Mammalian gas exchange Flashcards
Respiratory system: nasal cavity
Main route by which air enters the gas exchange system
Functions of the nasal cavity
Respiratory system:
Air can enter the respiratory system here but misses out on the cleaning, warming & moisturizing effects of the nasal route
Respiratory system: Epiglottis
A flap of tissue that closes over the glottis in a reflex action when food is swallowed. This prevents food from entering the gas exchange system
Respiratory system: larynx
Uses the flow of air across it to produce sounds
Respiratory system: trachea
Major airway to the bronchi lined with cells including mucus-secreting goblet cells. Cilia on the surface of the trachea move mucus & any trapped microorganisms & dust away from the lungs
Respiratory system: bronchioles
Respiratory system:
Gas exchange at alveoli
In the lungs most of the gas exchange occurs in tiny air sacs known as alveoli
Gas exchange at alveoli: surface area
The alveoli prove an enormous surface area for the exchange of gases in the human body
Gas exchange at alveoli: steep concentration gradient
Gas exchange at alveoli:
Blood leaves lung
The blood now carries this oxygen to the cells of the body
Law of diffusion
The movement of the oxygen from the blood to the cells also follows the law of diffusion
It is highly concentrated within the blood
Meanwhile the concentration is low within the cell
Therefore the oxygen passes into the body cells
Inhalation
External intercostal muscles contract
Internal intercostal muscles relax
Ribcage & sternum moves upwards & outwards
Diaphragm contracts & flattens downwards
Thoracic volume increases
Pressure inside the thoracic decreases than atmospheric pressure
Air is pushed into the lungs
Exhalation
Internal intercostal muscles contract
External intercostal muscles relax
Ribcage & sternum moves downwards & inwards
Diaphragm relaxes & becomes dome shape
Thoracic volume decreases
Pressure inside the thoracic increases than atmospheric pressure
Air is pushed out of the lungs
