Nervous System Flashcards
Categories of the Nervous System
CNS and PNS
Motor neurons
Dendrites and axons
Travel along neurons by means of synapses
Impulses
Excite or inhibit neurons
Neurotransmitters
Fatty substance covering axons
Myelin
From the CNS
Motor neuron
Peripheral to CNS
Sensory neuron
-Cerebral—cortex; responsible for movement; motor and sensory neurons
-Pyramidal and extrapyramidal motor pathways
-Cerebellum—controls and coordinates muscle movements
-Brain stem—respirations, heartbeat, vasomotor activity
-Midbrain: connects pons and cerebellum
-Pons: transmits motor impulses from the brain to the spinal cord and sensory impulses from peripheral sensory neurons to the brain
-Medulla oblongata: transmits motor impulses from the brain to the spinal cord and sensory impulses from peripheral sensory neurons to the brain
-CNS Anatomy:
-Cerebrum consists of two hemispheres; each hemisphere has four lobes:
-Frontal
-Parietal
-Temporal
-Occipital
-Corpus callosum
-Skull: rigid bones
-Meninges
-3 Membranes
-Dura mater
-Arachnoid
-Pia mater
-Subarachnoid space
-Ventricles
-Manufacture and absorb cerebrospinal fluid (CSF)
-Functions of CSF
-Protects structures
-Maintains constant intracranial pressure
Brain parts
-Meninges
-Vertebrae (vertebral column)
-Functions
-Provides centers for reflex action
-Pathway for impulses to and from the brain
Spinal cord
-Structures: cranial nerves, spinal nerves, sympathetic and parasympathetic nerves
-Cranial nerves—12 pairs
-Types: I to XII
PNS
31 pairs, each have dorsal/ventral root
Spinal nerves
Sensory nerves
Dorsal
Motor nerves
Ventral
spinal nerve root innervates a specific area useful for identifying areas affected by certain viral infections such as shingles, anesthetizing, localized areas of the body, and assessing and evaluating spinal injuries.
Dermatomes
I: Olfactory nerve: Sense of smell
II: Optic nerve: Sight
III: Oculomotor nerve: Contraction of iris and eye muscles
IV: Trochlear nerve: Eye movement
V: Trigeminal nerve: Sensory nerve to face, chewing
VI: Abducens nerve: Eye movement
VII: Facial nerve: Facial expression, taste, secretions of salivary and lacrimal glands
VIII: Vestibulocochlear (or auditory) nerve: Hearing and balance
IX: Glossopharyngeal nerve: Taste, sensory fibers of pharynx and tongue, swallowing, and secretions of parotid gland
X: Vagus nerve: Motor fibers to glands producing digestive enzymes, heart rate, muscles of speech, gastrointestinal motility, respiration, swallowing, coughing, and vomiting reflex
XI: Accessory (or spinal accessory) nerve: Head and shoulder movement
XII: Hypoglossal nerve: Movement of the tongue
Cranial Nerves
Stimulation or inhibiting smooth muscle
Automatic nervous system
a type of automatic nervous system that is released during stressful situations, emotions, and severe illness
Sympathetic Nervous Sytem
Epinephrine, norepinephrine, dopamine
Catecholamines
Slowing heart rate, digestion food, eliminating body waste
Parasympathetic Nervous System
Allows passage of nerve impulses to effector structure
Acetylcholine
Inhibits acetylcholine
Acetylcholinesterase
Assessment of the Nervous system
-History—trauma, drug history, family medical history
-Speech patterns
-Mental status
-Intellectual functioning: reasoning ability
-Extremity strength and movement
-Physical Examination
-Mini-Mental Status Examination (MMSE/2): 11 questions/tasks to assess cognitive function
-Evaluate body posture: see next slide
-Cranial nerves—assessment techniques (see table 36-2)
-Motor function—large muscle atrophy; equality of size and strength
-Gait—movement and balance; Romberg test (assess for swaying when standing erect with eyes closed)
Assessment of cerebral Function
-Impaired Cerebral Function
-A. Decorticate posturing: arms flexed, fists clenched, legs extended
-B. Decerebrate posturing: stiff and rigid extremities
-C. Flaccidity: no motor response-no response to stimuli
Level of Consciousness Assessment
-Sensory Function
-Sensitivity to heat, cold, touch, and pain
-Level of Consciousness (LOC)
-Classifications: conscious, somnolent (drowsy, sleepy, arousable), stuporous (repetitive stimuli), semicomatose (mild pain-avoid stim), comatose (painful stimuli-delayed)
-Glasgow Coma Scale
-Parts—eye opening, verbal response, motor response
-Rancho Los Amigos Scale (preferred by rehabs due to its flexibility)
-Pupil Assessment
-Size: not pinpoint
-Equality—unequal, dilated, or pinpoint
-Reaction to light of pupils—failure to respond
-See Table 36-2
-Neck—stiffness or abnormal position, rigidity (head/chin to chest)
-Vital signs—sudden increase or decrease—CNS disorders
