muscles Flashcards
What is excitability?
ability to receive and respond to stimuli
What is contractility?
muscles ability to shorten
What is extensibility?
Muscle’s ability to be stretched without tearing
What is elasticity?
muscle’s ability to returned to its original shape
What is another word for muscle cell?
muscle fiber
What are the smaller parts of cells called?
organelles
How many important organelles does a muscle fiber have?
5
What is myofibril?
the individual proteins that make up a muscle fiber
What is a sarcolemma?
the muscle fiber cell membrane
What is the sarcoplasmic reticulum?
regulates levels of calcium ions (Ca 2+) in the muscle fiber
When are calcium ions released?
when stimulated by an electrical impulse
What are T-tubules?
part of the sarcolemma that protrude deep into the muscle fiber interior
what do T-tubules allow?
electrical impulses to reach the deepest parts of the sarcoplasmic reticulum
What are receptors?
binding sites on the muscle fiber that receives neurotransmitters
What are motor neurons?
neurons that deliver impulses from the brain to the muscle
What do motor neurons stimulate skeletal muscle fibers to do?
contract
What is action potential?
an electrical impulse that travels through a motor neuron
What is neuromuscular junction?
where a motor neuron and a muscle fiber come together
what is an axon terminal?
end of the axon of a neuron (sends an impulse away)
What is the synaptic cleft?
the space between the axon terminal of a motor neuron and a muscle fiber
What is a neurotransmitter?
a chemical message released by
neurons
What is ACh?
acetylcholine
What is ACh used for?
the neurotransmitter that motor neurons to use to tell skeletal muscle to contract
What is neuromuscular junction?
where a motor neuron and skeletal muscle fiber communicate
What is step 1 of neuromuscular junction?
the brain decides to contract a skeletal muscle
What is step 2 of neuromuscular junction?
motor neurons carry the action potential down the spinal cord to the skeletal muscle
What is step 3 of
neuromuscular junction?
the action potential arrives at the neuromuscular junction
What is step 4 of neuromuscular junction?
the action potential causes the axon terminal to releases ACh
What is step 5 of neuromuscular junction?
ACh binds to receptors on the sarcolemma
What is step 6 of neuromuscular junction?
the binding causes the action potential to travel down the sarcolemma
What is step 7 of neuromuscular junction?
The action potential travels down the T-tubules
What is step 8 of neuromuscular junction?
the sarcoplasmic reticulum is stimulated by the action potential and releases Ca 2+
What is step 9 of neuromuscular junction?
Ca 2+ triggers the muscles fiber to contract
What are I bands?
light bands, contains only thin (actin) filaments
What is the H zone?
Contains only thick filament
What is the A band?
dark band, contains the entire length of a thick (myosin) filament
What is the Z line?
boundary between sacromeres
What is myosin?
thick myofilament, has “heads” to bind to actin
What is the M line?
“middle line”, holds together the myosin myofilament
What is actin?
thin myofilament, two strands of pearls
