exscWeek5.pdf EXSC 223 001
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EXSC 223 001
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This 4 page Class Notes was uploaded by Chase Heffron on Sunday September 27, 2015. The Class Notes belongs to EXSC 223 001 at University of South Carolina taught by Thompson in Summer 2015. Since its upload, it has received 47 views. For similar materials see Anatomy and Physiology 1 in Physical Education at University of South Carolina.
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Date Created: 09/27/15
Week 5 Connective tissue continued Connective tissue proper loose Dense and elastic Fibroplasts produce all connective tissue proper Dense Regular Ct little ground substance little open space Lots of bers 2 lines of stress so all the bers run along together Found in tendons and ligaments Dense irregular ct bers run in a variety of different directions Fibers run oriented along lines of stress Multiple lines of stress Found in dermis of the skin brous capsules of organs and ofjoints Elastic CT dense regular tissue that contains a large proportion of elastic bers Makes up walls of arteries particular the aorta Aorta has to stretch to accommodate the blood pumping through it every heart contraction Cartilage Much more dense than connective tissue proper but not nearly as dense as bone Cartilage is avascular has no direct blood supply It also lacks nerve bers Cartilage has ground substance around it that acts as a lubricant This ground substance has chondroitin sulfate hyaluronic acid collagen and elastic bers The primary cell type for cartilage is chondroblast 3 types of cartilage Hvaline Cartilaoe articular cartilage associated at the end of long bones ribs trachea nose It is the most abundant cartilage in the body It is mostly collagen with ground substance on the surface Chondroblasts produce the matrix and when they mature and become chondrocytes they reside in the laucuna Elastic Associated with the epiglottis and ear Contains lots of elastic bers Fibrocartilage fairly abundant All intervertebral discs are made of this cartilage Designed to absorbed compressive shock and have high tensile strength Bone osseous mineralized collagen Compact bone is the dense kind of bone Has the appearance of tree rings The center of these rings contain blood vessels Bone is made by osteoblasts When osteoblasts become incased in bone they become osteocytes Hematopoiesis related to the 4th kind of stem cells Hematopoietic stem cells produce blood cells This is particularly found in bone marrow Bone marrow produces red and white blood cells and platelets Blood Blood is a connective tissue but it does not bind anything together usually It delivers oxygen and nutrients carries heat etc Epithelial membrane Continuous multicellular sheet composed of at least 2 primary tissue types 1 Cutaneous membrane skin has 2 components a Epidermis keratinized strati ed squamous epithelium b Dermis areolar and dense irregular connective tissue dry membrane 2 Mucous membrane line body cavities open to the exterior This being the inside of your mouth gastrointestinal tract lining of lungs etc This membrane is moist due to secretions Strati ed squamous or psuedostratifed epithelia Loose connective tissue 3 Serous membrane found on closed ventral body cavities A viscous uid ground substance is secreted to the interior of this sac as a lubricant It allows parietal and visceral layers to slide over each other Serous membranes lines organs where the contents change shape and size Serous membranes minimize friction between organs Simple squamous on loose areolar connective tissue Tissue injury ln ammation generalized immune response that results in swelling and tenderness Can be associated with tissue injury and infection Regeneration to make again Some tissues can regenerate Fibrosis scar this is the accumulation of connective tissue Fibrosis is the scienti c word for a scar 3 steps of tissue repair 1 In ammation stage nonspeci c or general response to the injury In ammatory chemicals chemoattractants cause white blood cells to migrate to the site of injury This causes swelling They also activate the clotting process Chemoattractants also cause the activation of platelets which plug in the holes There is also an increase in capillary permeability which causes uid leakage and uid accumulation 2 organization this is the recovery from the injury Any cells that died need to be ridded of Granulation tissue forms In this tissue new capillaries form and collagen bers are laid down The process of regeneration also begins in this phase 3 Regeneration and brosis epithelium is regenerated More collagen is laid down than usual This is what causes scarring lntegumentary System Functions of the skin 1 Protection a physical barrier that separates you from your environment keeps things out and other things in The skin secretes chemicals that allow for lifeforms to survive on our skin 2 Temperature regulation Blood vessels that sit within our skin help regulate our temperature When too warm our blood vessels dialate to bring our body heat to our surface to cool us down Sweating cools us off through evaporative cooling 3 Cutaneous sensation receptors in the skin 4 Metabolic function Vitamin D When you39re exposed to the sun your body converts vitamin D from an inactive to an active form 5 Blood reservoir Blood can go to rest for short periods of time 6 Secretion many glands secrete substances onto the skin 2 Regions of the skin The epidermis is the top layer of the skin It is made up 4 different cell types There are keratinocvtes these make up most of the epidermis The epidermis is avascular so the keratinocytes at the basal layer are best nourished These cells are the ones that divide Every 30 days or so the skin you see on your body is all new cells These cells are connected by desmosomes Another cell that exists in the epidermis is the lanoerhan cell this is a white blood cell that is classi ed as a dendritic cell This is the rst line of defense for activating your immune system There are also Merkel cells This cell exists in the basal layer of the epidermis When this cell is activated it secretes a chemical that activates neurons The 4th cell type is the melanocyte these also exist in the basal layer These cells produce a peptin called melanin These are responsible for giving us skin color The amount of melanin produced is what causes difference in skin color Caucasians have a low level of melanin Melanin protects cells from UV radiation speci cally UV B radiation UV light damages DNA By decreasing the amount of UV light that can damage DNA melanin decreases your chance of skin cancer Most skin on your body consist of four layers but the skin on palms and feet is classi ed as thick skin and there are 5 layers The deepest layer is the Stratum basale or basal layer These are the best nourished cells in the epidermis These are where mitotically active keratinocytes are The next layer up is the stratum spinosum the cells in this layer are alive and producing keratin They don39t have as great an access to nutrients as the in the basal layer but they are still capaple of producing keratin This is where the desmosome attachments form The next layer is the stratum oranulosum This is the layer where the organelles of the keratinocytes disintegrate and the cells become attened out The cells commit suicide The top layer of most skin is the stratum corneum these are dead keratinocyte cells Still connected by desmosomes An oil secreted by sebaceous glands make these cells water tight The Stratum Lucidum is the top layer in thick skin palms and feet This is a thick clear layer of skin This layer does not have to do with callouses A callous the body s response to an area of friction A blister is the separation of the epidermis from the dermis The dermis is the lower layer It is made up of two layers each with its own connective tissue The top layer of the dermis is known as the papillary layer This is a textured layer it is not at or smooth This prevents the epidermis from sliding off the dermis This layer is made up of loose areoar connective tissue There is also a lot of uid in this layer ground substance There are capillaries but not large vessels The majority of the dermis is known as the reticular layer this is an irregular dense connective tissue This is the tougher part of the dermis There is a lot less ground substance and more collagen There are sweat glands muscles that allow your skin to stand up blood vessels etc Cleavage lines within the reticular layer there are bers in an orientation This are important for cosmetic surgeons to understand Cutting along cleavage lines reduces scarring Cutting across these lines increase scarring Skin appendages Sweat glands these secrete through exocytosis found all over the body except for nipples and exterior genetalia There are eccrine sweat glands most abundant sweat glands and found in people of all ages although in infants they are not regulated well These glands secrete the watery sweat that we think of when we sweat This particular sweat is involved in thermoregulation You are always sweating When you don39t realize it this is nonsensible sweat Another kind of sweat gland is the apocrine sweat oland This gland is dependent on hormones These produce a water kind of sweat that is identical to eccrine sweat The difference is that they also secrete a fat in the sweat This sweat is associated with body odor The bacteria that breaks down the secreted fat is what causes body odor There are variations of apocrine glands A specialized apocrine gland is the mammary gland Another kind is the gland that produces ear wax Sebaceous glands Not sweat glands They produce lots of oil and when the cell gets so large it ruptures and releases its oil onto the skin This is holocrine secretion These types of cells are important in that they keep your skin from drying out Dermacydin which helps regulate bacteria growth on our skin is also secreted by these The glands are affected by sex steroids These glands also become more active after puberty This is where the increase in acne comes from Acne develops when the duct the sebaceous gland gets blocked The white pus that develops is white blood cells from in ammatory response The hypodermis is fat below the skin but it is not actual part of the skin It is not part of the integumentary system