Integument

Question 1

Name 5 conditions of the integument.

Answer 1

Cyst
Proud flesh
Laminitis
Skin allergy
Ulcer

Question 2

Define integumentum.

Answer 2

Organ system comprising of the skin and associated structures.

Covers the entire body – surface area ∝ body (kg)^0.67

Question 3

State 5 functions of the integument.

Answer 3

• Protection
• Sensory reception
• Pigmentation
• Synthesis
• Glandular secretions

Question 4

Describe the structure of the integument.

Answer 4

Epidermis - stratified squamous epithelia

Dermis - contains nerves, sweat glands, hair bulbs and papilla, collagen fibres

Hypodermis - contains blood vessels and subcutaneous adipose tissue

Question 5

How does integument provide protection?

Answer 5

• Prevention of water loss
• External barrier to mechanical, thermal, chemical and ultraviolet damage
• Immune protection
• Temperature control
• Defensive behaviours
• Carrying young
• Self-repair

Question 6

What is the integument’s role in exteroception?

Answer 6

Relating external stimuli to an organism. Sensory advance warning of environment.

Question 7

How does the integument allow for pigmentation?

Answer 7

• Number and type of pigment granules in epidermis
• Amount of blood
• Degree of haemoglobin oxygenation
• Pigment synthesised by melanocytes in basal layer and hair and feathers – eumelanins and pheomelanins

Question 8

What are some functions of pigmentation in animals?

Answer 8

Camouflage
Social signalling/display
Protection against radiation

Question 9

Name 3 glands that the integument contains and their functions.

Answer 9

Sebaceous gland – sebum lubricates skin

Apocrine sweat gland – pheromone secretion

Eccrine sweat gland – temperature regulation

Question 10

Describe the equine hoof as a horn-covered structure.

Answer 10

• Increased keratin in dermis to resist abrasion and water proofing.
• Grows diagonal downward direction from coronary band
• Periople is waxy outer layer of hoof that is waterproof and constantly being worn down.
• Hoof wall is horn layer. Tubular horn sections have holes through the horn that reinforce the structure. Lamina horn interdigitates with the dermis.

Question 11

List 6 types of feather.

Answer 11

Tall
Flight
Semiplume
Filoplume
Bristle
Downy

Question 12

Describe the structure and functions of feathers.

Answer 12

• Intricate structures to aid flight, resist water penetration and keep warm due to alignment of barbs and barbules that are part of the vane of a feather.
• Down feathers are short, lack hooklets and are close to the skin to provide insulation.
• Feathers grown on feather tracts and the body of feather is produced by multiplication of epidermal cells assisted by feather papilla.
• Gain colouration due to melanins and carotenoids in feed taken up by keratinocytes in the basal layers and transported to the surface.

Question 13

List 6 horn-covered structures.

Answer 13

Hooves
Claws
Horns
Beaks
Talons
Tortoise and turtle shells

Question 14

What is the structure of horn covered structures?

Answer 14

• Underlying vascularised connective tissue dermis called corium, very prominently folded into laminae. In some places corium is continuous with underlying periosteum of the bone.
• Contains blood vessels and nerves so corium is highly sensitive.
• Overlying cornification of epithelium are insensitive, as the keratins produced by it are highly resistant to damage.
• Dermis layer beneath gives 3D structures.
• The epidermis that produces the wall is called the coronary epidermis.

Question 15

What is the function of horn-covered structures?

Answer 15

Number of functions, including protection and weaponry, digging and to provide a tough covering to the feet where they contact the ground.

Question 16

How do horns and antlers differ?

Answer 16

Antlers are temporary organs that contain bone in the core (horn hollow and permanent) that deer, moose and reindeer develop during the summer season, usually only males as a secondary sexual characteristic and then shed.

Question 17

Describe what occurs in laminitis of an equine hoof.

Answer 17

• Severe laminitis can result in detachment of insensitive from sensitive laminae so that the intimate association between hoof wall and distal phalanx is lost.
• In such a case the distal phalanx may rotate downwards and the hoof wall grows abnormally producing an irregular flared wall and up-curled toe as can be seen in this x-ray and photograph.
• The tip is now pointing down more than normal as the interdigitation of the tissues has broken down.