Anatomy & Physiology: Muscular System Flashcards
Muscular System
Responsible for all types of body movement and provides support, stabilizing joints, and generating heat for the body.
Muscle Fibers
Specialized cells that make up all muscles.
Cardiac Muscle
Consists of muscle cells that are striated, short, branched, and found in the walls of the heart.
Skeletal Muscle
Cells are striated, long, and cylindrical. Attached to bones in the body.
Smooth Muscle
Non-striated muscle cells that are spindle-shaped and found in the walls of internal organs like the bladder and stomach.
Endomysium
Encases individual skeletal muscle fibers.
Perimysium
Muscle fibers that are bundled together by a connective tissue.
Fasciculi
Bundles of skeletal muscle fibers.
Epimysium
Fascicles are bundled together by a strong connective tissue.
Sarcolemma
The cell membrane that surrounds a skeletal muscle fiber.
Sarcoplasm
The cytoplasm of the skeletal muscle fiber.
Myofibrils
One muscle fiber is filled with several long, cylindrical proteins.
Sarcomere
The smallest contractile unit in a myofibril.
Myofilaments
A myofibril is the result of several of these. There are two types.
Myosin
Thick bands, or myofilaments, are made of several protein molecules.
Actin
Several protein molecules that link together to form the thin bands.
Z-Disk or Z-Line
Thin actin bands are attached to this.
I-Bands
Light-colored bands.
A-Bands
Dark-colored bands,
H-Zone
Found in the middle of the A-Bands.
M-Line
Found in the middle of the H-Zone, center of the sarcomere.
Slide Filament Theory
Actin filaments slide past myosin filaments, pulling the actin filaments closer to the center of the sarcomere, or M-Line. This sliding action happens because of interactions between the heads of actin and myosin. The heads of myosin form attachments with the actin myofilaments.
Crossbridges
Attachments that are formed from the heads of myosin and the actin myofilaments.
Sarcoplasmic Reticulum
Surrounds the myofibrils
Ligament
Attach bones to bone.
Joint
Where ligaments connect bones and the bones meet.
Immovable Joint
These consist of bones held together by connective tissues. The bones are in very close contact.
(Also known as Fibrous Joints)
Partly Movable Joint
These consist of bones held together by cartilage. These joints allow some degree of movement.
(Also known as Cartilaginous Joints)
Synovial Joint
These allow the largest freedom of movement because the bones are separated by a joint cavity.
Tendons
Attach muscle to bone.
Flexor Muscle
The muscle that causes a joint to bend.
Extension Muscle
The muscle that contracts and causes a joint to straighten.
