Sensory and Neurological System Flashcards

Neurological System: Anatomy & Physiology

Central Nervous System (CNS)

• Brain

• Spinal cord

• Cranial nerves I and II

Peripheral Nervous System (PNS)

• Cranial nerves III to XII

• Spinal nerves

Autonomic Nervous System (ANS)

Nervous System Cells

• Neurons: Primary functional unit

  • Excitability

  • Conductivity

  • Influence

• Glial cells: Support, nourish, and protect neurons.

Impulse Generation

• Nerve impulse: Initiation of neuronal message, generating action potential.

• Synapse: Structural/functional junction where nerve impulse transmits between neurons.

• Neurotransmitters: Chemicals affecting impulse transmission across the synapse.

  • Excitatory

  • Inhibitory

Central Nervous System (CNS) - Detailed

• Spinal cord

• Brain

  • Gray matter

    • Cerebrum: Right and left hemispheres

  • White matter

  • Brainstem: Midbrain, pons, and medulla

  • Cerebellum: Posterior cranial fossa below the occipital lobe

  • Ascending tracts

  • Descending tracts

• Reflex arc

• Upper motor neurons

  • Originate in the cerebral cortex and project downward.

  • Influence skeletal muscle tone (spasticity).

• Lower motor neurons

  • Final common pathway for descending motor tracts to influence skeletal muscle.

Peripheral Nervous System (PNS) - Detailed

• Spinal nerves

  • Series of spinal segments without visible boundaries.

  • Dorsal (afferent) pair: Sensory nerve fibers/roots.

  • Ventral (efferent) pair: Motor fibers/roots.

• Cranial nerves

  • 12 paired nerves exiting the cranial cavity.

• Autonomic Nervous System (ANS)

  • Sympathetic: Activates "fight or flight" response.

  • Parasympathetic: Conserves and restores energy; localized and discrete regions.

Blood-Brain Barrier

• Physiological barrier between capillaries and brain tissue. Protects brain from harmful agents, allows nutrient entry.

• Medication entry into CNS from bloodstream.

Protective Structures

• Meninges

• Skull

• Vertebral Column

Gerontological Changes

• CNS

• PNS

Assessment of the Nervous System

• Subjective data

  • Characteristics of present illness.

  • Birth history, TBI, stroke, degenerative disease.

  • Medications.

  • Surgery or other treatments.

  • Functional health patterns.

• Objective data

  • Physical examination.

  • Mental status: alert/oriented; thought process; mood and affect.

    • Assessment: person, place, time, and situation.

    • Documentation: A & O x4 (alert and oriented to person, place, time, and situation).

  • Cranial nerve function

    • Olfactory (CN I)—smell.

    • Optic nerve (CN II)- visual fields; visual acuity.

    • Oculomotor (CN III), trochlear (CN IV), and abducens (CN VI).

  • Motor function: gait and station

    • Strength: Push and pull against resistance

    • Pronator drift: Sensitive to vasospasm or edema in one cerebral hemisphere

    • Close eyes and hold out arms with palms up for 30 seconds

  • Sensory function: Sensation to light touch.

    • Extinction: Simultaneously touching both sides of the body symmetrically.

      • Normal: both are perceived.

      • Abnormal: stimulus perceived on only one side.

    • Pain.

    • Temperature: Assess only if response to deep pain is abnormal.

    • Position sense (proprioception): Romberg test.

  • Cerebellar function: Balance and coordination.

  • Reflexes: Measure response on a 0 – 5 scale.

    • 0 = absent reflex

    • 1 = weak response, seen only with reinforcement

    • 2 = normal response

    • 3 = brisk response

    • 4 = hyperreflexia with non-sustained clonus

    • 5 = hyperreflexia with sustained clonus

  • Diagnostic testing

    • Cerebrospinal fluid analysis

    • Lumbar puncture (LP)

      • Contraindications

      • Pre-procedure preparation

      • Post-procedure monitoring

    • PET scan

    • Single-photon emission computed tomography (SPECT)

    • Myelogram

  • Electrographic studies

    • Electroencephalography (EEG)

    • Electromyography (EMG)

    • Electroneurography (nerve conduction studies)

  • Ultrasound

    • Carotid artery duplex scan

    • Transcranial doppler

  • Biopsies