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type of muscle that is striated, light and dark, voluntary, neuron controlled
skeletal
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type of muscle that is striated, involuntary, autorhythmiciity, hormones and neurotransmitters change heart rate, etc
cardiac
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type of muscle that has walls of internal strucutres, non-striated, involuntary, and autorhythmicity
smooth muscle
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Functions of muscle
- 1. producing body movements - involving integrated functions of muscle, joints, and bones
- 2. stabilizing - postural positions, sustained contractions
- 3. storing and moving substances - sustaned contraction, sphinters
- 4. generate heat - thrmogenesis, involuntary shivering (skeletal muscles)
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ringlike bands of smooth muscle that close off outlets by the contraction and relaxation of smooth muscle, and also found in gi tract, urine, flow of lymph, and returns blood to the heart
sphincter
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four properties of muscle tissue
- electrical excitability
- contractibility
- extensibility
- elasticity
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electrical signals as a responce to stimuli that travel down the plasma membrane of cell
action potential
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types of stimuli
- autorhythmic electrical signals
- chemical stimuli by neurotransmitters, hormones, or ph change
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stiulation of actin potential that leads to a sliding of thin filaments across thick filaments
contractility (correct spelling)
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"strecthability," stomach, carciac muscles, allows muscle to contract forcefully when strecthed
extensibility
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ability to return to original size and length
elasticity
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muscle cells are refered to as
muscle cells
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connective tissue surrounds and protects muscular tissue which includes
- subcutaneous layer
- fascia
- epimysium
- perimysium
- fascicles
- endomysium
- tendon
- aponeurosis
- tendon sheaths
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also referred to as hypodermis, it separates muscle from skin and is composed of areolar connective tissue and adipose. provides a pathway for nerves, blood vessels, and lymphatic vessels to enter and exit muscles
subcutaneous layer
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stores most of the body's triglycerides and seves as an insulating layer that reduces heat loss, and protects muscle form physical trauma
adipose tissue
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dense shee of dense irrgular connectve tissue that lines tha body walls and limbs and supports and surrounds muscles and other organs of the body; allows free movement
fascia
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three layers of connctive tissue in skeletal muscle
- epimysium
- perimysium
- endomysium
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type of connective tissue encircling the entire muscle; dense irregular
epimysium
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type of connective tissue surrounds groups of 10-100 muscle fibers separating them into bundles called fascicles; dense irregular
perimysium
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type of connective tissue that penetrates the interior of each fascicle and separates individual muscle fibers from one another; also a thin sheath of areolar connective tissue
endomysium
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cord of dense regulare conncective tissue; parallel bundles of collagen fibers; connects muscle to bone
tendon
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connective tissue elements that extend as a braod, flat later; type of tendon
aponeurosis
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tubes of connective tissue containing an inner layer called visceral layer attached to the surface area and an outer layer called parietal layer with attached to the bone
tendon sheaths
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stimulates skeletal muscle; threadlike axon entends from spinal cord to a group of skeletal muscle fibers
somatic motor neurons
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small blood vessels found in muscle tissue
capillaries
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enlargement of fibers
hypertrophy
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increase in the number of fibers
hyperplasia
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plasma membrane of the cell
sarcolemma
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thousands of tiny invaginations of sarcolemma; open to the outside of cell; filled with interstitial fluid; where mucle action potiontial travel along sarcolemma and through T tubules to spread throughout mucscle tissue quickly
transverse tubules
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"cytoplasm," involves glycogen involved in ATP synthesis; myoglobin
sarcoplasm
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only in muscles and binds oxygen to diffuse into muscle resulting in the release into muscle for ATP production
sarcoplasm
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contractile organelles of skeletal muscle that entend the entire length of muscle fiber
myofibrils
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inside myofibrils and involved in contraction process; includes thick and thin filaments
filament
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2:1 ratio over thick filaments, anchored by z discs, actin
thin filaments
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mysoin proteins is associated with which filament
thick filament
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compartment that contains the filament; basic subunit of myofibrils
sarcomere
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sarcomere includes
- z discs
- A band
- I band
- H zone
- M line
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separation of sarcomeres
z disc
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dark, middle; entire length of thick filament; zone of overlap in sarcomere
A band
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lighter less dense; only thin filaments present with z disc in middle
I band
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only thick filament found here in sacromere
H zone
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middle; proteins that hold thick filaments together at center of H zone
M line
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Muscle proteins include three kinds of proteins found in the myofibrils
- contractile - generate force furing contraction
- regulatory - help switch the contraction process on and off
- structural proteins - keep the thick and thin filaments in the proper alignment, elasticity and extensibility to myofibrils and likn them to the sarcolemma and extracelluar matrix
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keep the thick and thin filaments in the proper alignment, elasticity
and extensibility to myofibrils and likn them to the sarcolemma and
extracelluar matrix
structural
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contracilte proteins in muscle
myosin and actin
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"motor protein" that push and pull cellular structures to acheive movement by the conversion of ATP, a chemical energy, into mechanical energy; myosin head and myosin tail
mysoin
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contains myosin binding sites where myosin head attaches; contains the regulatory proteins tropomyosin and troponin
actin protein
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In a relaxed muscle, myosin is blocked from binding to actin becase strands of ______ cover the mysoin-binding sites on actin
tropomyosin
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holds tropomyosin strands in place and undergoes a cange in shape when Ca++ binds to it resulting in moving tropomyosin away from mysoin-binding site
troponin
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calcium binds to troponin and chages shap to move tropomyosin away from myosin-binding site on actin where myosin binds to actin
contraction
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structural protein results in stability, extensibility, and elasticity of myofibrils and includes the following proteins
- titin molecules - connect z discs to m-line and return muscle
- alpha-actin - bind actin to titin
- myomesin - m-line
- nebulin - long, nonelastic, wrapped around entire molecule
- dystrophin - cytoskeletal protein liks thin filaments to sacromere
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contraction and relaxation of skeletal muscle fibers involves
- ATP hydrolysis
- Attachment of myosin to actin (crossbridges)
- Power Stroke (sliding of thin filament over thick filament)
- Detachment of mysoin from actin
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process that is essential for contraction of muscle to occur
sarcoplasmic reticulum releases calcium ions into cytosol; calcium binds to troponin; troponin moves tropmysin away from myosin binding sites
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the first step of conctraction cycle
mysoin head with ATP binding site and ATPase results in the hydolysis of ATP which reorients mysoin head and energizes it
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second step of contraction cycle
attachment of the myosin head with myosin-binding site located on the actin; formation of crossbridge as a release of phosphate group from ATP hydolysis
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third step of contraction cycle
Power Stroke as a result of an opening on the crossbridge where ADP is bound releasing ADP; release of ADP results in the rotation of the myosin crossbridges toward the center of the sarcomere
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forth step of contraction cycle
Detachment of mysoin from actin. Involves the binding of ATP to mysoin head so that crossbridges detach from actin
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Step connecting muscle action potential propagating along sarcolemma and through T-tubules to cause a contraction or sliding of filaments
Excitation-contraction coupling
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increase of Ca++ at cytosol
results in the contraction of muscle
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contains large resevoir of Ca++ to be released into the cytosol
sarcoplasmic reticulum
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miscule action traveling along sarcolemma and into t-tubules results directly in the release of calcium from to where
from sarcoplasmic reticulum membrane to cytosol
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plasma membrane of the muscle cell
sarcolemma
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uses ATP to move Ca++ from cytosol to SR
Calcium active transport
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propagation of action potential means that calcium release channels are open or closed
open
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calcium binding protein in SR which helps SR to have 10000x as many calcium molecules as cytosol in relaxed muscle
calsequestrin
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indicates how forcefulness of muscle contraction depends on length of the sarcomeres within a muscle before contraction begins
length-tension relationship
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