Unit 4- Nervous System

Four regions of a neuron?

Cell body, dendrites, axon, telodendria.

Function of dendrites?

Receive information from other neurons.

Function of axon?

Carries action potential toward target.

Function of telodendria?

Axon branches ending in synaptic terminals.

CNS myelinating cell?

Oligodendrocyte

PNS myelinating cell?

Schwann cell.

Function of myelin?

Increases action potential speed.

Depolarization?

Membrane becomes less negative.

Repolarization?

Membrane becomes more negative again.

Which channel opens first?

Sodium channels.

Which channel opens after peak?

Potassium channels.

Absolute refractory period?

No new action potential possible.

Relative refractory period?

Stronger stimulus may trigger AP.

Saltatory conduction?

AP jumps node to node.

Nodes of Ranvier?

Gaps in myelin where AP is regenerated.

Action potential is what type of phenomenon?

All-or-none.

Frontal lobe function?

Planning, decision making, voluntary movement.

Temporal lobe function?

Memory, hearing, language.

Parietal lobe function?

Sensory integration.

Occipital lobe function?

Vision

Precentral gyrus?

Voluntary motor control.

Postcentral gyrus?

Somatic sensory input.

Order of meninges?

Dura → Arachnoid → Pia.

Outermost meninx?

Dura mater.

Innermost meninx?

Pia mater.

CSF located where?

Subarachnoid space.

White matter contains?

Axons

Gray matter contains?

Cell bodies.

Dorsal root?

Sensory

Ventral root?

Motor.

Ganglion?

Cluster of neuron cell bodies in PNS.

Cervical spinal nerve pairs?

8

Thoracic spinal nerve pairs?

12

Lumbar spinal nerve pairs?

5

Sacral spinal nerve pairs?

5

Coccygeal spinal nerve pairs?

1

Sympathetic division?

Fight or flight.

Parasympathetic division?

Rest and digest.

CN I

Olfactory – Sensory – Smell

CN II

Optic – Sensory – Vision

CN III

Oculomotor – Motor – Eye movement, pupil constriction

CN IV

Trochlear – Motor – Superior oblique muscle

CN V

Trigeminal – Both – Facial sensation, mastication

CN VI

Abducens – Motor – Lateral rectus muscle

CN VII

Facial – Both – Taste anterior 2/3, facial expression

CN VIII

Vestibulocochlear – Sensory – Hearing and balance

CN IX

Glossopharyngeal – Both – Taste posterior 1/3, salivation

CN X

Vagus – Both – Viscera, swallowing

CN XI

Accessory – Motor – SCM and trapezius

CN XII

Hypoglossal – Motor – Tongue movement

Three parts of brain stem?

Midbrain, pons, medulla.

Conus medullaris?

End of spinal cord around L1-L2.

Cauda equina?

Bundle of spinal nerves below conus.

Filum terminale?

Pia mater extension attaching spinal cord to coccyx.

Cervical plexus?

C1-C5.

Brachial plexus?

C5-T1.

Lumbar plexus?

T12-L4.

Sacral plexus?

L4-S4.

Rods?

Night vision, no color.

Cones?

Color vision.

Macula lutea?

High acuity vision.

Fovea centralis?

Sharpest vision, only cones.

Optic disc?

Blind spot.

Aqueous humor?

Fluid in anterior chamber.

Vitreous humor?

Gel in posterior cavity.

Cochlea?

Hearing

Vestibule?

Gravity and linear acceleration.

Saccule?

Vertical movement.

Utricle?

Horizontal movement.

Semicircular canals?

Head rotation.

Otoliths?

Stones that stimulate hair cells.

Cupula?

Gelatinous structure in semicircular canals.

Olfactory epithelium?

Site of smell receptors.

Receptor cells?

Detect odor molecules.

Basal cells?

Replace receptor cells.

Five taste sensations?

Sweet, salty, sour, bitter, umami.

Stretch reflex?

Muscle contracts when stretched.

Withdrawal reflex?

Pull away from painful stimulus.

Crossed extensor reflex?

Opposite limb stabilizes body.

Babinski reflex?

Primitive infant reflex.