Morphology of Insect Sensilla Flashcards Preview

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Flashcards in Morphology of Insect Sensilla Deck (42)
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1

What are sense cells?

interface between the environment and the insects CNS
- present on surface of insect

2

Why can't insect sensilla be too specific?

have very few compared to mammals

3

How can a specific response be generated from sensilla of insects?

if many separate sensilla respond

4

What are the different types of sensilla? (surface)

- olfaction
- vision
- mechanoreceptors
- gustation

5

What are primary sense cells (Neurons)?

they receive the stimulus and transmit a message (electrical impulse) to the CNS

6

What are two broad categories of primary sense cells?

- Type 1 Neurons
- Type 2 Neurons

7

What are some functional types of type 1 neurons?

- mechanoreceptors (include sound receptors)
- light receptors (eyes, oceli)
- chemoreceptors (olfaction, gustation)

8

What are type 1 neurons?

receptors associated with cuticle, derived from a single epidermal cell
- have hair

9

What are type 2 neurons? what are they functionally alike?

receptors not associated with integument. Don't have hair. are internal. x cuticular element
- proprioreceptors

10

what are proprioreceptors?

receptors that respond to deformations and stresses (eg: stretch receptors)

11

What do type 1 neurons sense?

touch, vibration, pressure, air currents, water currents, cutaneous tension

12

What is the trichogen of type 1 neurons?

the inner sheath cell which produces the hair in trichoid sensilla

13

What is the tormogen of type 1 neurons?

the outer sheath cell. in chemosensilla produces the fluid that bathes the dendrites

14

What is the Neurilemma of type 1 neurons?

thecogene cell which ensheathes the nerve cell
- play a nutritive role for the nerve cell

15

What is the sensory cell of type 1 neurons?

a neuron

16

What are the neuron of mechanoreceptors like? how many are there?

mechanoreceptor sensilla contains a single neuron.
dendrites of the neuron may be fused to form a cuticular filament

17

How many neurons do chemoreceptors usually have?

chemoreceptors usually contain more than one neuron.

18

How are mechonoreceptors on the integument categorized?

by their morphology

19

What are the two types of mechanoreceptor?

1. trichodea
2. Campaniform sensilla

20

What are trichodea?

sensory hairs with scolopale affixed to the base of a hair

21

Where are trichodea found in the highest concentrations?

the tarsi, antennae, mouthparts and cerci

22

What are two types of trichodea?

1. long fine hairs - habituate rapidly
2. short, stiff hairs or pegs - habituate slowly

23

What do long, fine hairs of the trichodea respond to?

subtle stimuli such as wind, gravity, posture.

24

What do short, stiff hairs or pegs of the trichodea respond to?

direct deflection (touch)

25

What are campaniform sensilla?

mechanoreceptors which terminate in a dome-shaped plate of cuticle.
- neuron determines the degree of arching of the domed cap

26

Where are campaniform sensilla found in greatest concentration?

leg bases, wing bases and antennae

27

What do campaniform sensilla respond to?

- pressure changes
- body orientation
- location of legs, wings, antennae

28

What are two types of internal proprioreceptors?

1. chordotonal sensilla
2. Stretch receptors

29

What are chordontonal sensilla?

similar to trichodea but no cuticular component. usually exists as an organ
- a strand of nervous tissue stretched between two points (of cuticle)

30

What are chordontonal sensilla triggered by?

triggered internally by pressure changes eg:
- how much air in trachea
- how much hemolymph in body cavity