Aqa A Level Biology Unit 1: The Respiratory System

Front 1

Describe the process of inspiration.

Back 1

Inspiration is when:
- Diapragm contracts down and the intercostal muscles contract outwards and upwards.
- This causes the pressure in the thorax to be lower than outside the lungs and so air moves down a pressure gradient..
- This is an active process.

Front 2

Describe the process of expiration.

Back 2

Expiration is when:
- Diaphragm and intercostal muscles relax.
- This causes the pressure in the thorax to increase to higher than atmospheric and so air is pushed out of the lungs.
- This is a passive process.

Front 3

What is the equation for pulmonary ventilation?

Back 3

Pulmonary ventilation = Tidal volume x ventilation rate

Front 4

What happens to the lungs when someone has been infected with Pulmonary TB?

Back 4

Immune system cells bulid a wall around the bacteria in the lung. This forms small hard lumps callled tubercles. Infected tissue within tubercles dies and the gaseous exchange surface is damaged. Can also cause Fibrosis.

Front 5

How is TB spread?

Back 5

Droplet infection- infected person coughs and sneezes produces droplets which contain bateria if healthy person breaths that in they can become infected.

Front 6

What happens during an asthma attack?

Back 6

Airways become narrowed because if the muscle contracting and large amounts of mucus are produced. Sufferers wheeze and feel short of breath.

Front 7

What happens when someone has emphysema?

Back 7

A foreign particle (dust) gets trapped in the alveolus. This causes phagocytes to flood to the area. The phagoyctes produce an enzyme that breaks down elastin. Loss of elastin means that the alveoli can't recoil to expel air and so air is trapped in the lungs. This leads to destrucion and so surface area is reduced.