Integument

Question 1

Integumentary System

Answer 1

1. skin
2. scales, hair and feathers
3. antlers, horns and nails/claws
4. glands
5. sensory systems

Question 2

Integumentary System Function

Answer 2

1. Protection
   i. physical barrier
   ii. UV
2. water balance
   i. prevents water loss or gain
   ii. water gain in some organisms [frogs/toads]
3. Maintains body temperature
   i. heat gain in reptiles
   ii. sweating in mammals
   iii. heat conservation in birds and mammals
4. stimulus perception
   i. temperature
   ii. touch
   iii. pressure
   iv. pain
5. Coloration
   i. conspecific identification [same species]
   ii. reproductive behavior
   iii. camouflage
   iv. aposomatic coloration [warning]
6. Excretion
   i. water
   ii. salts
   iii. nitrogenous wastes
7. Secretion
   i. milk in mammals
   ii. oil
8. locomotion
   i. toe pads
   ii. hooves
   iii. air foils
9. vitamin D synthesis
10. respiration-skin in amphibians

Question 3

Epidermis

Answer 3

1. innervated but avascular [nerves but no blood vessels]
2. 2 main layers
   i. stratum basale
   ii. stratum corneum

Question 4

stratum basale

Answer 4

1. produces new cells which are pushed toward surface
2. layer rest on basement layer which holds it to the dermis
3. taxonomically varied layer
4. 2 major cell types
   
   1. mucous cells-mucus and poison
   2. proteinanceous cells-slime, poison, pheromones

Question 5

stratum corneum

Answer 5

1. outer layer
2. rows of flat dead cells filled with soft keratin
3. hard keratin in nails, claws, hooves, horns
4. continuously being shed and replaced

Question 6

Dermis

Answer 6

1. composed of connective tissue with collage and elastic fibers
2. varies in thickness
3. thick in palms and soles and is thin in eyelids
4. 2 layers
   i. stratum spongiosum
   ii. stratum compactum
5. chromatophores [color bearing cells]
   i. melanophores
   ii. iridophores
   iii. xanothophores
   iv. erythrophores

Question 7

melanophores

Answer 7

contains black, brown and red pigments

Question 8

iridophores

Answer 8

structural colors; color produced by refection like blue, white, and green

Question 9

xanthophores

Answer 9

yellow pigments

Question 10

erythrophores

Answer 10

red and orange pigments

Question 11

Agnathan fishes

Answer 11

Lack scales, epidermis is multi-laytered that contains many glands. The dermis is very tough and contains melanophores.

Question 12

Cartilaginous fishes

Answer 12

Has few glands and contain placoid scales and melanophores for counter shading ranging from light to dark.

Question 13

Placoid scales

Answer 13

Has an under laying layer of lamellar bone, a dentine middle layer, an enamel color and a spine arising from center.

Question 14

Bony fishes

Answer 14

Have a very thin skin with keratin mostly absent and replacement is constant. They contain lots of mucus glands that provide the majority of protection to the fish skin, cleans the body, prevents entry of foreign substances, reduce drag when swimming and osmoregulation. The fish scales are primarily dermal origin with different from the epidermal scales of tetrapods. Phylogenetic trend is from highly armored to less or non armored fish.

Question 15

Major types of scales on extant fishes

Answer 15

1. cosmoid scales
2. ganoid scales
3. teleost scales

Question 16

Cosmoid scales

Answer 16

Are primitive scales with a layer of dentine laying atop a double layer of bone. 1 layer of bone is vascular with a thin layer of enamel on the dentine. Cycloid [round] shape is the most common.

Question 17

Ganoid scales

Answer 17

Scales that contain a thick layer of enamel and lacks the underlying layer of dentine and a double layer of bone that forms the foundation. Vascular and lamellar bone in some and in others there is a single layer of lamellar bone.

Question 18

Teleost Scale

Answer 18

Scales that lack enamel, dentine, and vascular bone layer only noncalcified lamellar bone remains. Comes in different shapes: Ctenoid-fringed edge and cycloid-round outline