Functionally, all synovial joints are classified as , since all are freely mobile. Each synovial joint is composed of a double-layered capsule called the . Its outer layer is the , and the inner layer is a synovial membrane. All articulating bone surfaces in a synovial joint are covered by a thin layer of cartilage called articular cartilage. Only synovial joints house a , a space that permits separation of the articulating bones. Lining the joint cavity is the , which secretes .

Functionally, all synovial joints are classified as diarthrosis, since all are freely mobile. Each synovial joint is composed of a double-layered capsule called the articular capsule. Its outer layer is the fibrous layer, and the inner layer is a synovial membrane. All articulating bone surfaces in a synovial joint are covered by a thin layer of hyaline cartilage called articular cartilage. Only synovial joints house a joint cavity, a space that permits separation of the articulating bones. Lining the joint cavity is the synovial membranes, which secretes synovial fluid.

Explanation:

A synovial joint is a type of joint in which the two or more bones that are being articulated, are also covered by a joint capsule that continues itself with the bones' periosteum and is also filled with synovial fluid.

Synovial joints are the most movable type of joints. This is what classifies them as diarthrosis.

The joint or articular capsule help protect and maintain the structure of these very movable articulations, and the synovial fluid is a key element in reducing the friction between the articular cartilages during movement. The capsule's fibrous membrane contains ligaments that are also important for the movement and the stability of the joint.

Examples of synovial joints are the shoulder joint and the knee joint.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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they deliver oxygen to the blood