| A | B |
|---|
| Sarcomere | The repeating unit of myofibril |
| Neuron | The functional unit of the nervous system, a nerve cell |
| Synapse | The interface between a nerve cell and another cell |
| Neurotransmitter | A chemical released by a neuron. This chemical travels across the synaptic cleft, allowing the neuron to communicate with another cell. |
| Motor Unit | One motor neuron and all the muscle fibers it innervates |
| All-or-none law of skeletal muscle contraction | An individual muscle fiber contracts with equal force in response to each action potential |
| Subthreshold Stimulus | A stimulus too small to create an action potential in a neuron |
| Threshold Stimulus | A stimulus strong enough to create one action potential in a neuron |
| Submaximal Stimuli | Stimuli of increasing strength that create more action potentials along more neurons |
| Maximal Stimulus | A stimulus which is strong enough to create action potentials in all the motor neurons innervating a whole muscle |
| Muscle Tone | The state of partial contraction in a muscle, even when the muscle is not being used |
| Articulation | point of contact between bones |
| Joint | Movable Articulation |
| Syndesmoses | Ligaments join two bones |
| Gomphoses | Insertion of a conical process into a socket |
| Amphiarthroses | Bones of the joints are joined together by Hyaline Cartilage or Fibrocartilage |
| Symphases | Joints in which a pad or disk of Fibrocartilage connects two bones |
| Diarthroses (Synovial joints) | Having a Joint capsule, Synovial membrane, Articular cartilage and a Joint cavity |
| Synchondroses | Hyaline Cartilage present between articulating bones |
| Sutures | Tooth like projections from adjacent bones interlock with each other |
| Menisci | Fibrocartilage disks between articulating surfaces |
| Ligaments | White fibrous cords that hold the bones of the joint together |
| Bursae | Membranes filled with fluid to cushion joint |
| Uniaxial joints | Joints that permit movement around only one axis and in one plane |
| Hinge joint | single motion joint to allow only Flexion and Extension |
| Saddle joint | Articulating bones resemble reciprocally shaped miniature saddles |
| ondyloid | (Ellipsoidal), Condyle fits into an elliptical socket |
| Multiaxial joints | Permitting movement around three or more axes on three or more planes |
| Ball and socket joints | Ball shaped head of one bone fits into concave socket . |
| Gliding joints | Flat articulations that allow a gliding or sliding motion over a variety of planes |
| Biaxial joints | Joints permitting movements around two perpendicular axes in two perpendicular planes. |
| Flexion | The act of bending a joint or limb |
| Extension | The act of restoring a joint to the unflexed position |
| Pivot joint | A projection of one bone articulating with a ring or notch of another bone |
