5) Cardio-respiratory system

Question 1

Passage of air into the lungs

Answer 1

Air enters the body and is warmed as it travels through the mouth and nose.

It then enters the trachea.

The trachea divides into two bronchi. One bronchus enters each lung.

Each bronchus branches out into smaller tubes called bronchioles. Air travels through these bronchioles.

At the end of the bronchioles, the air enters one of the many millions of alveoli where gaseous exchange
takes place.

Question 2

Gaseous exchange

Answer 2

occurs at the alveoli in the lungs and takes place by diffusion.

Question 3

Lung volumes

Answer 3

Vital capacity
maximum amount of air that can be breathed out after breathing in as much air as possible.

Breathing rate(BR)
the number of breaths in a minute. 

Tidal volume(TV)
Amount of air breathed in with each normal breath.

Minute ventilation (VE)
total volume of air entering the lungs in a minute.

Minute ventilation = breathing rate × tidal volume

VE = BR × TV