12.6 - Avian Integumentary System

Question 1

The majority of the avian body is covered with ? Originating from the epidermis, these structures are a characteristic and unique feature of the class Aves.

Answer 1

feathers

Question 2

Where feathers are present, what is relatively thin?

Answer 2

skin

Question 3

While the structure of the avian epidermis is homologous with that of mammals, differences are apparent in the layers of the?

Answer 3

dermis

Question 4

During incubation, many bird species develop a median ventrosternal?
► Feathers are lost in this region and the vascularity of the dermis increases to facilitate the transfer of body heat to the eggs.

Answer 4

brood patch

Question 5

Waterfowl, such as ducks and geese, do not develop brood patches. Instead, they warmtheir eggs with?

Answer 5

plucked down feathers

Question 6

What layer of the epidermis is thicker in featherless regions, corresponding with the mechanical forces to which these parts of the body are subjected?

Answer 6

stratum corneum

Question 7

What is particularly hard at the edges of the beak, in the scales and spur, and on the dorsum of the claws?

Answer 7

horn (keratinised epidermis)

Question 8

What is found at the cere, between the scales and on the plantar surface of the claws?

Answer 8

Soft horn

Question 9

What glands birds don’t have?

Answer 9

sweat glands.

Question 10

These glands are found in only three locations:
► above the tail: the uropygial gland
► in the external acoustic meatus: the auricular glands
► in the cloaca: the vent glands

Answer 10

Sebaceous glands

Question 11

A mucoid substance is secreted by the ? located on the labia of the cloaca

Answer 11

glandulae venti

Question 12

► gland that is present consistently in chickens and water birds, but may be absent in psittacids and pigeons;
► The oily holocrine secretory product is used in preening to cover the feathers in a fatty waterproof film.
► It is thought to also play a role in the storage of Vitamin D, allowing this nutrient to be taken up by the beak during grooming

Answer 12

uropygial gland

Question 13

What are typical features of chickens, are variably developed in different breeds?

Answer 13

comb, wattles and earlobes

Question 14

What unpaired accessory cutaneous structure can reach considerable proportions in sexually aroused male turkeys?

Answer 14

snood

Question 15

The head of turkeys is also covered in numerous wart-like cutaneous ? that extend to the neck and breast

Answer 15

caruncles

Question 16

What accessory cutaneous structure of the guinea fowl consists of a cone-shaped peg of bone overlain by rough skin with a strongly keratinised epidermis?

Answer 16

► In Muscovy ducks the eyes and
the base of the beak are
surrounded by red cutaneous
papillae

Question 17

In Muscovy ducks the eyes and,the base of the beak are surrounded by?

Answer 17

red cutaneous papillae

Question 18

The flexor surfaces of the joints of the wings (alae) are spanned by membranous folds of skin referred to as?

Answer 18

patagia

Question 19

The interdigital space between the second, third and fourth pedal digits is spanned by short folds of skin known as?

Answer 19

interdigital webs

Question 20

Which bird species possess an additional interdigital web between digits 1 and 2?

Answer 20

Pelecaniformes

Question 21

The epidermal covering of the beak forms a hard keratinised sheath, the ?, which extends over the rostral portions of the maxilla and mandible. Its dermal layer is tightly attached to the periosteum. There is no subcutis.

Answer 21

rhamphotheca

Question 22

In some species, the skin at the base of the upper beak is variably thickened and is referred to as the?

Answer 22

cere

Question 23

The featherless skin of the tarsometatarsus and digits (podotheca) is covered in?

Answer 23

scales

Question 24

The featherless skin of the tarsometatarsus and digits (podotheca) is covered in scales
► On the dorsum these are relatively large called?

Answer 24

(scuta)

Question 25

The featherless skin of the tarsometatarsus and digits (podotheca) is covered in scales ► On the dorsum these are relatively large (scuta), while those found on the plantar surface are smaller and typically hexagonal in shape called?

Answer 25

(scutella)

Question 26

The joints of the pedal digits are underlain by?

Answer 26

pads

Question 27

► The joints of the pedal digits are underlain by pads ► These include the 1. ? which bears weight when the foot is placed on the ground, and the ? that conform closely to the underlying surface during perching.

Answer 27

1. metatarsal pad 2. digital pads

Question 28

What are located at the tips of the digits of the foot?

Answer 28

claws (ungues)

Question 29

Each claw forms a cone-shaped covering of the underlying bone. It consists of wht plates?

Answer 29

dorsal plate and a plantar plate

Question 30

What are an occasional atavistic finding in domestic chickens and geese

Answer 30

Claws on the wings (ungues digiti manus)

Question 31

► Well developed in male chickens and turkeys, it is usually manifests only as a wart-like scale in females. ► Located on the caudomedial tarsometatarsus where, in males, it is mounted on a large pyramidal bony protuberance. ► It grows approximately 1cm per year, up to a total of around 6cm, and can thus be used in estimating age

Answer 31

spur

Question 32

Related phylogenetically to the scales of reptiles, the distinguishable feature of all birds

Answer 32

feathers

Question 33

► The most numerous feathers, covering the bulk of the body of the bird. ► They are distinguished by the presence of an afterfeather with an aftershaft

Answer 33

Coverts

Question 34

What usually consist of a distal pennaceous portion (pars pennata) and a proximal plumaceous portion (pars plumacea)?

Answer 34

vexillae

Question 35

What are located on the antebrachium, manus and the alula. Their number is consistent within species.

Answer 35

remiges (sing. remex)

Question 36

Around 10–20 secondary remiges arise from the?

Answer 36

forearm

Question 37

ten primary remiges originate from the?

Answer 37

manus

Question 38

There are no remiges in what region ?, which is covered with coverts

Answer 38

brachial region

Question 39

► Arising from the rump, it form the basis of the tail. ► Their shaft is usually straight. ► Near the centre of the tail, the vexillae are generally symmetrical. Towards the periphery, there is an increasing tendency towards asymmetry of the vexillae (the medial vexillum becoming narrowed) and curvature of the shaft

Answer 39

Rectrices (sing. rectrix)

Question 40

► consist only of a calamus with alarge tuft of keratinised filaments at its tip

Answer 40

Down Feathers/Plumules

Question 41

► Hardly any down feathers are found on chickens, their function being taken over in this species by? ► These are similar to down feathers, but have a clearly defined rachis. Their association with an afterfeather, including an aftershaft, indicates that these are actually a modified form of covert. ► Like down feathers, their role is to provide thermal insulation

Answer 41

semiplumu;es

Question 42

► These feathers are specialised down feathers that continually produce a powdery substance consisting of minute (approximately 1µm) keratin granules. ► They are especially plentiful in pigeons. ► It is presumed that the powder acts as a waterproof coating for the plumage.

Answer 42

Powder down feathers

Question 43

What are down-like feathers that lie immediately adjacent to the follicle of contour feathers?

Answer 43

Filoplumes

Question 44

► These are located on the head. ► They line the base of the beak and form the eyelashes. ► These have a rigid shaft with few barbs and are associated with numerous mechanoreceptors.

Answer 44

Bristles