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Chapter 3 Part C
Integumentry System Structures
Question | Answer |
---|---|
integumentary system | skin and its accesory structures (sweat glands, hair, and nails). Note: skin is also called cutaneous membrane or integument. |
epidermis | the superficial layer of skin composed of squamous epithelial cells (squamous means "scale-like"). The cells of the epidermis are arranged in layers, called stratified squamous epithelium. The many layers of the epidermis create a barrier to infection. |
basal layer | the deepest layer of the epidermis. The cells in this layer are alive and actively dividing. Older cells are pushed to the surface by the newer cells forming below them. The dying cells are filled with a hard protien called keratin. |
keratinocytes | the most numerous cells in the basal layer of the epidermis. These squamous cells actively divide and replace cells that are sloughed off the skin surface. |
keratin | a protein found in the epidermis, hair, and nails. This hard protein fills dead cells in the superficial layer of epidermis. |
melanocytes | the pigment-producing cells in the basal layer of the epidermis. The black pigment produced is called melanin. There are fewer of these than keratinocytes, and these cells do not divide. |
melanin | black pigment in the skin that helps prevent damage by sun's ultraviolet rays. |
dermis | the layer of skin deep in the epidermis. This layer of connective tissue contains the protein collagen, which makes skin strong and flexible. It also contains elastin which allows it to rebound when stretched. |
collagen | the fibrous (rope-like) protein that gives dermis it's strength and flexibility. Collagen is the most abundant protein in the human body. |
exocrine glands | organs that secrete substances into a duct. Sebaceous glands and sweat glands are examples. |
sebaceous glands | exocrine glands in the skin that produce a secretion (called sebum) that soften and lubricates the hair and skin. These glands don't function in thermoregulation. Commonly called oil glands. |
sebum | a thick, oily substance secreted by sebaceous glands that lubricates the skin to prevent drying out. |
sweat glands | exocrine glands in the skin that function in thermoregulation by producing a secretion called sweat. The term thermoregulation refers to the body's ability to maintain it's internal temperature by creating a cooling effect when sweat evaporates. |
hair follicies | cavities in the dermis that contain the hair root. Hair grows longer from the root. |
nail bed | the portion of a finger or toe covered by the nail. |
subcutaneous layer | the layer of adipose tissue just deep to the dermis. The tissue protects the deeper tissue of the body and acts as an insulation of heat and cold. Also called hypodermis. |