Neural Tissue and Cranial Nerves Extra Credit

define and memorize

Parts of the Neuron

50. Soma

51. Nucleus

52. Myelin sheath

53. Nodes of Ranvier

54. Schwann cells

55. Axon terminal

56. Axon

57. Dendrite

Acetylcholine (ACH)

The most common excitatory neurotransmitter

Afferent (sensory) neurons

Carry impulses from receptors towards the CNS

Axon

Longer process (up to 3-4 ft) that conveys signals away from the soma.

Central nervous system

Brain and spinal cord

Dendrite

Typically shorter processes that convey impulses toward the soma.

Depolarization

A membrane will shift the membrane potential from -70 mv to +30 mv.

Effector

muscles and glands (organs)

Efferent (motor)

Carry impulses away from the CNS and to effectors (muscles or glands)

Interneuron (associative) neurons

Lie between sensory and motor neurons in the CNS and integrate incoming and outgoing signals.

Myelin sheath

Increase the speed of impulse transmissions.

Neuroglia

Support cells for the neurons.

Receptor

The body's receiver for different stimuli, converting them into signals the body can understand and react to.

Peripheral nervous system

Part of the nervous system outside the CNS

Polarized

A stimulus is applied to a polarized membrane, which causes the membrane to become permeable to Na.

Synapse

Occur between the axon of one cell and the dendrite of the next cell.

Olfactory

Type- sensory

Effect- smell

Optic

Type- sensory

Effect- vision

Oculomotor

Type- motor

Effect- focus, pupil, eyelids

Trochlear

Type- motor

Effect- move eyes

Trigeminal

Type- mixed

Effect- tears, move eyes, senses forehead

Abducens

Type- motor

Effect- move eyes

Facial

Type- mixed

Effect- taste, facial expression

Auditory

Type- sensory

effect- hearing, equilibrium

Glossopharyngeal

Type- mixed

Effect- swallowing, salivary glands

Vagus

Type- mixed

Effect- various thoracic organs

Spinal accessory

Type- motor

Effect- muscle of the neck and back

Hypoglossal

Type- motor

Effect- move tongue