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Integumentary System . ST110 Concorde Career College, Portland. Objectives. Define the term integument Describe the functions of the integumentary system List and identify the structures of the integumentary system and describe the function of each Identify the layers of the skin.
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Integumentary System ST110 Concorde Career College, Portland
Objectives • Define the term integument • Describe the functions of the integumentary system • List and identify the structures of the integumentary system and describe the function of each • Identify the layers of the skin
Objectives • List the appendages of the integumentary system and describe the function of each • Describe the mechanism by which the integumentary system helps to maintain homeostasis
Objectives • Describe common diseases, disorders, and conditions of the integumentary system including signs and symptoms, diagnosis, and available treatment options • Demonstrate knowledge of medical terminology related to the integumentary system verbally and in the written form
General Information • The term integument means covering • The integumentary system consists of the skin and its appendages • The skin is a membrane because it is a thin layer of tissue that covers the entire body
General Information • Largest organ • First line of defense • Protects against the invasion of microbes • Barrier for ultraviolet rays • Covers and protect external surface & internal structures • Aids in control of body temperature • Sense of touch- organ activity • Self-repairing/Regenerating • Waterproof barrier • Manufacturing of Vitamin D • Drug absorption
Interesting Facts Contents of one square centimeter of skin!
Three Main Functions of the Skin 1. Protection 2. Regulation 3. Receptors
Function - Protection • First line of defense from microbes, chemicals, UV rays… • Melanin protects us to a degree, however repeated & long exposure to the sun w/o protection can lead to skin cancer
Function - Regulation • Body Temperature • Radiation • Conduction • Convection • Hypothermia • Hyperthermia
Function - Regulation • Vitamin D • UV rays from the sun stimulate the production of Vitamin D progenitor molecules by the skin • These molecules travel to the liver and kidneys where they mature into Vitamin D • Essential for metabolism of calcium
Function - Receptors • Sensation • Touch/pressure • Pain • Warmth • Cold • Nerve endings act as receptors for sensation • Thermoreceptors: Temperature • Nociceptors: Pain • Mechanoreceptors: Touch/pressure/stretch • Receptors send messages to the cerebral cortex for interpretation
Functions - Receptors • Merkel Discs (Cells): touch impulses • Pacinian Corpuscles: sense pressure & vibrations • Meissner’s Corpuscles: sense changes in texture & slow vibrations • Ruffini Corpuscles: senses slipping and stretching • Krause end Bulbs aka mucocutaneous Corpuscles: detect temperature
Structures of the Integumentary System • Epidermis • Dermis • Subcutaneous Layer • Appendages of the skin • Sweat glands • Sebaceous glands • Hair • Nails
Epidermis squamous epithelium (scale like) “tightly packed together”
Epidermis • Outer most layer of the skin and is avascular • Composed of Stratified SquamousKeratinized Epithelium • Keratinocytes –epidermal cells • Does not contain blood vessels
Layers of the Epidermis 1. Stratum corneum 2. Stratum lucidum 3. Stratum granulosum 4. Stratum spinosum 5. Stratum basale
Integumentary System Stratum Germinativum • Deepest layer • Contains the only cells that perform mitosis • Also called the stratum basale • The layer that rests on the superficial fascia • Contains melanocytes - melanin is produced in this layer
Integumentary System Stratum Spinosum • Many layers • Spiny-shaped cells
Integumentary System Stratum Granulosum • Two or three layers thick • Flattened cells • Granules accumulate here
Integumentary System Stratum Lucidum • Just below the stratum corneum • Cells are transparent and flat • One or two layers thick
Integumentary System Stratum Corneum • Outermost layer of the epidermis • Consists of dead cells converted to protein • Surrounded by lipids • Constantly being sloughed off • Dandruff • The thickness of the layer is determined by the amount of stimulation or pressure • Callus-area exposed to much abrasion and friction • Corn-abrasions on bony prominences of the foot
Dermis • Deeper of the two layers of skin • Aka corium • Located below the epidermis • Contains capillary vessels, nerves, hair follicles, and glands • Composed of loose fibrous connective tissue • Divided into 2 layers: • Papillary layer • Dermal papillae • Reticular layer
Integumentary System Divisions of the Dermis 1. Papillary layer 2. Reticular layer
Dermis Cells loosely packed together (mostly connective tissue)
Subcutaneous Tissue Layer • Aka Hypodermis • Connects dermis to underlying structures • Consists of areolar and adipose tissue • Adipocytes: cells that store fat • Insulates from cold • Acts as a cushion for internal organs
Hair • Characteristic of all mammals • Amount of hair is related to genetic factors • Growth • The deepest layer of cells is responsible for mitosis and continuously is pushed up from the basement membrane • Hair growth begins in the hair bulb • Scalp Hair typically grows for 3 years and rests for 1 to 2 years • The presence of the hair follicles allows for new growth
Hair • Hair areas: • Cuticle-outermost portion • Cortex-underneath the cuticle • Medulla-central portion • Shaft-visible portion • Hair root-inside hair follicle in the stratum germinativum • ArrectorPili Muscle-attached to hair follicle
Hair • Texture • Genetics control if the hair is curly, straight, kinky • Color • Determined by heredity and some environmental factors • Gray hair starts to occur when pigment is absent in the cortex
Hair • Alopecia (al-uh-pee-shee-uh)= The partial or complete absence of hair from areas of the body where it normally grows; baldness • Hirsutism (hur-soo-tiz-uhm) = Excessive hairiness, especially in women
Nails Medical Term onxy/onych = nail
Nails • Very hard keratinized cells • Nail areas • Lunula-white half-moon shaped area at nail base • Nail body-visible area • Nail root-inside the nail bed • Cuticle-a layer of stratum corneum extending over the nail body • Free edge
Sebaceous Glands • Along the walls of hair follicles • Produce sebum-oily substance that lubricates skin • Vernixcaseosa • Acne
Sebaceous Glands • Located throughout the body • Largest # in face • Very active in puberty (due to androgen) • Excess of sebum within the glands • Glands become clogged (blackhead) • Easily infected (pimple) • Meibomian Glands: • Largest sebaceous glands • Located in the eyelids
Sudoriferous Glands Sweat Glands (Sudoriferous Glands) • Two main types • Merocrine • Apocrine • Found in most body regions except margins of lips and head of penis • Consist of a secretory portion and an excretory duct • Body Odor • Modified glands • Ceruminous, ciliary, mammary
Trivia • The odor associated with apocrine gland secretion is not caused by the secretion itself… it is caused by the contamination and decomposition of the secretion by skin bacteria!!!
Ceruminous Glands • Located in the dermis of the auditory canal • Secrete yellow substance called Cerumen(ear wax) • Prevents auditory canal and tympanic membrane from drying out
Blood Supply • Arterioles supplying the skin help maintain body temperature • Vasodilate: increasing blood flow to the dermis, transferring heat to the skin surface to escape from the body
Skin Pigmentation • Melanin concentrations determine the variations in skin color of individuals and races as well as Suntans and Freckles • Melanin protects keratinocytes from the carcinogenic ultraviolet rays of the sun • Albinism – recessive gene or mutation that prevents the production of melanin. Therefore the individual has no skin color • Cyanosis - Caused by a lack of blood oxygen or decreased blood flow; turns skin a bluish-gray color
Immune Response of the Skin • Langerhans cells • phagocytize bacteria that enter through breaks in the skin • Attack cancerous cells • Attract T-cells important in allergic reactions • Allergic contact dermatitis
Common Disorders and Diseases • Ringworm • Fungus • Athlete’s foot • Jock itch
Common Disorders and Diseases • Psoriasis • Unknown cause • Red patches covered with thick, dry scales • Overproduction of epithelial cells