Structure & Function
The integumentary system is the body’s outer protective covering and includes all structures that make up the skin and its related components.
It is composed of:
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Skin — the main organ, consisting of:
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Epidermis: the outermost layer made mostly of keratinized stratified squamous epithelium.
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Dermis: the thicker inner layer containing connective tissue, blood vessels, nerves, glands, and hair follicles.
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(Sometimes the hypodermis or subcutaneous layer is included; it lies beneath the skin and contains fat and connective tissue.)
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- Accessory structures (skin appendages):
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Hair — provides protection and helps with temperature regulation.
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Nails — protect the fingertips and aid in grasping.
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Sweat glands (sudoriferous glands) — help regulate body temperature by secreting sweat.
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Sebaceous glands — produce sebum (oil) that lubricates and waterproofs the skin and hair.
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- Associated sensory receptors — detect touch, pressure, pain, and temperature.
The physiology of the integumentary system centers on maintaining barrier integrity, thermoregulation, sensation, immunity, metabolism, and repair.