Integumentary system vertebrates


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Integumentary system vertebrates

  2. 2. THE SKIN (in general) <ul><li>The skin technically refers to the vertebrate integument </li></ul><ul><li>It has the same basic structure in all vertebrates, including fish, reptiles, birds, and humans and other mammals. </li></ul><ul><li>It is the largest organ with respect to surface area of the vertebrate body </li></ul>
  3. 3. THE SKIN: layers <ul><li>Epidermis </li></ul><ul><ul><li>The outermost layer of epithelial tissue </li></ul></ul><ul><li>Dermis </li></ul><ul><ul><li>Thicker than the epidermis </li></ul></ul><ul><ul><li>Made up of a thick layer of connective tissue and one to several cells thick </li></ul></ul><ul><ul><li>Contains the blood vessels, nerves, glands and auxiliaries </li></ul></ul><ul><li>Hypodermis </li></ul><ul><ul><li>Layer below the epidermis made up of loose connective tissues and adipose tissues </li></ul></ul>
  4. 4. SKIN OF JAWLESS FISHES <ul><li>They have relatively thick skin </li></ul><ul><li>Of the several types of epidermal glandular cells, one secretes the protective cuticle </li></ul><ul><li>Multicellular slime glands secrete large amount of mucous to cover the body surface for protection </li></ul>LAMPREY HAGFISH
  5. 5. SKIN OF CARTILAGINOUS FISHES <ul><li>Multilayered and contains mucus and sensory cells </li></ul><ul><li>The dermis contains bones in the form of placoid scales called denticles </li></ul><ul><li>Denticles contain blood vessels and nerves and is very familiar to vertebrate teeth </li></ul>COOKIE-CUTTER SHARK MANTA RAY
  6. 6. SKIN OF bony FISHES <ul><li>They contain scales </li></ul><ul><li>A thin layer of dermal tissue overlaid the superficial epidermis normally covers the scales </li></ul><ul><li>Because scales are not shed, they grow at the margins and over the lower surface </li></ul><ul><li>Their skin are permeable and can be used in gas exchange </li></ul><ul><li>Mucus are at help in fighting off bacterial and fungal infection at the surface </li></ul>BOWFIN BROWN BULLHEAD
  7. 7. SKIN OF amphibians <ul><li>Amphibians are transitional between aquatic and terrestrial vertebrates </li></ul><ul><li>Consists of stratified epidermis and a dermis containing mucus and serous glands plus pigmentation cells </li></ul><ul><li>The earliest amphibians were covered by dermal bone scales </li></ul>GREEN FROG HELLBENDER
  8. 8. <ul><li>Their skin reflects their greater commitment to a terrestrial existence </li></ul><ul><li>The outer layer of the epidermis (stratum corneum) is thick, lacks glands, and is modified into keratinized scales, scutes, plaques and beaks </li></ul><ul><li>The thick keratinized layer resists abrasion, inhibits dehydration and protects like a suit of armor </li></ul>SKIN OF REPTILES ALLIGATOR KING COBRA
  9. 9. SKIN OF BIRDS <ul><li>Over most of the birds body, the epidermis is usually thin and only two or three layers thick </li></ul><ul><li>The most prominent part of the epidermis are the feathers (collectively known as plumage) </li></ul><ul><li>Feathers are derived from the scales of reptilian ancestors and are, most complex of all derivatives of the vertebrate stratum corneum </li></ul>BALD EAGLE
  10. 10. SKIN OF BIRDS: feathers <ul><li>Feathers, provides the strong yet lightweight surface area needed for powered, aerodynamic flight. </li></ul><ul><li>They also serve as insulation, trapping pockets of air to help birds conserve their body heat. </li></ul><ul><li>The varied patterns, colors, textures, and shapes of feathers help birds to signal their age, sex, social status, and species identity to one another. </li></ul><ul><li>Some birds have plumage that blends in with their surroundings to provide camouflage, helping these birds escape notice by their predators. </li></ul>FISCHER’S LOVEBIRDS AFRICAN JACANA
  11. 11. <ul><li>Mammalian skin’s notable features include: </li></ul><ul><ul><li>Hair, </li></ul></ul><ul><ul><li>A variety of epidermal glands than in other vertebrate class, </li></ul></ul><ul><ul><li>A highly stratified cornified epidermis, </li></ul></ul><ul><ul><li>And a dermis many times thicker than the epidermis </li></ul></ul><ul><li>The prevention of dehydration is one of the evolutionary reasons mammals and other animals have been able to colonize terrestrial environment </li></ul>SKIN OF MAMMALS ENDAGERED SIBERIAN TIGER HORSE (ARABIAN)
  12. 12. <ul><li>It forms a barrier that helps prevent harmful microorganisms and chemicals from entering the body </li></ul><ul><li>It also prevents the loss of life-sustaining body fluids </li></ul><ul><li>It protects the vital structures inside the body from injury and potentially damaging ultraviolet rays of the sun </li></ul><ul><li>The skin also helps regulate body temperature, excretes some waste products, and is an important sensory organ </li></ul><ul><li>It contains various types of specialized nerve cells responsible for the sense of touch </li></ul>SKIN OF MAMMALS: functions
  13. 13. <ul><li>The skin consists of an outer, protective layer (epidermis) and an inner, living layer (dermis) which contains blood vessels, lymphatic vessels nerve endings, hair follicles, small muscles and glands. </li></ul><ul><li>The top layer of the epidermis is composed of dead cells containing keratin, the horny scleroprotein that also makes up hair and nails. </li></ul>SKIN OF MAMMALS: structures
  14. 14. <ul><li>Sudoriferous Glands (Sweat Glands) </li></ul><ul><ul><li>They secrete sweat by the process of perspiration which helps regulate body temperature and maintains homeostasis </li></ul></ul><ul><li>Sebaceous Glands (Oil Glands) </li></ul><ul><ul><li>They are connected to the hair follicles in the dermis </li></ul></ul><ul><ul><li>They lubricate and protect the skin by secreting sebum </li></ul></ul><ul><ul><li>Sebum is a permeability barrier and emollient – defense against microorganisms and skin softening </li></ul></ul>SKIN OF MAMMALS: glands
  15. 15. <ul><li>Hair </li></ul><ul><ul><li>Composed of keratin filled cells that develop from the epidermis </li></ul></ul><ul><ul><li>2 Parts: </li></ul></ul><ul><ul><ul><li>SHAFT – portion of the hair that protrudes from the skin </li></ul></ul></ul><ul><ul><ul><li>ROOT – portion of the hair embedded beneath the skin </li></ul></ul></ul>SKIN OF MAMMALS: appendages <ul><li>Arrector Pili Muscle </li></ul><ul><ul><li>Attaches to the connective tissue sheath of the hair follicle surrounding the bulb of the hair root </li></ul></ul><ul><ul><li>When the muscle contracts, it pulls the follicle and its hair to erect position (goosebumps) </li></ul></ul>
  16. 16. SKIN OF MAMMALS: appendages <ul><li>Nails </li></ul><ul><ul><li>Like hair, nails are modification of the epidermis </li></ul></ul><ul><ul><li>They are flat horny plates on the dorsal surface of the distal segments of the digits </li></ul></ul><ul><ul><li>They are made of dead cells containing the protein keratin </li></ul></ul><ul><ul><li>3 Parts: </li></ul></ul><ul><ul><ul><li>the concealed ROOT </li></ul></ul></ul><ul><ul><ul><li>the BODY, which is exposed but attached to skin </li></ul></ul></ul><ul><ul><ul><li>and the EDGE </li></ul></ul></ul><ul><ul><li>The nail grows out from the addition of new cells at the root </li></ul></ul>