Integumentary System: Skin and Epidermis Flashcards

Flashcards covering the integumentary system, focusing on the skin, epidermis, dermis, and hypodermis layers and their functions.

Integumentary System

The most superficial tissue layer of an animal's body; serving as the largest organ of the body, including skin, secretory glands, hair and nails.

Skin

The integument component covering the entire body surface.

Physical Barrier Protection

A skin function that serves as the first line of defense of the innate immune system.

Thermoregulation

A skin function involving evaporative cooling (sweating) to transfer body heat into sweat, cooling the body.

Sensory Input

A skin function involving nerve receptors in the skin that detect physical stimuli.

Vitamin D Synthesis

A skin function where exposure to UV light enables vitamin D production.

Excretion

A skin function involving water and salts lost during evaporative cooling (sweating).

Epidermis

The most superficial layer of the skin, composed of epithelial tissue and contains keratinocytes; protects against dehydration, UV radiation, and pathogens.

Corneum

Outermost, protective layer of the epidermis, formed by corneocytes.

Lucidum

Layer of the epidermis made of dead keratinocytes not yet differentiated into corneocytes, present only in palms and soles.

Granulosum

Layer of the epidermis containing keratinocytes that form a water barrier.

Spinosum

Layer of the epidermis containing keratinocytes with long extensions (“spines”), important for strength (desmosomes).

Basale

Layer of the epidermis where precursor keratinocyte stem cells proliferate; sight of light touch sensation (Merkel cells) and melanin synthesis (melanocytes).

Dermis

Consists mostly of connective tissue containing blood vessels and nerve endings; provides structural support to the skin and location of hair follicles.

Hypodermis

The deepest layer containing larger nerves and blood vessels; it is the subcutaneous layer composed of connective tissue and fat, which insulates the body and provide cushioning for underlying structures.