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32 Cards in this Set
- Front
- Back
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Muscle
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three types:
-skeletal, cardiac, smooth -purposes include: bodymovement, stabilizing body position, movement of substance through body, generating heat to maintain body temp |
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skeletal muscle
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-voluntary (controlled by somatic system of PNS)
-connects bones by tendons (muscle to bone) or ligaments (bone to bone) -work in groups where agonist contracts while a second muscle or antagonist stretches and bone moves in opposite directions -bi's and tri's are antagonistic and also synergistic in that they assist agonist by stabalizing the origin bone or by py positioning the insertion bone during movement. -contraction can squeeze blood and lymp vessels and aid circulation -related to leverage concept in physics: most lever systems of body act to increase required force of a muscle contraction, a greater force than mg is required to lift mass m, to reduce bulk of body and increase range of movement -multinnucleate |
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sarcomere
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-smallest functional unit of skeletal muscle
-composed of thick and thin protein filaments -positioned end to end to form myofibril |
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sarcoplasmic reticulum
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-specialized ER that surrounds myofybrils in skeletal muscle
-lumen is filled with Ca 2+ ions |
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sarcolemma
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-modified membrane that wraps several myofibrils together
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thick filament
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-protein filament that makes up sarcomere
-made of myosin |
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thin filament
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-made of actin
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5 stage cycle of skeletal muscle contraction
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-tropomyosin covers an active site on actin preventing the myosin head from binding
-myosin head remains cocked in high energy position -in presence of Ca 2+ troponin pulls tropomyosin back exposing active site allowing myosin head tobind to acin -myosin head expels a phosphate and ADP and bends into a low energy position dragging actin along (called power stroke because sarcomere shortens and muscle contracts) -ATP attaches to myosin head causing it to detach from active site which is covered by tropomyosin -ATP splits into inorganic phosphate and ADP causing myosin to cock in high energy position and cycle repeats to form contraction -H zone and I band get smaller while A band does not change |
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neuromuscular synapse
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-where neuron attaches to muscle delivering action potential via acetylcholine
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T-tubules
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-tubes that move deep into muscle spreading Action Potential allowing for uniform contraction
-transfers AP to sarcoplasmic reticulum where Ca2+ becomes permeable -Ca2+ is actively pumped back into sarcoplasmic reticulum afte end of each cycle |
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Motor Units
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-2-2000 fibers spread throughout the muscle are innervated by a single neuron
-motor units are independent of each other and force of contraction depends on number and size of motor units activated -smaller motor units are first to be activated and larger units are recruited -muscles that require intricate movements have smaller motor units where as muscles like the back have large motor units |
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skeletal muscle fiber type
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-slow oxidative (type I)
-fast oxidative (type IIA) -fast glycotic (type IIB) -most muscles have mixture of fibers -ratio of mixtures depends on type of contraction needed -large amounts of type I found in postural muscles -Large amounts of type IIA are found in legs -Large amounts of type IIB are found in upper arms -cells of muscle do not undergo mitosis bc they are so specialized, instead the fiber can increse in diameter, number of mitochondria increase and sarcomeres lengthen (hypertrophy) |
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Slow oxidative (type I) skeletal muscle
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-type of skeletal muscle fiber
-red -contain large amounts of myoglobin (similar to hemoglobin but can only carry 1 molecule of oxygen) -contain larg amounts of mitochondria -split ATP slowly -slow to fatigue but have slow contraction velocity |
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Fast oxidative (type IIA)
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-fast twitch muscle fibers
-red -split ATP at high rate relative to Type I -contract rapidly relative to type I -less resistant to fatigue relative to type I |
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Fast glycotic (type IIB)
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-fast twitch fibers
-low myoglobin content -white -contract rapidly -large amounts of glycogen |
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cardiac muscle
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-striated like skeletel muscle meaning it is composed of sarcomeres
-makes up heart -each muscle has one nucleus as opposed to multinucleus of skeletal muscle -muscle cell separated from neighbors by intercalated disk which contains gap junctions that allow spread of action potential -more and bigger mitochondria -not connected to bone it forms a net which contracts in upon itslef like a squeezing fist -involuntary (autonomic system) -depolarization created by slow voltage-gated calcium channels |
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smooth muscle
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-involuntary (autonomic nervous sytem)
-one nucleus just like cardiac muscle -contain intermediate filaments attached to dense bodies throughout cell -two types: single unit (visceral) - multi unit -contracts or relaxes in presence of hormones orto changes in pH, O2, and CO2, temperature, ion concentrations |
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single unit smooth muscle (aka visceral)
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-connected by gap junctions which allow cells to contract as single unit
-found in small arteries and veins, stomach, intestines, uterus, urinary bladder |
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multi-unit
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-attached directly to a neuron
-can contract independently of other muscle fibers -found in large arteries, bronchiles, pili muscles attached to hair follicles and iris |
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Bone
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-is living tissue
-support of soft tissue -protection of internal organs -assistance in movement -mineral storage -blood cell production -energy storage in the form of adipose cells in marrow |
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Osteoblasts
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-not capable of mitosis
-build bone |
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Osteocytes
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-incapable of mitosis
-exchange nutrients and waste material with blood |
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Osteoclasts
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-resorb bone matrix
-release minerals back into blood -inhibited by calcitonin -stimulated by parathyroid hormone |
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spongy bone
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-contain red bone marrow, site of rhemopoiesis or red blood cell development
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compact bone
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-surrounds medullary cavity
(medullary cavity holds yellow bone marrow) -highly organized -where the osteon system occurs |
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Osteon
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-entire system of lamellae and haversian canal
-haversian canal is when osteoclasts burrow haversian tunnels and are followed by osteoblasts which build bone forming rings called lamellae meanwhile osteocytes trapped between lamellae exchange nutrients via canaliculi -haversian canals connected by volkmans canal |
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hydroxyapatite
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-how most of Ca 2+ in body is stored
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Bone and mineral homeostasis
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-bones store calcium and phosphate helping maintain a consistent concentration in the blood
-stores energy -forms blood cells (spongy bone) |
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Cartilage
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flexible resilient connective tissue composed of collagen
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Skin
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-an organ
functions in: -thermoregulation -piloerection (hairs extend to trap insulating air via sympathetic stimulation) -protection -environmental and sensory input -excretion (water and salts) -immunity -hlood reservoir -vitamin D synthesis (activated when sunlight hits skin) |
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epidermis
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-no blood vessels
-90% composed of keratinocytes which produce keratin, protein that waterproofs skin -melanocytes transfer melanin (skin pigment) -langerhans cells interact with helper T-cells -Merkel cells: attach to sensory neurons in function of touch -five layers of epidermis -cells continuously divide to form keratinocytes and are pushed to top layer in process in which they lose organelles and cytoplasm |
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dermis
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connective tissue derived from mesodermal cells
-embedded by blood vessels, nerves, glands and hair follicles -collagen in dermis provies skin with strength integumentary system is made up by skin, hair, nails, glands, and nerve endings -from ectoderm -below epidermis |
