Integumentary System PDF

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Summary

Learning the integumentary system in both felines and canines...

Description

October 31, 2018 Integumentary System -the integument -the skin is only one part of the integument *p. 170-178* Functions -protection/defense -barrier against bacteria -secretes antimicrobial properties -camouflage -temperature regulation -sweating cools the skin when the sweat evaporates -animals do not sweat much, but horses do sweat a lot -warm body -hair; keeps the heat in via pili erection -adipose tissue in hypodermis -sensation -touch receptors -pressure receptors -heat receptors -pain receptors -mostly all in the dermis -secretion -sebum -prevention of water loss -via sebum -shock absorption and protection -foot pads protect distal phalanges -aides in hunting as well -colouration -camouflage -communication -attracting mates; courtship rituals -Vitamin D synthesis -do not produce a lot because of the hair covering their skin but this is still a function of the skin -mostly obtained through diet Structures -skin -accessory skin structures

Epidermis -outer/superficial layer -stratified squamous epithelium -outer cells dead, coated in keratin, and slough of -protein -provides protection -inner/deep layers produce new cells -depth of each layer varies between species -contains melanocytes produce melanin pigment Dermis -contains blood vessels, nerve endings and many accessory structures: -sweat glands Duct opens directly onto surface of skin/footpad -sebaceous glands -secrete sebum onto hair shaft, then it gets secreted onto skin -waterproof and lubricate -antibacterial properties -hair follicles Hypodermis -subcutaneous layer/subcutis -loose connective tissue and adipose tissue -has blood vessels -insulation (temperature regulation) -provides protection/cushioning Hair -guard hair/topcoat -long, straight, and stif -wool hair (beneath) -undercoat -lead to matting -very fine, soft, and wavy -tactile hair -vibrassae (plural) -whiskers -eyebrows -hairs on ankle (long) tell if prey is still alive -cilia -eyelashes -most cats do not have eyelashes Hooves, Claws, and Nails

-horny covering of the distal phalanx -outer portion of the nail is the sheath made of keratinized epithelium -hoof wall composed of keratinized epithelium -quick contains vein and artery and nerve Pads -external surface is keratinized epithelium -outer epidermis is quite thick on a lot of dogs -pads are full of adipose tissue, providing cushion and stealth Horns -made up of keratinized hair -small bone bud at base attached to skull -does have a blood supply (large amount, closer to the base) -polled cattle and some sheep have been bred not to grow horns -GENERAL RULE: most horns occur in both males and females -do not grow back if they fall of Antlers -made up of bone -not hair and not keratinized -shed annually -velvet (epithelium) covers the bone -this is where all of the nutrients come from to supply bone growth -has blood supply -so no nutrients after the skin is all rubbed of so the bone falls of -males AND females do not always grow antlers -mostly males grow -exception is caribou/reindeer, but they do this at diferent times of years Birds -feathers which are epidermal growths -insulation -retain body heat -essential for flight -camouflaging -mating attraction/rituals -beaks are modified epidermal structures from mandibles and maxilla -preen glands near tail that produces very efective waterproofing oil Reptile Integument -have scales DEFINITIONS TO KNOW

-alopecia -hair loss -usually an underlying medical reason; allergy, autoimmune skin diseases (eg. Lupus), external parasites (eg. Mange mites) -pruritus -itchiness -dermatitis -inflammation of the skin -subcutaneous -dermatology -study of skin and associated conditions...