Chapter 5: The Integumentary System

Epidermis

Outer skin layer made of keratinized stratified squamous epithelium.

Dermis

Inner skin layer with blood vessels.

Subcutaneous tissue

Hypodermis, mostly adipose tissue for insulation.

Stratum basale

Deepest epidermis layer with new cell growth, contains melanocytes (skin color).

Stratum spinosum

Contains dendritic cells for immune response.

Stratum granulosum

Keratinization begins; cells start dying- they lose nutrients from blood supply.

Stratum lucidum

Only in thick skin like palms, soles, or fingerprints.

Stratum corneum

Outer layer of dead cells that shed constantly.

Keratinocytes

Main epidermal cell type producing keratin.

Keratin

Protein that makes skin tough and waterproof.

Papillary layer

First Dermis layer: consists of loose connective tissue that provides nutrients and touch. (touch receptors)

Reticular layer

Second Dermis layer: Dense connective tissue providing skin strength and structure.

Fingerprints

Result from friction ridges on skin. Stratum lucidum

Cleavage (tension) lines

Natural skin patterns due to collagen arrangement.

Surgeons make cuts parallel to these lines to help healing.

Melanin

Brown/black pigment providing natural sun protection.

Made by melanocytes

Carotene

Yellow/orange pigment found in skin and carrots.

Hemoglobin

Red pigment giving light skin a pink hue.

Cyanosis

Blueness due to lack of oxygen.

Erythema

Redness from inflammation, fever, or increased blood flow.

Lunula

White part at nail base, white due to thickened matrix

Eccrine sweat glands

Sweat glands for temperature regulation, found in palms, soles, forehead

Apocrine glands

Sweat glands in armpits, produce thicker sweat (body order).

Basal Cell Carcinoma

Least dangerous, most common skin cancer type.

Malignant Melanoma

Most dangerous skin cancer, spreads quickly.

A B C D rule

Guideline for identifying skin cancer characteristics.

Burn classification

First, second, and third-degree based on severity.

Diabetes or hormone disorder

Brown/black patches in skin folds

Pallor

Paleness caused by low blood flow, anemia

Jaundice

Yellow by liver disease

Arrector pili muscle

Contracts to make hair stand (goosebumps)

Root hair plexus

Detects hair movement

Why is scalp hair longer than eyebrow hair

Scalp hair has a longer growth phase

Terminal hair turns into

With age, terminal hair turns into vellus hair, making it thinner

Nail matrix

Responsible for nail growth

Sebaceous (oil) glands

produce sebum, found everywhere except palms/soles

Chemical skin barrier

Melanin, defensins, acid mantle (fights bacteria).

Physical skin barrier

Intact epidermis (keeps out harmful substances).

Biological skin barrier

Dendritic cells, dermal macrophages (immune defense).

Body temperature regulation

Sweat production cools the body.

Blood vessels dilate or constrict to release or conserve heat.

Skin receptor: free nerve endings

Pain & temperature.

Skin receptor: Meissner's corpuscles

Light touch.

Skin receptor: Pacinian corpuscles

Deep pressure & vibration.

Skin receptor: Hair follicle receptors

Detect hair movement.

Vitamin D production

Skin helps absorb calcium in the digestive system.

Squamous Cell Carcinoma

(grows faster, may spread) Skin cancer

A B C D rule for skin cancer:

A = Asymmetry

B = Border irregularity

C = Color variation

D = Diameter larger than 6mm

Frist degree burn

Red, only epidermis (e.g., sunburn).

Second degree burn

Blisters, epidermis + upper dermis.

Third degree burn

Entire skin destroyed, may look white or black.

Why do burn patients need nutrients via IV or gastric tube

because skin loss affects metabolism and healing.

What is the main cause of death in burn patients

Infection