On wbs write out a flow diagram showing the route that O2 and CO2

gas takes

Structure of lungs and exchange

• Label the diagram to show the following:

– Red blood cells, capillaries, alveoli, air in , air out, Thin cell wall

• Colour in the arrows RED for the movement of oxygen and BLUE for the movement of carbon dioxide

• Describe and explain 3 adaptations of the alveoli for efficient gas exchange.

How are alveoli adapted?Alveoli have several adaptations that help to make gas exchange very efficient:

They are very thin – only one cell thick.

They are covered by a network of fine capillaries, enabling gases to pass almost directly between the lungs and bloodstream.

They are moist, encouraging gas molecules to easily dissolve.

They have a large combined surface area, allowing large amounts of gases to be exchanged with each breath.

Ventilation

Lesson objectives

• All will be able to describe the ventilation process

• Most will be explain how muscle bring about changes in pressure

• Some will be able to evaluate the limitations of the lungs in the bell jar as a model for ventilation

What are the differences between inhaled and exhaled air?

inhaled air

nitrogen (78%)oxygen (21%)carbon dioxide (0.04%)other

exhaled air

nitrogen (78%)oxygen (17%)carbon dioxide (4%)other

Ventilation

• How does inhaled and exhaled air differ?

• Can you explain why there are these differences?

Gas Inhaled Exhaled

Oxygen

Carbon dioxide

Nitrogen

Ventilation

• How do we get the oxygen and rid of carbon dioxide?

• Breathing in is also known as inhalation.

• Breathing out is also known as exhalation

Ventilation

• Place hand on your ribs and breathe in – what happens?

• What do the different parts in the bell jar represent?

• How does air get drawn into the lungs?

Ventilation

Ventilation

• Complete the statements to show how we inhale air– The intercostal muscles (between the ribs)

contract/relax

– The rib cage moves …… and …… and the diaphragm flattens.

– The volume of the thorax (chest) increases/decreases

– Causing the pressure to increase/decrease

– Air ……………………………….

Ventilation

• Now write your own flow diagram showing what happens when we breathe out…

Ventilation

• Complete the statements to show how we exhale air– The intercostal muscles (between the ribs)

contract/relax

– The rib cage moves …… and …… and the diaphragm becomes domed.

– The volume of the thorax (chest) increases/decreases

– Causing the pressure to increase/decrease

– Air ……………………………….