insects

Name the gas exchange surface of an insect

Tracheoles

Describe the tracheal system in insects.

a system of tracheal tubes throughout their bodies, which includes spiracles (openings at the side of their bodies) that open into a branching system of chitin-lined air tubes known as tracheae. The smallest tubes are called tracheoles, and the end of each tracheole contains a small amount of fluid in which gases dissolve.

Explain the function of spiracles in the insect tracheal system

Spiracles are openings located at the side of the insect's body that allow air to enter the tracheal system, facilitating gas exchange.

Define tracheae

Tracheae are the branching system of chitin-lined air tubes in insects that transport air from the spiracles to the tracheoles.

What is the significance of the fluid found at the end of tracheoles?

allow gases to dissolve, facilitating the exchange of oxygen and carbon dioxide in the insect's body.

do small insects ventilate

no. they rely on diffusion through the tracheal system alone to take in O2 and remove CO2

do large insects ventilate

yes

how does ventilation work in insects

• the abdomen expands and the thoracic spiracles open

• air enters through the thoracic spiracles

• the abdomen contracts and forces the air out of their open abdominal spiracles

why cant insects be bigger

• diffusion pathway would be too long to respiring cells

• tubing required would make them too heavy

Give the advantages of an insect gas exchange system

• Oxygen diffuses directly to cells

• no need to produce haemoglobin

• spiracles can be closed to reduce water loss

• Hairs in spiracles to trap moisture

Give the disadvantages of an insect gas exchange system

• Rate of diffusion limits size and shape of insect, mass of chitin could make it difficult to fly

where precisely does GE take place

at the end of the tracheoles

how are abdominal movements linked to ventilation

• causes change of pressure

• pressure changes cause air movements through tracheal system