Ch-05-Integumentary-handout

Integumentary System

Largest and most accessible organ system, covering 1.5–2 m² of surface area.

Cutaneous membrane

Composed of the epidermis and dermis, forming the outer layer of skin.

Cyanosis

Bluish discoloration of skin, indicative of poor circulation or oxygenation.

Epidermis

Outer layer of skin made up of 4 to 5 layers.

Dermis

Inner layer of skin composed of two layers: papillary and reticular.

Subcutaneous Layer

Also known as the hypodermis, this layer contains loose connective tissue.

Accessory Structures

Include glands, hair follicles, and nails associated with the integumentary system.

Thermoregulation

The process of maintaining an optimal body temperature via skin.

Keratinocytes

Primary cells in the epidermis that produce keratin.

Melanocytes

Cells that produce the pigment melanin, providing color to the skin.

Merkel Cells

Cells associated with sensory perception, especially fine touch.

Dendritic Cells

Wandering phagocytic cells involved in the immune response in the skin.

Stratum Basale

The deepest layer of the epidermis, primarily composed of basal cells.

Stratum Spinosum

Layer of the epidermis where keratin production begins, characterized by spiny appearance.

Stratum Granulosum

Layer of the epidermis where keratinocytes start to die and keratin production intensifies.

Stratum Lucidum

Clear layer found only in thick skin, consisting of dead keratinocytes.

Stratum Corneum

Most superficial layer of skin, made up of dead keratinocytes providing a protective barrier.

First-degree burn

A burn affecting only the upper epidermis.

Second-degree burn

A burn that damages the upper part of the dermis causing blisters.

Third-degree burn

A burn consuming the full thickness of skin, appearing white, red, or black.

Rule of nines

Method for estimating the percentage of body surface burned.

Melanin

Pigment produced by melanocytes, responsible for skin color.

Carotene

A pigment influencing skin color, derived from dietary sources.

Hemoglobin

Reddish pigment in red blood cells affecting skin color based on circulation.

Eccrine Sweat Glands

Most widespread sweat glands that regulate temperature through evaporative cooling.

Apocrine Sweat Glands

Sweat glands located in specific regions, activating at puberty and associated with body odor.

Sebaceous Glands

Glands that secrete sebum for lubrication and antimicrobial protection.

Ceruminous Glands

Glands that produce cerumen (earwax) in the external auditory canal.

Nail Plate

Covering structure formed by densely packed keratinocytes.

Nail Matrix

Region at the base of the nail responsible for nail growth.

Lunula

The crescent-shaped area of the nail that appears whitish due to a thickened matrix.

Eponychium

Cuticle area where the proximal nail fold meets the nail body.

Hyponychium

Thickening of stratum corneum beneath the free edge of the nail body.

Aging and the Integumentary System

Includes thinning of the epidermis, decreased glandular activity, and slower repair processes.

Dermal Papillae

Finger-like projections that interlock with epidermal ridges, increasing surface area.

Collagen fibers

Proteins in the dermis providing strength and structure.

Elastic fibers

Fibers that allow the skin to return to its original shape after stretching.

Capillary loops

Small blood vessels in the dermis that supply nutrients to the epidermis.

Dermal Circulation

Blood supply within the dermis, affecting skin color and temperature.

Sebum

Secreted by sebaceous glands; consists of lipids, proteins, and electrolytes.

Vernix Caseosa

A protective covering produced by fetal sebaceous glands.

Acne

Skin condition caused by blocked sebaceous glands.

Lanugo

Fine, soft hair that develops on the fetus.

Vellus Hair

Thin, short, and fine hair that replaces lanugo after birth.

Terminal Hair

Thick, long hair that develops during puberty.

Hair Follicle

Structure from which hair grows; includes the root and hair shaft.

Arrector Pili

Small muscle that causes hair to stand erect.

Root Hair Plexus

Bundle of nerve fibers around hair follicles, sensitive to touch.

Hair Matrix

Region at the base of the hair follicle where growth occurs.

Phalanx

Bone of the fingertip.

Accessory Structures of the Integument

Include nails, hair, and associated glands.

Epidermal Ridges

Fingerprints formed by the underlying dermal papillae.

Sympathetic Nervous System

Part of the autonomic nervous system responsible for involuntary responses.

Cholecalciferol

Vitamin D3 produced by skin in response to UV exposure.

Calcitriol

Active form of Vitamin D3 necessary for calcium absorption.

Hypodermis

Subcutaneous layer not part of the integument but important for fat storage.

Deep Pressure Sensors

Sensory receptors in the skin that respond to deep pressure.

Thick Skin

Type of skin found in the palmar and plantar regions.

Thin Skin

Type of skin found on the rest of the body, with fewer layers.

UV Exposure Effects

Increased melanin production, vitamin D synthesis, and potential DNA damage.

Body Odor

Result of bacterial breakdown of lipids and proteins in sweat.

Fetal Skin Protection

Function of sebaceous glands producing vernix caseosa.

Skin Cancer Types

Includes basal cell carcinoma, squamous cell carcinoma, and melanoma.

Keratinization

Process of keratin production and accumulation in epidermal layers.

Excretion

Process of removing waste through the skin.

Sensory Reception

Detection of stimuli via specialized skin receptors.

Physical Protection

Barrier provided by skin against pathogens and mechanical damage.

Vitamin D Synthesis

Process by which skin generates Vitamin D in the presence of UV light.

Lymphatic Vessels

Vessels that help drain excess fluids and play a role in immune response.

Areolar Connective Tissue

Loose connective tissue found in the papillary layer of the dermis.

Dense Irregular Connective Tissue (DICT)

Tissue forming the reticular layer of the dermis, providing strength.

Hair Cuticle

Outer layer of the hair shaft, composed of overlapping cells.

Hair Cortex

Middle layer of the hair shaft, containing melanin and keratin.

Hair Medulla

Inner layer of the hair shaft, present in some types of hair.

Body Surface Area

Measurement used in the Rule of Nines to assess burns.

Skin Repair Process

Healing of skin injuries involving various types of cells and signals.

Dermatology

Field of medicine specializing in skin disorders.

Sebaceous Follicles

Sebaceous glands with ducts leading directly to the skin surface.

Subpapillary Plexus

Network of blood vessels supplying the dermis and epidermis.

Cutaneous Plexus

Deep vascular network found in the dermis.

Hyperkeratosis

Thickening of the stratum corneum, often due to friction.

Hypopigmentation

Reduced melanin production resulting in lighter skin areas.

Constriction of Blood Vessels

Response to cold, reducing heat loss through the skin.

Expansion of Blood Vessels

Response to heat, allowing more blood flow and heat dissipation.