Exam 2 - Integument

Question 1

Integumentary system

Answer 1

1. Skin
2. Scales, hair, and feathers
3. Antlers, horns, and nails
4. Glands (also sensory systems)

Question 2

Functions of Integumentary system

Answer 2

1. protection -physical barrier and agains UV
2. Water balance - prevents water loss or gain
3. Maintains body temperature -heat gain in reptiles, sweating in mammals; heat conservation in birds and mammals
4. Stimulus perception -

• Temperature
• Touch
• Pressure
• Pain

5. Coloration

• Conspecific identification
• Reproductive behavior
• Camouflage
• Aposomatic coloration (warning coloration)

6. Excretion of water, salts and nitrogenous waste
7. Secretion

• Milk in mammals
• Oil or mucous (preserves skin)

8. Locomotion

• Toe pads (lizards)
• Hooves
• Air foils (wings)

9. Vitamin D synthesis
10. Respiration - skin in amphibians

Question 3

Epidermis

Answer 3

1. Inner gated but avascular (nerves, no blood)
2. 2 major layers - stratum basake and stratum corneum

Question 4

Stratum basale

Answer 4

a. Produces new cells which are pushed toward the surface
b. Layer rests on basement layer which holds it to the dermis
c. Taxonomically varied layer
d. Two major cells - mucous cells and proteinaceous cells

Question 5

Mucous cellls

Answer 5

One of the major cells of stratum basale; produces mucus and poison

Question 6

Proteinaceous cells

Answer 6

one of the major cells of stratum basale; produces slime, poison and pheromones

Question 7

Stratum corneum

Answer 7

a. Outer layer
b. Rows of flat, dead cells filled with soft keratin
c. Hard keratin in nails
d. Continuously being shed and replaced

Question 8

Dermis

Answer 8

1. Composed of connective tissue with collagen and elastic fibers
2. Varies in thickness
3. Thick on palms and soles and is thin in eyelids
4. Two layers
   i. Stratum spongiosum
   ii. Stratum compactum

Question 9

Chromatophores

Answer 9

pigment-containing and light-reflecting organelles in cells found in a wide range of animals ;

Examples are melanophores, iridophores, xanthophores, erythrophores

Question 10

Melanophores

Answer 10

pigments that produce black, brown, and red

Question 11

Iridophores

Answer 11

contains strucutral colors; color produced by reflection - blue, white, green

Question 12

Xanthophores

Answer 12

produce yellow pigments

Question 13

Erythrophores

Answer 13

pigments that produce red and orange

Question 14

Agnathas

Answer 14

1. Lack scales
2. Epidermis is multi layered
3. Contains many glands
4. Dermis is very tough
5. Contains melanophores

Question 15

Cartiginous fishes (Class Chondrichthyes)

Answer 15

1. Few glands
2. Placoid scales
   i. Underlying layer of lamellar bone
   ii. Dentine middle layer
   iii. Enamel cover
   iv. Spine arising from center
3. Melanophores for counter shading
   - counter shading is used for camouflage

Question 16

Bony fishes (Grade Teleostomi)

Answer 16

1. Skin
   i. Very thin
   ii. Keratin is absent, mostly
   iii. Replacement is constant
2. Lots of mucus glands
   i. Provides the majority of protection to the fish skin
   ii. Cleans body
   iii. Prevents entry of foreign substances
   iv. Reduces drag when swimming
   v. Osmoregulation (reduces dehydration)
3. Fish scales i. Primarily of dermal origin
   ii. Different from the epidermal scales of tetrapods
   iii. Phylogenetic trend is from highly armored to less or non-armored fish

Question 17

Major types of scales on extant fishes

Answer 17

cosmos scale

ganoid scale

teleost scale

Question 18

Cosmos scales

Answer 18

1) primitive
2) layer of dentine laying atop of a double layer bone
3) one layer of home is vascular
4) thin layer of enamel on the dentine
5) cycloid shape is the most common
‣ round outline

Question 19

Ganoid scales

Answer 19

1) thick layer of enamel
2) lacks an underlying layer of dentine
3) double layer of bone forms the foundation
4) vascular and lamellar bone in some
5) in others, there is a single layer of lamellar bone

Question 20

Teleost scale

Answer 20

1) lacks enamel, dentine, vascular bone layer
2) non calcified lamellar bone remains
3) several shapes:
4) ctenoid - fringed end (freshwater bass/sunfish)
5) cycloid - round outline (suckers/redfish/trout)

Question 21

Amphibians

Answer 21

1. Epidermis
   i. Very thin with 5 - 8 cell layers
   ii. Outermost layer is lost and constantly replaced
   iii. Contains keratin
2. Completely permeable to water and all water soluble chemicals
   ‣ Reason amphibians are not found on oceanic islands
3. Skin is respiratory organ at most
   ‣ Plethodontid salamanders
4. Frogs and salamanders lack scales
5. Skin contains many glands
   i. Mucus glands produce mucus to protect skin; and therefore are slimy
   ii. Granular glands ‒ poison makes animal distasteful or toxic

Question 22

Reptiles

Answer 22

B. Reptiles
1. Thick stratum corneum
2. Use keratin and lipids in the epidermis to air and waterproof their skins
3. Scales are epidermal ‒ they are simply folds in the epidermis
4. Some have a dermal bone inside the scale called an osteoderm
5. Junction between two scales is a flexible hinge
6. Scute - Special type of scale
i. Large plate-like epidermal scale
ii. Turtle and ventral scales of snakes
7. Ecdyis
i. Shedding of the skin
ii. Both lizards and snakes
Ctenoid and cycloid8. Glands are usually restricted to certain parts of the body
◦Ex: Femoral pores of lizards

Question 23

Birds

Answer 23

C. Birds
1. Feathers are modified epidermal scales
‣ Completely homologous to reptile scales
2. Epidermal scales on their legs and feet
3. Skin is weakly keratinized and loose
4. Feathers are highly keratinized
5. Skin has few glands
i. Uropygial gland and Salt gland

Question 24

Uropygial gland

Answer 24

a. Lipid-protein gland
b. Located at the base of the tail, dorsally
c. Oil used to preen feathers
d. Waterproofing

Question 25

Salt gland

Answer 25

a. Marine birds b. Excretes excess salts from the diet

Question 26

Kinds of feathers

Answer 26

i. Flight ii. Contour - covering iii. Down - insulation iv. Filoplume - display

Question 27

Parts of a flight feather

Answer 27

i. Calamus ii. Rachis (shaft) iii. Vane iv. Leading edge of flight feather v. Trailing edge

Question 28

Origin of feathers

Answer 28

i. Probably as a thermoregulatory device a. Dinosaurs had dinofuzz b. A feather resembling a frayed end of yarn ii. Later became functional in flight a. Feathers with the shaft evolved later b. Feathers overlapped c. Gave an aerodynamic advantage d. Many dinosaurs had "flight" feathers on all four limbs iii. First feathers were too thin and had delicate shafts a. We're not able to support the weight of huge bird that flapped its wings b. Nor the force of flapping of wings c. May have helped to glide or show decent from a jump

Question 29

New idea on origin of birds

Answer 29

a. Anchiornis huxleyi b. Lived in what is now northeastern China c. 151 and 161 mya d. Older than Archaeopteryx, considered a dinosaur e. Had a black and gray body plumage f. Reddish-brown feathers on the top and back of its head g. Reddish-brown spots on its head and neck h. White racing stripes on its legs and its wing-like forelimbs i. Suggested that feathers may initially served a behavioral function j. Possibly intraspecific or interspecific visual communication k. Later began to serve an aerodynamic function

Question 30

Some research now suggests birds did not descend from dinosaurs

Answer 30

a. Birds and dinosaurs probably had a common ancestor b. But evolved strategy on their own paths c. Some species currently thought to be dinosaurs may have descended from birds i. Birds may have given rise to the raptors 2. Velociraptor (smart) 3. More likely a flightless bird d. Evidence 1. Microraptor - had feathers on all four limbs 2. Glide simulations based on its structures concluded 3. Not practical for it to have flown from ground up 5. Could have flown from the trees down 6. Many researches believe that glider were the ancestors of modern birds e. More evidence 1. Birds occur in the fossil record before the elaboration of the dinosaurs they supposedly descended from 2. The position of the thigh bone and muscles in birds is critical to their ability to have adequate lung capacity for sustained long-distance flight 3. Theropod dinosaurs lack this feature

Question 31

Mammals

Answer 31

1. Skin is relatively thick 2. Glands - Sudoferous (sweat) and sebaceous(oil) 3. Hair 4. Claws and Nails 5. Horns and Antlers

Question 32

Eccrine glands

Answer 32

1) . Most common 2) . Open through pores onto this the skin's surface 3) . Function throughout life 4) . Produce a watery secretion to cool body 5) . Sweat glands confined to the least hairy regions of mammals (feet and lips) 6) . Humans have more than any other mammals (hairless)

Question 33

Apocrine glands

Answer 33

1) . Limited to auxiliary region (armpit), pubic region, and pigmented area around nipple (aerolae) 2) . Open into a hair follicle 3) . Begin to functional at sexual maturity 4) . Produce musk 5) . Mammary glands are modified apocrine glands

Question 34

Mammary glands

Answer 34

are modified apocrine glands ◦Number relatedness o litter size ◦Location varies ◦Many on ventral abdominal wall ◦Lemurs and marmosets in armpits ◦Nutria have 4 on their back

Question 35

Sebaceous (oil) glands

Answer 35

a. Secrete sebum - an oily mixture of fats, cholesterol, proteins and inorganic salts b. Lubricates and softens hair and skin and inhibits some bacteria c. Almost always associated with hair follicles and opens into the hair follicle

Question 36

function of hair

Answer 36

a. Protection b. Insulation c. Camouflage

Question 37

Structure

Answer 37

a. Shaft ‒ the superficial portion above the skin surface b. Root ‒ the superficial portion below the skin surface c. Follicle ‒ surrounds the hair root d. Bulb ‒ enlarged base of the follicle e. Papilla ‒ indented area at the base of the bulb; contains loose connective tissue and blood vessels in the matrix (germinal layer)

Question 38

Strucutres associated with each hair follicle

Answer 38

a. Arrector pili muscle ‒ pulls the hair upright-cold or fright - "goosebumps" b. Root hair plexuses ‒ nerve endings, sensitive to touch when hair is moved c Sebaceous glands

Question 39

Claws

Answer 39

e strong keratinized structures that wrap around the terminal bones of the digits

Question 40

Nails

Answer 40

hard, keratinized coverings over the dorsal tips of fingers and toes, protect tips of fingers and toes

Question 41

Hooves

Answer 41

highly modified claws

Question 42

Antlers

Answer 42

a. Bony outgrowths of the skull b. Shed and replaced annually c. When alive, covered with tissue called velvet d. When full size is reached, the velvet is shed and the antler dies

Question 43

Pronghorns

Answer 43

a. Horn is part of the skull b. Covered by an epidermal derived sheath c. Sheath is shed annually

Question 44

Horns

Answer 44

a. Bony cores that are vascularized b. Over core is a sheath of epidermis that is very keratinized c. Sheath grows continually d. Can see growth rings

Question 45

Scales

Answer 45

a. Some mammals have epidermal scales b. The hair is between the scales c. Usually found on tail or legs Ex: rats and beavers d. In some mammals scales occur all over the body Ex: armadillo and pangolins