Lecture 7: Cuticle Flashcards

1
Q

Structure of the cuticle:

A
  • Epidermis Basal lamina
  • Procuticle; Endocuticle and exocuticle
  • epicuticle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

are the endo and exo cuticle always the same ratios?

A

NO

-endo usually bigger but not necessarily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the epistle structure ____ in insects

A

varies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Epicuticle structure:

A

OUTSIDE

  • cement layer
  • superficial layer
  • lipid monolayer
  • -(wax canal starts continues through exocuticle where becomes pore canal)
  • outer epicuticle
  • inner epicuticle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

2 most important layers of epicuticle:

A
  • cement layer

- lipid monolayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

cement layer:

A
  • shellac like proteins

- maintains integrity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

lipid monolayer:

A
  • protects against water loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Procuticle: Exocuticle

A
  • Thicnkness varies - thick in stiff cuticle, non-existent in pleural membranes
  • hard and dark - melanised + sclerotised
  • proteins are cross-linked by “Tanning” - makes one of the strongest biopolymers known
  • by incorporating micro-fibres of chitin in parallel arrangements in off-set sheets: makes cuticle VERY strong
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Procuticle: Endocuticle:

A
  • thickness varies - thin in stiff cuticle, makes up pleural membrane
  • flexible and often transparent - no melanisation or sclerotisation
  • contains novel insect protein called “RESILIN” - v rubbery
  • endocuticle is important in many cuticular hines and springs
  • because it is not cross linked like exocuticle it can be recycled during moults
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Moulting steps:

A

1) nuclei & cells of basal lamina get larger + space between old cuticle and epidermis forms –> EXUVIAL SPACE
2) exuvial space filled with moulting fluid (INACTIVE) and new epicuticle begins to form
3) another membrane (ECDYSIAL membrane) separate active and inactive mf. Active MF digests & recycles old endocuticle
4) new pro cuticle not differentiates forms, old exocuticle gets shed
5) 24hrs differentiation occurs in pro cuticle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

pleural membrane:

A

Joints at abdomen (soft)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

melanisation:

A

chemical process cross linking involves melanin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sclerotised

A

cross linking process can crosslink but is transparent (i.e. eyes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

chitin:

A

orientation of each secretion different to increase strength

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

cuticle function:

A
  • mechanical protection
  • supports body & provides surfaces for muscle attachment
  • water retention & conservation
  • active barrier against pathogens (and pesticides)
  • location of colours for camouflage / courtship / aposematism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

aposematism:

A

warning colouration (wasps/ladybirds)

17
Q

consequences of cuticles material properties: - stiff & light

A

ideal for aerodynamic control surfaces (flight)

18
Q

consequences of cuticles material properties: hard

A
  • ideal for mouthparts that enable a range of feeding strategies
19
Q

consequences of cuticles material properties: flexible and strong -

A

ideal for mobility. When coupled with hard exoskeleton plates it means a mobile

20
Q

consequences of cuticles material properties: high efficiency in kinetic energy storage

A

resign enables insects to make incredible springs for jumping, flying and pumping