
The volume of air that moves into and out of the lungs with each resting breath.
What is vital capacity?
The volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible inhalation.
What is inspiratory reserve volume?
The maximum volume of air you can breathe in over and above a normal inhalation.
What is expiratory reserve volume?
The extra amount of air you can force out of your lungs over and above the normal tidal volume of air you breathe out.
What is residual volume?
The volume of air that is left in your lungs when you have exhaled as hard as possible.
What is total lung capacity?
He sum of the vital capacity and the residual volume.
What is breathing rate?
How many breaths are taken per unit time.
Usually per minute
What is oxygen uptake?
The rate at which a person uses up oxygen.
What is lung surfactant?
A soapy substance made from phospholipids that is secreted by epithelial cells in alveoli.
Why is lung surfactant important?
Without it, the watery lining of the alveoli would create s surface tension which causes the alveoli to collapse.
What three ways can be used to measure breathing rates?
A peak flow meter
Vitalographs
Spirometer
