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is a neurotransmitter, a chemical release by nerve cells that has either an excitatory or inhibitory effect on another excitable cell.


are muscles that create opposite movements, or muscles that oppose each other.


specialized muscle tissue of the heart.


is muscle contraction with muscle shortening


is muscle contraction with muscle lengthening... Load exceeds the maximum ability (slow lengthening)


arranged muscles in bundles, enclosed in a sheath of a type of fibrous connective tissue called fascia. Can contain a few dozen to thousands of individual muscle cells/fibers.

Fast Twitch

fibers can contract more quickly than slow twitch fibers because they break down ATP more quickly. Have fewer mitochondria, blood vessels and little to no myoglobin compared with slow twitch fibers they are also called white muscle.


(same + length) contractions, force is generated, muscle tension increases, and the muscle may even shorten a little as tendons are stretched slightly but bones and objects do not move.


is the end of the muscle attached to the bone that moves when the muscle moves.


is a general term for normal tone or tension. Contractions occur whenever a muscle shortens while maintaining a constant force.

Muscle cells

are tube shaped, larger and unusually longer than most other human cells.

Slow Twitch

fibers break down ATP slowly, and so they contract slowly. Contain many mitochondria and are well supplied with blood vessels so they draw more blood and oxygen than fast-twitch fibers.


is the increasing tone or force by activating more motor units


is the end of a muscle that is attached to the bone that does not move during muscular contractions.

Neuromuscular Junction

is the region where a motor neuron comes in close contact with a muscle cell. Neurotransmitter released by the motor neuron causes an electrical impulse to be generated in the muscle cell.


are contractile chain proteins that run the length of the muscle cell/fiber. Packed with contractile proteins called actin and myosin.


covers the Actin filaments myosin binding site. Once Troponin is bound to calcium, this moves. Allowing the myosin to grab a hold of the Actin.

Skeletal muscle

composed of cylindrical multinucleated cells with obcious striations. Attaches to the body's skeleton


is on the tropomyosin and has a receptor site for calcium to bind. Thus releasing or moving the tropomyosin off of the actin filament.


muscles work together to create a particular movement.

Smooth muscle

is spindle-shapped muscle cells with only centrally located nucleus and not externally visible striations. They are found mainly in the walls of hollow organs.


is a tube like extension of the cell membrane that transmits the electrical impulse deep into the interior of the cell. Job is to get the electrical impulse to all parts of the cell as quickly as possible.


is a contractile protein of muscle. It forms the thin filaments in the myofibrils.

All-or-none principle

is the principle that muscle cells always contract completely each time they are stimulated by their motor neuron, and that they do not contract at all if they are not stimulated by their motor neuron.


is defined as a decline in muscle performance during exercise.

Motor neuron

is a neuron in the peripheral nervous system that conducts nerve impulses from the central nervous system to body tissues and organs.

Motor unit

The motor neuron and all of the muscle cells it controls are called a motor unit.


is one of the principal contractile proteins found in muscle. ______ is composed of thick filaments with cross-bridges.


is a chemical released by a neuron that may stimulate or inhibit other neurons or effector cells.

Oxygen debt

is the amount of oxygen required after exercise to oxidize the lactic acid formed by anaerobic metabolism during exercise.


Increasing tone by activating more motor units is called Recruitment, this affects overall muscle force.


is the smallest contractile unit of a muscle myofibril. A _______ extends from one Z-line to the next.

Sarcoplasmic reticulum

Sarcoplasmic reticulum is a specialized endo-plasmic reticulum of muscle cells that surrounds the myofibrils and stores the calcium needed for the initiation of muscle contraction.

Sliding filament mechanism

is the mechanism of muscle contraction. Muscles contract when the thick and thin filaments slide past each other and sarcomeres shorten.


is the accumulation of effects, especially those of muscular or neural activity


is a complete cycle of contraction and relaxation in a muscle cell.

Axial skeleton

The portion of the skeleton that forms the main axis of the body, consisting of the skull, ribs, sternum, and backbone.


is a connective tissue that forms the bony skeleton. Bone consists of a few living cells encased in a hard extracellular matrix of mineral salts.

Appendicular skeleton

is the portion of the skeleton that forms the pectoral and pelvic girdles and the four extremities.

Carpal bones

are 8 small bones that make up the wrist.


is a white, semi-opaque, flexible connective tissue.

Cartilaginous joints

in which the bones are connected by hyaline cartilage, are slightly movable, allowing for some degree of flexibility. (vertebrae to back bone, lower ribs to sternum, pubic symphasis)


is a cartilage-forming cell. In the fetus, _______ produce the hyaline cartilage that forms the rudimentary models of future bones.


are the only cells found in cartilage. They produce and maintain the cartilaginous matrix, which consists mainly of collagen and proteoglycans.

Central (Haversian) canal

In bone, the hollow central tube of an osteon that contains nerves and blood vessels.


is the enlarged knob at each end of a long bone. Contain spongy bone as well as red bone marrow.

Compact bone

is a type of dense bone found on the outer surfaces and and shafts of bones.


are the bones that support the upper limbs, They extend across the top of the chest and attach to the scapula.


is the increasing of the angle of a joint


is the longest and strongest bone in the body.

Fibrous joints

are immovable. At birth flat bones in a baby's skull are separated by relatively large spaces filled with fibrous connective tissue. These_________ harden these immovable joints firmly connect the bones that protect and stabilize the skull and brain.


is the thinner lateral bone in the lower leg.


is the decrease of the angle of the joint.

Growth plate

is a cartilage plate located near the ends of bone. Bones become longer during childhood and adolescence because new cartilage is continually being added to the outer surface of the _________.

Intervertebral disk

is a disk of fibrocartilage between vertebrae.


is the junction or area of contact between two or more bones; also called an articulation.


is the long bone of the upper arm, fits into a socket in the scapula. The other meets the ulna & radius.


is a dense fibrous connective tissue that connects bone to bone.


are the 5 bones that form to make the palm of the hand

Joint Capsule

is the synovial membrane and the surrounding hyaline cartilages constitute the joint capsule.


is the area of the bone between the diaphysis and the Epiphysis. This area contains the growth plate.


is a mature bone cell.


is a cell that reabsorbs or breaks down bone.


is a bone forming cell.


is a cylindrical structure in bone composed of layers of living bone cells and hard extracellular material, arranged like the layers of an onion. In the center is a central canal through which nerves and blood vessels pass.


are the 14 bones that form the fingers and thumb.


is the rotation of the forearms so the palm faces posteriorly.


is a progressive disorder involving increased softening and thinning of bone. __________ results from an imbalance in the rates of bone resorption and bone formation.


is the small bone in the lower arm that is lateral when the body is in amatomical position. This bone is on the thumb side of the hand.


is the movement of a body part around its own axis.


are the supportive frames for the upper limbs. They are triangular bones in the upper back.


is the rotation of the forearms so the palm faces anteriorly

Synovial joints:

Bones are separated by a thin fluid filled cavity. This is the most freely moveable of joints.

Spongy bone

the type of bone tissue characterized by thin, hard interconnecting bony elements enclosing hollow spaces. Red blood cells are produced in the spaces between the bony elements.


are the 7 bones that form the ankle.


is a cord of dense fibrous connective tissue attaching muscle to bone.


the larger, medial bone in the lower leg.


are the 33 irregular bones that form the spine. Regions include cervical, thoracic, lumbar, sacral, & coccygeal.


is the smaller bone in the lower arm that is medial in the anatomical position. It is on the side of the hand as the little finger.

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