groups of muscles Flashcards
Muscles that flex the wrist are found on the __________ side of the forearm while those that extend the wrist are found on the __________ side of the forearm.
anterior
posterior
most muscles that move the thigh have their insertions on the __________.
femur
What is the role of motor neurons in skeletal muscle function?
Motor neurons release neurotransmitters that stimulate muscle contraction
What effect does lack of motor neuron innervation have on skeletal muscle function?
The muscle is unable to contract.
What effect does lack of motor neuron innervation have on the structure of a skeletal muscle?
The muscle becomes smaller in size due to lack of stimulation.
What term describes the change in muscle structure that results from lack of innervation, use, and/or stimulation?
Atrophy
What is the role of acetylcholine (ACh) at the neuromuscular junction?
It is released by the motor neuron, crosses the synaptic cleft and binds to receptors, stimulating the muscle cell.
The lack of ACh in the synaptic cleft due to the effects of botulinum toxin would result in
lack of muscular contraction (called flaccid paralysis).
The entry of calcium into the axon of the neuron triggers the release of __________ from synaptic vesicles.
acetylcholine
If the acetylcholine-specific receptors were blocked at the motor end plate and acetylcholine could not bind with the receptors, what would happen?
An action potential would not be generated in the muscle fiber.
what do muscle cells use as source of energy during strenuous exercise
ATP present in their cytoplasm
how do the muscle cells produce ATP as it becomes limited?
muscle cells start to use creatine phosphate present in the cytoplasm
how is ATP produced using creatine phosphate?
moving a phosphate and its energy from this molecule to ADP to form new ATP.
other than creatine phosphate, what else is used to produce ATP
glucose is used as a fuel
how does glycolysis use glucose?
the anaerobic pathway uses glucose to produce 2ATP and 2 molecules of pyruvic acid
what happens to the pyruvic acid if there’s little or no oxygen?
converted to lactic acid
what happens to the pyruvic acid if there’s oxygen?
pyruvic acid molecules enter the aerobic respiration pathways
what happens in the aerobic respiration pathway?
oxidation of each glucose molecule will produce 30 ATP molecules.
what is the latent period of muscle?
the short delay (1-2 ms) rom the time when the action potential reaches the muscle until tension can be observed in the muscle
what is the period of contraction?
when the muscle is generating tension and is associated with cycling of the cross bridges
what is the period of relaxation?
muscle relaxes, relieves tension or comes back to its original length.
which muscle type release calcium into the cytosol when stimulated?
smooth and skeletal
which muscle type respond to hormones?
smooth
which muscle type rely on actin and myosin during contraction?
smooth and skeletal
which muscle type respond to the neurotransmitter norepinephrine?
smooth
which muscle type are slower to contract and relax than the other muscle type?
smooth
which muscle type has regularly aligned thin and thick filaments?
skeletal
which muscle type can respond to neurotransmitters with inhibition of contraction?
smooth
which muscle type can respond to the neurotransmitter acetylcholine?
smooth and skeletal
whats the function of skeletal muscle?
move bones
whats the function of cardiac muscle?
pump blood
where is skeletal muscle found?
attached to bone
where is cardiac muscle found?
wall of the heart
how many nuclei in skeletal muscle cells?
multiple
how many nuclei in cardiac muscle cells?
singular
how is skeletal muscle controlled?
voluntarily
how is cardiac muscle controlled?
involuntarily
where are calcium ions in skeletal muscle from?
sarcoplasmic reticulum
where are calcium ions in cardiac muscle from?
extracellular fluid and sarcoplasmic reticulum
which muscle type contains intercalated discs?
cardiac
how is the skeletal muscle stimulated to contract?
each muscle cell needs to be stimulated by a neurotransmitter to contract
how is the cardiac muscle stimulated to contract?
stimulation travels rapidly from cell to cell causing contraction
what is an antagonist muscle?
the muscle that opposes that movement
what is an agonist muscle?
the muscle that initiates a movement
what is the synergist muscle?
additional muscles that assist the agonist
which muscles move the head?
sternocleidomastoid
splenius capitis
semispinalis capitis
scalenes
which muscles aid in mastication?
masseter
temporalis
which muscles help facial expression?
epicranius
orbicularis oculi
orbicularis oris
buccinator
zygomaticus
platysma
which muscle elevates the mandible?
masseter
which muscle pulls head to one side + flexes neck?
sternocleidomastoid
which muscle depresses the corner of the mouth?
platysma
which muscle closes the mouth?
orbicularis oris
which muscle compresses the cheeks?
buccinator
which muscle elevates the corner of the mouth?
zygomaticus
which muscle closes the eye?
orbicularis oculi
which muscles raise the eyebrows?
frontalis
occipitalis
whats the collective name for frontalis
and occipitalis?
epicranius
which muscle is an extensor?
triceps brachii
which muscle is a rotator?
supinator
pronator teres
pronator quadratus
which muscle is a flexor?
biceps brachii
brachialis
brachioradialis
what happens if there is an excess of acetylcholine produced?
increased contractility in skeletal muscles
what happens if motor neurons fire excessively?
increased contractility in skeletal muscles
what happens if there is a deficiency of acetylcholine produced?
reduced contractility in skeletal muscles
what happens if there is curare poisoning that blocks acetylcholine receptors?
reduced contractility in skeletal muscles
what happens if there is a botulism where toxin inhibits the release of acetylcholine?
reduced contractility in skeletal muscles
