Respiratory system

Question 0

Alveoli

Answer 0

Very thin walls
Rich blood supply
Moist lining
Huge surface area

Blood has high conc. of CO2 and alveoli have low conc of CO2 high Conc of O2. Simple diffusion occurs

Question 1

Path of Air

Answer 1

Nasal Cavity or Mouth
Pharynx (throat)
Past Larynx
Past epiglottis
Into Trachea
Bronchi into bronchioles into Alveoli

Question 2

Breathing in

Answer 2

Inspiration
Thoracic cavity expands - contraction of intercostal muscles. Diaphragm contracts.
Volume of lungs increase.
Air pressure in lungs decreases so air rushes into to fill the lungs

Question 3

Breathing out.

Answer 3

Expiration. 
Thoracic cavity decreases
Diaphragm relaxes
Volume of lungs decreased
Air pressure in lungs is greater then outside so air rushes out