Skin Physiology PDF

PRAYER BEFORE CLASS Holy Spirit, Divine Creator, true source of light and fountain of wisdom! Pour forth your brilliance upon our dense intellect, dissipate the darkness which covers us, that of sin and of ignorance. Grant us a penetrating mind to understand, a retentive memory, method and ease in l...

PRAYER BEFORE CLASS Holy Spirit, Divine Creator, true source of light and fountain of wisdom! Pour forth your brilliance upon our dense intellect, dissipate the darkness which covers us, that of sin and of ignorance. Grant us a penetrating mind to understand, a retentive memory, method and ease in learning, the lucidity to comprehend, and abundant grace in expressing ourselves. Guide the beginning of our work, direct its progress, and bring it to successful completion. This we ask through Jesus Christ, true God and true man, living and reigning with You and the Father, forever and ever. Amen  SKIN PHYSIOLOGY PREPARED BY: THEO. MD BCM625 LEC DEPT. OF BIOCHEMISTRY CONTENTS Functional Layers of the Skin Physiological Processes: a. Skin Color b. Vitamin D production c. Thermal regulation d. Gland Secretion and Cutaneous glands e. Cutaneous Sensations Skin cancer and Burns INTEGUMENTARY SYSTEM Main Components: 1. Skin 2. Hair 3. Glands 4. Nails General Functions: 1. Protection 2. Sensation 3. Vitamin D production 4. Temperature regulation 5. Excretion FUNCTIONAL LAYERS OF THE SKIN EPIDERMIS Undergoes keratinization along the strata Keratinocytes eventually die Form an outer layer of dead, rigid cells that resist abrasion and form a permeability barrier Stratum basale – cuboidal or columnar cells that undergo mitotic divisions about every 19 days Stratum corneum –consists of 25 or more layers of dead cells with keratin FUNCTIONAL LAYERS OF THE SKIN EPIDERMIS FUNCTIONAL LAYERS OF THE SKIN DERMIS Has 2 layers: Papillary layer and Reticular layer Composed of dense collagenous connective tissue Nerves, hair follicles, smooth muscles, glands, and lymphatic vessels extend into the dermis Collagen fibers are oriented to form cleavage lines Stretch marks - lines of scar tissue develop in the skin of individuals who have experienced rapid growth a. SKIN COLOR Melanin Group of pigments primarily responsible for skin, hair, and eye color. Largely found in freckles, moles, the nipples, the areolae of the breasts, the axillae, and the genitalia. Influenced by genetics, light exposure and hormones a. SKIN COLOR Melanin Produced by melanocytes Extends between the stratum basale and stratum spinosum Provides protection against ultraviolet light from the sun SKIN COLOR ALTERATION ERYTHEMA CYANOSIS XANTHODERMA ALBINISM JAUNDICE GLAND SECRETIONS Glands Secretory organs that are composed of epithelium and connective tissue Two types: Exocrine glands and Endocrine glands Mostly are multicellular Structures: Simple and Compound glands  GLAND SECRETIONS Type of Secretion: Merocrine Apocrine Holocrine CUTANEOUS GLANDS All are exocrine glands Not all are functional Types Sebaceous glands - sebum Sweat glands (sudoriferous glands) Eccrine – numerous in palms and soles Apocrine – armpits and genitalia Ceruminous glands Mammary gland  VITAMIN D PRODUCTION Enough sunlight exposure can provide an adequate amount Exogenous source: Fatty fish and Fortified milk Active vitamin D stimulates the small intestine to absorb calcium and phosphate https://clinref.com/rheumatology/vitamin-d-metabolism/ TEMPERATURE REGULATION HYPERTHERMIA HYPOTHERMIA SENSATION Process initiated by stimulating sensory receptors Sensory nerve endings or specialized cells Perception Conscious awareness of those stimuli GENERAL SENSES Widely distributed in the body (majority are in the skin) Sensory receptors are classified into: 1. Stimulus 2. Location 3. Structure Free nerve endings – simplest and most common sensory receptors 1. LOCATION OF SENSORY RECEPTORS CUTANEOUS RECEPTORS – external information VISCERORECEPTORS – internal information PROPRIOCEPTORS – body position, movement, and muscle stretching/contraction 2. STIMULI OF SENSORY RECEPTORS MECHANORECEPTORS – compression, bending, or stretching of cells CHEMORECEPTORS THERMORECEPTORS – cold and warm receptors PHOTORECEPTORS NOCICEPTORS - intense mechanical, chemical, and thermal stimuli 3. STRUCTURE OF SENSORY RECEPTORS OTHER PHYSIOLOGICAL FUNCTIONS ABSORPTION – Vitamins and other drugs EXCRETION – 400 mL of water vapor BLOOD RESERVOIR SKIN CANCER Most common type of cancer High-risk populations: Common Etiologies: Fair-skinned Chemicals Older than 50 X ray Radiations Family history of skin cancer UV light exposure History of repeated sunburns  MAIN TYPES OF SKIN CANCER 1. Basal Cell Carcinoma 2. Squamous Cell Carcinoma 3. Melanoma Affects the Basale and extends Affects the Spinosum Most deadly and highly to the dermis Nodular, keratinized tumor metastatic Varied appearance confined to the epidermis Arises from melanocytes Most are cured by surgical Tends to invade if untreated Appear as a large, flat, spreading removal or radiation therapy Most are cured by surgical lesion or as a deeply pigmented nodule (usually black or brown) removal or radiation therapy PREVENTION OF SKIN CANCERS Routine examination of the skin Limiting exposure to the sun Using broad- spectrum sunscreen BURNS Skin tissue injury caused by thermal, chemical, friction, electrical, or radiation Classified based on the depth Partial-thickness 1. First-degree 2. Second-degree Full-thickness 3. Third-degree  THANK YOU LISTENING! PREPARED BY: THEO. MD BCM625 LEC DEPT. OF BIOCHEMISTRY