Chapter9 Nervous System

A bundle of hundreds to thousands of axons plus associated connective tissue and blood vessels that lie outside the brain and spinal cord.

One of 12 pairs of nerves that leave the brain; pass through foramina in the skull; and supply sensory and motor neurons to the head, neck, part of the trunk, and viscera of the thorax and abdomen. Each is designated by a Roman numeral and a name.

One of the 31 pairs of nerves that originate on the spinal cord from posterior and anterior roots.

Small masses of nervous tissue, consisting primarily of neuron cell bodies, that are located outside the brain and spinal cord.

Extensive networks of neurons located in the walls of gastrointestinal tract organs that help regulate the digestive system

An organ of the body, either a muscle or a gland, that is innervated by somatic or autonomic motor neurons.

A nerve cell, consisting of a cell body, dendrites, and an axon. Provide most of the unique functions of the nervous system, such as sensing, thinking, remembering, controlling muscle activity, and regulating glandular secretions.

An electrical signal that propagates along the membrane of a neuron or muscle fiber (cell); a rapid change in membrane potential that involves a depolarization followed by a repolarization.

Receiving or input parts of a neuron. Short, tapering, and highly branched, forming a tree-shaped array of processes that emerge from the cell body

Conducts nerve impulses toward another neuron, a muscle fiber, or a gland cell. Long, cylindrical projection that ends by dividing into many fine processes called axon terminals.

Cone- shaped elevation where the axon joins the cell body. Nerve impulses usually arise at the axon hillock and then travel along the axon

Side branches of an axon

Site where two neurons or a neuron and an effector cell can communicate

Bulb shaped structures located on the ends of most axons

Tiny sacs located in the synaptic end bulb that store neurotransmitters. Neurotransmitter molecules released from synaptic vesicles are the means of communication at a synapse