Integumentary System Part 1

Objective: List the functions of the integumentary system. Functions: 1)______-keratin is a protein produced by the epidermis to provide physical strength and help create a water resistant protective barrier covering the body. is a brown pigment in the skin that absorbs UV radiation to protect from the damaging effects of the sun. 2)______regulation- The production of sweat on the surface of the skin that evaporates cooling the body down. 3)______- The skin contains a variety of exteroreceptors also known as somatosensory receptors that detect stimuli in the external environment this is what we commonly refer to as the sense of touch. This includes the hair follicle receptors at the base of hair follicles that detect the movement of hair. 4)______(chemical reactions)- of the skin enables the synthesis of vitamin D from cholesterol in the presence of UV-B radiation from sunlight.

Objective: Name the tissue types that compose the epidermis, dermis and hypodermis. Epidermis superficial keratinized stratified squamous epithelium facing the exterior of the body. Dermis composed of connective tissue deep to the epidermis that provides structural support and a route for blood vessels that provide nutritional support to the epidermis. • 5)______layer- most superficial layer of the dermis consists of areolar CT adjacent to epidermis • 6)______layer- dense irregular CT forming the majority of the dermis. 7)______(superficial fascia or subcutaneous adipose tissue)- layer of adipose connective tissue deep to the dermis.

Integumentary System Part 2

Objective: List the major cell types found in the epidermis and describe the five layers of the epidermis. Cells in the epidermis: • 8)______- most common cells in the epidermis and they produce the fibrous intermediate filament protein keratin that provides strength to the epidermis and helps make keep a water-resistant barrier. • 9)______- cells that produce a brown pigment called melanin that absorbs UV radiation to protect from the damaging effects of the sun. • 10)______- type of leukocyte found in the epidermis where they can monitor the skin for infections. • 11)______- specialized neuroepithelial somatosensory receptor cells that detect changes in the shape of the skin that contribute to our sense of touch. Layers of the epidermis: • Stratum 12)______- is literally translated as basal layer referring to the deepest layer of the epidermis forms firm attachments to the basal lamina. This layer is also called the stratum germinativum which comes from the latin word germinare meaning to sprout referring to the capacity of the stem cells in this layer to undergo rapid division to produce keratinocytes. that produce the brown pigment melanin and Merkel cells that detect touch are also found at the border of the dermis and the epidermis in the stratum basale.

1 • Stratum 13)______- literally means spiny layer and this refers to the 8-10 layers of cells superficial to the stratum basale. The keratinocytes in this layer contain a web- like system of intermediate filaments of the pre-keratin protein attached to desmosomes. Melanin granules and Langerhan’s cells are abundant in the stratum spinosum. Melanin granules are packages of melanin that are produced by melanocytes and taken up by keratinocytes. • Stratum 14)______- literally means granular layer is 3-4 cells thick containing keratinocytes that are becoming flattened and disintegrating their organelles and prepare to go through a programed cell death as they excrete lipid granules, the cytoplasm fills with keratin and the cell becomes flat and the plasma membrane thickens. • Stratum 15)______- literally means clear layer and it is a thin layer only a few cell thick that does not stain when prepared for light microscopy giving it a clear appearance. The stratum lucidum is superifical to the stratum granulosum and deep to the stratum corneum in thick skin covering palmar and plantar regions that does not have hair follicles. This layer is not present in the thin skin covering most of the body. • Stratum 16)______- literally translated is horny layer and refers to the superficial layer of dead keratinocytes filled with keratin and surrounded by glycolipids filling the extracellular space to create a water resistant barrier. This is the thickest layer of the epidermis accounting for about 2/3 of the epidermis. Cell are constantly being shed from the stratum corneum and born at the stratum basale. A cell takes 15-20 days to differentiate and die as it travels from the stratum basale to the stratum corneum. These dead keratinocytes stay attached to the epidermis for about 2 weeks before they are normally shed.

Objective: Describe how melanin, , and hemoglobin pigments contribute to skin color. What might cyanosis indicate? What might indicate? Pigments that color the skin: • 17)______produced by melanocytes gives the skin a brown color. and pigmented moles are examples of increased melanin accumulating within local regions of the skin. A tan is an increase in melanin resulting from exposure to the sun that activates melanocytes to produce more melanin. • 18)______is a red pigment found in erythrocytes. Increased blood flow can turn the skin red as when a person with light skin is blushing. The binding of oxygen to hemoglobin effects the color. Hemoglobin is bright red when saturated with oxygen but as it becomes deoxygenated the color shifts to a darker red that appears blue through the skin. o 19)______refers to the characteristic blue color of the skin that indicates lack of oxygen as occurs when a person is suffocating. • 20)______is a breakdown product of hemoglobin. § 21)______- is a yellow pigmentation of the skin and whites of the eyes due to high levels. § May indicate impaired function. • 22)______gives the skin an color. Carotene can be converted into . Many foods contain carotene including and excessive consumption of carrots can turn your skin orange in a condition known as carotenosis.

2 Integumentary System Part 3

Objective: Describe the structure function, and location of the following accessory structures: hair follicles, arrector pili, hair follicle receptors, Pacinian corpuscles, Meissner corpuscles, Merkel cells, sebaceous glands, eccrine glands, and nails. 23)______- are small accessory organs that produce hair- made of keratin. • Epithelium continuous with the epidermis but extending down deep into the dermis. The hair root grows out of the hair follicle and becomes the hair shaft as grows superficially out of the epidermis. • The hair bulb is the large bulge in the region surrounding the deep end of the hair root. The papilla at the base of the hair bulb contains blood vessels that provide nutrients to the growing epithelial cells hair follicle. Basal cells of the matrix within the hair bulb divide and differentiate as they move outward in the hair root causing the shaft to grow. • Functions of hair: protection, sensory input, thermoregulation, and communication. • Arrector pili muscle is a smooth muscle that pulls on the hair follicle to make the hair stand out causing goosebumps. • The Hair follicle receptor consists of specialized endings of neurons that detect movement of the hair. Sensory nerve fibers carry information from specialized somatosensory receptors: • Free nerve endings that extend through the dermis and epidermis contribute to the sense of pain. • 24)______corpuscle found deep in the reticular layer of the dermis is another somatosensory receptor that contributes to the sense of touch by detecting deep pressure and vibration. • 25)______corpuscle is a somatosensory receptor common in the skin on the tips of the fingers that are very sensitive to detect light touch. The Meissner’s corpuscle is found in the superficial portion of the dermis in Dermal papillae where areolar connective tissue forms the superficial layer of the dermis called the papillary layer. The Reticular layer is the deep layer of the dermis composed of dense irregular CT. • 26)______cells are specialized sensory receptors cell found in the deepest layer of the epidermis that are sensitive to movement of the epidermis. Exocrine Glands: • 27)______glands produce an oily secretion that protects and lubricates the hair and skin. Sebaceous glands are composed of a stratified cuboidal epithelium that uses the holocrine secretion mode to produce the oily sebum. • Sudoriferous (sweat) glands: coiled tubular glands that consist of stratified cuboidal epithelium that produces watery merocrine secretion to cool the body. o 28)______Glands: All over body, more in palmar & plantar regions. o 29)______Glands: Located in the Axilla, groin, face & nipples function at puberty made of stratified cuboidal epithelial tissue. 30)______are another accessory structure produced by modified epidermal tissue. The epithelial tissue of the nail matrix produces a hard secretion of keratin at the root of the nail that is covered by the proximal fold of skin. As the nail grows it pushes out past the cuticle or eponychium to produce the exposed body of the nail. • Functions: Protection, scratching, grasping small objects.

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