Exchange surfaces Flashcards
(32 cards)
What are the features that make the lungs an efficient exchange surface?
Increased surface area due to many alveoli.
The walls of the alveoli and the capillaries are thin (only 1 cell thick) , decreasing the distance needed for the diffusion of gases.
A good blood supply. There is a capillary close to each alveolus, rapidly taking the oxygenated blood away and bringing in deoxygenated blood. This ensures that a steep concentration gradient for oxygen and carbon dioxide is maintained.
Where is cartilage found?
Trachea and bronchi
Where are goblet cells found?
Trachea and bronchi
Where is smooth muscle found?
Trachea, bronchi, bronchioles
Where is ciliated epithelium found?
Trachea, bronchi, bronchioles
Where are elastic fibres found?
Trachea, bronchi, bronchioles, alveoli
What is the function of cartilage?
Holds the airways open
What is the function of goblet cells?
Secrete mucus in order to trap pathogens and particles in the lungs.
What is the function of smooth muscle?
Constricts airways to prevent harmful gases from entering the lungs.
What is the function of ciliated epithelium?
Surface is covered in cilia that move mucus out of the lungs.
What is the function of elastic fibres?
Allow recoil of the smooth muscle or the alveoli back to their original size.
What is inspiration?
Breathing in
What is expiration?
Breathing out
What is the mechanism of inspiration?
Intercostal muscles contract. The ribcage moves upwards and outwards.
Diaphragm contracts and becomes flatter.
Thoracic cavity expands and volume increases. This deccreases the pressure to below atmospheric pressure.
Air moves into the lungs from high pressure to low pressure.
What is the mechanism for expiration?
Intercostal muscles relax. The ribcage moves downwards and inwards.
Diaphragm relaxes and becomes dome-shaped.
Thoracic cavity reduces and volume decreases. THis increases the pressure above at atmospheric pressure.
Air moves out of the lungs from high pressure to low pressure. The recoil of the elastic fibres in the alveoli helps to expel this air.
What is a spirometer?
The air chamber is filled with air or oxygen. When a person exhales into the spirometer, the air chamber rises. When a person inhales, air is removed from spirometer and the air chamber moves down. Thismovement drwas the graph. The soda lime absorbs any carbon dioxide in the exhaled air.
What can a spirometer trace be used for?
A spirometer trace can also be used to work out a person’s breathing rate and rate of oxygen uptake.
What is the tidal volume?
The volume of air breathed in and out of the lungs in one breath, when the person is at rest.
How do you measure tidal volume on a graph?
Measure the distance from the top to the bottom of a small peak.
What is the vital capacity?
The maximum volume of air that can be inhaled or exhaled in one breath.
How do you measure the vital capacity on a graph?
Measure the distance from the top to the bottom of the largest peak.
How do you calculate breathing rate?
Divide the number of breaths by a given time (s), and multiply by 60 to get breaths per minute.
How do you calculate rate of oxygen uptake?
Divide the amount of oxygen used by a given time and multiply by 60 to get oxygen uptake per minute.
How do fish ventilate?
Water enters the fish’s mouth, or buccal cavity, when the mouth opens, lowering the pressure inside the buccal cavity compared to the surrounding water. When the fish closes its mouth, the pressure in the buccal cavity increases and water flows over the gills and out of the fish, behind a flap called the operculum.
