3.1 Exchange surfaces Flashcards
What do goblet cells do in the gaseous exchange system?
Secrete mucus.
The mucus traps microorganisms and dust particles carried by the inhaled air, stopping them from reaching the alveoli.
What do the cilia do in the gaseous exchange system?
Line airways and beat the mucus.
This moves the mucus upwards and away from the alveoli.
This helps prevent lung infections.
What do elastic fibres do in the gaseous exchange system?
In the walls of the trachea, bronchi, bronchioles, and alveoli.
Help the process of expiration.
In inspiration, the lungs inflate and the elastic fibres are stretched.
Then, the fibres recoil to help push the air out during expiration.
What does smooth muscle do in the gaseous exchange system?
In the walls of the trachea, bronchi, and bronchioles.
Allows their diameter to be controlled.
During exercise, the smooth muscle relaxes, making the tubes wider.
This means that there is less resistance to airflow.
What do the cartilage rings do in the gaseous exchange system?
In the walls of the trachea and bronchi.
Provides support.
Strong but flexible.
Stops the trachea and bronchi collapsing when you breath in and the pressure drops.
What makes up the trachea?
Ciliated epithelium
Cartilage
Elastic fibres
Smooth muscle
What makes up the bronchi?
Ciliated epithelium
Cartilage
Elastic fibres
Smooth muscle
What makes up the bronchioles?
Ciliated epithelium
Elastic fibres
Smooth muscle
What makes up the alveoli?
Alveolar epithelium
Elastic fibres
Blood capillary
What happens during inspiration in mammals?
External intercostal muscles and diaphragm contract.
Ribcage moves upwards and outwards.
Diaphragm flattens, increasing the volume of the thorax.
Lung pressure decreases so air flows into the lungs.
It is an active process so requires ATP
What happens during expiration in mammals?
External intercostal muscles and diaphragm relaxes.
Ribcage moves downwards and inwards.
Diaphragm curves, decreasing the volume of the thorax.
Air pressure increases so air is forced out.
What is the difference between normal and forced expiration?
Normal - passive process so it doesn’t require ATP.
Forced - active process so it does require ATP
What is tidal volume on a spirometer?
Volume of air in each breath.
What is vital capacity on a spirometer?
Maximum volume of air that can be breathed in or out.
What is breathing rate on a spirometer?
How many breaths are taken in a set amount of time.
What is oxygen consumption/oxygen uptake on a spirometer?
The rate at which an organism uses up oxygen.
What does a spirometer produce?
Kymograph.
What do fish use for gas exchange?
Counter-current system
Gills; what are they made up of?
Thin branches called gill filaments/primary lamellae.
The gill filaments are covered in lots of tiny structures called gill plates/secondary lamellae.
Each gill is supported by a gill arch.
What is the counter current mechanism?
Blood flows through the gill plates in one direction and water flows over in the opposite direction.
Why is a counter current mechanism useful?
Maintains a large concentration gradient between the water and the blood.
Ventilation: The fish opens it’s mouth…
which lowers the floor of the buccal cavity.
Volume increases, pressure decreases.
Water is sucked in.
Ventilation: The fish closes its mouth…
the floor of the buccal cavity is raised.
Volume decreases, pressure increases.
Water is forced out of the cavity across gill filaments.
Ventilation: Operculum covers…
and protects gill.
Increase in pressure forces the operculum to open, allowing water to leave.
