3.2 The Integumentary System Latest Version Already Passed

3.2 The Integumentary System Latest Version Already Passed Dermis Layer of skin between the epidermis and hypodermis; includes nerve endings, glands, and hair follicles Epidermal dendritic cells Skin cells that initiate an immune system response to the presence of foreign bacteria or viruses Epidermis The outer layer of skin Hypodermis The layer of skin beneath the dermis, which serves as a storage repository for fat Integumentary system Enveloping organ of the body that includes the epidermis, dermis, sudoriferous and sebaceous glands, and nails and hair Keratin A tough protein found in the hair and nails. It also strengthens skin. Keratinocytes Cells within the epidermis that produce keratin Melanin A pigment that protects the body against harmful effects of ultraviolet ray damage from the sun Melanocytes Specialized cells in the skin that produce melanin Merkel cells Touch receptors in the skin Papillary layer The outer layer of the dermis Reticular layer The layer of skin deep to the papillary layer. Sebaceous glands Glands located all over the body that produce sebum Sebum An oily substance that helps to keep the skin and hair soft Stratum basale The deepest layer of the epidermis 5 Stratum corneum The outer layer of the epidermis 1 Stratum granulosum A layer of somewhat flattened cells lying just superficial to the stratum spinosum and inferior to the stratum lucidum 3 Stratum lucidum The clear layer of thick skin found only on the palms of the hands, fingers, soles of the feet, and toes 2 Stratum spinosum The layer of cells in the epidermis superior to the stratum basale and inferior to the stratum granulosum 4 Sudoriferous glands Sweat glands that are distributed in the dermis over the entire body Name the functions of the integumentary system. The integumentary system provides protection, water barrier, temperature regulation, vitamin D production, waste elimination, and sensory reception. How does the skin regulate skin temperature? Capillaries dilate to dissipate heat and constrict to reserve heat. Sweat evaporation provides a cooling effect. How many layers of tissue does the epidermis include? Five layers. What are the names of the layers of epidermis? Stratum corneum, stratum lucidum, stratum granolosum, stratum spinosum, stratum basale. The skin contains structures that overlap with another body system. These structures allow the skin to sense and feel pressure, temperature, or pain. What are these structures, and what other body system are they a part of? Receptors cells are a part of the integumentary and central nervous system. How does the skin constantly renew itself? Cells from the stratum spinosum and stratum granulosum moves up and become flatter and more filled with keratin. The outer layer of the epidermis is made of dead skin cells that flake and sluff off. The epidermis completely replaces itself every 25-45 days. What substance determines your skin color? Melanin. It can make pigments from reddish yellow to brown and black. Explain the anatomy behind tanning. Melanocytes can make too much melanin in overexposure to sun, and so melanin granules are pushed into neighboring skin cells, resulting in tanning. What kind of response do foreign bacteria or viruses stimulate in epidermal dendritic cells? An immune system response. What is the function of the hypodermis? It stores fat, connects the skin to the underlying tissues, and provides cushioning and insulation against extreme external temperatures. What happens to the collagen and elastic fibers during aging? They decrease in number. How many appendages of the skin are there, and what are they? Four: sebaceous glands, sudoriferous glands, hair, and nails. Explain how sweat develops an unpleasant odor. Sweat is originally odorless, but when it is left on skin, bacteria will chemically damage it. What are the benefits of sebum, the oil substance secreted through hair follicles and the skin? It keeps hair and skin soft and contains chemicals that kill bacteria. Why does hair gray with age? The melanocytes produce less pigment, and they produce the pigments that color hair. What are the three shapes of hair follicles, and how do the different shaped follicles affect the nature of hair? Round, oval, and flat-shaped. Round follicles produce straight hair, oval produces wavy, and flat produces curly. Describe the anatomy behind goosebumps. Arrector pili muscles are connected either side of the hair follicle to the epidermis. When stimulated, the muscles contract, pulling the hair upright, causing the appearance of goosebumps. Fingernails and toenails are actually transparent, but appear pink. Why? The capillary supply under the stratum basale make nails appear pink. Why is skin called the integumentary system? "Integumentary" comes from the Latin word "integumentum," meaning "covering." The skin is a membranous covering, but it is part of an entire system that includes a cutaneous membrane, sweat and oil glands, and nails and hair. How do sweat glands protect against bacterial infections? Acidic sweat protects against bacterial infections. What are the two layers of skin? An outer epidermis and an underlying dermis (the hypodermis is not part of the skin). How does the epidermis receive nutrients? The epidermal layers don't include a blood supply (they're avascular). The stratum basale absorbs nutrients from the underlying dermis. What are cutaneous sensory receptors? They are part of the nervous system. The receptors transmit nerve signals that contain information about the environment, including touch, pressure, vibration, pain, and temperature. Subcutaneous fascia is another name for what? The hypodermis. What does "dermis" mean? True skin. What does "-epi" mean? On. What does "-hypo" mean? Under. What is provitamin D3? A modified cholesterol molecule that, when exposed to UVB rays, will convert into vitamin D. What is albinism? An inherited condition that prevents the normal production of melanin. It produces very little pigment in the skin, hair, and eyes. What are phagocytes? Specialized white blood cells that are distributed throughout the dermis that ingest foreign materials, including bacteria and dead cells. What is the dermal papillae? Structures that protrude from its surface up into the epidermis. What are lipocytes? Fat cells. What are eccrine glands? The major sweat glands of the body. They open directly onto the skin and produce a acidic fluid that is made of 99% water, but also contains wastes like urea, uric acid, salts, and vitamin C. What are apocrine glands? Glands that begin to function in puberty that are larger than eccrine glands. They secrete a milky fluid consisting of sweat, fatty acids, and proteins. They empty into hair follicles. What is the matrix? The growth zone in the base of a follicle that are specialized cells that generate and divide in living hair cells. They are pushed up towards the scalp, where they are killed with keratin and die. What is the nail bed? A specialized region underneath the statum basale. What is the nail matrix? A thickened region of the nail bed at the proximal end that is the growth zone. It's where nail growht occurs, with new cells rapidly being keratinized and dying. What is the lunule? The white, crescent moon-shaped region at the base of the nail, which is positioned over the thickened nail matrix.