gas exchange Flashcards
what are the projections on a gill arch called?
gill filaments
what are the projections on gill filaments called?
lamellae
in what direction do blood and water flow across the lamellae ?
opposite directions
(counter-current flow)
what does the counter current flow ensure?
a steep diffusion gradient is maintained so equilibrium is never reached and all the oxygen can be diffused out of the blood
what is inspiration?
breathing in
what is expiration?
breathing out
what happens in inspiration?
external intercostal muscles and diaphragm contract , volume of thoracic cavity increase , lung pressure decreases , air flows in
what happens in expiration?
external intercostal muscles and diaphragm relax , volume of thoracic cavity decreases , air pressure increases , air forced out
what happens in forced expiration?
external intercostal muscles relax , internal intercostal muscles contract ,
what are the air sacs in the lungs called?
alveoli
how are the alveoli adapted?
wall is a single layer of thin flat cells to ensure a short diffusion pathway
walls of the alveoli contain elastin protein to help the alveoli return to their normal shape after inhaling and exhaling
what is the movement of oxygen through the body?
moves down the trachea , bronchi and bronchioles and into the alveoli down a pressure gradient , diffuses into the blood where it can be transported around the body
lots of them so there is a very large surface area to increase the rate of oxygen diffusion and gas exchange
what is tidal volume?
the volume of air in each breath
what is ventilation rate?
the number of breaths per minute
what is forced expiratory volume?
the maximum volume of air that can be breathed out in 1 secondw
what is forced vital capacity?
the maximum volume of air it is possible to breathe forcefully out of the lungs after a really deep breath itn
how do lung diseases affect gas exchange?
reduce the rate of gas exchange in the alveoli
how does lung disease affect a person?
the rate of gas exchange is reduced , so less oxygen is able to diffuse into the bloodstream , therefore the body cells receive less oxygen so the rate of aerobic respiration is reduced so less energy is released and the person may feel tired and weak
what are 4 things that need to be exchanged with the environment?
respiratory gases
nutrients
excretory products
heat
what are spiracles and how do they work?
they are tiny pores on the body surface of the insect that open and close using a valve
they can allow water vapour to evaporate from them and tend to shut to avoid water loss
