General Zoology Integumentary System PDF

General Zoology Finals: Integumentary System Prepared by: Kian Elman 1  Learning Outcomes Describe the different integumentary system. Contrast integumentary structure and function in fishes, amphibians, reptiles (including birds), and mammals....

General Zoology Finals: Integumentary System Prepared by: Kian Elman 1  Learning Outcomes Describe the different integumentary system. Contrast integumentary structure and function in fishes, amphibians, reptiles (including birds), and mammals. Describe the accessory structures of the skin. Describe adaptations of the skin of amphibians, reptiles (including birds), and mammals for life in terrestrial environments. 2  Introduction The integumentary (in-teg-u--MEN-tar-e-; in inward; tegere to cover) system is composed of the skin, hair, oil and sweat glands, nails, and sensory receptors. 3  Skin and Tissues Composed of several tissue types Maintains homeostasis Protective covering Retards water loss Regulates body temperature Houses sensory receptors Contains immune system cells Synthesizes chemicals Excretes small amounts of wastes 4  Layers of Skin Epidermis - Outer epithelial layer. Dermis - Middle layer of the skin that provides strength, elasticity, and support. Subcutaneous layer - The innermost layer beneath the dermis, connecting the skin to underlying muscles and bones. 5  Epidermis Melanocytes provide Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. melanin Keratinized Rests on basement membrane Mucus secretion to protect the animal. 6  Epidermis There are five (5) layers of the epidermis: Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Stratum corneum Stratum lucidum Stratum granulosum Stratum spinosum Stratum basale Basement membrane Dermal papilla Dermis (a) (b) 7 b: © The McGraw-Hill Companies, Inc./Al Telser, photographer  Dermis On average 1.0-2.0mm thick Contains dermal papillae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hair shaft Binds epidermis to Sweat gland pore Sweat Stratum corneum underlying tissues Epidermis Stratum basale Capillary Dermal papilla Muscle cells Basement membrane Tactile (Meissner’s) corpuscle Dermis Sebaceous gland Arrector pili muscle Nerve cell processes Sweat gland duct Lamellated (Pacinian) corpuscle Hair follicle Specialized sensory receptors SubcutaneousSubcutaneous layer Sweat gland Nerve cell process Adipose tissue Blood vessels Blood vessels Muscle layer Hair follicles (a) Glands Irregular dense connective tissue 8  Dermis There are two (2) layers to the dermis: Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Papillary layer Superficial Hair shaft Sweat gland pore Sweat Dermal papillae Stratum corneum Epidermis Stratum basale Capillary Dermal papilla Basement membrane Tactile (Meissner’s) corpuscle Dermis Sebaceous gland Reticular layer Arrector pili muscle Sweat gland duct Cleavage and tension Lamellated (Pacinian) corpuscle Hair follicle SubcutaneousSubcutaneous Sweat gland Langerhans’ lines. layer Nerve cell process Adipose tissue Blood vessels Muscle layer (a) 9  Subcutaneous Layer Aka hypodermis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Loose connective Hair shaft Sweat gland pore tissue Sweat Stratum corneum Epidermis Stratum basale Capillary Adipose tissue Dermal papilla Basement membrane Tactile (Meissner’s) corpuscle Insulates Dermis Sebaceous gland Arrector pili muscle Sweat gland duct Major blood vessels Lamellated (Pacinian) corpuscle Hair follicle SubcutaneousSubcutaneous Sweat gland present layer Nerve cell process Adipose tissue Blood vessels Muscle layer (a) 10  Accessory Structures of the Skin Accessory structures of the skin originate from the epidermis and include: Hair follicles Nails Skin glands 11  Hair Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Epidermal cells Tube-like depression Hair shaft Pore Extends into dermis Melanin Sebaceous gland Arrector pili muscle Three (3) parts of hair: Arrector pili muscle Hair root Hair shaft (keratinized cells) Hair follicle Eccrine Hair root sweat gland Region of cell division Hair papilla Hair papilla DermalDermal blood vessels (a) 12  Nails Protective coverings Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Lunula Nail bed Nail plate Three (3) parts: Nail plate Nail bed Lunula 13  Sebaceous Glands Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Usually associated with hair follicles Sebaceous gland Holocrine glands Hair follicle Secrete sebum (oil) Hair © Per H. Kjeldsen 14  Sweat Glands Widespread in skin Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Originates in deeper dermis or hypodermis Hair shaft Pore Eccrine glands: Water, Dermal Salt, and Urea papilla Sebaceous Apocrine glands: gland Duct Stress sweat Hair follicle Eccrine Mammary glands: Milk sweat gland Apocrine sweat gland 15  Integument Integumentofofdifferent animals Invertebrates EPIDERMIS When the epidermis is overlain by a cuticle, the epidermis is often referred to as a hypodermis. DERMIS Invertebrates lack a dermis in the vertebrate sense. In cnidaria, mesoglea In arthropods, hemolymph In annelids, this layer aids in respiration and locomotion through its association with capillaries and muscles. HYPODERMIS In arthropods, the hypodermis is key to molting (ecdysis) by secreting new cuticle layers and dissolving old ones. In nematodes, the hypodermis is involved in maintaining the hydrostatic skeleton by resisting internal pressure generated by body fluids. 16 Skin of Fishes In aquatic vertebrates (e.g., fish), the dermis produces scales. Shark (Selachimorpha) skin contains toothlike denticles. Slime is secreted when the hagfish is irritated and discourages predators whose gills may be clogged by copious slime discharge. 17 Skin of Amphibians The epidermis of amphibian skin is layered (stratified) and gives rise to mucus and granular glands. Frogs have a keratinized outermost layer. In many frogs, respiration occurs not only through the lungs but also through the skin. The dermis houses chromatophores, specialized cells responsible for pigmentation. Granular glands of frogs are responsible for the toxic substances that act as a defense mechanism against predators. 18 Skin of Reptiles The resulting scales from keratin are epidermal in origin. Epidermal keratinization also contributes to the formation of scutes in snakes, beaks in turtles, and claws in most reptiles. In reptiles and amphibians, the hypodermis is less fatty and primarily supports skin movement and flexibility. 19 Skin of Mammals Other epidermal derivatives of mammalian skin include nails (primates only), claws, and hooves. Scent or musk glands secrete pheromones that may be involved with defensive, courtship, and other behaviors. In marine mammals (e.g., whales, seals), the hypodermis develops into a thick layer of blubber, providing insulation and buoyancy. 20 THANK YOU! 21