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Flashcards in Chapter 8 Deck (67):
1

skeletal muscle

voluntary muscle tissue

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tendon

how muscle attaches to bones

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ligament

connects bone to bone

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agonist

(muscle responsible for movement contracts)

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antagonist

stretches ;

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when antagonist contracts

bone moves in the opposite direction which stretches the agonist

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synergistic

assist the agonist by stabilizing the origin bone or by positioning the insertion bone during the movement

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contraction of skeletal muscle

may squeeze blood and lymph vessels aiding circulation, produce a lot of heat

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shivering

controlled by the hypothalamus, rapid contraction of skeletal muscle to warm the body

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sarcomere

smallest functional untit of the skeletal muscle

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thick and thin filament

laid side by side to form a cylindrical segment

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myofibril

sacromeres are positioned end to end to form this

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SR

surround the myofibril, specialized type of ER

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skeletal muscle

multinucleate

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sarcolemma

wraps several myofibrils together to form a muscle cell or muscle fiber

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thick filament

sarcromere made up of myosin, several long mysoin molecules wrap around each other to form one thick filament

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thin filament

composed mainly of a polymer of the globular protein actin, attached to actin are troponin and tropomyosin

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contraction of skeletal muscle 1

tropomyosin covers the active site on the actin preventing the myosin head from binding. mysoin head remains cocked in a high energy position with a phosphate and ADP group attached

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contraction part 2

in the presence of calcium tropnin pulls tropomyosin back exposing the active site, allowing the myosin head to bind to theactin

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contraction part 3

the myosin head expels a phospahte and ADP and bends into a low energy position dragging the actin along with it -- power stoke : causes muscle contraction

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contraction part 4

ATP attaches to myosin head --> this releases the myosin head from the active site, which is covered immediately by tropomyosin

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contraction part 5

ATP splits to inorganic phosphate and ADP causing the musoin head to cock into the high erngy position

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muscle contraction

begins with AP

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neuromuscular synapse

neuron attaches to a muscle cell forming a neuromuscle synapse

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AP of the neuron

release acetylcholine into the synaptic cleft

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acetylcholine

activates ion channels in the sarcolemma of the muscle cell creating an AP, AP moves deep into the muscle cell via small tunnels in the membrane called T-tubules

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t-tubules

allow for a uniform contraction of the muscle by allowing the AP to spread through the muscle cell more rapidly

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AP

transferred to SR which becomes permeable calcium ions, begins muscle cycle, at the end Ca is pumped back into the SR

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motor unit

neuronand the muscle fibers that it intervates; independent of each other , smaller ones are first to activated -- results in a smooth increase in the force generated by the muscle -- fingers have smaller motor units

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slow twitch muscle fibers

have large amounts of myoglobin (like hemoglobin with 1 protein subunits), large amounts of mitoochondria, split ATP at a slow rate, slow to fatigure, have slow contraction velocity , postural muscles

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type II A (fast twitch A fibers)

red, split ATP at a high rate, contract more rapidly, slow to fatigue but not as resistant as type I -- upper muscles

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type II B

low myoglobin content, appear white, contain large amounts of glycogen -- upper arms

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cardiac muscle

striated, one nucleus, separated by an intercalated disc (contain gap juctions, help AP to spread from one cardiac cell to another), bigger mitochondria and more of the, like a net (contracts on itself, not connectd to bone), involuntary

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hypertrophy

no mitosis, repetitive contraction the muscle changes, cell diameter and change in muscle confirmation, sarcomeres lengthen, # of sarcomeres and mitochondria increase

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smooth muscle

involuntary (ANS), thick, thin and intermediate filaments(attached to dense bodies throught cell), contraction -- smoothe muscle shrinks length wise, thin and think filaments attached to the intermediate filaments -- pull dense bodies

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single unit smooth muscle

visceral, connected by gap jucntions AP from a single neuron through a larger group of cell allowing the cells to contract as single unit, found in small arteries, viens, stoach, uterus and urinary bladder

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multiunit smooth muscle

attached directly to a neuron, can contract independently of other muscle fibers in the same location, found in the larger arteries, bronchioles, pili muscles attached to hair follices and the iris

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smooth muscle extra info

contracts or relaxes in the presence of hormones, change in pH, oxygen and carbon dioxide levels, temp and ion concentration

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bone

support of soft tissue, protection of internal organ, body movement, mineral and energy storage (adipose cells), blood ell protection

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osteoblasts

secrete collage and organic compounds, no mitosis, enveloped by the materials they release -- differentiate into osteocytes

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osteocytes

incapable of mitosis, exchange nutrients and waste materials in the blood

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osteoclasts

resorb blood matrix, release minerals back ito the blood

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spongy bone

red bone marrow, site of red blood cell developmenet

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compact bone

surround the medullary cavity which holds yellow bone marrow -- contains adipose cells for fat storage

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remodeling process

osteoclasts burrow Haversian canals in the compact bone, then osteoblasts lay down new matrix onto the tunnel walls forming lamellae, osteocytes trapped between the lamellae exchange nutrients via canaliculi. Haversian canals contain blood and lymph vessels and are connected by Volkmann's canals.

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osteon

lamella and Haversian canal system

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Caclium in the blood

bound mostly by proteins and a little bit by phosphates

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too much calcium

hypoexcitable membranes -- lethargy, fatigure memory loss

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too little

cramps and convulsion

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most Ca in the body

in hydroxyapatite , lie along side collage fibers give bone great compressive strength

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someCa

exists in the bone of slightly soluble calcium salts , these salts buffer ca levels

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bone acts as

storage site for calcium and anion

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long bone

shaft curved for strength, composed of compact and spongy bone -- leg arm finder and toe bones

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short bones

cuboidal -- ankle and wrist bones

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flat bones

made from spongy bone surrounded by compact bone, provide large areas for muscle attachement and organ protection -- skull, sternum, ribs and shoulder blades

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irregular bones

has an irregular shape and variable amounts of compact and spongy bone

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cartilage

flexible, resilent connective tissue, made mostly of collagen, tensile strength, no blood vessels or nerves, hyaline cartilage -- reduces friction and absorbs shock in joings

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fibrous joings

occur between 2 bones held closely and tightly together by fibrous tissue premitting little or no movement. skull bones form fibrous joints with each other; teeth form fibrous joints with the mandible

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cartilagous joints

little or no movement, occur btwn two bones tightly connected by cartilge such as the ribs and the sternum or public symphysis in the hip bone

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synovial joints

seprate for the cartilage by a capsule filled synovial fluid -- provides lubrication and nourishment to the cartilage, contains phagocyotic cells that remove microbes and particles which result from wear and tear from joint movement. allow for wide range of movement

61

skin

thermoregulation (blood shunted away from the capillaries), protection, enviornmental sensory input, excretion, immunity, blood reservoir, vitamin D synthesis

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epidermis

avascular, four cell types 1. keratinocytes -- produces kertain that waterproofs the skin 2. melanocytes transfer melanin to kertainocyes 3. langerhans interact with helper T-cells of the immune system 4. merkel cells attach to sensory neurons and function in the senation of touch

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subcutaneous tissue

heat insulator, maintains core body temp on cold days while the skin apporaches the temp of the environment

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layers of the epidermis

deepest layer-- merkel cell and stem cells, stem cells continually divide to produce kertainocytes and other cells, keratinocytes are pushed to the top layer, as they rise -- get keratin and die -- when they become the outermost later of the skin, slough off the body -- takes2-4 weeks. outermost-- 25 to 30 layers of flat dead cells.

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callus

exposure to friction or pressure stimulate the epidermis to thicken

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dermis

mesodermal cells--embedded by blood vessels, nerves, glands and hair folicles ; collagen and elastic fibers provide skin with strength, extensibility and elasticity, thick in the palsm and soles

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hair

kertainized cells held closely together. most hairs associated with oil gland , smooth muscle also associated with each hair stands hair up when skin is contracted