Ch.23 Jarvis: Neurological System

1. CNS
   1. Componets
      1. Cerebral Cortex
         1. 2. Frontal lobe
            1. Personality, behavior, emotions, intellectual
            2. Broca's area
               1. Motor speech
         2. 1.Parietal lobe
            1. Sensation
         3. 3.Occipital lobe
            1. Vision
         4. 4.Temporal lobe
            1. Primary hearing, taste, smell
            2. Wernicke's Area
               1. Language comprehension
      2. Basal ganglia

         Nota:

         • Helps initiate and coordinate movement and control automatic associated movements of the body
      3. Thalamus

         Nota:

         • Main relay station with connections that are crucial for emotion and creativity
      4. Hypothalamus

         Nota:

         • Major respiratory center with basic vital function: temp, appetite, sex drive, HR, BP, sleep -anterior and posterior pituitary gland regulator -coordinator of autonomic nervous system activity and stress response
      5. Cerebellum

         Nota:

         • Doesn't initiate movement, coordinates and smooths it
      6. Brainstem
         1. Midbrain

            Nota:

            • Merges thalamus and hypothalamus; contains many motor neurons and tracts
         2. Pons

            Nota:

            • Two respiratory centers (pneumotaxic and apneustic) coordinates with the main respiratory center in medulla
         3. Medulla

            Nota:

            • Contains all ascending and descending cover tracts. -vital autonomic centers (respiratory, heart, GI) and nuclei for cranial nerves 8-12 -pyramidal ducussation (crossing of motor fibers) occurs here
         4. Spinal cord

            Nota:

            • Main highway for ascending and descending fiver tracts that connect brain to spinal nerves -mediates reflexes of posture control, urination, and pain response
   2. Pathways

      Nota:

      • Crossed representation: left cerebral cortex controls motor fxn to right side of body, vice Versa Afferent=messages to the CNS Efferent=message from the CNS to muscles and glands
      1. Sensory
         1. Spinothalamic Tract

            Nota:

            • Transmit pain sensation, temp, crude or light touch -enter dorsal root of spinal cord and synapse with a second sensory neuron (refer to pg 635 for full route to brain and visual)
         2. Dorsal column

            Nota:

            • Conduct sensations of position, vibration, finely localized touch (without looking can identify object) -enter dorsal root plans proceed immediately up the same side of spinal cord to brainstem and synapse at medulla with second sensory neuron ... (refer to pg 636 for full route and visual)
      2. Motor
         1. Corticospinal/pyramidal tract

            Nota:

            • Motor nerve fibers originate in the motor cortex and travel to brain stem, cross to opposite or pyramidal decusationbajdbthej to lateral column of spinal cord - see 636 for full route and visual -mediate voluntary movement (skilled ex is writing)
         2. Extrapyramidal Tracts

            Nota:

            • Motor fibers originating in the motor cortex that are outside the pyramidal tract -maintain muscle tone, control body movements- esp automatic such as walking
         3. Cerebellum System

            Nota:

            • Coordinates movement, maintains equilibrium, helps maintains posture on a subconscious level.
   3. Upper motor neurons

      Nota:

      • Located completely within CNS
   4. Lower motor neurons

      Nota:

      • Located mostly in peripheral system; "common final pathway" because direct contact with muscles
2. PNS
   1. Reflex Arc

      Nota:

      • Involuntary; permits quick reaction to potentially painful or damaging situations. 4 types of reflexes: 1.deep tendon reflexes (knee jerk) 2.superficial (corneal or an reflex) 3.visceral (pupil to light) 4.pathologic (abnormal extensor plantar reflex)
   2. Cranial nerves

      Nota:

      • Lower motor neurons enter and exit brain than spinal cord -cranial I and II extend from cerebrum -III to XII extend 1-12 cranial nerves supply head and neck besides vagus nerve- travels to heart, respiratory muscles, stomach and fall bladder
   3. Spinal Nerves

      Nota:

      • 31 pairs arise from length of spinal cord and supply rest of body -named for region of spine from which they exit
      1. Dermal segmentaion

         Nota:

         • Cutaneous distribution of various spinal nerves
      2. Dermatome

         Nota:

         • Limited skin area that is supplied mainly from one spinal cord segment through a particular spinal nerve -dermatomes overlap See page 639 to see where they are
   4. Automatic Nervous System
      1. Somatic fibers
         1. Voluntary muscles
      2. Autonomic fibers
         1. Involuntary muscles

1. Steady loss of neuron structure in brain and spinal cord

   Nota:

   • Loss of muscle bulk, tone in face, neck and around spine -decreased strength, impaired fine coordination and agility -loss of reflexes and position in space -velocity if nerve conduction decreases=touch, sensation, taste, smell diminished

1. Strokes higher among African Americans and Caucasians
2. Metabolic syndrome common among hispanics
3. Disparities of access to care
4. Stroke belt

   Nota:

   • 8 states with high stroke mortality rate

Nota:

• Exam for each nerve including questions to ask

1. For older adults, be aware of slower response
2. Neurological recheck

   Nota:

   • Pts monitored for improvement or deterioration in neurological status
   1. 1.level of consciousness 2.motor function 3. Pupillary response 4. Vital signs
   2. Glasgow Coma Scale

      Nota:

      • See page 672 -describes levels of consciousness as in numeric value (brain as whole) 1. Eye opening 2. Verbal response 3. Motor response

1. F.A.S.T.

   Nota:

   • F: face dropping A: Arm weakness S: Speech Difficulty T: time to call 9-1-1