Biomed Muscles

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Actin
A contractile protein that is part of the thin filaments in muscle fibers
Afferent neurons
Nerve cells that carry impulses towards the central nervous system
Cardiac muscle
Striated muscle fibers (cells) that form the wall of the heart; stimulated by the intrinsic conduction system and autonomic motor neurons
Carpal tunnel syndrome
A condition caused by compression of the median nerve in the carpal tunnel and characterized especially by weakness, pain, and disturbances of sensation in the hand and finger
Contract
To shorten and thicken
Efferent neurons
Nerve cells that conduct impulses away from the central nervous system
Endomysium
The delicate connective tissue surrounding the individual muscular fibers within the smallest bundles
Epimysium
The external connective-tissue sheath of a muscle
Fascicle
A small bundle or cluster, especially of nerve or muscle fibers
Insertion
The attachment of a muscle tendon to a moveable bone or the end opposite the origin
Muscle
An organ composed of one of the three types of muscular tissue (skeletal, cardiac, and smooth), specialized for contraction to produce voluntary and involuntary movements of parts of the body
Myofibril
A threadlike structure, extending longitudinally through a muscle fiber (cell) consisting mainly of think filaments (myosin) and thin filaments (actin, troponin, and tropomyosin)
Myosin
The contractile protein that makes up the thick filaments of muscle fibers
Nerve
A cordlike bundle of neuronal axons and/or dendrites and associated connective tissue coursing together outside the central nervous system
Origin
The attachment of a muscle tendon to a stationary bone or the end opposite the insertion
Perimysium
The connective-tissue sheath that surrounds a muscle and forms sheaths for the bundles of muscle fibers
Plexus
Network of interlacing blood vessels or nerves
Rigor mortis
Temporary rigidity of muscles occurring after death
Sarcomere
Any of the repeating structural units of striated muscle fibrils
Skeletal muscle
An organ specialized for contraction, composed of striated muscle fibers (cells), supported by connective tissue, attached to bone by a tendon or aponeurosis, and stimulated by somatic motor neurons
Sliding filament mechanism
The explanation of how thick and thin filaments slide relative to one another during striated muscle contraction to decrease sarcomere length
Smooth muscle
A tissue specialized for contraction, composed of smooth muscle fibers (cells), located in the walls of hollow internal organs, and innervated by the autonomic motor neurons
Striation
Any of the alternate dark and light cross bands of a myofibril of striated muscle
Tropomyosin
A protein of muscle that forms a complex with troponin regulating the interaction of actin and myosin in muscular contraction
Troponin
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
How do muscles assist with movement of the body and of substances around the body?
It is attached to both the bones by strong cords called tendons making the muscles contract.
When the muscles contracts, usually just one bone moves.
How do the structure and function of the three types of muscle tissue compare?
Skeletal muscle or voluntary muscle is anchored by tendons. Smooth muscle or involuntary muscle is found within the walls of organs and structures. Unlike skeletal muscle, smooth muscle is not under conscious control. Cardiac muscle is also an involuntary muscle but is more akin in structure to skeletal muscle, and is found only in the heart.
How are muscle fibers and membranes organized to form a whole skeletal muscle?
A muscle is made of tiny fibers. First it starts with one fiber that is surrounded by a layer of endomysium (connective tissue). Next a few more single strands of fibers are added to this one and wrapped around that is a layer of perimysium. this group of fibers is called a fasicle. then a bunch more fasicles get added to this one and is surrounded by a layer of epimysium. this creates the entire skeletal muscle.
What do skeletal muscle structure and attachment to bones tell you about function?
it tells you that this muscle moves the bones for movement.
How are muscles named?
Muscles are named according to their location, origin and insertion, direction of muscle fibers, size, shape, type of action produced, or other criteria, such as nearby bones
What role do calcium play in muscle contraction?
calcium binds to troponin and moves tropomyosin away from the actin strand allowing the myosin head to bind to actin and facilitate contraction
How does a sarcomere contract and lengthen to cause muscle contraction?
Myosin pulls actin, and actin pulls the sarcomere's ends toward the middle
How is the condition rigor mortis related to muscle contraction?
It's caused by the skeletal muscles partially contracting. The muscles are unable to relax, so the joints become fixed in place.
How do nerves interact with muscles?
The nervous system tells your muscles to contract through electrical signals and then the muscles lift your bones.
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