Gas Exchange: Humans Flashcards
Alveoli Structure
Small air filled sacs
Surrounded by capillaries
Thin endothelium
Adaptions for diffusion of alveoli
Wall is 1 cell thick
Wall is made of squamous epithelium cells
What do ciliated epithelial and goblet cells do?
remove dust, pollen, and spores
What does cartilage do?
Holds airways open
What does smooth muscle do?
Control and constrict the diameter of airways
What is the importance of ventilation?
Increases concentration of oxygen in the blood
Decreases concentration of carbon dioxide in the blood
Therefore higher concentration gradient
Structure of cartilage in the trachea
C shaped, allows food to run down the oesophagus which is behind the trachea
What are goblet cells?
They secret mucus
Compare the trachea and bronchi
Bronchi narrower
Both have cartilage, less regular in bronchi
Compare bronchioles and bronchi
Bronchioles narrower
Bronchioles have no cartilage
What are bronchioles made of?
elastic fibres and smooth muscle
Explain the function of smooth muscles contracting
constrict airways
makes lumen narrower
Restricts air flow to and from alveoli
Important if there’s harmful substances in the air
Inspiration
Diaphragm contracts
External intercostal muscles contract
Volume of chest cavity increases
Pressure in chest drops below atmospheric pressure
Air moves into lungs
Expiration
Diaphragm relaxes
External intercostal muscles relax
Volume of chest decreases
Pressure in lungs higher than atmospheric pressure
Air moved out of lungs
What is the breathing rate?
The number of breaths per minute
