Ch 44: Muscular-Skeletal Systems

Front 1

Hydrostatic Skeleton

Back 1

A fluid-filled body cavity in certain soft-bodied invertebrates that is surrounded by muscles and provides support and shape. (Hydra, annelids)

Front 2

Exoskeleton

Back 2

An external skeleton made of chitin and protein that surrounds and protects most of the body surface of animals such as insects.

Front 3

Ecdysis

Back 3

Molting; the process of periodically shedding, regrowing, & strengthening again.

Front 4

Endoskeleton

Back 4

An internal hard skeleton covered by soft tissue; present in echinoderms and vertebrates.

Front 5

Axial Skeleton

Back 5

The bones of the head and trunk of an organism. In humans, it consists of 80 bones and is composed of eight parts; the skull bones, the ossicles of the middle ear, the hyoid bone, the rib cage, sternum and the vertebral column.

Front 6

Appendicular Skeleton

Back 6

Includes the arms, legs pelvis & pectoral girdle

Front 7

Bone

Back 7

A relatively hard component of the vertebrate skeleton; a living, dynamic tissue composed of organic molecules and minerals.The mineral component is made of a crystalline mixture of Ca2+ and PO42−, and other ions that provide bone its rigidity.

Front 8

Cardiac Muscle

Back 8

A type of muscle tissue found only in hearts in which physical and electrical connections between individual cells enable many of the cells to contract simultaneously.

Front 9

Smooth Muscle

Back 9

A type of muscle tissue that surrounds hollow tubes and cavities inside the body's organs; it is not under conscious control.

Front 10

Striated Muscles

Back 10

Skeletal and cardiac muscle with a series of light and dark bands perpendicular to the muscle's long axis.

Front 11

Myofibrils

Back 11

Individual muscle cells within a muscle, each of which contains thick and thin filaments.

Front 12

Sarcomere

Back 12

One complete unit of the repeating pattern of thick and thin filaments within a myofibril.

Front 13

Thick Filament

Back 13

A section of the repeating pattern in a myofibril composed almost entirely of the motor protein myosin.

Front 14

Myosin

Back 14

A motor protein found abundantly in muscle cells and also in other cell types.

Front 15

Thin Filaments

Back 15

A section of the repeating pattern in a myofibril that contains the cytoskeletal protein actin, as well as two other proteins—troponin and tropomyosin—that play important roles in regulating contraction.

Front 16

Actin

Back 16

A cytoskeletal protein.

Front 17

A band

Back 17

A wide, dark band in a myofibril produced by the orderly parallel arrangement of the thick filaments in the middle of each sarcomere.

Front 18

Z line

Back 18

A network of proteins in a myofibril that anchors thin filaments at the ends of each sarcomere.

Front 19

I band

Back 19

In a myofibril, a light band that lies between the A bands of two adjacent sarcomeres.

Front 20

H zone

Back 20

In a myofibril, a narrow, light region in the center of the A band that corresponds to the space between the two sets of thin filaments in each sarcomere.

Front 21

M line

Back 21

In a myofibril, a narrow, dark band in the center of the H zone where proteins link the central regions of adjacent thick filaments.

Front 22

Cross-bridges

Back 22

A region of myosin molecules that extend from the surface of the thick filaments toward the thin filaments in skeletal muscle.

Front 23

Sliding Filament Mechanism

Back 23

The way a muscle fiber shortens during contraction. The sarcomeres shorten, but not thick nor thin filaments. Instead, the thick filaments remain stationary while the thin filaments slide, pulling on the Z lines & shortening the sarcomere. (I band & H zone shorten)

Front 24

Cross-Bridge Cycle

Back 24

During muscle contraction, the sequence of events that occurs between the time when a cross-bridge binds to a thin filament and when it is set to repeat the process.

Front 25

Tropomyosin

Back 25

A rod-shaped protein that plays an important role in regulating muscle contraction.

Front 26

Troponin

Back 26

A small globular-shaped protein that plays an important role in regulating muscle contraction through its ability to bind Ca2+.

Front 27

Excitation-contraction Coupling

Back 27

The sequence of events by which an action potential in the plasma membrane of a muscle fiber leads to cross-bridge activity.

Front 28

Sarcoplasm Reticulum

Back 28

A cellular organelle that provides a muscle fiber's source of the calcium involved in muscle contraction; a specialized form of the endoplasmic reticulum.

Front 29

Transverse Tubules (T-tubules)

Back 29

Invaginations of the plasma membrane of skeletal muscle cells that open to the extracellular fluid and conduct action potentials from the outer surface to the myofibrils.

Front 30

Neuromusclular Junction

Back 30

The junction between a motor neuron's axon and a skeletal or cardiac muscle fiber.

Front 31

Motor End Plate

Back 31

The region of a skeletal muscle cell that lies beneath an axon terminal at the neuromuscular junction; contain many ACh receptors.

Front 32

Slow Fibers

Back 32

A skeletal muscle fiber containing myosin with a low rate of ATP hydrolysis.

Front 33

Fast Fibers

Back 33

A skeletal muscle fiber containing myosin with a high rate of ATP hydrolysis.

Front 34

Oxidative Fibers

Back 34

A skeletal muscle fiber that contains numerous mitochondria and has a high capacity for oxidative phosphorylation.

Front 35

Myoglobin

Back 35

An oxygen-binding protein that provides an intracellular reservoir of oxygen for muscle fibers.

Front 36

Glycoltic Fibers

Back 36

A skeletal muscle fiber that has few mitochondria but possesses both a high concentration of glycolytic enzymes and large stores of glycogen.

Front 37

Atrophy

Back 37

A reduction in the size of a structure, such as a muscle.

Front 38

Flexor

Back 38

A muscle that bends a limb at a joint.

Front 39

Extensor

Back 39

A muscle that straightens a limb at a joint.

Front 40

Antagonist

Back 40

A muscle or group of muscles that produces oppositely directed movements at a joint.

Front 41

Osteomalacia (Rickets)

Back 41

Bone deformation in adults due to inadequate mineral intake or absorption from the intestines. Preventable with vitamin D

Front 42

Osteoporosis

Back 42

A disease in which the mineral and organic components of bone are reduced. Commonly caused by hormonal imbalances (low estrogen).

Front 43

Myasthenia Gravis

Back 43

A disease characterized by loss of ACh receptors on skeletal muscle, due to the body's own immune system destroying the receptors.

Front 44

Muscular Dystrophy

Back 44

A group of diseases associated with progressive degeneration of skeletal and cardiac muscle fibers.