Ch.23 Jarvis: Neurological System

Ch.23 Jarvis: Neurological System

1. System Review

   • CNS
     • Componets
       • Cerebral Cortex
         • 2. Frontal lobe
           • Personality, behavior, emotions, intellectual
           • Broca's area
             • Motor speech
         • 1.Parietal lobe
           • Sensation
         • 3.Occipital lobe
           • Vision
         • 4.Temporal lobe
           • Primary hearing, taste, smell
           • Wernicke's Area
             • Language comprehension
       • Basal ganglia
         • Helps initiate and coordinate movement and control automatic associated movements of the body
       • Thalamus
         • Main relay station with connections that are crucial for emotion and creativity
       • Hypothalamus
         • 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
       • Cerebellum
         • Doesn't initiate movement, coordinates and smooths it
       • Brainstem
         • Midbrain
           • Merges thalamus and hypothalamus; contains many motor neurons and tracts
         • Pons
           • Two respiratory centers (pneumotaxic and apneustic) coordinates with the main respiratory center in medulla
         • Medulla
           • 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
         • Spinal cord
           • Main highway for ascending and descending fiver tracts that connect brain to spinal nerves -mediates reflexes of posture control, urination, and pain response
     • Pathways
       • 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
       • Sensory
         • Spinothalamic Tract
           • 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)
         • Dorsal column
           • 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)
       • Motor
         • Corticospinal/pyramidal tract
           • 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)
         • Extrapyramidal Tracts
           • Motor fibers originating in the motor cortex that are outside the pyramidal tract -maintain muscle tone, control body movements- esp automatic such as walking
         • Cerebellum System
           • Coordinates movement, maintains equilibrium, helps maintains posture on a subconscious level.
     • Upper motor neurons
       • Located completely within CNS
     • Lower motor neurons
       • Located mostly in peripheral system; "common final pathway" because direct contact with muscles
   • PNS
     • Reflex Arc
       • 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)
     • Cranial nerves
       • 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
     • Spinal Nerves
       • 31 pairs arise from length of spinal cord and supply rest of body -named for region of spine from which they exit
       • Dermal segmentaion
         • Cutaneous distribution of various spinal nerves
       • Dermatome
         • 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
     • Automatic Nervous System
       • Somatic fibers
         • Voluntary muscles
       • Autonomic fibers
         • Involuntary muscles

2. The aging adult

   • Steady loss of neuron structure in brain and spinal cord
     • 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

3. Culture and genetics

   • Strokes higher among African Americans and Caucasians
   • Metabolic syndrome common among hispanics
   • Disparities of access to care
   • Stroke belt
     • 8 states with high stroke mortality rate

4. Physical Exam Details see pages 643-660

   • Exam for each nerve including questions to ask
   • For older adults, be aware of slower response
   • Neurological recheck
     • Pts monitored for improvement or deterioration in neurological status
     • 1.level of consciousness 2.motor function 3. Pupillary response 4. Vital signs
     • Glasgow Coma Scale
       • See page 672 -describes levels of consciousness as in numeric value (brain as whole) 1. Eye opening 2. Verbal response 3. Motor response

5. Stroke prevention

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