Integumentary System Notes

Flashcards about the integumentary system, covering skin structure, epidermis, dermis, skin color, hair, nails, glands, functions, cancer, burns and development.

What are the components of the integumentary system?

Skin, hair, nails, sweat glands, and sebaceous (oil) glands

What are the two distinct regions of the skin?

Epidermis (superficial, epithelial, avascular) and Dermis (underlying, fibrous connective tissue, vascular)

What is the hypodermis?

A subcutaneous layer deep to the skin composed mostly of adipose tissue that absorbs shock and insulates providing an anchor to underlying structures.

What tissue type is the epidermis primarily composed of?

Keratinized stratified squamous epithelium

Name the four cell types found in the epidermis.

Keratinocytes, Melanocytes, Dendritic (Langerhans) cells, and Tactile (Merkel) cells

What is the function of keratinocytes?

Produce fibrous keratin, providing protection

What is the function of melanocytes?

Produce melanin, shielding keratinocyte nuclei from UV damage

What is the function of Dendritic (Langerhans) cells?

Key activators of the immune system

What is the function of Tactile (Merkel) cells?

Sensory touch receptors

List the five layers of the epidermis (from deepest to most superficial).

Stratum basale, Stratum spinosum, Stratum granulosum, Stratum lucidum, Stratum corneum

Which epidermal layer is only found in thick skin?

Stratum lucidum

What is the stratum basale?

The deepest epidermal layer with actively dividing stem cells and melanocytes.

What is the stratum spinosum?

Several cell layers thick, containing prekeratin filaments and dendritic cells.

What is the stratum granulosum?

A thin layer where cells flatten, keratinization begins, and cells accumulate keratohyaline and lamellar granules. Cells die above this layer

What is the stratum lucidum?

A clear layer of flat, dead keratinocytes found only in thick skin.

What is the stratum corneum?

The outermost layer with many rows of dead, keratinized cells that protect against the environment, prevent water loss, and act as a barrier.

What is the dermis?

Strong, flexible connective tissue containing fibroblasts, macrophages, nerves, blood vessels, and glands.

What are the two layers of the dermis?

Papillary and Reticular

What is the papillary layer?

The superficial layer of areolar connective tissue containing dermal papillae with capillary loops and nerve endings.

What is the reticular layer?

The deeper layer consisting of dense fibrous connective tissue, elastic fibers, and collagen fibers

What are cleavage (tension) lines?

Parallel collagen fibers in the reticular layer important for surgical incisions.

What are flexure lines?

Dermal folds at or near joints where the dermis is tightly secured.

What are striae?

Silvery white scars caused by dermal tears from extreme stretching of the skin.

Name the three pigments that contribute to skin color.

Melanin, Carotene, and Hemoglobin

What is melanin?

A pigment produced by melanocytes from tyrosine that protects skin from UV radiation.

What is carotene?

A yellow to orange pigment accumulating in the stratum corneum and hypodermis, which can be converted to vitamin A.

What contributes to the pinkish hue of fair skin?

Hemoglobin

What is cyanosis?

Blue skin color due to low oxygenation of hemoglobin.

What is pallor?

Blanching or pale color due to anemia or low blood pressure.

What is erythema?

Redness due to fever, hypertension, or allergy.

What is jaundice?

Yellow cast due to liver disorders.

What are bruises (ecchymoses or hematomas)?

Clotted blood beneath the skin.

What is hair (pili)?

Flexible strands of dead, keratinized cells produced by hair follicles.

What are the functions of hair?

Warning of insects, protection against physical trauma and heat loss, and shielding skin from sunlight.

What are the regions of hair?

Shaft (above scalp) and Root (within scalp)

Name the three parts of the hair shaft.

Medulla, Cortex, and Cuticle

What creates different hair colors?

Combinations of different melanins (yellow, rust, brown, black) and pheomelanin (red).

What is the hair bulb?

The expanded area at the deep end of the hair follicle which also contains the hair matrix

What is the hair matrix?

Actively dividing area of bulb that produces hair cells

What is the arrector pili?

Small band of smooth muscle attached to follicle, responsible for goose bumps.

What are the types of hair?

Vellus (pale, fine body hair) and Terminal (coarse, long hair).

What is alopecia?

Hair thinning in both sexes after age 40.

What is true (frank) baldness?

Genetically determined and sex-influenced condition in men that is also known as male pattern baldness.

What are nails?

Scale-like modifications of epidermis that contain hard keratin.

What is the nail matrix?

Thickened portion of nail bed, responsible for nail growth.

What is the eponychium?

Nail fold that projects onto surface of nail body also called the cuticle

What is the hyponychium?

Area under free edge of plate that accumulates dirt.

What is the lunule?

Thickened nail matrix, appears white.

What are sudoriferous glands?

Sweat Glands

Name the two types of sudoriferous glands.

Eccrine (merocrine) and Apocrine

What are myoepithelial cells?

Cells that contract upon nervous system stimulation to force sweat into ducts

Where are eccrine sweat glands most abundant?

Palms, soles, and forehead

What is the primary function of eccrine sweat glands?

Thermoregulation

Where are apocrine sweat glands confined?

Axillary and anogenital areas

What is the function of ceruminous glands?

Secrete cerumen (earwax) into the external ear canal.

What is the function of mammary glands?

Secrete milk

Where are sebaceous glands mostly located?

Develop from hair follicles and secrete into hair follicles.

What is sebum?

Oily holocrine secretion that softens hair and skin and has antibacterial properties. It is also secreted by sebaceous glands.

Name the functions of the skin.

Protection, Body temperature regulation, Cutaneous sensations, Metabolic functions, Blood reservoir, and Excretion of wastes

What are the three barriers provided by the skin for protection?

Chemical, Physical, and Biological

What is the acid mantle?

Low pH of skin that retards bacterial multiplication.

What is insensible perspiration?

Unnoticeable sweat production of about 500 ml/day under normal, resting body temperature.

What is sensible perspiration?

Noticeable sweat production designed to cool the body when body temperature rises.

What are exteroreceptors?

Cutaneous sensory receptors that respond to stimuli outside the body, such as temperature and touch.

What vitamin can the skin synthesize?

Vitamin D

What are the three major types of skin cancer?

Basal cell carcinoma, Squamous cell carcinoma, and Melanoma

Which is the least malignant and most common form of skin cancer?

Basal cell carcinoma

Which involves keratinocytes of stratum spinosum?

Squamous cell carcinoma

Which type of skin cancer is the most dangerous?

Melanoma

What is the ABCD rule?

Asymmetry, Border irregularity, Color, and Diameter (used for detecting melanoma)

Define First-degree burns.

Epidermal damage only

Define Second-degree burns.

Epidermal and upper dermal damage

Define Third-degree burns.

Entire thickness of skin involved

What is the Rule of Nines?

A method to estimate the extent and severity of burns by dividing the body into 11 sections, each representing 9% of body surface.

What is lanugo coat?

Delicate hairs in 5th and 6th month of fetal development.

What is Vernix caseosa?

Sebaceous gland secretion that protects skin of fetus while in watery amniotic fluid.