Exchange Surfaces Flashcards
Ventilation
Breathing movements
Ensures O₂ in alveolus is higher than in blood and
CO₂ in alveolus is lower than in blood
Alveoli comprised of
Squamous epithelium
Alveolus walls contain _______ _____ which _______ ______ ___________ and ______ __ ____ ___ ___
Elastic fibres
Stretch during inspiration
Recoil to push air out
Airways are lined with ________ __________ which have ____ ____ __________
Ciliated epithelium
Hair like extensions
Bronchioles have ______ ______ and _______ ______ instead of _________
Smooth muscle
Elastic fibres
Cartilage
Smooth muscle is
Involuntary muscle which contracts without thought
Constricts airways making lumen narrower and constricting air flow to alveoli if there are harmful substances
Elastic fibres
Deform and recoil to original size
Elongate smooth muscle again, as they recoil, the muscle relaxes
Spirometer
Measures movement of air in and out Air floats on tank of water Air out, lid goes down Air in, lid goes up CO₂ exhaled passes through soda lime so only measures O₂
Spirometer precautions
Healthy subject Fresh soda lime Sterilised mouthpiece No overflow of water No air leaks
Vital capacity
Maximum air moved in, in 1 breath
Deep breath
Expiring all air
Tidal volume
Air moved in and out with 1 breath at rest
Breathing rate
Number of breaths per minute
=Volume change/time
Oxygen uptake
Volume of O₂ absorbed in 1 minute
In insects, air enters via
Spiracles then tracheae then tracheoles filled with tracheal fluid
In insects, gas exchange is between
Air in tracheole and fluid
