Chapter 2 Flashcards
There are about how many ….. skeletal muscles that usually work in cooperation with each other to perform opposite actions at the joints they cross
215
Muscles work in groups rather than independently to achieve a given joint motion
Aggregate muscle action
Muscles also have four other functions… what are they?
- provide protection
- contribute to support & posture
- Produce a major portion of body heat
- Provide dynamic stability
Muscles are usually named based on their:
- visual appearance
- functions
- anatomical locations
True or false: A muscle can be identified by a combination of two or more of these features
true
What does maximus and minimus mean? what does longus and brevis mean? what characteristics is this dsecribing?
Maximus- large
Minimus - small
Longus- Long
Brevis- short
Visual appearance: Directional fibers: What do the following mean?
Oblique
Rectus
Transverse
Oblique- slanting fibers
Rectus - Parallel fibers
Transverse - horizontal fibers
Skeletal muscle is made up of what ? They are stimulated by what when they are contracted?
They are made of up individual muscle fibers.; A motor nerve.
Muscle fiber arrangement affects:
- Muscle’s ability to exert force
- Cross-sectional- area
- Range through which the muscle can effectively exert force
4: Longer muscles can shorten through a greater range: move joints through larger range of motion
What are the two major types of fiber arrangements?
- Parallel & Pennate
Describe the diffrence between parallel and pennate fibers
Parallel fibers are fibers that are parallel in length to the muscle. They produce greater movement than simialr sized pennate muscles
Pennate fibers on the other hand are fibers that are shorter and arranged obliquely to their tendons. They have a greater cross sectional area; thus greater power.
The part of the muscle that attaches farthest from the midline or center of the body
insertion
The part of the muscle that attaches closest to the midline or center of the body
orgin
Fibrous connective tissue that connects muscles to bones and other structures
Tendon
Development of tension in a muscle as a result of a stimulus
Contraction
There are two types of muscle contraction? What are they?
Isotonic and isometric
There are 3 primary things a muscle contraction focuses on?
Cause; control; and prevent of a joint movement
What happens during an isometric concentration?
During an isometric concentration, muscle tension is being created; however, the joint angles remain constant. In other words, I am holding a weight in a stable condition. I am not moving my arm up or down. Therefore, my muscles are contracting and creating tension and being used to stay in that stable condition
Muscle develops active tension but joint angles remain constant (static contraction)
Isometric contraction
There are two types of isotonic contraction? What are they?
Eccentric & concentric
Muscle develops active tension to either cause or control joint movements (dynamic stability)
isotonic contraction
What is another name for static contraction?
isometric contraction
What is another name for dynamic contraction?
isotonic contraction
muscle develops active tension as it shortens
Concentric contraction
does muscle lengthen or shorten in concentric contraction?
shorten
describe the muscle force in concentric contraction
The muscle force is greater than resistance. In other words, during concentric contraction, my angle of joint is shortening. I am moving my arm toward my forearm. My backpack wants to fall down to the ground but im using my arm to use greater force to lift my backup up.
muscle lengthens under active tension
Control motion
Eccentric contraction
Does muscle lengthen or shorten during eccentric contraction?
lengthen
Describe the muscle force in eccentric contraction
During eccentric contraction, the muscle force is lesser than the resistance . this is because my arm that was holding the backpack wants the backpack to be put down. In other words, gravity and resistance wants the backpack to be put down; therefore, its gonna work in the direction of external forces. I will have decelerate movement.
Movement may occur at any given joint without any muscle contraction whatsoever
Passive movement
Movement at a joint depends upon several factors:
Relative contraction or relaxation of muscles acting on the joint
THE MOTOR UNITS ACTIVATED
Joint position at the time of contraction
Planes of motion and axis of rotation possible in the joint
Muscle length
Some agonists may contribute more than others due to relative location, size, length, or force generation capacity; these muscles are called
prime movers
AGONIST muscles that contribute significantly less to the joint motion are commonly referred as …..
assisters
Example: Elbow Flexion
Agonists:
Assisted by
what is the agonists? Biceps brachii
assisters? Brachialis: brachioradialis
Located on the opposite side of joint from the agonist muscles, and have opposite concentric actions
antagonist muscles
Work in cooperation with agonist muscles by
relaxing and allowing
Refine movement and prevent undesired motions
Prevent unwanted movements of the agonist muscle, and may also help agonists move the joint in the desired manner
synergists
Surround the joint or body part and contract to stabilize the area, allowing another body segment to move
stabilizer muscles
Similar to stabilizers, in that they prevent undesired movements of other muscles
neutralizers
Neurons consist of three things:
cell body
dendrites
axon
Dendrites.. what do they do with impulses?
dendrites transport impulses to the cell body and neurons
Axon
transports impulses to the cell body and neurons
Basic functional units of the nervous system responsible for generating and transmitting impulses
neurons
What are the 3 types of neuron?
motor, sensory and interneurons
What do motor, sensory, and interneurons mean?
Motor-transport impulses from the CNS– ( transport impulses away from the CNS)
Sensory- transport impulses to the CNS( transport impulses from the PNS to the CNS)
Interneurons- transports impulses between neurons
Nervous system innervates….. within a muscle
muscle fibers…
True or falseA muscle may be innervated by more than one nerve, and a particular nerve may innervate more than one muscle or portion of a muscle
True
motor nerve and all the muscle fibers it supplies
motor unit
There are 5 levels of the CNS… what are they? From highest to lowest
- Cerebral Cortex
- Basal Gangilla
- CEREBELLUM
- Brain stem
- Spinal Cord
Aggregates muscle action to create ……
Interprets sensory stimuli to determine needed responses
voluntary movement
Cerebral Cortex
Controls maintenance of…..
Controls …..
Controls sensory integration for balance and rhythmic activities
Postures; equilibrum
Learned movements
Basal gangilla
Integrates sensory impulses
Provides feedback relative to motion
Controls timing and intensity of muscle activity to refine movements
Cerebellum
Integrates all CNS activity through excitation and inhibition of desired neuromuscular functions
Brain stem
Pathway between CNS and peripheral nervous system (PNS)
Spinal cord
Provide both motor and sensory function for their respective portions of the body
Spinal nerve
Mechanism by which body is able to regulate posture and movement
Proppriception
-Proprioceptors are internal receptors located in the skin, joints, muscles, and tendons that provide feedback relative…
provide feedback relative to the tension, length, and contraction state of muscle, the position of the body and limbs, and movements of the joints
Proprioceptors work in combination with other sense organs to accomplish …..
Kinesthesis
What is kinesthesis?
Conscious awareness of the position and movement of the body in space
Proprioceptors specific to muscles are
Muscles spindles
Golgi tendon organs (GTO)
Located in …. between the fibers
muscle belly
Number of spindles within muscle varies depending upon level of control needed-
True
Tapping the patella tendon causes a quick stretch of the ….., which activates the …
……. neuron sends information via the ……to the spinal cord, where it synapses with a motor neuron
This carries a motor response via its axon
Quadriceps contracts and the knee extends
quadriceps; muscle spindle
sensory; axon
Located in the tendon near junction with muscle
Golgi tendon organs
GTO detect tension applied to a tendon as muscles contract
….. neurons conduct information to ……., where they synapse with inhibitory ….. that synapse with motor neurons
Inhibition of the motor neurons causes muscle …. relieving the tension applied to the tendon
GTO also help activate antagonistic muscles
Sensory; spinal cord ; interneurons
relaxation
single motor neuron and all the muscle fibers it innervates
Motor unit
Stimulus produces action potential within the motor unit
Threshold Stimulus
Stimuli strong enough to produce action potentials in additional motor units
Submaximal unit
Stimuli strong enough to produce action potentials in all motor units of a particular muscle
Maximalii stimuli
Brief period of inaction following a stimulus
latent period
Muscle fiber begins shortening
contraction phase
How long does the muscle contraction phase last?
40 miliseconds
Follows the contraction phase
relaxation phase
how long does the relxation phase last?
50 miliseconds
Maximal stimulus applied at a frequency allowing complete relaxation between contractions
Slightly greater tension is produced by the ….. stimulus than by the first, and 3rd> 2nd
Only occurs with the first few stimuli
second:
Treppe
Generates a greater amount of tension than a single contraction would produce individually
summation
Occurs when the stimuli are provided at a frequency high enough that no relaxation can occur between contractions
Tetanus
Developed as muscle is stretched beyond it normal resting length
Passive tension
Also related to muscle length
Active tension
Describe the muscle length tension relationship
Maximal ability of a muscle to develop tension and exert force depends upon muscle length during contraction
What is the optimal length to produce greatest tension?
100-130%
Cross and act directly only on the joint that they cross
unarticulr muscle
Cross and act on two different joints
biarticular muscle
Cross and act on three or more joints
multiarticular muscle
same action at both joints
opposite actions occurring simultaneously at both joints
concurrent movement
Countercurrent movement
