KIN 223 CHAPTER 6 LESSON OBJECTIVES

Stratum Corneum

Most superficial layer of the epidermis with 20-30 layers of dead, flattened, keratin-filled keratinocytes.

Stratum Lucidum

Layer seen only in thick skin, such as palms and soles; may not be present in all skin types.

Stratum Granulosum

Contains 3 to 5 layers of keratinocytes where keratinization begins, leading to cell death.

Stratum Spinosum

Several layers of keratinocytes with new cells pushed from the stratum basale; contains epidermal dendritic cells.

Stratum Basale

Deepest layer of the epidermis with a single layer of cuboidal to columnar cells; contains keratinocytes, melanocytes, and tactile cells.

Thick Skin

Found on palms and soles, has 5 layers of epidermal strata, sweat glands, but no hair or sebaceous glands.

Thin Skin

Covers most of the body, lacks stratum lucidum, has sweat glands, hair follicles, and sebaceous glands.

Hemoglobin

Oxygen-binding protein in red blood cells that gives a red color when bound to oxygen.

Melanin

Dark pigment produced by melanocytes in response to UV light; includes eumelanin (brown/black) and pheomelanin (lighter shades).

Carotene

Yellow-orange pigment acquired from certain vegetables.

Nevus

A mole on the skin.

Freckles

Yellowish or brown spots due to melanocyte activity.

Hemangiomas

Skin discoloration caused by benign blood vessel tumors.

Friction Ridges

Fingerprints formed by large folds and valleys of dermis and epidermis.

Papillary Layer

Superficial region of the dermis made of areolar connective tissue with dermal papillae.

Reticular Layer

Deeper portion of the dermis composed of dense irregular connective tissue.

Cleavage Lines

Lines in the dermis that indicate the direction of collagen and elastic fibers, important for surgical incisions.

Subcutaneous Layer

Deep to the dermis, composed of areolar and adipose connective tissue; functions in protection, energy storage, and insulation.

Integument Functions

Protection, prevention of water loss/gain, vitamin D synthesis, secretion, absorption, immune function, temperature regulation, and sensory reception.

Temperature Regulation

Dermal blood vessels can vasoconstrict to conserve heat or vasodilate to release heat.

Nail Structure

Form on the dorsal edges of fingers and toes, protecting distal tips and assisting in grasping objects.

Hair Structure

Found almost everywhere except certain areas; includes hair bulb, hair papilla, root, shaft, and hair matrix.

Anagen Phase

Growth phase of hair where living cells in the hair bulb rapidly divide and transform into hair.

Catagen Phase

Transitional phase where cell division ceases and the hair follicle undergoes involution.

Telogen Phase

Phase where hair is shed.

Merocrine Sweat Glands

Simple coiled tubular glands that discharge secretions directly onto the skin surface; primarily for thermoregulation.

Apocrine Sweat Glands

Coiled tubular glands that release secretions into hair follicles in specific body regions.

Regeneration

Replacement of damaged cells with the same cell type, restoring tissue function.

Fibrosis

Process of scar tissue formation in connective tissue healing, binding damaged parts together.

Wound Healing Process

Involves bleeding, blood clot formation, leukocyte cleaning, blood vessel regrowth, granulation tissue formation, and regeneration of epithelium.

Ectoderm

The layer that forms the epidermis during development.

Mesoderm

The layer that gives rise to the dermis during development.

Development of Nails, Hair, and Glands

Begins around the 10th week of development; nails reach tips by 32 weeks, hair follicles appear between 9-12 weeks.

Aging Skin Changes

Reduced stem cell activity leads to thinner skin, decreased collagen fibers, and increased susceptibility to mechanical trauma.

Skin Cancer Risk Factors

Excessive UV exposure, new moles after sunburn, and raised scales are warning signs.