Comparative Anatomy - Integumentary System

1. By: C ariñO , Micaelle Kristiene D ela cruz , jabob P ulido , fiona V illanueva, Isaias

2. INTRODUCTION Definition and general structure of the vertebrate integument II. FUNCTIONS OF THE GENERAL STRUCTURES Epidermis -Layers Dermis -Layers Chromatophores -Types Glands -Types O UTLINE

3. DEVELOPMENT OF SKIN IN VERTEBRATES Fishes Amphibians Reptiles Birds Mammals IV. COMPARISON OF VERTEBRATES INTEGUMENT

4. I. INTRODUCTION Integument came from the Latin word that means “to cover”. It is alternative name for skin It includes the accessory organs such as hair, feathers, scales, claws, hoofs etc. Two main parts: epidermis and dermis

5. Functions of the skin: Serves as barrier against infection or injury Regulates body temperature Prevents water loss Excretion of body wastes( sweat) Synthesizes Vitamin D

6. Layers of the SKIN Skin is composed of three primary layers: epidermis which provides waterproofing and serves as a barrier to infection; dermis which serves as a location for the appendages of skin; hypodermis (subcutaneous adipose layer), which is called the basement membrane .

7. II. FUNCTIONS OF THE GENERAL STRUCTURES General structures of the integumentary system: Epidermis - outer covering; ectodermal derivative Layers: Stratum basale or germinativum – innermost layer; cells actively divides Stratum spinosum – superficial to stratum basale ; keratinocytes produce lamellar bodies Stratum granulosum - cytoplasm of keratinocytes appear granular Startum lucidum - 4 th layer superficial to stratum granulosum ; found in palms and soles Stratum corneum - outermost layer; cornified

8. 2. Dermis - deepest layer; mesodermal derivative Layers: Stratum papillare - composed of loose areolar connective tissue Stratum reticulare - lies under papillary; composed of dense irregular connective tissue

9. 3. Chromatophores - pigment bearing cells - provides concealing coloration to the integument Types: Melanophores - contain melanin - brown, gray or lack pigment Lipophores - contain carotenoids - Produce yellow, orange and red pigment - e rythrophores and xanthophores

10. Iridophores or Guanophores - contains crystal of guanin - Causes iridiscence in vertebrates 4. Glands - forms stratum germinativum Types( as to composition): Unicellular gland - single-celled mucus-secreting glands Multicellular gland - growth of s. germinativum into dermal region

11. Types of unicellular glands (based on shape): Club cells - elongated, binucleated cells - secretes mucus Granular cells - secretes mucus in skin of lampreys & other fishes Goblet cells - narrowed base and wide apical end - secretes mucus in chodrichthyes and osteichthyes Sacciform cells - secrete large, membrane-bound toxic products to repel enemies

12. Types of multicellular glands (based on shape): 1. TUBULAR GLANDS TYPES CHARACTERISTICS EXAMPLES 1. Simple Tubular - Short blind tubes located in the epidermis -Thumb pads( male anurans) - Ceruminous glands(mammals) 2. Simple coiled tubular - Long, narrow tube, coiled distal end located in epidermis - Sweat glands of mammals 3. Simple branched tubular - Divides at its distal end to two or more - Terminal portions may or may not be coiled - Large sweat glands of axillae or armpit 4. Compound tubular - Consist of varying number of simple tubular glands -Mammary glands of monotremes

13. 2. SACCULAR GLANDS TYPES CHARACTERSTICS EXAMPLES 1. Simple saccular - With only one expanded bulb or acinus at the end of the duct - Mucous and poison glands in skin of amphibians 2. Simple branched saccular - With several acini arranged along single excretory duct - With single acinus divided by partitions into smaller acini - Meibomian glands of eyelid - Sebaceous gland of skin 3. Compound saccular - Consist of several simple saccular glands (lobules) - Mammary glands of matatherian and eutherian mammals

14. Types as to method of excretion: Merocrine gland - true glands; not destroyed during secretion; sweatgland Holocrine glands - glandular cells die and are discharge with their secretion forming new cells; oil & sebaceous glands (birds and mammals) Apocrine glands - secretion accumulates at the outer ends of glandular cells then pinched off with cytoplasm; mammary glands and sweat glands

15. Mucous glands - secretes mucus; e.g. unicellular glands and simples saccular glands Serous glands - secretes watery substance; e.g. sweat glands Sebaceous glands - secretes oily substance; e.g. uropygial gland, ceruminous gland, meibomian gland

16. Mucous gland - Frog skin

17. Types of Scales Based on structure and development Epidermal scales Dermal scales Serves as exoskeleton of vertebrates for protection of the body

18. TYPES OF DERMAL SCALES Cosmoid scales Placoid scales Rhomboid scales or Ganoid scales Cycloid and Ctenoid scales (Teleost scale)

19. Types of FEATHERS 1. Filoplumes or hair feather - long, slender shaft Plumulae or down feather - more complex than hair feathers Plumae or contour feathers - found in MOST BIRDS except in PENGUINS and OSTRICHES Modified reptilian scales formed from the beta keratin layer of the epidermis

20. HAIR Found in ALL MAMMALS and is composed primarily of alpha keratin of epidermis Consists of a base or root and a shaft or the remaining length of the stand.

21. Integument of Fishes Characterize as bony , cartilaginous, jawless . Jawless( Class Agnatha ) Ostracoderms and Placoderms - with dermal scales that functioned as armor Hagfishes and Lampreys- smooth and w/o dermal scales Epidermis- is composed of stacked layers of numerous epidermal cells the skin of Hagfishes- - with thread cells

22. Dermis- is arranged into regular layers of fibrous connective tissue Tie themselves in a knot – is a way to clean the mucus off their bodies Hypodermis – includes adipose tissue

23. Class Chondrichthyes Cartilaginous Fishes- absent of dermal bone but have placoid scales secretory cells and stratified epidermal cells are present in the epidermis Chromatophores occur in the lower part of the epidermis and upper region of the dermis The dermis is composed of elastic and collagen fibers

24. Class Osteichthyes Bony Fishes- the dermis is sub-divided into a superficial layer of loose connective tissue and a deep layer of dense fibrous connective tissue Chromatophores occur within the dermis Dermal scales of Bony Fishes do not actually pierce the epidermis

25. Integument of Tetrapods Characterize as Amphibians, Reptiles, Aves, and Mammals. With a highly keratinized cells and with Cornified layer as covering that forms the stratum corneum

26. Class Amphibia The skin of Amphibians helps for the gas exchange Frogs and salamanders – lack dermal scales Caecilians have dermal scales present as vestiges.   Larval Salamanders- the dermis is composed of fibrous connective tissues Terrestrial adult amphibians – the dermis is relatively thinner and is divided into 2 layers: 1) stratum songiosum 2) stratum compactum

27. the epidermis lack in Leydig cells Nuptial pads- are formed in the digits or limbs of the male salamander Mucous and granular poison glands - located in the dermis and opens in the surface through connecting ducts Chromatophores can be located in the dermis but sometimes it can be in the epidermis Capillary beds- reach in the lower part of the epidermis for cutaneous respiration

28. Class Reptilia Reptiles - adapted to the terrestrial environment than the amphibians Highly keratinized Scutes in the turtle Epidermal scales can be crests, spines or horn-like processes Dermal bones are present in many reptiles Osteoderms - is the plate of the dermal bone located under the epidermal scales

29. The dermis is composed of fibrous connective tissues Epidermis is divided into 3 layers: stratum basale stratum granulosum stratum corneum

30. Molting or ecdysis in Snake TURTLES and CROCODILES molting is modest

31. Skin glands that Protects the reptiles from the predators: a . )Femoral glands- in many Lizards b .)Scent glands-in Crocodiles and some Turtles , open into the cloaca and on the margins of the lower jaw

32. Class Aves the skin of the Birds is adapted to free movement over the muscles Epidermis – Stratum Basale and stratum corneum Dermis- richly supplied with blood vessels, sensory nerves and smooth muscles

33. Skin in Mammals m ost complex system relatively thick h ave hair layer of insulation (fat) – hypodermis Composed of two other layers of cells, epidermis and dermis

34. The epidermis made up of cell types: Keratinocytes – most prominent cell type Langerhans cells – participate in immune response Merkel cells – connected with sensory nerves (mechanoreceptors) Chromatophores – secrete pigment melanin - In humans, melanophores protect us against Uv rays

35. Dermis c omposed of irregularly arranged fibrous CT b lood vessels, nerves and smooth muscles p roduces dermal bones With rich blood supply Many hair follicles, sweat and sebaceous glands d ivided into two sub layers, outer papillary layer(dermal papillae) and the deeper reticular layer separated by a superficial fascia

36. Claws, Nails, and Hooves Most t etrapods (+) claws Primates have nails – flattened version of claws Hooves- UNGULATES

37. Hooves-homologous to fingernails in amniotes

38. Since the dermis may have a potential to form bones…

39. Antlers vs. Horns Antlers – made of bone ( family CERVIDAE) Horns – have an outer keratinized layer (family BOVIDAE)

40. Fishes Amphibians Reptiles Mammals Birds Epidermis -very thin w/ 2 types of cell: ● epidermal cells ● unicellular glands -mucous cuticle on surface. - with thin stratum corneum and very little keratin; Leydig cells - epidermal scale, with thick outer layer of keratin Epidermis with 5 layers : - corneum - lucidum - granolosum - spinosum - basale -thin and bilayered Comprises of: - corneum - basale

41. Fishes Amphibians Reptiles Mammals Birds Dermis - contains chromatophores . -o rganized into regular layers of fibrous connective tissue. - with chromatophores , poison glands and mucous glands. - composed of fibrous connective tissues. - With chromatophores in many. May possess Osteoderms - fibrous connectve tissues. well- vasculari zed and innervated Outer papillary layer Deeper reticular layer well- vasculari zed and innervated -richly supplied by blood vessels, sensory nerves and smooth muscles.