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69 terms

Chapter 8. The Muscular System

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Musculoskeletal system
The bones, muscles, and joints together form an integrated system called the _____.
Myology
The scientific study of muscles.
my/o
Muscle CF.
-logy
Study of suffix.
Orthopedics
The branch of medical science concerned with the prevention or correction of disorders of the musculoskeletal system.
Orth/o
Correct (straight) CF
Ped/i
Child (foot) CF
40% - 50%
(Skeletal) Muscle tissue constitutes about _____ of the total body weight.
Skeletal , cardiac , smooth
Three types of muscular tissue.
Skeletal muscle tissue
Is attached to bones and moves parts of the skeleton.
Striations
Alternating dark and light protein bands visible under a microscope.
Voluntary
Muscle that can be made to contract and relax by conscious control.
Cardiac muscle tissue
Found only in the heart, forms the bulk of the heart wall.
Involuntary
Muscles contractions are not under conscious control.
Smooth muscle tissue
Is located in the walls of hollow internal structures, such as blood vessels, airways, the stomach, and the intestines.
Skeletal muscle tissue
Striated & Voluntary.
Skeletal muscle tissue
Function includes stabilizing body positions.
Cardiac muscle tissue
Striated & Involuntary.
Cardiac muscle tissue
Develops pressure for arterial blood flow.
Smooth muscle tissue
Nonstriated & Involuntary.
Smooth muscle tissue
Maintains diameter of tubes.
Smooth muscle tissue
Moves material in GI tract and reproductive organs.
Sphincters
Ring-like muscles that close body openings.
Producing body movements
Stabilizing body positions
Storing and moving substances
Producing heat
Functions of muscular tissue.
Smooth muscle tissue
Sphincters regulate flow in tubes.
Muscle fibers
Connective tissue
Nerves
Blood vessels
Muscles consist of.
Epimysium
Layer of connective tissue that wraps the entire muscle.
Epi-
Above, upon (prefix).
Perimysium
Layer of connective tissue that surrounds the fascicle.
Fascicle
Bundle of muscle fibres.
Peri-
Around (prefix).
Endomysium
Layer of connective tissue that surrounds each individual muscle fibre.
Endo-
In, within (prefix).
Tendon
Three layers of connective tissue that extend beyond the muscle as a _____.
Skeletal muscle tissue
Well-supplied with blood vessels and nerves.
Skeletal muscle tissue
Terminal of a neuron on each muscle fibre.
Muscle fiber
Elongated cylindrical cells.
Sarcolemma
Plasma membrane covering each muscle fibre.
Transverse (T) tubule
Tunnel in from the surface to center of each muscle fibre.
Multiple nuclei
Lie near the surface of cell (muscle fibre) under the sarcolemma.
Sarcoplasm
The muscle fiber's cytoplasm.
Sarcoplasmic reticulum
A network of fluid filled membrane enclosed tubules.
Sarcoplasm
Contains many mitochondria that produce large amounts of ATP during muscle contraction.
Sarcoplasmic reticulum
Stores calcium ions required for muscle contraction.
Sarcoplasm
Contains myoglobin.
Myoglobin
Red pigmented protein related to Hemoglobin that carries oxygen.
Myofibrils
Cylindrical structures extending along the entire length of the muscle fibre.
Thin filaments , Thick filaments
Myofibrils consist of two types of protein filaments called _____ and _____.
Sarcomere
Filaments overlap in repeating patterns.
Z discs
Sarcomeres are separated from one another by.
A band
Dark area that extends the entire length of the thick filaments.
H zone
At the centre of each A band is a narrow zone which contains only the thick filaments.
I band
A lighter coloured area to either side of the A band that contains thin filaments no thick filaments.
Myosin
Thick filaments are composed of the protein _____ which is shaped like two golf clubs twisted together.
Myosin tails
Golf club handles are arranged parallel to each other, forming the shaft of the thick filament.
Myosin heads
The heads of the golf clubs project outward from the surface of the shaft.
Actin
Thin filaments are anchored to Z disks, and are composed of the protein _____.
Tropomyosin
In a relaxed muscle, myosin is blocked from binding to actin because strands of the protein _____ cover the myosin binding sites on actin.
Myosin binding site
Each actin molecule contains a _____ where a myosin head can attach.
Troponin
The tropomyosin strands are held in place my the protein _____.
Motor unit
Neuron plus triggered fibers.
Neuromuscular Junction (NMJ)
Neuronal ending to muscle fibre.
Synaptic end bulb
At neuron terminal.
Synaptic end bulb
Release neurotransmitters.
Motor end plate
Muscular area.
Synaptic cleft
Gap between synaptic end bulb and motor end plate.
1. Release of acetylcholine (ACh)
Diffuses across cleft
3. Activation of ACh receptors
5. Generation of Muscle Action Potential
Repeats with each neuronal action potential
7. Breakdown of ACh
Action at NMJ.
1. Muscle action potential causes Ca2+ to release from Sacroplasmic Reticulum (SR).
2. Ca2+ binds to troponin.
3. Moves tropomyosin off actin sites.
4. Myosin binds & starts cycle.
Contraction Trigger.
1. Breakdown of ACh to stop muscle action potentials.
2. Ca2+ ions transported back into SR lowering concentration, This takes ATP.
3. Tropomyosin covers actin binding sites.
Relaxation.