Studied by 3 people
Anatomy and Physiology
What is a myofibril?
the individual proteins that make up a muscle fiber
What is a sarcolemma?
The muscle fiiber cell membrane
What is a sarcoplasmic reticulum?
It is a regulator of calcium levels in muscle fibers
What are t-tubules?
They are part of the sarcolemma that protrude deep into the muscle fiber interior
What are receptors?
They are binding sites on the muscle fiber that receive neurotransmitters
What is action potential?
It is an electrical impulse that travels through a motor neuron
What is a neuromuscular junction?
It is where a motor neuron and a muscle fiber come together
What is an axon terminal?
It is the end of the axon of a neuron which sends impulses away
What is the synaptic cleft?
It is the space between the axon terminal of a motor neuron and a muscle fiber
What is a neurotransmitter?
It is a chemical message released by neurons
What is ACh (Acetylcholine)?
It is a neurotransmitter that motor neurons use to tell the skeletal muscle to contract
What is a neuromuscular junction?
It is where a motor neuron and a skeletal muscle fiber communicate
What is the first step in muscle contraction?
The brain decides to contract a skeletal muscle
What is the second step in muscle contraction?
Motor neurons carry the action potential down the spinal cord to the skeletal muscle
What is the third step in muscle contraction?
The action potential arrives at the neuromuscular junction
What is the fourth step in muscle contraction?
The action potential causes the axon terminal to release ACh
What is the fifth step in muscle contraction?
ACh binds to receptors on the sarcolemma
What is the sixth step in muscle contraction?
The binding causes the action potential to travel down the sarcolemma
What is the seventh step in muscle contraction?
the action potential travels down the t-tubules
What is the eighth step in muscle contraction?
The sarcoplasmic reticulum is stimulated by the action potential and releases Ca+2
What is the ninth step of muscle contraction?
Ca+2 triggers the muscle fiber to contract
A muscle is made up of many ____
fascicles
A fascicle is made up of many ____
muscle fibers
A muscle fiber is made up of many _____
myofibrils
A myofibril is made up of many ____
sarcomeres
Aa sarcomere is made up of many ______
myofilaments
The two myofilaments are called ____ and _____
actin and myosin
The thin myofilament is called ____
actin
The thick myofilament is called ____
myosin
A ____ wraps around the muscle
epimysium
A ____ wraps around a fascicle
perimysium
A ____ wraps around a muscle fiber
endomysium
What is a sarcolemma?
It is the plasma membrane around each muscle fiber
What is the I band in a sarcomere?
It is the light band, and only contains actin filaments
What is the H zone in a sarcomere?
It contains only myosin filaments
What is the A band in a sarcomere?
It is the dark band, and it contrains the ENTIRE length of a myosin filament.
What is the Z line in a sarcomere?
It is a boundary BETWEEN sarcomeres
What is myosin?
It is the thick filament that has “hands” to bind to actin
What is the M line in a sarcomere?
It is the middle line, and it holds together the myosin
What is actin?
It is the thin filament that is made up of two strands of “pearls”.
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Flashcard (21)