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Flashcards in Respiratory System of Insects Deck (47)
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1

What are the two main components of the respiratory system of an insect?

1. Spiracles
2. Trachea

2

What are spiracles?

External openings, hypothetically one per segment

3

Where do spiracles usually occur?

On the Mesothorax, Metathorax, and abdominal segments (1-8)

4

What are trachea?

Series of air-filled tubes unique to insects that are entirely separate from the circulatory system.
- Excessively branched

5

What are trachea lined with?

lined with cuticle

6

What are tracheal trunks?

Logitudinal tubes connected to the main tubes from the spiracles

7

What are Taenidia?

Spiral circular thickening running through trachea

8

What is the function of the taenidia?

prevents tubes from collapsing under reduced pressure

9

What are tracheoles?

smallest diameter tubes that cover most of the insects body, even extending between muscle fibres

10

When are tracheoles fluid filled?

At rest

11

When are tracheoles air filled? why?

during activity for maximum gas diffusion

12

What are two types of ventilation in insects?

Passive and active

13

What insects might use passive ventilation?

Smaller insects

14

What is passive ventilation?

The simple diffusion of O2 and CO2 controlled by spiracles

15

What happens during passive ventilation?

1. Continuous O2 uptake and CO2 storage to create suction
2. CO2 is expelled in cylindrical bursts and stored in the hemolympth as bicarbonate in between creating negative pressure -> air gets sucked into trachea
3. When CO2 conc. in trachea is greater than 6.5%, the spiracles relax and CO2 is released

16

Which insects might use active ventilation? why?

Large insects - they need to physically move air in and out of their tracheal system

17

How is active ventilation performed?

1. Close forward spiracles and force air out of rear ones via blood pressure or muscle contraction in order to create negative pressure up front when rear spiracles closed
2. Close rear spiracles in order to suck air into front spiracles

18

What is the purpose of the tracheal air sac in flying insects?

Can increase tidal flow, reduce density of the insect and can provide room for egg development

19

During flight, how do locusts create separate ventilation in the pterothorax?

via movement of the nota/pleura during wing beats

20

What is a holopneustic arrangement of spiracles?

All spiracles are functional

21

What is a Metapneustic arrangement of spiracles?give an example

only abdominal segment 9 is functional - mosquito larvae

22

What is a Propneustic arrangement of spiracles?give an example

only prothoracic spiracles and functional - mosquito pupae

23

What is a Apneustic arrangement of spiracles? give an example

no functional spiracles, tracheal gills may be present - mayfly, damselfly naiads

24

How do giant water bugs breathe?

through a pair of siphons at the posterior end of the abdomen

25

How do diving beetles breathe?

Trap an air bubble between the elytra and the abdominal terga; spiracles have migrated to the dorsal surface of the abdomen and use bubble for air

26

How do Waterboatmen breathe?

Hair on the abdomen hold a thin, continuous air bubble in place, giving the abdomen a silvery appearance

27

how do Atracheate insects breathe? give examples

All gas exchange takes place through the integument - collembola (springtails) and hymenopterous larvae

28

What are some additional functions of the tracheal system? (7)

1. Suspend internal organs
2. Create air pressure needed for ecdysis
3. Thermoregulation - create insulating layer of trachea around flight muscles
4. Create pathways for the development of the nervous system
5. Reduce weight of the insect - hollow structures
6. Sound perception - tympanum is modified spiracle
7. defense

29

What kind of a circulatory system do insects have?

An open system (blood is not enclosed in vessels)

30

What is the hemocoel?

The body cavity of an insect