The Breathing System(Complete) Flashcards
What is breathing?
The mechanism of taking air in and out of the lungs, caused by movements of the ribcage and diaphragm.
What is the diaphragm?
A sheet of involuntary muscle which forms the base of the thoracic cavity.
What is the ribcage?
The ribs and intercostal muscle which form the walls of the thoracic cavity.
What is the function of the nasal and buccal cavity?
Allows air to enter the breathing system.
Air is warmed, moistened and filtered in the nasal cavity due to mucus, cilia and a blood capillary network.
What is the function of the pharynx?
Connects the nasal and buccal cavity to the larynx.
What is the function of the larynx?
The voice box which contains vocal cords which vibrate to produce sound.
What is the function of the trachea?
A wide tube which allows air to enter the lungs.
Rings of cartilage surround it to keep it permanently open.
The epiglottis prevents water and food from entering the trachea.
Mucous traps pathogens and cilia create a current which pushes mucous and entrapped matter towards the pharynx where it is then swallowed.
What is the function of the bronchi and bronchioles?
Bronchi allow air to enter into the lungs.
Finer branched bronchioles allow air to enter the alveoli.
Bronchi have cartilage.
Bronchioles have no cartilage.
What is the function of the alveoli?
Microscopic gas-filled chambers which have a major role in gas exchange.
What are the adaptations of the alveoli for gas exchange?
Wall is one cell thick.
Provide a moist surface.
Provide a large surface area as there are many of them.
Describe the structure of the lungs.
They are pink spongy elastic organs.
Where are the lungs located?
In the thoracic cavity, on either side of the heart.
How are the lungs protected?
They are protected by the ribcage.
They are surrounded by pleural membranes with pleural fluid which allows for the friction-free movement of the lungs.
Where is the intercostal muscle located?
Between the ribs in the ribcage.
What is the role of the lungs?
It is the gas exchange organ which expands easily during inhalation and recoils rapidly to expel air during exhalation.
What gas controls the breathing rate?
Carbon dioxide.
How is breathing controlled?
It is an involuntary process controlled by the medulla oblongata in the brain.
How does the medulla oblongata respond to high levels of CO2?
Aerobic respiration results in high levels of CO2 which makes the blood and tissue fluid more acidic.
When carbon dioxide dissolves in water, what does it form?
Carbonic acid.
What is the role of carbon dioxide in the control of human breathing?
The medulla oblongata registers levels of co2 in the blood.
When co2 levels increase the breathing rate increases to remove excess co2 and blood becomes more acidic.
Describe the process of inhalation.
The brain sends an impulse to the breathing muscles.
The intercostal and diaphragm muscles contract.
The ribcage moves up and out.
The diaphragm lowers and flattens.
The volume of the thoracic cavity increases.
The pressure in the thoracic cavity decreases.
Air is drawn into the lungs.
Describe the process of exhalation.
The diaphragm and intercostal muscles relax.
The ribcage moves down and in.
The diaphragm recoils to its dome shape.
The volume of the thoracic cavity decreases.
The pressure in the thoracic cavity increases.
Air is forced out of the lungs.
Which process is active and which process is passive?
Inhalation is an active process as the diaphragm and intercostal muscles contract to draw air into the lungs.
Exhalation is a passive process as the diaphragm and intercostal muscles relax to force air out of the lungs.
What process does gas exchange occur by?
Diffusion.
