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39 Cards in this Set
- Front
- Back
skeleton arises from
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mesoderm
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two types skeleton
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exoskeleton: cover outside of organism like anthropods
endoskeleton: in side like humans ie vertabrates exo good since protects outside and inside better major drawback is need to shed exo but dont in endo |
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skeleton divided into (2)
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axial: skull vertabrae ribcage its the framework
appendicular: all other parts attaching to axial for stability |
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2 main components of skeleton
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bone, cartilage both made of CT
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cartilage
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-flexible/softer than bone
-made of chondrin-->firm/elastic matrix (made by chondrocytes) and connective tissue -find lots in fetus in pre/postnatal development turns/calcifies into bone -in adult find in places need flexibility ie ears, nose, joints, larynx/trachea walls -degradation-->arthritis since bones rub -avascular (without blood/lymph vessels) |
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compact bone vs spongy (cancellous) bone
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compact:strong compact
spongy: consists of trabeculae (bony spicules) , looks like sponge |
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trabeculae cavities filled with
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bone marrow-->red or yellow
red: hematopoeitic stem cells generate all cells in blood yellow: made of fat and pretty inactive |
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appendicular made of___bones what are their characterisitics
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-long
-diaphyses=shaft -epiphysis=rounded ends -periphery of both surrounded by compact bone -long bone diaphyses: bone marrow inside -long bone epiphyses: spongy inside -peritoneum= fibrous sheath surrounding long bone also for muscle attachment, need for growth/repair, some cells can become bone forming cells |
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epiphyseal plate
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-separates epiphysis and diaphysis
-cartilaginous -site of longitudinal growth |
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bone structure:
-compact bone strength from _____made of 2 parts__&___ -describe them -osteon, haversian canal, lamellae, lacunae, canaliculi |
-bone matrix, organic and inorganic compounds
-organic: collagen, glycoproteins, peptides inorganic: calcium, phosphate, hydroxide *minerals also found in bone like Na, Mg, K -structural unit of bone encircles canal, blood vessels/nerves/lymph for bone, surround canal, spaced in matrix have osteocytes (bone maintenance), link lacunae for exchange nutrients/waste between canal and canaliculi |
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bone formation (ossification)
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-two types
1) endochondral: cartilage-->bone most long bones made this way 2)intramembranous: undifferentiated embryonic CT ie mesenchymal tissue-->bone |
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bone remodelling via (2) cells and (2) hormones and (1) vitamin
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-osteoblasts: build
-osteoclast: resorb/breakdown both help maintain bone when reforming material comes from blood, when breaking material released into blood ie cycle remodelling affected by use/exercise ie use it or lose it -parathyroid, calcitonin -D |
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joints
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-made of connective tissue
-2 types 1)movable: allow bones to move, strengthened by ligaments (connect bone to bone) and synovial cap (encloses joint cavity) . use synovial fluid/articular cartilage 2)immovable: ex)skull, dont move, |
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skeletal muscle innervated by
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somatic NS
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basic unit of muscle=_____these put together end to end get___
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sarcomere, myofibrils
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myofibrils covered by____outside from this have___,
*cell membrane called |
-sarcoplasmic reticulum (lots of calcium)
-sarcoplasm -sarcolemma-->generates AP, T-tubules connect to it and orient perpendicular to myofibrils to allow ion flow |
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many myofibrils in a
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myocyte
*mutinucleated due to fusion |
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why skeletal muscle look striated
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z line alignment and density of them
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skeletal muscle made of (2) fibers
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red: slow twitch, HIGH myoglobin, get energy AEROBIC
white: fast twitch, ANAEROBIC, LESS myoglobin *red mitochondria rich, white mito poor (dont use electron transport chain) *white easier to tire, but contract quicker |
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myoglobin vs hemoglobin
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-myoglobin higher oxygen affinity
-myoglobin single polypeptide chain |
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sarcomere structure:
made of thin and thick filaments what are they made up of Z lines M line I band H zone A band During contraction what happens to above lengths |
-thick: myosin
-thin: actin, tropomyosin, troponin -boundaries of sarcomere -runs down centre of sarcomere -region of only thin filaments -region of only thick filaments -region of all the thick filament length (which will include some thin in it) - H,I and distance between Z lines get smaller, A band size remain CONSTANT |
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3 steps of contraction
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1) initiation: send signal via motor neuron,motor neuron--> nerve terminal (bouton)-->neurotransmitter into synapse and binds to muscle receptors=contraction. If enough acetylcholine binding=depolarized ie AP generated=increase sarcolemma permeability
2) sarcomere shortening: AP cause release of calcium from SR. calcium bind troponin-->tropomyosin to shift--> exposes myosin binding site on actin-->myosin binds--> myosin pulls on actin-->draws thin filaments to center of H zone--> shortens sarcomere *ATPase activity in myosin for stroke and for removal of myosin from actin *myosin resets by binding ATP 3) relaxation: no more SR stimulation=decrease calcium--> tropomyosin cover binding sites therefore no more contraction |
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ATP needed for both contraction and release of muscle fibers true or false
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true, rigor mortis due to loss of ATP during death and so muscles rigid since no ATP to release
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how stimulation coupled to muscle response
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-stimulus intensity:
-simple twitch -summation and tetanus |
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stimulus intensity :
muscles show___response tonus = |
-all or none, this response strength cant be adjusted, instead muscle control force by # fibers recruited
-muscles in constant state of low level contraction for both voluntary/involuntary |
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simple twitch
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-response of 1 fiber to brief stimulation at or above threshold, 3 periods; latent, contraction, relaxation
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latent period
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-time between reaching threshold and onset of contraction -when AP spreads and release calcium,
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refractory period
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-after latent
-muscle unresponsive to stimulus -2 types 1) absolute: no amount stimulus will make response since restoring resting potential 2) relative: higher than normal needed to get response |
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summation and tetanus
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-freq summation= prolonged/frequent exposure cause not enough time to relax, contractions combine= stronger/longer
-tetanus= contractions so frequent no time to relax, stronger than simple twitch, prolonged tetanus=fatigue |
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why muscle fibers contract all or none
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innervated by neurons who signal is AP which is all or none
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smooth muscle
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-non striated
-involuntary -ANS innervates it -one nucleus/cell -calcium for contraction -smooth continuous contraction -longer more sustained contraction *will respond to nervous input DOES NOT need external signals to contract= MYOGENIC ACTIVITY (can contract with no NS input) |
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cardiac muscle
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-striated
-involuntary -ANS innervation -1-2 nuclei/cell -calcium for contraction -may have myogenic activity |
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muscles need energy can use fats, glycogen and glucose also have (2) rother energy reserves
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1) creatine+ATP<-->creatine phosphate+ADP, do reverse when need quick supply of atp
2) myoglobin: binds oxygen more than hemoglobin, when oxygen used during muscle use myoglobin releases oxygen to keep aerobic going *exhausted reserves then get ferment of left pyruvate to get NAD and start glycolysis again |
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loose connective tissue
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-attach epithelium to underlying tissues
-3 protein fibers 1)collagenous: collagen, strong 2)elastic: elastin, give resilience 3)reticular: branched, connect CT to tissue -2 cell types 1)fibroblasts (make stuff for extracell fibers) 2)macrophages |
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dense CT
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-high conc of collagenous fiber
-forms tendons (muscle to bone) and ligaments (bone to bone thru joints) |
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muscle bone interaction:
-muscle end attached to stationary bone= -muscle end attached to moving bone= |
-origin, ie proximal end in limbs
-insertion, ie distal end in limbs |
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muscles antagonistic in that
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one contracts while other lengthens
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synergistic muscles
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-helps principle muscles during movement
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flexor=
extensor= abductor= adductor= |
-contracts-->decrease angle of joint
-contract--> straighten joint -move part of body AWAY from midline -move part of body TOWARD midline |