Muscular System Flashcards
(29 cards)
function of the muscular system is:
movement through muscles contracting and relaxing
-also provides stability and protection of the spine as well as posture
what are proprioceptors?
sensory receptors that provide the body with kinesthetic awareness of its surroundings via stimuli which helps protect the body from injury and provide a sense of coordination in space
the main structural unit of a muscle is
the sarcomere which are composed of a series of muscle fibers
what are muscle fibers?
-what is found within each fiber?
they are elongated individual cells that stretch from one end of the muscle to the other
-hundreds of myofibrils
myofibrils are what?
-long strands within the cells that contain alternating layers of thin filaments made of the protein actin and think filaments made of the protein myosin
what is the thin filaments found within myofibris?
actin protein
what is the thick filaments found within myofibris?
myosin
what proteins play a role in muscle contraction and relaxation?
-actin and myosin
during muscle contractions, what happens?
myosin pulls the thin filaments of actin to the center of the sarcomere , causing the entire sarcomere to shorten/contract which creates movement
how are skeletal muscles activated?
through motor neurons which
what is a motor unit
when a motor neuron and skeletal muscle fibers associate
where are motor neurons for motor units located?
-within the spinal cord and branch out to the muscles to send the nervous impulses for muscular contraction
this is the site at which the motor neuron and muscle fibers join to form a chemical synapse for nervous transmission to muscle
neuromuscular junction
what are the three types of muscle?
-cardiac, visceral and skeletal
cardiac muscle is found?
-in the heart and contracts involuntarily creating the heartbeat and pumping blood
visceral muscles are found?
-they are also called? because?
in many of the body’s essential organs including the stomach, intestines. they slowly contract and relax to move nutrients, blood and other substances throughout the body
-they are aka smooth muscles because it is not composed of sarcomeres with alternating thick and thin filaments
skeletal muscle is responsible for?
-what are the 3 different movements they engage in?
-voluntary movement and linked to the skeletal system
-concentric (shorten), eccentric (elongate), and isometric (force without change of muscle)
what is concentric movement?
muscular contraction in which the length of the muscle is shortening to lift the resistance (upward curl of bicep)
what is eccentric movement?
muscular contraction in which the muscle is resisting a force as it lengthens (downward curl of bicep)
what is isometric movement?
muscular contracting in which the resistance and force are even and no movement is taking place (holding an object)
muscle strain is when
muscle fibers are overstretched causing pain, stiffness, and bruising
what is muscular dystrophy?
disease that weakens muscle fibers and is genetically inherited and limits movement
what is rhabdomyolysis?
the rapid breakdown of dead muscle tissue
which type of muscle is found in blood vessels?
visceral muscle
