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The Integumentary System

The Integumentary System. Integumentary System. Organ - two or more kinds of tissues grouped toghether and performing specialized functions. Skin is an organ composed of sheetlike membranes of epithelium and connective tissue. Types of Membranes. Serous membrane

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The Integumentary System

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  1. The Integumentary System

  2. Integumentary System • Organ - two or more kinds of tissues grouped toghether and performing specialized functions. • Skin is an organ composed of sheetlike membranes of epithelium and connective tissue.

  3. Types of Membranes • Serous membrane • Line body cavities that lack openings to the outside. • Secrete serous fluid for lubrication. • Found in the inner lining of the thorax and abdomen.

  4. Types of Membranes • Mucous Membranes • Line cavities and tubes that open to the outside of the body. • Secrete mucus • Found in oral and nasal cavities and tubes of digestive, respiratory, urinary and reproductive systems.

  5. Types of Membranes • Synovial membranes • Form inner linings of the joint cavities between the ends of bones at freely moving joints (synovial joints) • Secrete thick, colorless synovial fluid • Cutaneous membrane - the external body covering, SKIN

  6. The Functions of Skin • Protective covering • Regulates body temperature • Slows water loss • Contains sensory receptors • Synthesizes biochemicals • Excretes wastes

  7. Skin and Its Tissues

  8. Epidermis • Stratum basale - deepest layer of the epidermis, cells undergo mitosis. • Keratinization occurs as cells are pushed towards the surface. • Stratum corneum - outermost layer of dead cells.

  9. Epidermis • Epidermis protects underlying tissues against water loss, mechanical injury, and effects of harmful chemicals. • Melanin protects from UV light. • Melanocytes transfer melanin to epidermal cells.

  10. Epidermis Dead cells As cells are pushed up they become keratinized Basal cells undergoing mitosis

  11. Skin Color • All people have about the same concentration of melanocytes. • Skin color is due to the amount of melanin and the size of pigment granules in the epidermis. • Skin color is influences by environmental and physiological factors as well as genes.

  12. Skin Color • Albinism - genetic disorder characterized by no melanin, resulting in white skin and hair.

  13. Dermis • Binds the epidermis to the underlying tissues • Contains blood vessels that supply all skin cells with nutrients and regulate body temperature.

  14. Dermis • Contains nerve fibers • May carry impulses to muscles and glands of the skin. • May be associated with sensory receptors in the skin. • Contains hair follicles, sebaceous glands, and sweat glands.

  15. Subcutaneous Layer • Loose connective and adipose tissue • Conserves body heat. • Contains blood vessels that supply the skin and adipose tissue.

  16. Accessory Organs of the Skin • Hair follicles • Hair develops from epidermal cells at the base of a tubelike hair follicle. • Cells are keratinized and pushed towards the surface as new cells are formed.

  17. Accessory Organs of the Skin Hair Follicles cont…. • Smooth muscle cells attached to each follicle. • Hair color is determine by genes that determine how much melanin is produced.

  18. Accessory Organs of the Skin • Sebacceous Glands • Attached to hair follicles. • Secrete sebum (oily secretion) which keeps hair soft and water proof • Acne - infection of sebacceous glands

  19. Accessory Organs of the Skin • Nails • Protective covers on ends of fingers and toes. • Keratinized epidermal cells produce nails. • Keratin of nails is harder than that produced by the skin’s epidermal cells

  20. Accessory Organs of the Skin • Sweat Glands • Consists of a coiled tube. • Sweat - mostly water, also contains salts and waste products. • Eccrine sweat glands respond to elevated body temperature, while apocrine sweat glands respond to emotional stress.

  21. Regulation of Body Temperature • Regulation of body temperature is vital because heat affects the rates of metabolic reactions. • Normal body temperature is 37ºC (98.6ºF)

  22. Regulation of Body Temperature • Increase in body temperature causes dermal blood vessels to dilate and sweat glands to secrete sweat. • Decrease in body temperature causes dermal blood vessels to constrict and sweat glands become inactive.

  23. Regulation of Body Temperature • Excessive heat loss stimulates skeletal muscles to contract involuntarily. • Fever results from an elevated temperature set point.

  24. Healing of Wounds • Inflammation - affected area becomes red, warm, swollen and tender. • Dividing epithelial cells fill in shallow cuts. • Clots close deeper cuts, sometimes leaving a scar where connective tissue replaces skin. • Granulations form as part of the healing process.

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