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HAP Quiz #3 Muscle System
Terms in this set (72)
Types of muscle
-skeletal: striated and voluntary
-cardiac: heart and involuntary
Muscles and Muscle Fiber Structure
-muscles are composed of many fibers that are arranged in bundles called fascicles
-individual muscles are separated by fascia, which also forms tendons
-epimysium: outermost layer, surrounds entire muscle
-perimysium: separates and surrounds fascicles
-endomysium: surrounds each individual muscle fiber
-sarcolemma: muscle fiber membrane
-sarcoplasm: inner material surrounding fibers (like cytoplasm)
-sacroplasmic reticulum: transport
-myofibrils: individual parallel muscle fibers within sarcoplasm
-actin: thin filaments
-myosin: thick filaments
-form dark and light bands
-A band = dArk = thicK (myosin)
-I band = LIght = thIn (actin)
Hierarchy of Muscle Structure
-Muscle composed of fascicles
-Fascicles composed of myofibrils
-Myofibrils composed of myofilaments
-Myofilaments = individual types of actin and myosin
How Muscles Work with the Nervous System
-NEUROMUSCULAR JUNCTION - where a nerve
and muscle fiber come together
-MOTOR END PLATE - folded area where muscle
and neuron communicate
-SYNAPTIC CLEFT - gap between the neuron and
motor end plate
-SYNAPTIC VESICLES - where neurotransmitters
are stored, these are released into the cleft
and tell the muscle to contract
Motor Unit or Neuromuscular Junction
-The neurotransmitter that crosses the gap is
-ACH is broken down by CHOLINESTERASE
-This is what activates the muscle
-Stored in vesicles
Sliding Filament Theory
-the theory of how muscle contracts is the sliding filament theory. The contraction of a muscle occurs as the thin filament slide past the thick filaments.
-ATP is produced by cellular respiration
which occurs in the mitochondria
-creatine phosphate increases regeneration of ATP
-Only 25% of energy produced during cellular respiration is used in metabolic processes - the rest is in the form of HEAT.
-maintains body temperature.
-move away from the midline
-move toward the midline
-palm or sole turns downward
-palm or sole turns upward
-Minimal strength required to cause a contraction
-Motor neuron releases enough acetylcholine to reach threshold
-Fibers do not contract partially, they either do or don't
-The muscle fiber + the motor neuron
-more and more fibers contract as the intensity of the stimulus increases
-Sustained contraction of individual fibers, even when muscle is at rest
-muscles enlarge (working out or
-muscles become small and weak due to disuse
-muscle loses ability to
contract after prolonged exercise or strain
-a sustained involuntary
-oxygen is used to create ATP, not have enough oxygen causes lactic acid to accumulate in the muscles → soreness
Origin and Insertion
-origin: the immovable end of the muscle
-insertion: the moveable end of the muscle
-the change in electrical potential, passage of an impulse along the membrane (sarcolemma) of the muscle cell
-a few hours after a person or animal dies, the joints of the body
stiffen and become locked in place. This stiffening is called rigor mortis.
-depending on temperature and other conditions, rigor
mortis lasts approximately 72 hours.
-tetanus: causes cholinesterase to not break down the acetylcholine in the synapse. this results in a person's muscles contracting and not relaxing.
-myotonia: delayed relaxation of the skeletal muscles after voluntary
contraction, electrical stimulation, or even being startled.
-myasthenia gravis: means "grave muscular weakness", autoimmune disease, acetylcholine receptors are damaged
-muscular dystrophy: Muscles progressively get weaker, often resulting in inability to walk, talk or breathe.
-ALS: ALS, or amyotrophic lateral
sclerosis, is a progressive neurodegenerative disease. the motor nerves that are affected are the motor neurons (motor unit) that provide voluntary movements and muscle control.
Poisons that Affect the Neuromuscular Junction
-strychnine: Lowers the threshold
level for an action
potential, making it
more likely the muscles will contract. death occurs from convulsions and
-curare: classified as a neuromuscular
blocking agent—it produces flaccidity
in skeletal muscle by competing with the neurotransmitter acetylcholine at
the neuromuscular junction
What chemical helps to regenerate ATP?
Skeletal muscles are responsible for moving
Muscles fibers are made of individual fibers (not filaments) called
Connective tissue that surrounds fascicles is
Poisons such as botulism that prevent the release of acetylcholine would cause muscles to
What type of muscles are primarily voluntary
-Found in the heart
-Found in the digestive tract
What neurotransmitter is associated with the muscles
What cell organelle provides the ATP needed for muscle activity?
The gap between the nerve and the muscle is called the
What is hypertrophy?
-makes muscles enlarge
-makes muscles shrink
A person who has a disease that inhibits the production of cholinesterase would have what kind of symptoms?
-muscles stay contracted
Cholinesterase is an enzyme that breaks down
During a muscle contraction, cross bridges form between what two structures?
-actin and myosin
In a sarcomere, the I band is made of __________ and the A band is made of _________
The dark and light fibers of the muscles give cells a ________ appearance
The energy source for muscle contraction is
Vesicles in the motor neuron store what substance?
When recruitment occurs, the number of motor units being activated
Sustained contraction of individual fibers, even when muscle is at rest is known as
The immovable ends of the muscle is the
The moveable ends of the muscle is the
Muscle fatigue is likely due to a buildup of
A sarcomere is defined as the region between two
The condition where a body becomes stiff after death is called
When ATP has been used it becomes
-ADP and phosphate
What is a motor unit?
-motor neuron and muscle fiber cell
Myofibrils are composed of
-actin and myosin (myofilaments)
The muscle fiber membrane is specialized to form a __________________ at the neurotransmitter junction
-motor end plate
Which type of connective tissue surrounds fascicles (bundles)?
What type of tissues surround the entire muscle?
The substance that crosses the gap between a neuron and a muscle fiber is the
-muscles to bones
Bundles of muscle fibers are called
The minimum amount of stimulus required for a muscle contraction to occur is the
What model explains how muscles contract?
-sliding filament theory
Place the following in the correct order:
___Actin and myosin form links
___Acetylcholine crosses the gap at the neuromuscular junction
___Calcium is released into the sarcoplasm
___Myosin cross-bridges pull actin filaments inward
The A bands are _____ whereas the I bands are ____
The muscle fiber membrane is called the
The transport network of the muscle is called the
Label the components of a sarcomere
Label the components of a neuromuscular junction
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