The Muscular System Flashcards
Tendons
Strong connective tissue formed primarily of collagen
Attach muscles to bones
Skeletal muscle
Role is to contract in response to conscious intent
Cardiac muscle
Found only in the wall of the heart
Innervated by autonomic nervous system
Smooth muscle
Found in the walls of all hollow organs - GI tract, the urinary system, uterus
Responsible for GI motility, constriction of blood vessels, uterine contractions
Innervated by autonomic nervous system
Origin
Point where the muscle attaches
Insertion
Point where the muscle attaches on the bone marrow distant from the center of the body
Antagonistic
Muscles that are responsible for movement in opposite directions
Synergistic
Muscles that move a joint in the same direction
Myofibrils
It is responsible for the striated appearance of the skeletal muscle and generates the contractile force of skeletal muscle
Tropomyosin
A long fibrous protein that winds around the actin polymer, blocking all the myosin binding sites
Troponin
A globular protein bound to the tropomyosin that can bind Ca2+
Neuromuscular junction
The synapse between an axon terminus and a myofiber
A long trough or invagination of the cell membrane
Ach is the neurotransmitter
Transverse tubules
Allow the action potential to travel into the thick cell
Sarcoplasmic reticulum
Sequester and release calcium
Contains voltage-gates calcium channels - allow calcium to rush out of the sarcoplasmic reticulum into the sarcoplasm upon depolarization
Motor unit
A group of myofibers innervated by the branches of a single motor neuron’s axon
Myoglobin
Provides an oxygen reserve by taking oxygen from hemoglobin and then releasing it as needed
Type IIA Fast Twitch Fibers
Somewhat resistant to fatigue
Cannot maintain activity for as long as slow twitch fibers
Type IIB Fast Twitch Fibers
Called white fast twitch fibers because they lack mitochondria
Fatigue easily
Contract very quickly with great force
Provide the explosive force needed for jump shots and pole vaults
Intercalated disks
Gap junction sin heart muscle cells
Allow action potentials to propagate throughout the entire heart without allowing nuclei and cytoplasmic contents to be shared
