Text Book - exchange surfaces Flashcards
When exercising more air is breathed in and out of the lungs. Explain what physiological changes occur and how this enables exercise to happen
The volume of air breathed in and out of the lungs increases
-supplies more oxygen to the alveoli, replacing the oxygen more frequently, so that the concentration gradient is maintained at a higher level and more oxygen is transported by the blood. Muscles can respire more
What enables more air to enter/leave the lungs than normal
Diaphragm contracts more, internal intercostal muscles contract to raise ribs so that more air is inhaled. The external intercostal muscles contract to ensure more rapid expiration
How does smoking lead to infection
Smoke paralyses the cilia. Therefore, mucus is not moved along and accumulates in the airway. Pathogens have ideal conditions to reproduce
How is there residual volume
Alveoli are held open by elastic fibres and airways are held open by cartilage – the space inside is filled by air
What happens to a fish out of water
1) Fish cannot survive out of water as there gills will collapse so SA exposed to the air will be small – insufficient for gaseous exchange eventually the gills will dry out
How has insects developed there system
4) With an open circulation, an insect cannot easily direct the flow of blood to the tissues that need it most; the flow is also affected by body movements. Using separate air-filled tubes allows development of a system that can bring more air to the tissues that need it. If the insect relies on diffusion to some extent, the oxygen can diffuse more quickly through air than through blood fluid
What happens to the tracheal fluid when the insect is active
5) Tracheal fluid is withdrawn into the body when the tissue is very active: Oxygen can diffuse through the walls at the end of the tracheoles into the tissue fluid, withdrawing fluid from the end of the tube increases the surface area over which exchange can occur.
Tidal/vital capacity
Tidal volume – is the volume of air inhaled/exhaled in one breath
Vital capacity – maximum volume of air inhaled/exhaled in one breath
Why oxygen in tissues is delivered in insects in gaseous form
Distance is too great; to supply enough oxygen for active tissues; by diffusion; therefore, mass flow/transport is needed; (insects have) open blood circulatory system; movement of blood not as directional/efficient (as closed system); diffusion in liquid slower than in air.
