The common integument Flashcards
Common integument
ordinary skin with its covering of hair and variety of skin glands as well as more specialized parts such as claws, hoofs and horns.
Roles of the skin
- Covers the body and protects it from injury.
- Temperature control
- Enables the animal to respond to various external stimuli
3 types of hair
- Guard hair
- Wavy wool hair
- Tactile hair
Layers of skin
- Epidermis (out)
- Dermis (in)
- These rest on a loose connective tissue named: Subcutis, hypodermis, superficial fascia
Guard hairs
- Straight, rather stiff
- “Topcoat”
- lie close against the skin and sweep uniformly in broad tracts; giving the coat a smooth appearance disturbed only by the whorls and crest.
-Promotes the run off of rain. Preventing chilling if water made contact with skin
- Occasionally, animals are born with a disturbed coat pattern which may seriously impair their ability to withstand severe weather
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Wool hairs
- Fine, thin
- Provide soft Undercoat
- wavy
- shorter and more numerous than the guard hair
- concealed between the guard hairs
Tactile hairs
- substantially thicker
- generally protrude beyond the neighboring guard hairs and reach deep into the subcutis or even the superficial muscles
- characterized by the presence of a venous sinus filled with blood and located between inner and outer layers of the dermal sheath.
- restricted distribution
- associated with touch receptors
- nerve ending responsive within the dermal sheath
- example: whiskers
Hair structure
- Cuticle
- Cortex
- Medulla
Melanin
- Responsible for color of hair
- Pigment produced in a special group of cells known as melanocytes. It also colors the skin.
Follicle
- tiny pit where hair grows to protrude above the surface of the skin
- develops from a ectodermal bud
Topography of tactile hair
- Face
- Principally on the upper lip and about the eyes
- Although other are scattered (in species-variable fashion) on the lower lip, the chin, and elsewhere on the head
Tactile hair functionality
- nerve endings responsive to mechanical stimulation
- the stimulus provided by disturbance of the hair is amplified by wave motion in the blood
Tactile hair development
- follicles of tactile hairs appear in early development before those of the coat hairs.
Torus/Tori
Torus (singular) and Tori (plural)
- a bulging or rounded projection or swelling
- Torus- used in connection with the common integument, detonates a pad
- it includes the thick epidermal covering, the dermis, and the subcutaneous cushion or pulvinus
Pulvinus
subcutaneous cushion
Footpads structure
- naked, densely cornified epidermis
- dermis is unremarkable
-thick, resilient subcutis
-admixture of collagenous and elastic fibers interspersed with adipose tissue (fat)
- footpads are the digital cushion on which animals walk
Plantigrade
Digitigrade
Ruminants and pigs digital pads
bulb
Horses digital pads
frog
Nails, claws and hoofs
- similar structures enclosing the distal phalanx appear strikingly different
- local modification of skin
- Serve primarily to protect the underlying tissues
What are Nails, claws and hoofs used for?
- Scratching
- Digging
- Weapon
- Grab the food
