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Integumenary System

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Integumenary System
7th Grade Science
Class Notes – Integumentary System

Integumentary System
The body system composed of the skin, glands, hair, and nails
The largest system in the body

Functions of the Skin
Protect internal organs
Maintain proper temperature
Gather sensory information
Vitamin D production

Three Main Layers of the Skin
1. Epidermis
2. Dermis
3. Subcutaneous Tissue

Epidermis
Outermost layer
Continuously being renewed
Thicker in some places (like the thick soles of your feet and on your palms) than in other places of the body (like the thin skin over your eyelids).
The epidermis on a person’s fingertips forms ridges. Each person’s ridge pattern is unique so that no one has the exact same fingerprints. Ridge patterns are usually loops, whorls, or arches.
LOOP
WHORL
ARCH

Lines enter at one side of the finger and leave on the same side
Lines enter at the side of the finger and spiral inward ending at the center
Lines enter at one side of the finger and leave on the opposite side
60-70% common
25-35% common
About 5% common

Melanocyte
A type of cell found in the epidermis
Produces the pigment melanin which gives people their skin color
People get their skin color via genetics and by how active their melanin is
When you lay out in the sun and tan, you are activating the melanin in your melanocytes.
Keratinocyte
The most common type of cell in the epidermis (makes up 95% of the cells in this layer)
Provide a barrier against environmental damage such as: pathogens (bacterium, virus, or other microorganism that can cause disease) heat and UV radiation water loss
Broken down into 5 Layers

Dermis
Middle layer is the dermis.
Contains all of the blood vessels, nerves, muscles, even some glands (glands are accessory organs that secrete specific substances).
1. Sweat gland sends sweat up to the epidermis to maintain proper body temperature.
2. Sebaceous glands secrete oils (sebum) that helps protect the

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