Bones, Muscles and Skin

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Bones, Muscles and Skin. Chapter 32 pages 920 - 945. Axial skeleton skull, vertebrae and rib cage. Appendicular skeleton arms, legs, shoulder, pelvis. Skeletal system functions. Support and shape Protection Movement Mineral Storage ( Ca ) Hematopoeisis production of blood cells. - PowerPoint PPT Presentation

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<p>FileNewTemplate</p> <p>Bones, Muscles and SkinChapter 32 pages 920 - 945Axial skeleton skull, vertebrae and rib cage.Appendicular skeleton arms, legs, shoulder, pelvis</p> <p>Skeletal system functionsSupport and shape ProtectionMovementMineral Storage (Ca)Hematopoeisis production of blood cells</p> <p>Bone StructureBones are a network of living cells embedded in a protein mesh that is covered with Calcium phosphate crystals.</p> <p>Osteonic canal is the same as the Haversian canalOsteon is a group of concentric rings (Lamellae)Lacuna are the little caves where the bone cells, the Osteocytes, live.Canaliculus are the small passageways that link the osteocytes together.5</p> <p>Spongy bone is located inside of compact bone, often near the ends of bone. There is a trabecular network of bone that provides strength, but light weight. Within this space is where the red bone marrow can be found. Yellow bone marrow will be farther down in the middle of the bone. Red bone marrow produces blood cells, and yellow bone marrow primarily is fat.6</p> <p>Endochondral bone formation ossification, osteoblasts mature into osteocytes.7Osteoclast resorbs bone putting Ca+2 in the blood stream</p> <p>An osteoclast (from the Greek words for "bone" () and "broken" ()) is a type of bone cell that resorbs bone tissue. This function is critical in the maintenance and repair of compact bones in the mammalian skeleton. These bones are stronger than aluminum on a weight basis by being a composite material of approximately equal amounts of hydrated protein and mineral.[1] The osteoclast disassembles this very strong composite at a molecular level by secreting acid and a collagenase. This process is known as bone resorption. Osteoclasts and osteoblasts are instrumental in controlling the amount of bone tissue: osteoblasts form bone, osteoclasts re-absorb bone.8osteoporosishttp://www.youtube.com/watch?v=rHyeZhcoZcQJointsPlaces where bones meet.Three kinds:Immovable joints; skull, teeth, sacroiliacSlightly movable joints; vertebrae, lower leg, wristMovable joints; permit movement in more than one direction.</p> <p>A joint or articulation (or articulate surface) is the location at which bones connect.[1][2] They are constructed to allow movement (except for skull bones) and provide mechanical support, and are classified structurally and functionall10Freely movable jointsSynovial joints are freely movable. Hard, shiny, smooth hyaline cartilage covers the ends of the bone. Softer cushioning cartilage is placed between the bones. The joint is encased in a sac (bursa) that has a fluid (synovial) circulating within. The bones are tied together with tough, collagenous ligaments.</p> <p>Synovial joints are freely movable. Hard, shiny, smooth hyaline cartilage covers the ends of the bone. Softer cushioning cartilage is placed between the bones. The joint is encased in a sac (bursa) that has a fluid (synovial) circulating within. The bones are tied together with tough, collagenous ligaments.12LigamentsLigaments are composed primarily of collagen.They connect bones to bones.They are connected to bones by fibers that go deep into the bones structure.When they break they break in the middle</p> <p>In anatomy, a ligament is the fibrous tissue that connects bones to other bones and is also known as articular ligament, articular larua,[1] fibrous ligament, or true ligament.Ligament can also refer to:Peritoneal ligament: a fold of peritoneum or other membranes.Fetal remnant ligament: the remnants of a fetal tubular structure.Periodontal ligament: a group of fibers that attach the cementum of teeth to the surrounding alveolar bone.The study of ligaments is known as desmology (from Greek , desmos, "bond"; and -, -logia).Ligaments are similar to tendons and fasciae as they are all made of connective tissue. The differences in them are in the connections that they make; ligaments connect one bone to another bone, tendons connect muscle to bone and fasciae connect muscles to other muscles. These are all found in the skeletal system of the human body. Ligaments cannot usually be regenerated naturally, however there are periodontal ligament stem cells located near the periodontal ligament which are involved in the adult regeneration of periodontal ligament.</p> <p>13Anterior Cruciate Surgeryhttp://www.youtube.com/watch?v=q96M0jRqn7kSkeletal Muscle TissueVoluntaryMultinucleated, long (up to 30 cm) fibers.Striated, can see definite stripes caused by the overlapping myosin and actin myofibrils.Red color comes from myoglobin, a pigment that stores O2.Usually attached to bones</p> <p>Skeletal muscle or "voluntary muscle" or "striated muscle" is anchored by tendons (or by aponeuroses at a few places) to bone and is used to effect skeletal movement such as locomotion and in maintaining posture. Though this postural control is generally maintained as an unconscious reflex (see proprioception), the muscles responsible react to conscious control like non-postural muscles. An average adult male is made up of 42% of skeletal muscle and an average adult female is made up of 36% (as a percentage of body mass).[2] It also has striations unlike smooth muscle.15Cardiac Muscle Tissue-Found only in the Heart. Striated and branched. Joined with other muscle cell fibers via intercalated discs. One or two nuclei/cell. Are striated. </p> <p>Smooth Muscle Tissue.Non-striated. Spindle shaped cells with a single nucleus. Usually involuntary. Found in the walls of arteries, intestines, the eye, alveoli. Most can function without direct stimulation from the nervous system. Connected to each other by gap junctions </p> <p>Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit (unitary) and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by gap junctions to neighboring cells such that the whole bundle or sheet contracts as a syncytium (i.e., a multinucleate mass of cytoplasm that is not separated into cells). Multiunit smooth muscle tissues innervate individual cells; as such, they allow for fine control and gradual responses, much like motor unit recruitment in skeletal muscle.Smooth muscle is found within the walls of blood vessels (such smooth muscle specifically being termed vascular smooth muscle) such as in the tunica media layer of large (aorta) and small arteries, arterioles and veins. Smooth muscle is also found in lymphatic vessels, the urinary bladder, uterus (termed uterine smooth muscle), male and female reproductive tracts, gastrointestinal tract, respiratory tract, erector pili of skin, the ciliary muscle, and iris of the eye. The structure and function is basically the same in smooth muscle cells in different organs, but the inducing stimuli differ substantially, in order to perform individual effects in the body at individual times. In addition, the glomeruli of the kidneys contain smooth muscle-like cells called mesangial cells.</p> <p>17Muscle Fiber Structure.Thick myosin and thin actin myofibrils. Anchored at the Z line in a functional unit called the Sarcomere.When stimulated, paddles on the myosin attached to sites on the actin and pull causing the whole sarcomere to shorten.</p> <p>The Process of Muscle Cell Contractionhttp://www.youtube.com/watch?v=CepeYFvqmk4The Neuromuscular Junction is bridged by acetylcholine. </p> <p>The neuromuscular junction connects the nervous system to the muscular system via synapses between efferent nerve fibers and muscle fibers, also known as muscle cells. As an action potential reaches the end of a motor neuron, voltage-dependent calcium channels open allowing calcium to enter the neuron. Calcium binds to sensor proteins (synaptobrevin) on synaptic vesicles triggering vesicle fusion with the plasma membrane and subsequent neurotransmitter release from the motor neuron into the synaptic cleft. In vertebrates, motor neurons release acetylcholine (ACh), a small molecule neurotransmitter, which diffuses through the synapse and binds nicotinic acetylcholine receptors (nAChRs) on the plasma membrane of the muscle fiber, also known as the sarcolemma. nAChRs are ionotropic, meaning they serve as ligand gated ion channels. The binding of ACh to the receptor can depolarize the muscle fiber, causing a cascade that eventually results in muscle contraction.20Muscles and MovementMuscles are attached to bones by tendons.Tendon composition is mostly collagen.Muscles do their work by contraction.Muscles grouped in opposing pairs, what one muscle does the other undoes.</p> <p>Slow Twitch (Type I)The slow muscles are more efficient at using oxygen to generate more fuel (known as ATP) for continuous, extended muscle contractions over a long time. They fire more slowly than fast twitch fibers and can go for a long time before they fatigue. Therefore, slow twitch fibers are great at helping athletes run marathons and bicycle for hours.Fast Twitch (Type II)Because fast twitch fibers use anaerobic metabolism to create fuel, they are much better at generating short bursts of strength or speed than slow muscles. However, they fatigue more quickly. Fast twitch fibers generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly. Having more fast twitch fibers can be an asset to a sprinter since she needs to quickly generate a lot of force.</p> <p>22Exercise and HealthMuscles, the circulatory system, the heart and the lungs respond to regular exercise.The system becomes more efficient, with increased size and number of calories.This also strengthens bones.Astronauts must exercise to maintain their skeletal and muscular systems.</p> <p>SkinSkin is the soft outer covering of vertebrates.It is the largest organ of the body with a total area of 20 ft2.It is composed of 3 layers, epidermis, dermis and hypodermis.The outer layer is composed of dead cells filled with keratin.Scanning electron microscope photo of epidermis, 650X</p> <p>Skin is the soft outer covering of vertebrates. Other animal coverings such as the arthropod exoskeleton have different developmental origin, structure and chemical composition. The adjective cutaneous means "of the skin" (from Latin cutis, skin). In mammals, the skin is an organ of the integumentary system made up of multiple layers of ectodermal tissue, and guards the underlying muscles, bones, ligaments and internal organs.[1] Skin of a different nature exists in amphibians, reptiles, and birds.[2] All mammals have some hair on their skin, even marine mammals which appear to be hairless. The skin interfaces with the environment and is the first line of defense from external factors. For example, the skin plays a key role in protecting the body against pathogens[3] and excessive water loss.[4] Its other functions are insulation, temperature regulation, sensation, and the production of vitamin D folates. Severely damaged skin may heal by forming scar tissue. This is sometimes discoloured and depigmented. The thickness of skin also varies from location to location on an organism. In humans for example, the skin located under the eyes and around the eyelids is the thinnest skin in the body at 0.5mm thick, and is one of the first areas to show signs of aging such as "crows feet" and wrinkles. The skin on the palms and the soles of the feet is 4mm thick and the thickest skin in the body. The speed and quality of wound healing in skin is promoted by the reception of estrogen.[5][6][7]Fur is dense hair. Primarily, fur augments the insulation the skin provides but can also serve as a secondary sexual characteristic or as camouflage. On some animals, the skin is very hard and thick, and can be processed to create leather. Reptiles and fish have hard protective scales on their skin for protection, and birds have hard feathers, all made of tough -keratins. Amphibian skin is not a strong barrier, especially regarding the passage of chemicals via skin and is often subject to osmosis and diffusive forces. For example, a frog sitting in an anesthetic solution would be sedated quickly, as the chemical diffuses through its skin.</p> <p>24Skin FunctionsProtection: an anatomical barrier from pathogens and chemicals.Sensation: various sensory nervesTemp. regulation sweatControl evaporationStores fats and waterAbsorbs some O2.Water resistance. Oily layer helps us from drying out</p> <p>Protection: an anatomical barrier from pathogens and damage between the internal and external environment in bodily defense; Langerhans cells in the skin are part of the adaptive immune system.[3][4] Sensation: contains a variety of nerve endings that jump to heat and cold, touch, pressure, vibration, and tissue injury (see somatosensory system and haptic perception). Thermoregulation: eccrine (sweat) glands and dilated blood vessels (increased superficial perfusion) aid heat loss, while constricted vessels greatly reduce cutaneous blood flow and conserve heat. Erector pili muscles in mammals adjust the angle of hair shafts to change the degree of insulation provided by hair or fur. Control of evaporation: the skin provides a relatively dry and semi-impermeable barrier to reduce fluid loss.[4] Storage and synthesis: acts as a storage center for lipids and water Absorption: oxygen, nitrogen and carbon dioxide can diffuse into the epidermis in small amounts; some animals use their skin as their sole respiration organ (in humans, the cells comprising the outermost 0.250.40mm of the skin are "almost exclusively supplied by external oxygen", although the "contribution to total respiration is negligible")[8] Water resistance: The skin acts as a water resistant barrier so essential nutrients aren't washed out of the body. The nutrients and oils that help hydrate the skin are covered by the most outer skin layer, the epidermis. This is helped in part by the sebaceous glands that release sebum, an oily liquid. Water itself will not cause the elimination of oils on the skin, because the oils residing in our dermis flow and would be affected by water without the epidermis.25Skin AnatomyComposed of 3 parts: epidermis, dermis, hypodermis.Outer layer is composed of dead, flattened cells filled with keratin.Melanocytes, specialized cells in the stratum basale produce melanin which causes the skin to look darker. </p> <p>EpidermisNote the melanocyte. Stratum basale is the last layer with a blood supply.Langerhans cells are part of the immune system.</p> <p>DermisContains collagen network, blood vessels, nerves and glands.Sweat glands help to keep us cool.Sebaceous glands secrete oil to keep skin water proof and supple.Hair follicles are found here.Hair is composed of keratin</p> <p>Hair follicleHair follicles contain stem cells that help to renew skin and heal wounds.Grows fastest in the morning.Has an active phase and a resting phase.Follicles can be transplanted.</p> <p>Hair TransplantationCan also be used for eyelashes and eyebrows.Du...</p>

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