Common integument Flashcards
→ what is the common integument → anatomy and physiology of skin, hair and modifications
What is the common integument?
The outer protective layer of the body, including skin, hair, glands, and modifications like hooves, nails, and horns
What are the main components of the integument?
- Skin (including hair and glands).
- Subcutaneous layer (separates the skin from underlying organs).
- Modifications (mammary glands, hooves, claws, horns, footpads).
What are the main functions of the integument?
- Body temperature regulation.
- Cell fluid maintenance.
- Synthesis of vitamin D.
- Detection of stimuli (touch, pain, temperature).
- Immune defense.
- Storage and secretion of substances.
- Protection as a barrier
How thick is the skin?
Usually 1-5 mm thick, varying by species and body region
- Thicker in dorsal areas.
- Thinner in ventral areas.
What are the two main layers of the skin?
- Epidermis (outermost layer).
- Dermis (thickest layer beneath the epidermis)
What type of epithelium makes up the epidermis?
Cornified, stratified squamous epithelium
How does the thickness of the epidermis vary?
- Thin = Hairy skin.
- Thick = Non-hairy skin.
- Thickest = Hooves and digital pads.
What percentage of the epidermis is keratinocytes?
85%. Keratinocytes produce keratin, which is essential for skin defense and immune function
What is cornification?
The differentiation of keratinocytes into hardened tissue (e.g., hooves)
What are melanocytes, and what do they do?
Cells in the epidermis responsible for pigmentation
What makes up the dermis?
Collagen and elastic fibers, allowing skin elasticity
Why is the dermis thicker than the epidermis?
It contains blood vessels, lymph vessels, nerves, and connective tissue
What are the two types of sweat glands?
- Apocrine glands: Associated with hair follicles (e.g., horses).
- Eccrine glands: Not associated with hair follicles (e.g., primates)
Where is hair formed?
In the epidermis
What determines hair color?
The amount of melanin present
What are the types of hair?
- Guard hairs: Superficial protective hairs.
- Wool hairs: Underneath the guard hairs (e.g., in sheep).
- Tactile hairs: Modified guard hairs used for touch (e.g., whiskers)
What are the main parts of a hair?
- Hair bulb: Grows from the epidermis but is encased in the dermis.
- Hair shaft: The visible part above the skin
What are the main modifications of the integument?
- Mammary glands.
- Footpads and digit structures.
- Hooves, nails, and claws.
- Horns.
What are mammary glands?
A modified sweat gland that produces milk
How do mammary glands vary between species?
The location, number, and structure of the glands and teats differ
What is the hoof capsule in horses?
The dermis and epidermis suspend the distal phalanx in the hoof capsule, converting stress to the sole
What are secondary lamellae, and which species have them?
- Small structures that increase surface area for better support.
- Present in horses, absent in other species.
What are the functions of footpads?
- Protection from mechanical injury.
- Shock absorption via digital cushions
What are the three types of footpads?
- Carpal/Tarsal pads.
- Metacarpal/Metatarsal pads.
- Digital pads
