tightly packed filament bundles found within fascicles
thick filament of protein with heads found in skeletal muscle cells
thin filament of protein found in muscles with myosin head receptors
the smallest unit of muscle contraction
the point of contact between a motor neuron and a skeletal muscle cell
neurotransmitter that transmits an impulse in a muscle cell
tough connective tissue that connects skeletal muscles to bones
Three types of muscle tissue
skeletal, cardiac, and smooth
found attached to bones ,voluntary, appears to have striations of light and dark, controlled by the central nervous system, haven many nuclei
found throughout the organs, not voluntary, spindle shaped, single nucleus, contract on their own
makes up most of the mass of the heart, not voluntary, striations of light and dark, one or two nuclei, contract on their own, intercalated disks
when myosin filaments form crossbridges with actin filaments. The cross bridges then change shape, pulling the actin filaments toward the center of the sarcomere.
a skeletal muscle whose contraction extends or stretches a body part and increases the angle between two bones
a muscle that bends a joint to decrease the angle between two bones.
Muscle pair contractions
when one muscle pair contracts, the other muscle in the pair relaxes (biceps- relaxes, triceps- contracted)
Two types of skeletal muscle fibers
red and white
slow-twitch muscle,contains many mitochondria, useful for endurance activities
oxygen storing protein in blood within the red muscle
fast-twitch muscle, contract more rapidly, contain only few mitochondria and tire quickly, useful for great strength or quick bursts of speed
involuntary waves of muscle contraction that keep food moving along in one direction through the digestive system.
alternate dark and light bands found on skeletal and cardiac muscle
proteins anchoring thin filaments of adjacent sarcomeres
supporting proteins that hold the thick myosin filaments together in the center of a sarcomere
a bundle of muscle fibers
bind to the protein that blocks the myosin-binding sites on actin.
a protein of muscle that together with tropomyosin forms a regulatory protein complex controlling the interaction of actin and myosin and that when combined with calcium ions permits muscular contraction
a protein that covers myosin binding sites on the actin molecules
(adenosine triphosphate) the main energy source that cells use for most of their work. In the case of muscles, ATP fuels myosin heads to attach to actin receptors to contract muscle
Sliding filament model
the system where the thick myosin and thin actin filaments slide past each other so that their degree of overlap increases to create a muscle contraction