Hair, Feathers And Scales

Question 1

What does the epidermis interact with to help develop hair, feathers and scales

Answer 1

Mesenchymal tissue
( teeth and mammary glands also develop from epidermal-mesenchymal interaction)

Question 2

What is a hair and what are its components?

Answer 2

A hair is a long thin chain of keratin protein composed of A central medulla, a thick cortex and an outer cuticle

Question 3

True or False wool hairs have a central medulla?

Answer 3

False

Question 4

Name the 3 types of hair

Answer 4

Guard hairs (topcoat)
Wool hairs (undercoat)
Tactile hairs (sensory function) ie whiskers

Question 5

What do you call guard hairs in sheep?

Answer 5

Kemp hairs
Sheep hardly have any Guard hairs. Fleece is almost exclusively wool hairs.

Question 6

What surrounds the follicle of a tactile hair?

Answer 6

The follicle is surrounded by a venous sinus (blood wave amplifies the stimulation)

Question 7

What kind of hairs are found at the carpus of cats?

Answer 7

Tactile hairs

Question 8

Why do guard hairs run in tracts of the same direction?

Answer 8

Promotes water runoff preventing the undercoat from getting wet and cold.

Question 9

What gland helps regulate hair shedding? And what factors affect hair shedding?

Answer 9

Regulated by pineal gland
Day length, temperature and nutrition are al factors that affect hair shedding

Question 10

What are the names of the 3 stages in the hair growth cycle. What happens ar each stage?

Answer 10

Anagen - growing phase
Catagen - transition phase and growth slows. Follicle shrinks.
Telogen - resting phase and growth stops. Hair breaks free and can be shed.

Question 11

What are the functions of each of the 3 hair types?

Answer 11

Guard hairs - waterproofing, communication (arector pili)
Wool hairs - insulation
Tactile hairs - sensory function

Question 12

How many epidermal layers do birds have and what are they?

Answer 12

2
Stratum corneum
Stratum germinativum

Question 13

How many types of glands to birds have and what are they?

Answer 13

Preen gland
Vent gland
Aural gland

Question 14

Why is cuting/plucking out developing feathers bad?

Answer 14

As developing Feathers contain a core of vascular dermis. So cutting or plucking these feathers can cause serious blood loss

Question 15

Name the 6 different types of feathers?

Answer 15

Contour feathers
Hyopenna (afterfeathers) feathers
Down feathers
Semi-plumes
Bristles
Filopumes

Question 16

What are ‘powder down’s feathers?

Answer 16

They produce a fine, waxy keratin powder similar to the function of the preen gland. (Cleaning/waterproofing)
Bird species without a preen gland have more abundant powder down feathers.

Question 17

Name the 3 layers of the reptile epidermis?

Answer 17

Stratum germinativum
Stratum intermedium
Stratum corneum

Question 18

What are Osteoderms that are present in some reptiles?

Answer 18

Bony plates in the dermis
(Osteoderms form the shell in tortoises)

Question 19

Ecdysis

Answer 19

Skin shedding controlled by the thyroid gland

Question 20

Name some of the examples of scales with specialised functions

Answer 20

Clear spectacle scales over eyes
Scales aid locomotion
Heat sensitive pits for prey detection
Crest,grills,horns for display/defence

Question 21

Fish scales are dermally derived from the ……….

Answer 21

Mesoderm