Unit 1 - Section 4 - The Gaseous Exchange System

Front 1

As you breathe in air enters the ..1.. The ..1.. splits into two ..2.. - One bronchus leading to each lung. Each Bronchus branches off in smaller tubes called ..3.. The ..3.. end in small 'air sacs' called ..4..

Back 1

1=Trachea
2=Bronchi
3=Bronchioles
4=Alveoli

Front 2

Each alveoli is surrounded by ... giving each alveolus its own blood supply.

Back 2

Capillaries

Front 3

Each alveolus is made from a single layer of thin, flattened cells called the ..1.. and the walls of the capillary are made of ..2..

Back 3

Alveolar epithelium
Capillary endothelium

Front 4

All exchange surfaces are adapted from efficient gas exchange. They have :

Back 4

A large surface area which increases the rate of diffusion.
They're thin which provides a short diffusion pathway which increases the rate of diffusion.
A steep concentration gradient of oxygen and carbon dioxide which increases the rate of diffusion.

Front 5

The lungs have other specific adaptations for gas exchange:

Back 5

Many alveoli which provide a large surface area for diffusion.
The alveolar epithelium and capillary endothelium are only one cell thick giving a short diffusion pathway.
The alveoli have a good blood supply. This helps maintain a concentration gradient.

Front 6

Goblet cells secrete mucus. the mucus...

Back 6

traps micro-organisms and dust particles in the air and stops them from reaching the alveoli

Front 7

Cilia waft the mucus secreted by the goblet cells. This...

Back 7

Moves the mucus towards the throat, Where it is swallowed. This prevents lung infections.

Front 8

Elastic fibres help the process of breathing out. On breathing in...

Back 8

The lungs inflate and the elastic fibres are stretched. then the fibres recoil to help push the air out when exhaling.

Front 9

Smooth muscle allows the diameter of the airways to be controlled. During exercise...

Back 9

The smooth muscle relaxes, making the lumen wider, which means there's less resistance to airflow and air can move into the lungs more easily. The smooth muscle can also contract and constrict the airways. This helps stop harmful substances entering the lungs.

Front 10

Cartilage supports the...

Back 10

Trachea and Bronchi. It stops the Trachea and Bronchi collapsing when you breathe in and the pressure drops. Cartilage is also C shaped which means that you can move your neck without restricting the airways.

Front 11

Trachea contains:

Back 11

Smooth muscle, elastic fibres, cartilage and ciliated epithelium containing goblet cells.

Front 12

Bronchus contains:

Back 12

Smooth muscle, Small pieces of cartilage, elastic fibres and ciliated epithelium containing goblet cells.

Front 13

Bronchiole contains:

Back 13

Smooth muscle with elastic fibres and ciliated epithelium with some goblet cells.

Front 14

Alveolus contains:

Back 14

Elastic fibres and alveolar epithelium.