Integument 2; Hair, feathers, scales Flashcards

1
Q

What do hairs, feathers and scales all develop from?

A

-Develop from the epidermis interacting with the underlying mesenchymal tissue

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

These are all homologous structures, what does this mean?

A

They share a common ancestry

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

What else develops through an epidermal-mesenchymal transition?

A

Teeth and mammary glands

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

How does a hair follicle develop?

A

1) Ectodermal bud grows into the mesenchymal beneath
2) There is then differentiation of the bud and sweat and sebaceous glands start form
3) The developed hair follicle is then formed with all the accessory structures

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

What are the 3 layers of a hair?

A

1) Cuticle
2) Cortex
3) Medulla

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

What is hair made of?

A

A long thin chain of keratin proteins

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

What is different about the structure of wool hairs?

A

They have no medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the 3 different types of hair?

A

1) Guard hairs (stiff and straight)
2) Wool hairs (fine and wavy)
3) Tactile hairs (sensory function)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the difference between a compound follicle and a single follicle?

A

Compound follicle - several hairs share a single follicle opening
Single follicle - one, primary guard hair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe a compound follicle

A
  • One primary guard hair, several secondary wool hairs.
  • Below the sebaceous gland, each hair has its own follicle and bulb
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Which species have compound follicles?

A

Compound = dogs, cats, sheep, goats

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

Which have single follicles?

A

Single = horses, cattle, pigs, humans

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

What is the orientation of guard hairs?

A

They lie against the skin and run in tracts in the same direction

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

What features on horses are made of guard cells?

A

Mane, tail, fetlock tufts

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

What about on cattle and goats?

A
  • Long tail hairs on cattle
  • Beards on goats
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is unique about the structure of tactile hairs?

A
  • Reach deep into the subcutis
  • Surrounded by a venous sinus
  • There is a dermal sheath surrounding the follicle which contains nerve endings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the importance of this venous sinus?

A

When the hair vibrates, the liquid in the sinus moves and vibrations are amplified in the dermis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What gland regulates the hair growth cycle?

A

Pineal gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What factors affect shedding and hair growth?

A
  • Seasonal (shedding peaks in spring and autumn)
  • Affected by day length, temp and nutrition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What phase of the growth cycle are most hairs in?

A

Anagen phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens in each of the 3 phases of hair growth?

A

1) Anagan = growing phase
2) Catagen = transition phase, growth slows
3) Telogen = resting phase, growing stops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What type of diseases can cause hair loss?

A

Endocrine diseases

23
Q

In the anagen phase, which cells produce the hair and what cells make up the hair shaft?

A
  • Epidermal stem cells divide to produce the hair
  • Hair shaft made of dead keratinocytes
24
Q

How is the hair anchored to the follicle in the anagen phase?

A

Tightly anchored by root sheaths

25
How is apoptosis used in the catagen phase?
Programmed cell death at the base of the follicle to make the follicle shorten - follicle is shortest in telogen phase.
26
How does the hair provide a protective function?
- Tough keratin hairs cover sensitive surfaces - Can cover sensory organs such as the eye
27
How do hairs aid with water resistance?
- Oily sebaceous glands open into follicles - Guard hairs run unidirectional to encourage water flow off
28
How do hairs aid with thermoregulation?
- Wool hairs trap air - Arrector pili and guard hairs - Some sweat glands open into follicle
29
How do hairs aid with communication and camouflage?
- Melanin (colour) - Glands open into follicle
30
What 2 layers are present in the epidermis in birds?
- Stratum germinativum - Stratum corneum
31
What 3 glands are present in bird skin?
1) Uropygial gland (preen gland) 2) Aural gland 3) Vent gland
32
What feathers should be avoided when wing clipping?
Blood feathers
33
Describe the structure of a feather
- Rachis runs down the middle - Vane on either edge - Barbs either side of the rachis - Calamus at the base of the quill
34
What are the 6 different types of feather?
1) Contour feathers 2) Hyopenna 3) Down feathers 4) Semi-plumers 5) Filoplumes
35
What type of feather helps with water waterproofing and flight?
Contour feathers
36
What type of feather is good for insulation?
Down feathers
37
What are powder down feathers?
Down feathers that produces fine, waxy keratin powder (helps to keep feathers clean) + waterproofing Absence of powder can indicate disease
38
What are the 3 layers of the epidermis in reptiles?
- Stratum germinatium - Stratum intermedium - Stratum corneum
39
What do reptiles (and some amphibians) have that other animals do not?
Osteoderms (bony plates in the dermis)
40
What leads to reduced skin sensation in reptiles?
Thick keratinised cells
41
Which gland controls ecdysis (skin shedding)?
Thyroid gland
42
What are some specialized cutaneous features of reptiles?
- Clear spectacle scale over eyes - Belly scales aid locomotion in snakes - Heat sensitive pits aid prey detection
43
What is dysecdysis?
Improper shedding = old skin can dehydrate and shrink to cut off circulation
44
What happens to the spectacle scale during shedding?
- Goes opaque
45
What are the 2 types of skin glands?
1) Sebaceous glands 2) Sweat glands
46
Describe the structure and location of sweat glands
They are coiled, tubular glands They sit within the dermis but are derived from the epidermis
47
What are the 2 different types of sweat glands?
- Eccrine - Apocrine
48
What do sebaceous glands look like?
Lobed, acinar structure
49
What do sebaceous glands produce?
Produces fatty, oily sebum - Moisturises and waterproofs hair and skin - Antimicrobial function - Pheromones released
50
What do apocrine sweat glands produce?
Discharge albuminous sweat (protein rich) - Reacts with bacteria to produce odour
51
Where are apocrine sweat glands found?
Found in haired skin
52
What do eccrine sweat glands produce?
Discharge watery sweat onto the skin surface
53
Where are eccrine sweat glands found?
Found in particular areas of naked skin (e.g., foot pads/ nasolabial plate of cattle)