Life Sciences P1 - Grade 11 - Gaseous Exchange

Describe the movement of air during exhalation

Alveolus -> Bronchiole -> Bronchus -> Trachea

The carbon dioxide is transported in the blood mainly in the form of ...

Bicarbonate ions

Whhat factor will determine the rate of breathing in humans?

Carbon dioxide level in the blood

The blood tissue that transports oxygen is/are the ...

Red blood cells

The region of the brain that controls the rate of breathing in humans

Medulla oblongata

Name the epithelial tissue that lines the inside of the trachea

Ciliated epithelial tissue

Describe the process of inhalation

- Air rich in oxygen is drawn in through the air passages into the lungs

- Diaphragm contracts and becomes flattened

-The external intercostal muscles contract

- The internal intercostal muscles relax

- Rib-cage is lifted

- Volume of the thoracic cavity increases

- Pressure on the lungs decreases

Describe the process of exhalation

- Air is forced out of the lungs

- Diaphragm relaxes

- External intercostal muscles relax

- The internal intercostal muscles contract

- Rib-cage moves inward

- Volume of the thoracic cavity decreases

- Pressure on the lungs increases

Explain four ways in which an alveolus is adapted to carry out its function

- Lined by single layer of squamous epithelium to provide a thin surface for gaseous exchange

- Alveolus is lobbed to increase the surface area for gaseous exchange

- Film of moisture in alveolus for oxygen to dissolve for effective diffusion

- Alveolus richly supplied with blood capillaries for the transport of oxygen to tissues and carbon dioxide to the lungs

Name three forms in which carbon dioxide is transported in the blood

1 - Bicarbonate ions

2 - Carbhaemoglobin

3 - In solution in the plasma

Name two forms in which oxygen is transported in the blood

1 - Oxyhaemoglobin

2 - In solution in the plasma

During inhalation and exhalation, friction is reduced by fluid between the ...

Pleural membranes

State the function of the C-shaped cartilage rings

The C-shaped cartilage rings keep the trachea open at all times

The molecule that gives blood its red colour

Haemoglobin

Define gaseous exchange

The physical process which involves the exchange of gases that occurs in the lungs and body tissues

The type of epithelium that forms the wall of the alveolus

Squamous

A protective membrane surrounding the lungs

Pleural

The part of the lungs where exchange of gases takes place

Alveoli

The muscles found between the ribs that are involved in the mechanism of breathing

Intercostal muscles

The blood vessels carrying blood, rich is oxygen, from the lungs to the heart

Pulmonary veins

Name three adaptations of the lungs for their functions

- The lungs are spongy and elastic so that they can expand and contract easily during breathing

- Lungs are surrounded by a double membrane with interpleural fluid between the two membrane that prevents friction during breathing

- Bronchioles eventually end in millions of alveoli that increases the gaseous exchange surface