Integumentary (Skin) System
Integumentary (Skin) System 80197 - BIOL 2220 - 001
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80197 - BIOL 2220 - 001
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This 7 page Class Notes was uploaded by Jeni Erickson on Tuesday September 27, 2016. The Class Notes belongs to 80197 - BIOL 2220 - 001 at Clemson University taught by John R Cummings in Fall 2016. Since its upload, it has received 4 views.
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Date Created: 09/27/16
Blue stuff is not on test Integumentary System (SKIN) 1. Organ system a. Group of organs that operate collectively to perform specialized functions 2. Skin derivatives a. Hair b. Nails c. Glands d. Receptors 3. Covers entire body 4. Weighs 9-11 pounds 5. Accounts for 7% of total body mass 6. Has surface area of 1.2-2.2 square meters 7. Varies in thickness from 1.5-4.0 mm 8. Cutaneous membrane that is dry. 9. Regions a. Epidermis: epithelial b. Dermis: fibrous connective tissue/ dense irregular tissue i. Amount of fibers decrease with age c. Hypodermis: adipose tissue (superficial fascia) i. Extra layer of cushion (protective layer) ii. The thickness of the hypodermis increases with age. 10. Epidermal Cells a. Keratinocytes i. They undergo keratinization and produce keratin. ii. Most of the cells in the epidermis iii. Reproductive cells of the skin (stem cells) are at the bottom layer of the epidermis. As they divide, the cells are pushed upward and they accumulate keratin as they get pushed up to the top of the skin. iv. The cell becomes modified to store keratin. (gets rid of nucleus and organelles). v. Anything that is stored within a cell is a cellular inclusion. vi. The whole outer layer of epidermis is replaced every 25-45 days. Two weeks from one cells to get slumped off. b. Melanocytes: i. Melanin producing cells ii. Skin pigment that causes darkening of the skin. c. Langerhans’s cells Blue stuff is not on test i. Derivative of bone marrow. Important for the production of white blood cells. ii. They have an immune function. These interact with anything that breeches the surface of the skin. d. Merkel cells i. Always at the base of the epidermis. They do not migrate. ii. Function for sensory reception iii. They detect light touch iv. This is why we can feel bugs on us. v. Located at the dermis/epidermis mortar 11. Epidermal Layers a. Stratum basale (deepest layer) i. Single layer of cells ii. Stem cells and undergo replication iii. Responsible for the cell division that makes up the rest of the layers. (germinatidum layer) b. Stratum spinosum i. “Prickly layer”. ii. Several layers thick iii. Web like system of intermediate filaments inside of cells. They attach to desmosomes. iv. As the cells begin to shrink, the desmosomes are still linked and they look kind of prickly. c. Stratum granulosum i. Contains a vesicle inside cells. ii. 3-5 cells thick iii. Represents the last of the living cells iv. Contains granules: 1. keratinohyalin granuoles. They contain keratin. 2. Lamellated granuoles . They contain glycolipid. This water proof layer keeps water from just evaporating off of our skin. d. Stratum lucidum i. Only found in thick skin. ii. Dead cells e. Stratum corneum i. 20-30 layers of keratin rich cells that are dead in thin skin 12. Dermal layers a. Papillary i. Extends into the irregularities of dermis. Consists of areolar connective tissue. Blue stuff is not on test ii. Dermal papillae- parts of the dermis that extend up into the epidermis. b. Reticular i. Dense irregular connective tissue. 13. All connective tissues come from the mesoderm, therefore dermis skin comes from the mesoderm because it is composed from 14. Epidermis is from the ectoderm 15. Hypoderm is from the mesoderm 16. Determined by pigments a. Melanin i. Epidermis ii. Darker color iii. Amount varies from person to person. iv. Tyrosinase converts tyrosine in to melanin. b. Carotene i. Orange appearance ii. Dermis iii. Amount varies from person to person. c. Hemoglobin i. In the blood ii. If we didn’t have other pigments, it would shine through and give a pinky color. 17. Surface features a. Ridges: genetic control. Unique identifier of who we are. They give us grip so that we can grab hold of things. Increase friction i. Dermal ridges cause epidermal ridges. b. Grooves: divides skin into diamonds. In areas that have hair, the hair is t the intersection of the diamond. These grooves from our skin are apparently left over from the evolutionary history of having scales. 18. Skin Appendages a. Sudoriferous glands: sweat glands i. Eccrine: covers the surface of the body. Function throughout our entire life and they function for thermoregulation. ii. Apocrine: under our arms and between our legs. They don’t start functioning until puberty. Prevents friction. There is some sort of linkage to mate attraction. They are odorless. They smell comes from Blue stuff is not on test a bacterium that feeds on the secretion from the gland. iii. Ceruminous: modified apocrine glands. They produce a liquid sweat with a lot of lipids that is called wax that protects the entry into the ear canal. iv. Mammary: modified apocrine glands for the production of sweat with proteins that is called milk. b. Sebaceous glands i. Oil producing glands. They produce sebum. Associated with the hair follicle and covers the hair so that hair doesn’t break off immediately. Sebum can help prevent water loss. It can also kill bacteria. They respond to hormonal secretions (especially male hormones). Testosterone increases in boys and their skin becomes really oily. c. Nails i. A scale like modification of the epidermis.’ ii. Nail parts 1. Nail body: all the parts we can see 2. Free edge: the distal part that we cut off. 3. Lanula: the white portion at the body of the body of the cell. The proximal portion of the nail body. 4. Nail fold: they skin that holds around the body of the nail 5. Nail bed: all of the tissue that is under the nail. 6. Nail matrix: the active growing and dividing part. We cannot see this. 7. Eponychium: tissue that covers the nail matrix. 8. Hyponychium: the attachment of skin to nail on the free edge side. iii. Nails are protection. d. Hair: i. Multicellular ii. Helps protect us from physical trauma. iii. Helps prevent the loss of heat and sunlight. iv. Acts as a filter. v. Hair structure: 1. Shaft: the part we can see a. Medulla: inner portion b. Cortex: c. Cuticle: outermost layer of highly keratinized cells. d. The pigments in the cortex determine hair color. (Melanin and theo-melanin) 2. Root: under the skin Blue stuff is not on test 3. Follicle: active dividing part. a. External root sheath b. Internal root sheath. c. Bulb: large portion of the base. d. Papilla: indentation of the bulb i. The bulb contains the matrix, which contains the new hair. e. Arrector pili muscle: this muscle contains and allows the hair to stand up. When hair stands up, it contracts and traps air to stop heat loss. Root hair plexus- if something touches the hair, signals go off and tell the brain something touched you. 19. Functions of the Integument a. Protection i. Physical: hair ii. Chemical iii. Biological: Langerhans cells. b. Regulation of body temp i. Diameter of blood vessels allows us to warm up and cool down. c. Sensation i. Nerval cells d. Metabolic functions i. Skin produces vitamin D and is required for the absorption of calcium. (Exposure to sunlight). e. Maintains blood reservoir i. Because of all of our capillaries in the skin, we can store extra blood. f. Excretion: i. We can get rid of hydrogenous water products through sweat. 20. Tactile Sensors a. light touch sensitive nerve endings i. Meissner’s corpuscles: dermis ii. Merkel’s discs: epidermis b. Deep pressure and when the pressure is first applied. i. Pacinian corpuscles: deep in the dermis 21. Burn: a. Tissue damage caused by intense heat, electricity, radiation or chemicals that results in protein denaturation b. Can lead to cell death Blue stuff is not on test c. Dehydration and loss of electrolytes is a major danger in burn patients. d. Burn Classification i. First-degree: partial thickness burn. Only epidermis. Redness, swelling, and pain. Will take 2-3 days to heal. ii. Second-degree burn: partial thickness. Partial dermis and epidermis. Redness, swelling, pain, and blistering. 3-4 weeks to heal. iii. Third-degree burn: Full thickness burn. Complete loss of function. The only way for this to heal is with assistant. Nerve endings are destroyed. Third degree doesn’t give pain, but the second degree and first degree around it does have pain. 22. Skin Disorders a. Acne b. Lupus: autoimmune disease of the skin. They are attack there own bodies. The skin appears to look like a wolf bit you. The butterfly rash across the cheeks and over the nose. Mostly in post-pubescent females. c. Psoriasis: itching, scaly skin. Possibly an autoimmune disease. Phototherapy is a treatment. Treat with steroid drugs (They shut down the immune system). Could be genetic, but not necessarily. There are lots of triggers. i. Trauma ii. Infection iii. Hormonal Changes iv. Stress d. Decubitus ulcers: open wounds on the body where it is not getting enough oxygen. The skin begins to rot and smell. Usually due to pressure. e. Vitiligo: pigmentation disorder. Absence of melanocytes in spots of the spot, but not everywhere. Looks like scar tissue. You can be born with this, or you can get it over time. f. Albinism: No pigmentation at all. Genetic condition that prevents the production of tyosinase. g. Freckles: Linked to red heads. Extra amounts of melanocytes. Potential genetic component because it is linked to ethnicities. h. Birthmarks: Baby is born with this pigmentation. Dense collection of dermal blood vessels in the body. Blue stuff is not on test Tactile cells, in conjunction with their sensory nerve endings, function as touch receptors. The hypodermis, not tactile cells, anchors skin to the body. In addition to protection (physical and chemical barrier), the skin serves other functions. Which of the following is another vital function of the skin? It converts modified epidermal cholesterol to a vitamin D precursor important to calcium metabolism.