BIOL 2120K: Human A&P I - Integumentary System Notes (copy)

Epidermis

The superficial region of the skin made of epithelial tissue.

Dermis

The layer of skin primarily composed of fibrous connective tissue beneath the epidermis.

Hypodermis

The layer of tissue mostly made of adipose tissue that is not part of the skin but performs functions like shock absorption and heat insulation.

Keratinocytes

The predominant cell type in the epidermis that produces the fibrous protein keratin.

Melanocytes

Cells found in the deepest epidermis, responsible for producing the pigment melanin.

Dendritic Cells

Immune system activators found in the epidermis that play a role in antigen presentation.

Tactile Cells

Sensory touch receptors located in the epidermis.

Stratum corneum

The most superficial layer of the epidermis, consisting of keratinized dead cells.

Stratum lucidum

A translucent layer found only in thick skin, such as the palms and soles.

Stratum granulosum

A layer of the epidermis where organelles start to deteriorate and cytoplasm fills with granules.

Stratum spinosum

An intermediate layer of the epidermis with desmosomes and contains melanosomes.

Stratum basale

The deepest layer of the epidermis where mitotic stem cells are found.

Dermal papillae

Peg-like projections in the dermis that enhance grip and contribute to fingerprint patterns.

Cleavage lines

Collagen fibers in the dermis that run parallel to the skin surface, important for surgical markings.

Flexure lines

Dermal folds at joints that securely attach the dermis to underlying structures.

Striae

Silvery-white scars resulting from dermal tearing due to extreme stretching.

Blister

A fluid-filled pocket that separates the epidermal and dermal layers, usually from trauma.

Melanin

A pigment produced by melanocytes that contributes to skin color and protects against UV damage.

Carotene

A yellow to orange pigment that accumulates in the stratum corneum and hypodermis and can convert to vitamin A.

Hemoglobin

A protein in red blood cells responsible for carrying oxygen and contributing to the pinkish hue of fair skin.

Cyanosis

A condition indicating low oxygenation of hemoglobin, resulting in a bluish tint of the skin.

Erythema

Redness of the skin resulting from fever, inflammation, or allergic reactions.

Pallor

An unnatural paleness of the skin often associated with anemia or low blood pressure.

Jaundice

A yellowing of the skin and eyes indicating liver dysfunction.

Alopecia

Hair thinning or loss that can occur in both sexes, especially with aging.

Sebaceous (Oil) Glands

Glands that secrete sebum to lubricate skin and hair, helping to slow water loss.

Merocrine Sweat Glands

Sweat glands that are most numerous and play a key role in thermoregulation, primarily found on palms, soles, and forehead.

Apocrine Sweat Glands

Larger sweat glands located in axillary and anogenital areas; secrets a thicker, milky sweat.

Basal Cell Carcinoma

The least malignant and most common type of skin cancer originating from stratum basale cells.

Squamous Cell Carcinoma

A skin cancer that can metastasize, largely affecting keratinocytes of the stratum spinosum.

Melanoma

The most serious form of skin cancer, arising from melanocytes and known for its high metastatic potential.

Burns

Tissue damage caused by heat, chemicals, or electricity, classified by severity and requiring medical attention.

First-degree burn

A burn that affects only the epidermis, causing redness and pain.

Second-degree burn

A burn affecting the epidermis and upper dermis, characterized by blisters and discoloration.

Third-degree burn

A full-thickness burn that destroys the entire skin layer, often requiring skin grafts for treatment.