integumentary system
Epidermis- Protecting the body from the outside as the outermost layer, keeping your skin hydrated, producing new skin cells, and determining your skin color
Dermis- The middle layer of skin, contains collagen, blood vessels, glands, hair follicles, and nerve endings support and protect the skin and deeper layers, assist in thermoregulation, and aid in sensation.
Hypodermis (subcutaneous)- The innermost layer of skin, storing energy, connecting the dermis layer of your skin to your muscles and bones, insulating your body, and protecting your body from harm.
Dermal papillae- Regulate hair growth, protrusions of dermal connective tissue into the epidermal layer.
Melanocytes- produce and distribute melanin, which is a skin pigment.
Stratum corneum- First line of defense against the environment.
Stratum lucidum- Thin somewhat translucent layer of cells lying superficial to the stratum granulosum and under the stratum corneum, found especially in thickened parts of the epidermis (as of the palms or the soles of the feet)
Stratum granulosum- Accumulate dense basophilic keratohyalin granules that contain lipids helping to form a waterproof barrier which prevents fluid loss from the body
Stratum spinosum- This layer mostly consists of keratinocytes held together by sticky proteins called desmosomes, helping make your skin flexible and strong
Stratum basale- Deepest of the five layers of the epidermis, contains the only layer where the proliferation of skin cells can occur and attaches epidermis to the dermis
The epidermis consists of stratified squamous epithelium arranged in layers or strata. The layers are:
Stratum corneum
Stratum lucidum
Stratum granulosum
Stratum spinosum
Stratum basale
The stratum corneum is the most superficial layer of the epidermis. It consists of cells that have been hardened with keratin. Keratin is secreted by cells located in the deep layers of the epidermis called keratinocytes.
The stratum lucidum is an additional layer that is found only in the palms of the hands and soles of the feet. It provides an added thickness to these layers.
The stratum granulosum contains cells that have lost their nuclei. These cells remain active and secrete keratin. The cells contain granules in their cytoplasm that harbor keratin.
The stratum spinosum contains cells called prickle cells. These cells have small radiating processes that connect with other cells. Keratin is synthesized in this layer.
The stratum basale or basal cell layer contains epidermal stem cells. This is the deepest layer of the epidermis. It consists of one layer of cells that divide and begin their migration to the superficial layers. This is the layer where basal cell cancer develops.
Dermis- The middle layer of skin, contains collagen, blood vessels, glands, hair follicles, and nerve endings support and protect the skin and deeper layers, assist in thermoregulation, and aid in sensation.
Hypodermis (subcutaneous)- The innermost layer of skin, storing energy, connecting the dermis layer of your skin to your muscles and bones, insulating your body, and protecting your body from harm.
Dermal papillae- Protrusions of dermal connective tissue into the epidermal layer.
Melanocytes- produce and distribute melanin, which is a skin pigment.
Sebaceous glands- Microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum
Sudiferous (sweat glands)- Found in the dermis, sweat duct that transports the secretion to the surface of the epidermis (eccrine glands) or into a hair follicle (apocrine glands).
Eccrine- Sweat glands that are the most numerous and widely distributed over the body.