Nervous Physiology: Anatomy and Laws of Excitation

Vocabulary flashcards covering the structural components of the nervous system and the physiological laws governing nerve excitation.

Nervous Physiology

The branch of biology dedicated to studying the functioning of the nervous system.

Nervous Center

The central structural core of the nervous system, composed of the encephalon and the spinal cord.

Peripheral Nervous System

The division of the nervous system constituted by the spinal nerves, which emerge from the spinal cord and terminate in the body organs.

Encephalon

The organ housed within the cranial cavity, consisting primarily of the cerebrum, the cerebellum, and the medulla oblongata.

Cerebrum

The largest portion of the encephalon, formed by two cerebral hemispheres whose surfaces are marked by fissures and sulci.

Spinal Cord

A cylindrical tube situated inside the vertebral column that connects to the encephalon and spinal nerves, featuring a deeper posterior sulcus and a wider, shallower anterior sulcus.

White Matter

Nervous tissue formed by nerve fibers; it is located internally in the cerebral hemispheres and externally in the spinal cord.

Gray Matter

Nervous tissue composed of neuronal cell bodies embedded within neuroglia; it is located externally in the cerebral hemispheres and internally in the spinal cord.

Neuroglia

The supportive tissue in which neuronal cell bodies are embedded within the gray matter.

Effective Excitation

A stimulus or excitation that successfully produces an observable physiological response.

Rheobase (Threshold Intensity)

The minimum or weakest electrical stimulus intensity capable of evoking an initial physiological response.

Useful Time (Temps Utile)

The application duration of an electrical stimulus required to generate an effective excitation.

Latent Summation

The phenomenon in which several sub-threshold or individually ineffective stimuli produce an effective excitation when delivered in rapid succession at short intervals.

All-or-None Law

The principle stating that an individual nerve fiber or neuron responds to an effective stimulus with an immediate, maximal response or no response at all.

Excitability Curve

A graphical representation plotting the relationship between stimulus intensity (in $mV$) and duration (in $ms$) required to evoke an excitation in a nerve or nerve fiber.