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Exercise Physiology Test #3

Terms in this set (110)

Acetylcholine
_________________ is the neurotransmitter that stimulates the muscle fiber to depolarize, which is the signal to start the contractile process
control of the internal environment, voluntary control of movement, programming spinal cord reflexes, Assimilation of experiences necessary for memory and learning
What are the 4 main nervous system functions?
CNS
contains brain and spinal cord
PNS
consists of the nerves outside the brain and spinal cord
sensory, motor
What are the 2 divisions of the PNS?
sensory division
PNS division where afferent fibers transmit impulses from receptors to CNS
motor division
PNS division where efferent fibers transmit impulses from CNS to effector organs
nervous system
the body's means of perceiving and responding to events in the internal and external environments.
cell body, dendrites, axon
What are the 3 main structures of a neuron?
cell body
part of neuron that Contains the nucleus
Dendrites
part of neuron that conduct impulses toward cell body
Axon
part of neuron that carries electrical impulse away from cell body
Schwann cells
Forms discontinuous myelin sheath along length of axon
Nodes of Ranvier
gaps between the myelin sheath of a nerve between Schwann cells
synapse
Contact points between axon of one neuron and dendrite of another neuron
multiple sclerosis
Neurological disease that destroys myelin sheaths of axons Due to immune attack on myelin; Results in progressive loss of nervous system function
excitable
Neurons are an "__________ tissue"
irritability
Ability to respond to a stimulus and convert it to a neural impulse
Conductivity
Transmission of the impulse along the axon
negative
Resting membrane potential has ________ charge inside cells at rest
Permeability of plasma membrane to ions, difference in ion concentrations across membrane
Resting membrane potential is determined by what 2 things?
sodium-potassium pump
resting membrane potential is maintained by what?
2, 3
the sodium-potassium pump moves ____ K+ in and _______. Na+ out
action potential
Occurs when a stimulus of sufficient strength depolarizes the cell; Opens Na+ channels, and Na+ diffuses into cell; Inside becomes more positive
Repolarization
Return to resting membrane potential; K+ leaves the cell rapidly and Na+ channels close
All-or-none law
Once a nerve impulse is initiated, it will travel the length of the neuron
synapse
Small gap between presynaptic neuron and postsynaptic neuron
neurotransmitter
Chemical messenger released from presynaptic membrane; Binds to receptor on postsynaptic membrane and Causes depolarization of postsynaptic membrane
Temporal summation
Summing several EPSPs from one presynaptic neuron
Spatial summation
Summing from several different presynaptic neurons
neurons
specialized cells that respond to physical or chemical changes in their environment
excitatory
_________ postsynaptic potentials Causes depolarization
inhibitory
________ postsynaptic potentials Causes hyperpolarization
Proprioceptors
Receptors that provide CNS with information about body position; Located in joints and muscles
Kinesthesia
Conscious recognition of the position of body parts; Limb movement rates
free nerve endings, Golgi-type receptors, pacinian corpuscles
What are the 3 main types of joint proprioceptors?
free nerve endings
joint proprioceptors that are Sensitive to touch and pressure; Initially strongly stimulated, then adapt
Golgi-type receptors
joint proprioceptors that are Found in ligaments and around joints; Similar to free nerve endings
Pacinian corpuscles
joint proprioceptors that are In tissues around joints; Detect rate of joint rotation
muscle spindle, Golgi tendon organ
What are the 2 main muscle proprioceptors?
muscle proprioceptors
Provide sensory feedback to nervous system; Tension development by muscle; Account of muscle length
muscle spindle
muscle proprioceptor that Responds to changes in muscle length
Golgi tendon organ
muscle proprioceptor that monitors tension developed in muscle; Prevents muscle damage during excessive force generation
reflex relaxation, stretch reflex
Golgi tendon organ stimulation results is ________ ________ while muscle spindle stimulation results in _______ ________
muscle chemoreceptors
Provide CNS with information about metabolic rate of muscular activity; Sensitive to changes in the chemical environment surrounding a muscle
cardiovascular, pulmonary
muscle chemoreceptors are important in regulation of _____________ and _____________ responses
somatic motor
portion of the peripheral nervous system is responsible for carrying neural messages from the spinal cord to the skeletal muscle fibers
motor unit
Motor neuron and all the muscle fibers it innervates
innervation ratio
Number of muscle fibers per motor neuron
size principle
the progressive recruitment of motor units beginning with the smallest motor units and progressing to larger and larger motor neurons
Vestibular Apparatus
Located in the inner ear and is Responsible for maintaining general equilibrium and balance; Sensitive to changes in linear and angular acceleration; Also controls head and eye movement during exercise
cerebral cortex, motor cortex
What are the 2 main parts of the cerebrum?
cerebral cortex
part of cerebrum that does Organization of complex movement; Storage of learned experiences; Reception of sensory information
motor cortex
part of cerebrum that does Motor control and voluntary movement
Cerebellum
Coordinates and monitors complex movement; Incorporates feedback from proprioceptors
motor cortex, brain stem, spinal cord
the cerebellum has connections to what 3 things?
brain stem, cerebrum, cerebellum
the brain can be divided into what 3 parts?
metabolic functions, cardiorespiratory control, complex reflexes
The brain stem is responsible for what 3 things?
central, peripheral
Current research suggests that fatigue is related to both ________ and ___________ factors
spinal tuning
Voluntary movement translated into appropriate muscle action
reflexes
__________ provide the body with rapid, unconscious means of reacting to a painful stimuli
cerebellum, basal ganglia, motor cortex
in motor function cortical and subcortical motivation areas send "rough draft" of the movement, then __________ and ________ convert "rough draft" into movement plan then the sent through the thalamus to the _________ which forwards the message for spinal tuning and onto muscles
Autonomic Nervous System
Responsible for maintaining internal environment
sympathetic, parasympathetic
What are the 2 divisions of the autonomic nervous system?
Sympathetic division
division of autonomic nervous system that Releases norepinephrine (NE) and Excites an effector organ
Parasympathetic division
division of autonomic nervous system that Releases acetylcholine (ACh) and inhibits effector organ
brain function
research shows Exercise improves ________ ___________ and reduces the risk of cognitive impairment associated with aging
withdrawal reflex
Reflex contraction of skeletal muscle that occurs in response to sensory input
600, 40, 50
Human body contains over _______ skeletal muscles which is _____-______ % of total body weight
Force production for locomotion and breathing; Force production for postural support; Heat production during cold stress
What are the 3 functions of skeletal muscle?
Epimysium
connective tissue that surrounds entire muscle
Perimysium
connective tissue that surrounds bundles of muscle fibers
Endomysium
connective tissue that surrounds individual muscle fibers
Basement membrane
area of skeletal muscle Just below endomysium
Sarcolemma
skeletal muscle cell membrane
satellite cells
Play role in muscle growth and repair; Increase number of nuclei; Important for adaptations to strength training
actin, myosin
What are the 2 main types of contractile protein that myofibrils contain?
actin
thin filmament
myosin
thick filament
Myofibrils
muscle fiber structure that contains contractile proteins
neuromuscular junction
Junction between motor neuron and muscle fiber
neuromuscular cleft
Short gap between neuron and muscle fiber
motor end plate
Pocket formed around motor neuron by sarcolemma
single
The importance of the myonuclear domain is that a ________ nucleus is responsible for the gene expression for its surrounding cytoplasm
Acetylcholine
________________ is the neurotransmitter that stimulates the muscle fiber to depolarize, which is the signal to start the contractile process
sliding filament model
Muscle shortening occurs due to the movement of the actin filament over the myosin filament; Formation of cross-bridges between actin and myosin filaments; Reduction in the distance between Z lines of the sarcomere
ATP
_______ is required for muscle contraction
PC system, Glycolysis, Oxidative phosphorylation
What are the 3 sources of ATP for muscle contraction?
muscular contraction
the process of _________ ____________ can be best explained by the sliding filament/swinging cross-bridge model, which proposes that muscle shortening occurs due to movement of the actin filament over the myosin filament
Excitation-contraction coupling
refers to the sequence of events in which the nerve impulse (action potential) depolarizes the muscle fiber, leading to muscle shortening by cross-bridge cycling
calcium
The trigger to initiate muscle contraction is the depolarization-induced release of _________ from the sarcoplasmic reticulum
contraction
Muscular __________ occurs via the binding of the myosin cross- bridge to actin
relaxation
Muscle ____________ occurs when the motor neuron stops exciting the muscle fiber and calcium is pumped backed into the sarcoplasmic reticulum
muscle fatigue
a reduction in muscle power output that results from decreased muscle force generation and shortening velocity
muscle cramps
spasmodic and involuntary skeletal muscle contractions
biochemical, contractile
What are the two properties of muscle fiber types?
Type 1, Type IIa, Type IIx
What are the 3 types of fibers?
type I
Slow-twitch fibers; Slow-oxidative fibers
type IIa
Intermediate fibers; Fast-oxidative glycolytic fibers
type Iix
Fast-twitch fibers; Fast-glycolytic fibers
50, 50, fast, slow
non athletes have ______% slow and ___50% fast fibers, power athletes have higher percentage of _______ fibers, endurance athletes have higher percentage of ______ fibers
Isometric
Muscle exerts force without changing length; Pulling against immovable object
Concentric
Muscle shortens during force production
Eccentric
Muscle produces force but length increases; Associated with muscle fiber injury and soreness
muscle twitch
Contraction as the result of a single stimulus
types and number of motor units recruited, the initial muscle length, the nature of the motor units neural stimulation.
The amount of force generated during muscular contraction is dependent on what 3 factors?
summation
The addition of muscle twitches
tetanus
the frequency of neural stimulation to a motor unit is increased, individual contractions are fused in a sustained contraction called _________
decreases
The peak force generated by muscle ____________ as the speed of movement increases
decreases
force __________ with increasing movement speed during muscular contraction
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