The Muscular System Intro Flashcards
are responsible for all types of body movement – they contract or shorten and are the machine of the body
Muscles
Muscle – Latin: ___ “a muscle,” literally “little mouse,” diminutive of mus “mouse”
musculus
Prefix myo refers to
muscle
Prefix sarco refers to
flesh
Muscle cells are elongated (muscle cell =
muscle fiber)
Contraction of muscles is due to the movement of?
microfilaments
What are the Three basic muscle types found in the body
- Skeletal muscle
- Cardiac muscle
- Smooth muscle
*Skeletal Muscle Characteristics
Most are attached by
tendons to bones
*Skeletal Muscle Characteristics
Cells are
multinucleate
*Skeletal Muscle Characteristics
– have visible banding
Striated
*Connective Tissue Wrappings of Skeletal Muscle
around single muscle fiber
Endomysium
*Skeletal Muscle Characteristics
– subject to conscious control
Voluntary
*Connective Tissue Wrappings of Skeletal Muscle
around a fascicle (bundle) of fibers
Perimysium
*Connective Tissue Wrappings of Skeletal Muscle
covers the entire skeletal muscle
Epimysium
*Connective Tissue Wrappings of Skeletal Muscle
on the outside of the epimysium
Fascia
– cord-like structures
Tendons
– sheet-like structures
Aponeuroses
Sites of muscle attachment
Bones
Cartilages
Connective tissue coverings
*Accessory Structures of Muscles
located in certain tendons or joint capsules specifically at friction points; derived from the Latin word “sesamum” (sesame seed), due to the small size of most sesamoids
Functions:
a. protect tendons especially those passing over bony prominences
b. provide greater surface area for attachment of tendons over certain joints
c. divert the pull of tendons so that greater force is applied to the part being moved
Sesamoid bones
*Accessory Structures of Muscles
are connective tissue sacs filled with a viscous fluid and they reduce friction; they usually develop between tendons, ligament or muscle or between a bony growth and the skin
Bursae
*Accessory Structures of Muscles
are double-layered sacs with synovial fluid or synovia; they wrap tendons as they pass bony or fibrous projections.
Synovial tendon sheaths
or “synovium”
*Accessory Structures of Muscles
are the auxillary tissues that connect muscle to muscle.
Fasciae
*Accessory Structures of Muscles
are connective tissues that connect one bone to another bone.
Ligaments
*Accessory Structures of Muscles
are connective tissues that connect muscles to bones.
Aponeuroses and tendons
also called aponeurotica
an extremely delicate, thin sheath-like structure, which attaches muscles to the bones
white, transparent sheath, a flat structure
When a muscle moves by flexing or extending, an aponeurosis acts like a spring to bear the extra pressure and tension.
Aponeurosis
tough, rounded cord-like structure which are extensions of the muscle
white, shiny and glazed, rope- like tough structure
moves a bone when a muscle contracts. This allow the body to move and be flexible while aponeuroses allow the body to be strong and stable.
Tendon
Has no striations
Spindle-shaped cells
Single nucleus
Involuntary – no conscious control
Found mainly in the walls of hollow organs
Slow, sustained and tireless
Smooth Muscle
Has striations
Usually has a single nucleus
Joined to another muscle cell at an intercalated disc
Involuntary
Found only in the heart
Steady pace!
Cardiac Muscle
Function of Muscles
Produce movement
Maintain posture
Stabilize joints
Generate heatis
attained due to
a muscle
moving an
attached bone
is attained due to a muscle moving an attached bone
Movement
Muscles are attached to at least two points, which are
Origin and Insertion
attachment to a moveable bone
origin
Results of increased muscle use (4)
Increase in muscle size
Increase in muscle strength
Increase in muscle efficiency
Muscle becomes more fatigue resistant
*Naming of Skeletal Muscles
Direction of muscle fibers
rectus (straight)
*Naming of Skeletal Muscles
Relative size of the muscle
maximus (largest)
*Naming of Skeletal Muscles
Location of the muscle
many muscles are named
for bones (e.g., temporalis)
*Naming of Skeletal Muscles
Number of origins
triceps (three heads)
*Naming of Skeletal Muscles
Location of the muscles origin and insertion
sterno (on the sternum)
*Naming of Skeletal Muscles
Shape of the muscle
deltoid (triangular)
*Naming of Skeletal Muscles
Action of the muscle
flexor and extensor (flexes or
extends a bone)
These muscles cause the movement to occur by contracting. They are also referred to as prime movers since they are the muscles that are primarily responsible for generating the movement
agonists
These muscles act in opposition to the movement generated by the agonists and are responsible for returning a limb to its initial position.
antagonists
These muscles perform, or assist in performing, the same set of joint motion as the agonists. These are sometimes referred to as neutralizers because they help cancel out, or neutralize, extra motion from the agonists to make sure that the force generated works within the desired plane of motion.
synergists
These muscles provide the necessary support to assist in holding the rest of the body in place while the movement occurs. These are also sometimes called stabilizers.
fixators
The biceps brachii flex the lower arm. The brachoradialis, in the forearm, and brachialis, located deep to the biceps in the upper arm, are both synergists that aid in this motion.
Prime Movers and Synergists:
To extend the leg at the knee, a group of four muscles called the ______ in the anterior compartment of the thigh are activated (and would be called the ___ of leg extension at the knee). A set of ____ called the __ in the posterior compartment of the thigh are activated to slow or stop the movement.
quadriceps femoris
agonists
antagonists
hamstring
inherited, muscle enlarge due to increased fat and connective tissue, but fibers degenerate and atrophy
Muscular Dystrophy
lacking a protein to maintain the sarcolemma
Duchenne MD
progressive weakness due to a shortage of acetylcholine receptors
Myasthemia Gravis
