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3 types of muscle
- 1) skeletal
- 2) Cardiac
- 3) smooth
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5 Key Function of muscles
- 1) Movement
- 2) Maintain posture and position
- 3) Support soft tissues
- 4) Guard entrances
- 5) Maintain body temperature
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Epimyium
a dense layer of collagen tissues
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Perimysuim
Connective tissue that divides the muscle tissue into into individual muscle fibers
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Fascicle
a bond of muscle fibers
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Endomysium
Connective tissue that surrounds the individual skeletal muscle cells
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Sarcolema
cell membrane of a muscle fiber surrounds the sarcoplasm
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Sarcoplasm
cytoplasm of a muscle fiber
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T-Tubules
narrow tubes that are continuous with the sacroplasm at right angles
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Myofibrils
Cylindrical structures surrounded by a T-Tubule
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Myofilament
Protein filaments that make up myofibrils, contain actin and myosin
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Actin (Thin)
Thin filaments that make up the myofilaments, participate in muscle contraction
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Myosin (thick)
Thick filaments that make up the myofilaments that participate in muscle contraction
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Sarcomere
Individual contraction units of myosin and actin
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F- actin
- 300-400 molecules of G actin twisted together
- have active sites that bind to thick filaments
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Tropomyosin
- strands of these cover active sites on F-actin to keep interaction ffrom happening at the wrong time
- each one covers 7 actives sites
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Tropanin
- Made of three globular subunits
- 1) binds to tropomysin- locking them together
- 2) binds to G-actin, holding the troponin
- 3) has a receptor that binds the Ca+2 when empty while resting
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Sliding Filaments theory- when muscle fibers contract
- 1) the H-zone and 1 bands get smaller
- 2) the Zones of overlap get larger
- 3) the Z lines move closer together
- 4) the width of the A band remains constant
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Neuromusclar Junction
Special junction in control of skeletal muscle activity
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Synaptic cleft
Separates the terminal from the neuron
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Neuron stimulation in muscle fibers
(Memorize the order)
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All-or-None Principle
muscle fibers contract all the way or not at all
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Summation
The smooth and steady increase of tension caused by increasing the number of units active
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2 types of Isotonic Contraction
- Concentric- muscle tension exceeds resistance and the muscle shortens
- Eccentric- Peak tension is less than resistance and the muscle elongates
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ATP stored as creatine phosphate formula
ATP + creatine --- ADP + creatine phosphate
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Normal muscle function requirements (3)
- 1) Substantial inter-cellular energy reserves
- 2) Normal circulatory
- 3) Normal blood oxygen concentration
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Oxygen debt
Oxygen needs to supply what was not there during anaerobic respiration
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3 types of muscle fibers
- 1) fast
- 2) slow
- 3) Intermediate
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Fast fibers (know one characteristic)
- Most Muscle cells
- Contract in less than 0,01 seconds
- Large in diameter
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slow fibers
- 1/2 the diameter of fast fibers
- more specialized
- can sustain contractions longer
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Intermediate Fibers
- Have properties of slow and fast
- look more like fast fibers but with more capillaries
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Hypertrophy
Enlargement of the muscle
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Atrophy
Reduction in muscle size and mass
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Anaerobic
being activity in which the body incurs an oxygen dept
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Aerobic
involving, utilizing, or increasing oxygen consumption for metabolic process in the body
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Aging Effects
- 1) Skeletal muscle fibers get smaller in diameter
- 2) Less elasticity
- 3) Exercise tolerance decreases
- 4) Ability to recover from injuries decreases
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Plasticity
Can stretch and adjust to the new length without contracting
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