ANPH - Integumentary System

• Integumentary System: consists of the skin and accessory structures such as the hair, glands, and nails
• The appearance of the skin can indicate physiologic imbalances in the body
• Functions of the Integumentary System: Protection, Sensation, Vitamin D production, Temperature regulation, Excretion
• Sensation: important function of the dermis to detect the different sensations of heat, cold, pressure, contact, and pain.
• Protection: Skin is an elastic covering. It protects you against exposure to dangerous things in the environment such as bacteria.
• Protection: Also repels water, minimizes water loss from the body and protects underlying structures such as blood vessels, nerves and organs
• Thermoregulation: process that allows the body to maintain its core internal temperature.
• Secretion: Sebum (oil) secreted by sebaceous glands has antifungal and antibacterial properties and helps maintain the texture of the skin
• The skin consists of two layers: the epidermis, and a deeper layer of dense irregular connective tissue, the dermis (also known as corium)
• Epidermis: This is the outer, relatively thin layer of the skin that is composed of closely packed cells with little intercellular material
• Epidermis: It is composed of stratified squamous epithelium that in most areas can be divided into different sub-layers.
• Sub-Layer of Epidermis: Stratum Corneum, Stratum Lucidum, Stratum Granulosum, Stratum Spinosum, Stratum Basale
• Stratum Corneum: It forms the outermost layer of the epidermis and consists of dead cells completely filled with protein called keratin.
• Stratum Corneum: where keratinized cells are constantly in the process of flaking off the surface of the skin in the form of dandruff. And exposed to the outside environment
• Stratum Lucidum: A smooth, seemingly translucent layer of the epidermis located just above the stratum granulosum and below the stratum corneum.
• Stratum Lucidum: The keratinocytes that compose this sub-layer are dead and flattened. These cells are densely packed with eleiden, a clear protein rich in lipids, derived from keratohyalin.
• Stratum Granulosum: Latin term which literally means granular layer
• Stratum Granulosum: This layer is found in between the stratum corneum (or stratum lucidum, when present) and the stratum spinosum. These keratinocytes are particularly referred to as granular cells.
• Stratum Granulosum: They contain keratohyalin granules, which aid in the binding of the keratin filaments together. These cells also have lamellar bodies filled with lipids, which are released into the extracellular space through exocytosis.
• Lipids: These diverse compounds that make up the lipid family are grouped because they are insoluble in water. They are also soluble in other organic solvents such as ether, acetone, and other lipids
• Stratum Spinosum: The keratinocytes in this sub-layer are referred to as prickle cells. This layer is found in between the stratum basale and the stratum granulosum.
• Stratum Spinosum: where the keratinocytes are polyhedral in shape and with large pale-staining nuclei and are actively synthesizing fibrillary proteins that are essential for the formation of desmosomes
• Stratum Basale: also called Stratum Germinativum
• Stratum Basale: Is the deepest epidermal layer and attaches the epidermis to the basal lamina.
• Dermis: Composed of dense collagenous connective tissue containing fibroblasts, adipocytes, and macrophages
• Dermis: Nerves, hair follicles, smooth muscles, glands, and lymphatic vessels extend here
• Reticular Layer: Deep part of dermis composed of dense irregular connective tissue
• Hypodermis: Composed of loose connective tissue that separates the dermis from underlying structures such as bone and deep fascia.
• Hypodermis: It permits a layer of fat to be interposed between the skin and deeper structures
• Cleavage Lines: separation of bundles of collagen fibers form lines of cleavage in the skin
• Cleavage Lines or Langer's cleavage lines
• Blepharoplasty: repairs the droopy eyelids; remove excess skin, muscles, and fat
• Intradermal injection: into the dermis. e.g. skin test
• Subcutaneous injection: below the dermis. e.g. insulin
• Intramuscular injection: into the muscle; vaccines
• Factors that determine skin color: Skin pigments, Blood circulating through the skin, Thickness of the stratum corneum
• Melanin: pigments primarily responsible for skin, hair, and eye color which protects us against UV light
• Melanocytes: produces melanin
• Vitiligo: of unknown cause, may be autoimmune in nature where melanocytes either die or become non-functional
• Albinism: congenital disorder caused by lack of skin pigments; caused by mutation in the TRP-1 gene leading to deficiency of an enzyme (Tyrosinase) required in melanin production