The Integumentary System A Skin 1 Anatomy 2

The Integumentary System A. Skin 1. Anatomy 2. Physiology 3. Epidermis 4. Dermis B. Glands 1. Sebaceous (oil) glands 2. Sudoriferous (sweat) glands a. Eccrine b. Apocrine C. Thermoregulation: homeostasis of body temperature

Cells Tissues Organs System Integumentary System- Skin, hair, nails, glands, and enamel of teeth

Integumentary System 1. epidermis 2. dermis 3. derivatives ________ 4. hypodermis

Skin Has 7 Functions 1. 2. 3. 4. 5. 6. 7. regulation of body temperature protection sensation excretion immunity blood reservoir synthesis of vitamin D

Epidermis 1. keratinized stratified squamous epithelium 2. four main cell types: a. keratinocytes (90%) b. melanocytes (about 8%) c. Langerhans cells (1%) d. Merkel cells (1%)

Epidermal Layers 1. stratum basale 2. stratum spinosum 3. stratum granulosum 4. stratum lucidum 5. stratum corneum __________ keratinizing system Thick Skin

Keratinizing System Keratin gives skin a waterproof, anti-microbial, and abrasion-resistant barrier 25 -30 rows of fat dead cells filled with keratin Thick skin only 3 -5 rows of clear, dead cells packed With eleidin-keratin intermediate 3 -5 rows-begin producing keratohyalin 8 -10 rows-derived from Keratinocytes below- receive Melanin. Mitotic zone-keratinocyte stem Cells, melanocytes and Merkel cells.

EPIDERMAL LAYERS (the keratinizing system) thick skin exfoliation cell death keratin eleidin keratinization stratum corneum stratum lucidum stratum granulosum keratohyalin stratum spinosum mitosis stratum basale dermis

The House Dust Mite. Dermatophagoides

Dermis 1. papillary 2. reticular ______ functions Loose areolar tissue Elasticity, Extensibility, And Thermoregulation Dense irregular

Skin Glands Axillary region, pubic, breasts, Beards in men. Viscous milky Fluid-no odor Sebum 1. Sebaceous (oil) glands 2. 2. Sudoriferous (sweat) glands. Secretion 3. a. merocrine (eccrine) Combines with Sweat forms 4. b. apocrine Acid mantle (eccrine) Most Common 90% water Thermoregulation

Protective Functions of the Epidermis 1. 2. 3. 4. acid mantle role of keratin role of the stratum corneum role of the stratum granulosum

Thermoregulation 1. homeotherms vs poikilotherms 2. arterio-venous (AV) plexuses AV plexus

BODY TEMPERATURE CONTROLLED CONDITION A stimulus or stress disrupts homeostasis by causing an increase in body temperature negative feedback RETURN TO HOMEOSTASIS Evaporation of sweat from skin removes body heat, thus lowering body temperature and mechanism turns off RECEPTOR Thermoreceptors in skin and hypothalamus are activated and send nerve impulses to the control center EFFECTORS 1. Increased sweat output 2. blood vessels vasodilate, bringing heat to body surface CONTROL CENTER Hypothalamic control center sends nerve impulses to sweat glands and skin blood vessels end