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BY:
CARIÑO, MICAELLE KRISTIENE
DELA CRUZ, JABOB
PULIDO, FIONA
VILLANUEVA, ISAIAS
I. INTRODUCTION Definition and general structure of the vertebrate integument
II. FUNCTIONS OF THE GENERAL STRUCTURES1. Epidermis
-Layers2. Dermis
-Layers3. Chromatophores
-Types4. Glands
-Types
OUTLINE
III. DEVELOPMENT OF SKIN IN VERTEBRATES Fishes Amphibians Reptiles Birds Mammals
IV. COMPARISON OF VERTEBRATES INTEGUMENT
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
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
Layers of the SKIN• Skin is composed of three primary layers:
1. epidermis which provides waterproofing and serves as a barrier to infection;
2. dermis which serves as a location for the appendages of skin;
3. hypodermis (subcutaneous adipose layer), which is called the basement membrane.
II. FUNCTIONS OF THE GENERAL STRUCTURES
General structures of the integumentary system:
1. 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 - 4th layer superficial to stratum granulosum;
found in palms and soles Stratum corneum - outermost layer; cornified
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
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
- erythrophores and xanthophores
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
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
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
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
Types as to method of excretion:1. Merocrine gland - true glands; not destroyed
during secretion; sweatgland
2. Holocrine glands - glandular cells die and are discharge with their secretion forming new cells; oil & sebaceous glands (birds and mammals)
3. Apocrine glands - secretion accumulates at the outer ends of glandular cells then pinched off with cytoplasm; mammary glands and sweat glands
1. Mucous glands - secretes mucus; e.g. unicellular glands and simples saccular glands
2. Serous glands - secretes watery substance; e.g. sweat glands
3. Sebaceous glands - secretes oily substance; e.g. uropygial gland, ceruminous gland, meibomian gland
Mucous gland - Frog skin
Types of ScalesBased on structureand development
1. Epidermal scales2. Dermal scales
Serves as exoskeleton of vertebrates for protection of the body
TYPES OF DERMAL SCALES
1. Cosmoid scales2. Placoid scales3. Rhomboid scales or Ganoid scales4. Cycloid and Ctenoid scales (Teleost scale)
Types of FEATHERS
1. Filoplumes or hair feather- long, slender shaft
2. Plumulae or down feather- more complex than hair feathers
3. Plumae or contour feathers- found in MOST BIRDS except in PENGUINS andOSTRICHES
Modified reptilian scales formed from the beta keratin layer of the epidermis
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.
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
• 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
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
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
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
Class AmphibiaThe 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
• 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
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
• The dermis is composed of fibrous connective tissues
• Epidermis is divided into 3 layers: • stratum basale• stratum granulosum• stratum corneum
• Molting or ecdysis in Snake
• TURTLES and CROCODILES molting is modest
• 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
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
Skin in Mammals
• most complex system• relatively thick• have hair• layer of insulation (fat) – hypodermis• Composed of two other layers of cells,
epidermis and dermis
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
Dermis
• composed of irregularly arranged fibrous CT• blood vessels, nerves and smooth muscles• produces dermal bones• With rich blood supply• Many hair follicles, sweat and sebaceous glands• divided into two sub layers, outer papillary
layer(dermal papillae) and the deeper reticular layer
• separated by a superficial fascia
Claws, Nails, and Hooves
• Most tetrapods (+) claws• Primates have nails – flattened version of
claws• Hooves- UNGULATES
Hooves-homologous to fingernails in amniotes
• Since the dermis may have a potential to form bones…
Antlers vs. Horns
• Antlers – made of bone ( family CERVIDAE)• Horns – have an outer keratinized layer
(family BOVIDAE)
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
Fishes Amphibians Reptiles Mammals Birds
Dermis - contains chromatophores.
-organizedinto 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-vascularized and innervated
- Outer papillary layer
- Deeper reticular layer
well-vascularized and innervated
-richly supplied by blood vessels, sensory nerves and smooth muscles.