Lesson 7 Describe the components of the integumentary system The components of the integumentary system are the cutaneous membrane which is the epidermis and dermis and it s accessory structures The dermis has two layers papillary reticular What are the accessory structures The accessory structures originate in the dermis and extend through the epidermis to the surface of the skin The accessory structures are hair nails and exocrine glands What are their functions Hair follicles protect the skull and provide delicate touch sensation on general body surface Nails protect and support tips of fingers and toes Exocrine glands assist in temperature regulation and waste excretion Explain how the integumentary system is linked to the cardiovascular and nervous system The integumentary system is connected to the cardiovascular system by blood vessels in the dermis The integumentary is linked to the nervous system by sensory receptors that detect stimuli for pain touch and temperature Describe the main functions of the cutaneous membrane The main functions of the cutaneous membrane epidermis dermis are physical protection from environmental hazards storage of lipids and coordination of immune response to pathogens cancers in the skin Describe the major layers of skin There are fiver layers in thick skin and four in thin skin The stratum lucidum is only found in thick skin The layers are the stratum basale spinosum granulosum lucidum and corneum Inferior superior 1 What are the characteristics of each layer Stratum corneum Multiple layers of flattened dead interlocking keratinocytes Water resistant NOT waterproof Stratum lucidum Appears as a glassy layer in thick skin only Stratum granulosum keratohyalin Cells stop dividing and start producing keratin and Keratinocytes produce keratohyalin keratin Keratin fibers develop as cells become thinner and flatter Gradually the plasma membranes thicken the organelles disintegrate and the cells die Keratinocytes are bound together by desmosomes Stratum spinosum Stratum basale Deepest layer Attached to basement membrane Contains basal stem cells melanocytes and tactile Merkel cells Stratum corneum 15 30 layers of keratinized cells that are shed replaced every 2 weeks The horn layer Stratum lucidum The clear layer Cells are flattened and densely packed with keratin Stratum granulosum The grainy layer Keratinocytes produce keratohyalin keratin o Keratin A tough fibrous protein Makes up hair and nails 2 What are the components of each layer o Keratohyalin Dense granules Cross link keratin fibers Produced protein fibers Stratum spinosum The spiny layer 8 10 layers of keratinocytes Cytoskeletons stick out Contains Langerhans cells Stratum basale Merkel cells Melanocytes o Found in hairless skin o Respond to touch trigger nervous system o Contain the pigment melanin o Scattered throughout stratum basale How are the layers different than each other The stratum lucidum is only found in thick skin In the third layer stratum granulosum thick skin second layer in thin cell division stops Division occurs in the rest of the layers How are fingerprints formed The epidermal ridges of the stratum basale form fingerprints They are determined by genetics uterine environment during fetal development Why are they important Fingerprints are important for gripping things Explain the difference between insensible and sensible perspiration In insensible perspiration water in sweat evaporates through the stratum corneum before the body perceives it as moisture on the skin In sensible perspiration water is sensed as moisture on the skin the water is excreted by sweat glands Explain how carotene and melanin affect skin color 3 Carotene has a orange yellow pigment and melanin has a yellow brown black pigment that affects the color of skin What are the differences between these two pigments Carotene Accumulates in epidermal cells fatty tissues of the dermis Converted to vitamin A to maintain epithelia and photoreceptor function Found in orange veggies Melanin Produced by melanocytes in the stratum basale w tyrosine Stored in melanosomes Transferred to keratinocytes What kind of effect does UV light have on skin UV radiation has a harmful effect on skin It causes DNA mutations and burns that lead to cancer and wrinkles Explain how different conditions can affect skin color Jaundice caused by build up of bile produced by the liver Yellow color Pituitary tumor caused by excess MSH melanocyte stimulating hormone production Extremely bronze tan Addison s disease disease of pituitary gland releases more ACTH adrenocorticotropic hormone similar effect on skin color as MSH Vitiligo Loss of color due to loss of melanocytes probably caused by autoimmune reaction by antibodies Cyanosis Bluish skin tint caused by severe reduction in blood flow or oxygenation Explain how vitamin D3 is produced and the importance of this vitamin Epidermal cells produce cholecalciferol vitamin D3 is the presence of UV radiation Then the liver kidneys convert it into calcitriol which helps in the absorption of calcium phosphorus 4 Describe the different components of the dermis The dermis consists of two layers the papillary reticular The Papillary Layer o Consists of areolar tissue o Contains smaller capillaries lymphatics and sensory neurons o Has dermal papillae projecting between epidermal ridges The Reticular Layer o Consists of dense irregular connective tissue o Contains larger blood vessels lymphatic vessels and nerve fibers o Contains collagen and elastic fibers o Contains connective tissue proper What are the functions of the collagen and elastic fibers Collagen fibers resist stretching but bend easily they provide flexibility Collagen fibers limit flexibility to prevent damage to tissue Elastic fibers permit stretching and provide flexibility and then recoil to original length How are cleavage lines related to these fibers and why are they important 5 Cleavage lines are formed from collagen elastic fibers They are important to surgeons To ensure that an incision heals and minimal scarring occurs they cut parallel to the cleavage lines Describe the different conditions that can affect the skin Damage to the skin can be caused by several factors Sagging wrinkles are caused by dehydration age hormonal changes and UV exposure Stretch marks are thickened tissue that result due to stretching via pregnancy or weight gain Decubitis ulcers result from bed rest and affect the epidermis and dermis Explain the
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