Integumentary system

Integumentary System

An organ system consisting of the skin, hairs, nails, and glands.

Skin

The biggest organ in the body, weighing approximately 20 lbs in an adult person.

Skin, hairs, nails, and glands.

Components of the Integumentary System

Protection, sensation, vitamin D production, temperature regulation, and excretion.

Functions of the Integumentary System

Touch Sensory Receptor

Detected by Meissner's corpuscle.

Pain Sensory Receptor

Detected by bare nerve endings.

Heat Sensory Receptor

Detected by corpuscle of Ruffini.

Cold Sensory Receptor

Detected by end bulb of Krause.

Pressure Sensory Receptor

Detected by Vater Pacinian corpuscles.

Epidermis

The outer layer of the skin that prevents water loss and resists abrasion, consisting of 5 layers.

stratum corneum, stratum lucidum, stratum granulosum, stratum germinativum, and stratum basale.

Layers of the Epidermis

Keratinization

The process where skin cells are filled with the protein keratin, making them more rigid and durable, eventually leading to dead epithelial cells that form a rigid, semi-permeable membrane that resists abrasion.

Dermis

The skin layer composed of dense collagenous connective tissues containing fibroblasts, adipocytes, macrophages, nerves, hair follicles, smooth muscles, glands, and lymphatic vessels.

Melanin

A group of pigments primarily responsible for skin, hair, and eye color that provides protection from ultraviolet light of the sun and is concentrated in moles, freckles, genitalia, and nipples.

Melanocytes

Specialized pigment-producing cells located in the epidermis that produce melanin.

Melanosomes

Tiny vesicles within melanocytes where melanin is synthesized and stored.

Eumelanin

A type of melanin responsible for brown and black colors in skin, hair, and eyes.

Pheomelanin

A type of melanin that produces a reddish-brown color, often seen in red hair and freckles.

Melanin Functions

Functions of melanin include UV protection, coloration, antioxidant properties (free radical scavenger of ROS), immune function, and thermoregulation.

genetics, UV exposure, melanocyte size, and diseases such as albinism.

Factors Influencing Melanin

Hair

An accessory structure where each hair arises from a hair follicle, functions for protection, and includes parts such as the shaft, hair root, hair bulb, cortex, medulla, and papilla.

Glands

Structures such as sebaceous and sweat glands that produce sebum and sweat.

Sebum

An oily white substance rich in lipids that lubricates the hair and skin surface, prevents drying, and protects against bacteria.

Nails

Thin plates consisting of layers of dead stratum corneum cells containing a very hard type of keratin.

Protective Functions of the Integumentary System

Includes intact skin reducing water loss, barrier against microbes and foreign substances, protection against abrasion, melanin absorbing UVR, hair acting as an insulator and nasal hair trapping dust particles, and nails used as defense.