Term
| Muscle Tissue is derived from which tissue? |
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Definition
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Term
| Muscle Cells are known as.... |
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Definition
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Term
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Definition
Type I - Slow Oxidative
Type IIA - Intermediate
Type IIB - Fast glycolitic |
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Term
| True/False Muscle fibers types vary in amount of mitochondria, myoglobin, and other enzymes? |
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Definition
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Term
| Lists the three layers that muscle cells are organized into? |
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Definition
Epimysium
Perimysium
Endomysium |
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Term
| Perimysium divides muscles into _____ and is highly ______ |
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Definition
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Term
| Characteristics of endomysium |
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Definition
- pathway for capillaries
- contains extrafusal and intrafusal cells
- rich in collagen and retiular fibers
- divides muscle into individual fibers |
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Term
| Function of Alpha Actinin? |
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Definition
| Binds actin to the Z-disk |
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Term
| Myofibrils are composed of? |
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Definition
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Term
| Sarcomere associated proteins can be found attached where? |
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Definition
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Term
| True/False Tropomyosin is a globular protein? |
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Definition
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Term
| Muscle tissue can be broken down to below the cellular level, describe breakdown |
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Definition
| Muscle - muscle fiber - myofibrils (sarcomeres) - myofilaments |
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Term
| An actin molecule is a polymer of? |
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Definition
| Two intertwined molecules of filamentous actin.... each filamentous actin strand is composed of polymers of G-actin |
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Term
| A polymer of myosin is composed of around how many subunit molecules? |
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Definition
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Term
| What is the function of myomesin? |
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Definition
| To cross link myosin filaments, apparent at the M-line |
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Term
| True/False each muscle cell contains only one type of muscle fiber? |
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Definition
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Term
| True/False the A band does not shorten during contraction? |
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Definition
| True - The A band contains BOTH actin and myosin, since filaments never shorten, only slide past one another, the A band will not shorten |
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Term
| True/False none of "bands" associated with the sarcomere shorten during contraction? |
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Definition
| False - The I bands (Actin only), H bands (only myosin), and Z disk shorten/drawn closer |
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Term
| The Z Disk of the sarcomere is found where? |
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Definition
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Term
| Describe the relationships between A and H bands with M line |
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Definition
| The H band bisects the A band, in turn the M line bisects the H band |
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Term
| Explain Afferent fibers of muscle spindles |
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Definition
Two types
1.)Anulospiral - composed of type I neuron fibers and consists of nuclear bag and chain fibers, respond to stretch rate
2.)Flower Spray - type IIA nerve fibers and are found on either side of annulospiral, monitor duration of stretching |
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Term
| In terms of myofibrils a sarcomere is measured.... |
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Definition
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Term
| True/False Myosin is the principal contractile protein of thin myofilaments? |
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Definition
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Term
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Definition
| A neuron and all of the muscle cells that it innervates |
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Term
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Definition
| Found connected to the Z-disk and spans all the way to the M line (half the length of a sarcomere) gives the sarcomere its elastic properties |
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Term
| sER in muscle cells is known as? what is its function? |
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Definition
| Sarcoplasmic Reticulum / Sequesters Calcium (in skeletal muscle) and releases calcium into cytoplasm |
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Term
| Which myofilament is the thick/thin filament? |
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Definition
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Term
| What role does calcium play in actin myosin binding in skeletal muscle? |
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Definition
| ca binds to troponin C, which interrupts TnI/actin interaction and slides tropomyosin out of the way |
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Term
| Efferent fibers of muscle spindles are composed of what type of neuron fiber? |
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Definition
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Term
| True/False the sarcoplasmic reticulum in cardiac cell leaks at a constant rate? |
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Definition
| True - allows for autonomic rhythyms |
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Term
| True/False a Triad is found in cardiac muscle cell |
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Definition
| False - dyads are found in cardiac, triads in skeletal |
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Term
| Five Steps of the contraction cycle |
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Definition
1.)Attachment - No ATP
2.)Release - ATP binds to myosin
3.)Bending - ATP hydrolyzed but still bound (head pivots)
4.)Force Generation -(ADP and P released)power stroke occurs
5.)Reattachment - myosin head undergoes conformational change and attaches to another actin |
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Term
| If cardiac muscle is damaged it is replaced by.... |
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Definition
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Term
| How is ATP generated in type IIB fibers? |
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Definition
| Glycolysis Type IIB = slow glycolytic/white |
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Term
| Sarcolemma is depolarized at the.... |
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Definition
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Term
| Primary function of ANS on cardiac muscle cells? |
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Definition
| To speed up/slow down contraction rates |
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Term
| The T- Tubules are found where in skeletal muscle cells? |
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Definition
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Term
| ANP is found where? and what is its fxn? |
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Definition
| In Atrial granular cell (have ANP precursor) and raises BP |
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Term
| Glycogen, lipid, and mitochondria are found where in cardiac cells? |
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Definition
| mainly in the poles, known as the sarcoplasmic cone |
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Term
| Troponin is a globular protein composed of... |
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Definition
Tnc - binds calcium
TnI - Binds actin
TnT - binds to tropomyosin |
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Term
| Skeletal muscle contraction will continue as long as..... |
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Definition
| There is unbound free calcium in the cytoplasm |
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Term
| True/False Calcium is removed in skeletal muscle cytoplasm via Calcioesterase? |
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Definition
| False - pumps on sER membrane |
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Term
| Strength of muscle contraction depends on? |
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Definition
| The Number of motor units involved |
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Term
| True/False fibers of the same muscle unit will contract in unison |
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Definition
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Term
| Dense Plaques are similar to what structure? |
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Definition
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Term
| The plasma membrane of a muscle cell is known as the... |
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Definition
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Term
| T Tubule system in cardiac vs skeletal |
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Definition
| Larger, sER less developed, arranged into diads vs triads, found at Z disk vs AI junction |
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Term
| True/False SMC contraction will stop when there is no more calcium in the cytosol |
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Definition
| False - although calcium is responsible for reaction cascade, contraction will not stop until myosin is dephosphorylated |
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Term
| True/False Smooth muscle has the slowest contraction rate of all muscles? |
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Definition
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Term
| True/False Muscle Spindles contain both afferent and efferent innervation |
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Definition
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Term
| traits of myoepithelial cells and myofibroblasts |
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Definition
both are contractile non muscle cells
Myoepi - b/w epithelium and basal lamina of certain glands ducts - mammary glands, similar in shape and contraction mechanism to SMCs but from ectoderm (SMCs from mesoderm)
2.)Myofibroblasts - resemble fibroblasts but have high amounts of actin and myosin - wound healing |
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Term
| True/False Type I fibers generate ATP via Glycolysis |
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Definition
| False - Type I = slow oxidative (red) ATP is generated via Oxidative phosphorylation, takes longer but more ATP generated, therefore fatigues slower than white fibers |
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Term
| True/False myofilaments are organized into myofibrils in all muscle cell types? |
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Definition
| False - does not arrange like that in smooth muscle |
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Term
| other names for a motor end plate? |
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Definition
| myoneural/neuromuscular jxn |
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Term
| function of efferent nerve fibers found in muscle spindles? |
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Definition
| depolarized muscle spindles to contract to counteract muscle stretching |
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Term
| Muscle Tissue composes how much of your total body weight? |
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Definition
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Term
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Definition
| an extra-sarcomere protein, connects the sarcoplasm to the ECM via actin |
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Term
| What is the name of the protein that sequesters calcium in skeletal muscle? |
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Definition
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Term
| True/False cardiac muscle is regenerative |
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Definition
| False - only skeletal and smooth |
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Term
| True/False Skeletal muscle cells have more glycogen, lipid, and mitochondria than cardiac muscle |
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Definition
| False - Consider contraction rates |
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Term
| Purkinje Fibers are modified __________ and are found in the _______ |
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Definition
| cardiac muscle cells/AV bundle of HIS |
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Term
| Two Types of Smooth muscle cells? |
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Definition
1.)Unitary/visceral
gap jxns found in between cells for depolarization propogation
2.)Multiunit
found in Iris and large arteries, ANS precisely controls contraction, poor/no gap jxns |
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Term
| What effects electrical properties of Multiunit SMCs? |
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Definition
| hormones and ANS neurotransmitters epi and norepi |
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Term
| most of a SMCs sarcoplasm is occupied by what? |
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Definition
| actin fillaments inserting into dense plaques (cytoplasmic densities) |
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Term
| Describe Intercalated discs |
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Definition
Found in cardiac muscle, two portions
1.)transverse - across fibers contains fascia adherents (zonula adherens) and maculae adherents (prevent seperation from contraction)
2.)lateral - parallel to fibers
contains gap jxns for electrical coupling |
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Term
| Intermediate Filaments contained in SMCs? |
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Definition
Desmin - non vascular
Vimentin - Vascular |
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Term
| True/False muscle spindles are known as extrafusal cells? |
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Definition
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Term
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Definition
| function in uptake and release of Ca in SMCs found in periphery |
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Term
| Myosin Activation in SMCs |
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Definition
- Ca binds to calmodulin
- ca/calmodulin complex activates MLCK
- phosphorylates MLC which interacts with actin
- MLC is dephosphorylated preventing actin binding |
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