Test 1- Part 3: Muscular System Flashcards
How much body weight do muscles make up?
40-50%
What are muscle functions?
Joint movement
Dynamic stability of joints
Posture and support
Major producer of heat
What are the four muscle tissue properties?
Irritability
Contractility
Extensibility
Elasticity
Ability to return to shape after being contracted
Extensibility
Sensitive or responsive to chemical, electrical, and mechanical stimuli
Irritability
Ability to contract and develop tension against resistance when stimulated
Contractility
Ability to return to original shape after stretching
Elasticity
Example of muscle named after its shape:
Rhomboid
Example of muscle named after its size:
Gluteus maximus
Teres minor
Example of muscle named after its number of divisions:
Triceps brachii
Example of muscle named after its direction of fibers:
External oblique
Example of muscle named after its location:
Rectus femoris
Palmaris longus
Example of muscle named after its points of attachment
Coracobrachialis
Extensor hallus longus
Example of muscle named after its action:
Erector spinae
Supinator
Example of muscle named after its action & shape:
Pronator quadratus
Example of muscle named after its action & size:
Adductor magnus
Example of muscle named after its shape & location:
Serratus (means “notched”) anterior
Example of muscle named after its location & attachment:
Brachioradialis
Example of muscle named after its location & number of divisions:
Biceps femoris
FIbers arranged parallel to length of the muscle; produce greater ROM and endurance
Parallel
Shorter fibers that are arranged obliquely to their tendon
Pennate
Types of parallel muscles:
Flat Fusiform Strap Spincter Radiate
Types of pennate muscles:
Unipennate
Bipennate
Multipennate
Thin and broad originating from broad, fibrous, sheet like aponeurosis allowing force distribution. Give example
Flat
Rectus abdominus & external oblique
Long muscle with uniform diameter throughout allowing force to be focused onto small bony targets. Give example:
Strap
Sartorius
Spindle-shaped with belly that tapers toward each end allowing force to be focused onto small bony targets. Give example:
Fusiform
Brachialis & brachioradialis
Fibers concentrically arranged around a body opening. Endless strap muscle to surround and close openings. Give example:
Spincter Orbicularis oris (surrounds mouth)
Similar to flat on one end and fusiform on the other end. Give example:
Radiate
Pectoralis major & trapezius
Fibers run obliquely from a tendon on one side only. Give example:
Unipennate
Biceps femoris & tibialis posterior
Several tendons w/ fibers running diagonally between them. Give example:
Multipennate
Deltoid
Fibers run obliquely on both sides from central tendon
Rectus femoris
Muscles located within or belonging to the part on which they act
Intrinsic
Muscles that arise or originate outside of the body part on which they act
Extrinsic
The distal attachment of a muscle
Insertion
Specific movement of a joint that results from a contraction of a muscle that crosses the joint
Action
Usually the proximal attachment of a muscle
Origin
Tough, flexible bands of fibrous tissue that connect muscles to bones
Tendon
Central, fleshy portion of muscle
Gastor
- Tendinous expansion of dense fibrous connective tissue that is sheet like in appearance
- Serves as fascia to bind muscles together or to bone
Aponeurosis
- Band of fibrous connective tissue that envelopes, seperates, or binds parts of the body (muscles, organs, etc)
- Some joints have a fascia that form retinaculum to retain tendons close to the body
Fascia
What are the 3 muscle contractions?
Isometric Isontonic - Concentric - Eccentric Isokinetic
Tension develops as muscle shortens, causes movement against gravity
Concentric contraction
Maintains static or stable position; joint angle remains constant
Isometric contraction
Lengthens while maintaining tension; resistance overcomes force (negative)
Eccentric
Means “same speed”; uses concentric & eccentric muscle actions (dynamic)
Isokinetic contraction
What are the 5 roles of muscles?
Agonist Antagonist Stabilizers Synergists Neutralizers
Have the opposite concentric actions as agonists. Opposite side of joint
Antagonist
Surrounds joint or body part. Contracts to fixate or stabilize an area to allow another limb to exert force
Stabilizer
Any muscle that causes a specific joint motion.
Agonist
Prime movers & assisters
Neutralize unwanted motion in muscles that have multiple functions
Neutralizers
Muscles that assist in the action of an agonist but are not prime movers
Synergist
What are some determination of muscle actions?
Lines of pull Dissection Palpation Models EMG Electrical stimulation
Combines a knowledge of the joint’s functional design and the location of musculotendinous units
Lines of pull
What two systems work together resulting in all voluntary movement?
Muscular & nervous system
What are the 5 major parts of the central nervous system (CNS)?
Cerebral cortex Basal ganglia Cerebellum Brain stem Spinal cord
This CNS part controls maintenance of posture, equilibrium, and learned movements (walking, bike, driving).
Basal ganglia
This CNS part is the highest level of control and is where the creation of voluntary movement starts but not specific muscle activity
Cerebral cortex
This CNS part is the major integrator of sensory impulses and providing feedback
Cerebellum
This CNS part controls balance and rhythmic activities
Basal ganglia
This CNS part integrates all central nervous system activity through excitation and inhibition of neuromusclular actions
Brain stem
This CNS part is the common pathway between CNS and PNS
Spinal cord
This CNS part controls timing and intensity of contraction, assists in refinement
Cerebellum
This CNS part functions in maintaining a wakeful state
Brain stem
All the remaining nerves make up
Peripheral nervous system
This PNS division goes down (efferent) from the CNS to the muscles
Motor (Myotomes)
This PNS division goes up (afferent) from the receptors to the CNS
Sensory (Dermatomes)
Internal receptors located in the skin, joints, muscles, and tendons
Proprioceptors
This proprioception part is located in the muscle belly between fibers. Sensitive to stretch and rate of stretch (reflexes & balances)
Muscle spindle
This prevents your muscles from bursting. (tells/makes you stop when lifting too heavy)
Golgi tendon organ
Responds to changes in joint angles. Located arount joint capsules, ligaments, tendon, and beneath skin
Pacinian corpuscles
Located in deep layers of skin and joint capsules. Activated by strong and sudden joint movements as well as pressure changes
Ruffini’s corpuscles
Single muscle neuron and all of the muscle fibers it innervates
Motor unit
Muscles will contract maximally or NOT AT ALL; amount of force depends on # of fibers recruited
All or none principle
Developed when muscle is stretched beyond resting length
Passive tension
Dependent on # of motor units and their respective muscle fibers recruited
Active tension
Max tension depends on the length of muscle during contraction
Muscle length-tension relationship
Rate of length change is related to amount of force production
Muscle force-velocity relationship
Cross and act on only one joint
Unilarticular
- Muscles that cross and act on two different joints
- May cause actions at one or both joints when contracted
- May shorten at one joint and lengthen at another
Biarticular
- Concurrent: squat to stand; hip and knee both extending
* Counterconcurrent: kicking a ball; hip flexes and knee extends
Concurrent vs. countercurrent
When agonist contracts, antagonist muscle groups must relax and lengthen
Reciprocal inhibition
