Comprehensive Integumentary System Anatomy, Histology, Physiology, and Pathology (copy)

Epidermis

The outermost protective shield of the body, composed of keratinized stratified squamous epithelium.

Dermis

The vascular, tough layer of fibrous connective tissue located beneath the epidermis.

Hypodermis

The subcutaneous layer composed primarily of adipose connective tissue.

Keratinocytes

The predominant cell type in the epidermis responsible for synthesizing keratin.

Melanocytes

Cells that synthesize the pigment melanin and are located in the stratum basale.

Dendritic Cells

Star-shaped macrophages in the epidermis that act as antigen-presenting immune sentinels.

Tactile Cells

Cells associated with sensory nerve terminals that function as mechanoreceptors for light touch.

Stratum Basale

The deepest layer of the epidermis with actively mitotic cells attached to the dermis.

Stratum Corneum

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

Keratinization

The process by which keratinocytes transition from living cells to dead, keratin-filled cells.

Thick Skin

Skin type containing five strata found in high-friction areas like palms and soles.

Thin Skin

Skin type covering most of the body and lacking the stratum lucidum.

Sebaceous Glands

Glands that secrete sebum and are associated with hair follicles.

Sudoriferous Glands

Sweat glands categorized into eccrine and apocrine types.

Vascularized Dermis

The layer of skin that supplies nutrients to the avascular epidermis through diffusion.

Cutaneous Plexus

A network of blood vessels located at the junction of the reticular dermis and hypodermis.

Cleavage Lines

Lines in the skin defined by the orientation of collagen fibers, important for surgical incisions.

Flexure Lines

Lines formed in the skin at joints due to the tighness of the dermis.

Cyanosis

Bluish discoloration of the skin indicating low oxygen saturation in hemoglobin.

Erythema

Abnormal redness of the skin often due to increased blood flow.

Jaundice

A yellowing of the skin and eyes due to bile pigment buildup.

Photolyzed Cholesterol

Cholesterol in skin converted to vitamin D3 by UV radiation.

First-Degree Burn

Burn affecting only the epidermis, marked by redness and pain.

Second-Degree Burn

Burn affecting the entire epidermis and part of the dermis, causing blisters.

Third-Degree Burn

Burn destroying the full thickness of the skin, resulting in charred tissue.

Rule of Nines

A method to estimate the total body surface area (BSA) burned.

Vernix Caseosa

A greasy protective coating formed by sebaceous glands in fetuses.

Derivatives of the Epidermis

Structures like hair, nails, and glands formed from epidermal cells.

Melanin

A pigment produced by melanocytes responsible for skin color.

Carotene

A yellow-orange pigment found in some fruits and vegetables that can accumulate in the skin.

Hemoglobin

A protein in red blood cells that carries oxygen and affects skin color.

Alopecia

Generalized thinning of hair or baldness.

Acne

Chronic inflammatory skin condition caused by bacterial infection of sebaceous glands.

Striae

Stretch marks resulting from rapid skin stretching.

Blister

A fluid-filled pocket that forms in response to friction or burn.

Myofibrils

Cells in muscle tissue that facilitate contraction and movement.

Sensation

The ability to perceive stimuli through sensory receptors in the skin.

Soft Tissue

The tissues that surround and support organs including skin, fat, and connective tissues.

Fluid Resuscitation

The process of replenishing bodily fluids lost to burns or dehydration.

Epidermal Growth Factors

Proteins that stimulate cell division to aid skin repair and regeneration.

Steroids

Hormones that can affect hair growth and skin thickness.

Lymphatic Vessels

Vessels that transport lymph, playing a role in immune function within the skin.

Integumentary System

The organ system that includes skin, hair, nails, and glands.

Thermoregulation

The process of maintaining an optimal body temperature through sweating and blood flow.

Mast Cells

Cells that play a crucial role in allergic reactions and local immune responses.

Pacinian Corpuscles

Mechanoreceptors that detect deep pressure and vibration.

Merkel Cells

Cells in the skin that function as touch receptors.

Basal Cell Carcinoma

The most common type of skin cancer arising from the stratum basale.

Squamous Cell Carcinoma

Skin cancer that arises from keratinocytes in the stratum spinosum.

Melanoma

The deadliest form of skin cancer, originating from melanocytes.

Sebum

An oily substance produced by sebaceous glands to lubricate skin and hair.

Hypoxia

A deficiency of oxygen in the tissues, often leading to cyanosis.

Desmosomes

Cell junctions that anchor cells together in the epidermis.

Intermediate Filaments

Structural components that provide mechanical support to the cytoskeleton.

Homeostasis

The regulatory process to maintain stability in the body's internal environment.

Granulation Tissue

New connective tissue formed during wound healing.

Apocrine Sweat Glands

Sweat glands that secrete a thicker fluid and become active during puberty.

Monocytes

A type of white blood cell that differentiates into macrophages in tissues.

Keratin

A structural protein that forms the outer layer of skin, hair, and nails.

Skin Cancer Risk Factors

Factors such as UV exposure that increase the likelihood of developing skin cancer.

Nail Matrix

The region of growth for the nail, beneath the cuticle.

Basement Membrane

A thin layer separating the epidermis from the dermis.

What are the epidermal layers in order (deep to superficial)?

basale, spinosum, granulosum, lucidum, corneum.

Which epidermal layers contain living cells?

Basale and spinosum; cells begin dying in granulosum.

What is special about the stratum basale?

Deepest layer; actively dividing cells (mitosis).

What is special about the stratum spinosum?

Spiky keratinocytes, desmosomes, melanosomes, dendritic cells.

What is special about the stratum granulosum?

Keratinization begins; lamellar granules resist water loss.

Where is the stratum lucidum found?

Only in thick skin: palms and soles.

What is special about the stratum corneum?

Outermost; dead keratinized cells that shed; ~75% of epidermis.

Which dermal layer makes up about 80% of the dermis?

Reticular layer; dense connective tissue with collagen and elastic fibers.

What is the papillary dermis made of?

Areolar connective tissue; dermal papillae help form friction ridges.

Where are apocrine and eccrine sweat glands located?

Apocrine: armpits and anogenital region. Eccrine: palms, soles, forehead and most skin.

What are the three regions of a hair shaft?

Medulla, cortex, cuticle.

What is alopecia areata?

Hair loss caused by an immune system disorder.

What are the two nail folds/regions called eponychium and hyponychium?

Eponychium: cuticle at nail base. Hyponychium: skin beneath free nail edge.

What gives the nail bed its pink color?

Blood in underlying capillaries.

What is the difference between basal cell carcinoma, squamous cell carcinoma, and melanoma?

Basal: basale, most common; squamous: spinosum keratinocytes; melanoma: melanocytes, deadliest.

Which skin cancer is most common and which is most deadly?

Most common: basal cell carcinoma. Most deadly: melanoma.

How does skin help prevent infection?

Keratinized layers, tight junctions, antimicrobial defensins and immune cells.

What happens to skin blood vessels in cold vs heat?

Cold: constrict to conserve heat. Heat: dilate to release heat.

What are the key differences between first-, second-, and third-degree burns?

First: epidermis only; second: epidermis and part of dermis; third: full thickness.

What are the functions of apocrine vs eccrine glands?

Apocrine: scent-related secretion; eccrine: cooling through sweating.

What is the difference between melanin and melanocytes?

Melanocytes make melanin; melanin pigment protects DNA from UV.

What is the lamellated (Pacinian) corpuscle responsible for?

Sensing deep pressure and vibration