Nervous System
Study Guide
Yoga Sundram
CENTRAL NERVOUS SYSTEM
BRAIN and SPINAL CORD
BRAIN
Protected by: Outer duramater (tough layer)
Middle arachnoidmater
Inner piamater (thin but vascular layer)
Cerebrum Anterior (Larger part)
Cerebellum Posterior (Smaller part)
Brain Stem Posterior ventral (continues as spinal cord)
Cerebrum: Frontal lobe, Parietal lobes, Temporal lobes, Occipital lobe
Left and right hemispheres; these are connected by Corpus Callosum
Thalamus and Hypothalamus
Gyri (gyrus); ridges
Sulci (sulcus); grooves
Fissures deep grooves - separate the lobes
Ventricles: (cavities) 1st ventricle; left cerebral hemisphere
2nd ventricle; right cerebral hemisphere
3rd ventricle; center
4th ventricle; brain stem
Cerebral cortex and white matter
Cerebellum: Cerebellar cortex
Arbor vitae
Peduncles
Brain Stem: Mid brain
Pons
Medulla oblongata
Brain Functions:
Cerebrum:
Interpretation
Memory storage and retrieval
Reasoning
Starting muscle activity
Intelligence and personality
Sensory Areas of Cerebrum
Primary somatosensory :
Posterior frontal
Somatosensory Association: Posterior frontal
Visual:
Posterior occipital
Auditory:
Superior temporal
Olfactory:
Medial temporal
Gustatory:
Medial temporal - Insula
Visceral:
Posterior temporal
Vestibular:
Posterior insula
Fall / 09
Left Hemisphere: Language, Math, Logic
Right Hemisphere: Insight, Visual, Intuition, Artistry
Thalamus &
Hypothalamus
Brain stem
Mid Brain
Homeostasis: Temperature and Pressure regulation
Head and Eye movement
Posture
Pons
Regulates breathing
Medulla
oblongata
Controls heart and lungs
Cerebellum
Controls body position
Limb movements
SPINAL CORD: Extends from foramen magnum (end of brain stem) to Cauda Equina (at
2nd / 3rd lumbar vertebrae
Cervical enlargement: supplies upper limbs
Lumbar enlargement: supplies lower limbs
Gray and white matter
Gray matter Butterfly shaped, Anterior horns, posterior horns, lateral horns
Contains interneurons
Posterior Horn (dorsal root): Sensory fibers: impulses travel towards spinal cord
Anterior Horn (ventral root): Motor fibers: impulses travel away from spinal cord
PERIPHERAL NERVOUS SYSTEM
CRANIAL NERVES and SPINAL NERVES
CRANIAL NERVES (12 nerves) sensory (s), motor (m) or both (b)
i
ii
iii
iv
v
vi
vii
viii
ix
x
xi
xii
Olfactory:
Smell (s)
Optic:
Sight (s)
Occulomotor:
Eye muscles (m)
Trochlear:
Smallest cranial nerve: Fifth pair of eye muscle, (m)
Trigeminal:
Largest cranial nerve: Eye, Maxilla, Mandible, (b)
Abducens:
Eye muscle (m)
Facial:
Taste, facial expression, salivary and tear glands (b)
Vestibulocochlear: Hearing, balance (s)
Glossopharyngeal: Swallowing (b)
Vagus:
Speech, swallowing, heart, other organs in thorax and abdomen (b)
Accessory:
Muscles of palate, pharynx, trapezius, sternocleidomastoid (m)
Hypoglossal:
Tongue (m)
Nerves i, ii and viii
Mainly Sensory
Nerves iii, iv, vi, xi and xii
Mainly Motor
Nerves v, vii, ix and x
Both
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SPINAL NERVES (31 nerves)
Cervical (C1 to C8) : Total 8
Thoracic (T1 to T12) : Total 12
Lumbar (L1 to L5) : Total 5
Sacral
(S1 to S5) : Total 5
Coccygeal (Co) :
Total 1
Somatic and Autonomic nervous systems
Somatic Pathway : Voluntary, involves skeletal muscles
Sense Organ  Sensory Neuron  Dorsal Root Ganglion  Interneurons (In brain or spinal cord)
Motor Neuron Skeletal Muscle
Autonomic Pathway : Involuntary, involves viscera, heart, glands, other internal organs
Sense Organ  Sensory Neuron  Dorsal Root Ganglion  Interneurons (in brain or spinal
cord) Preganglionic Fiber Autonomic Ganglion Postganglionic Fiber  Viscera
Autonomic nervous system ---- Sympathetic system ( Action, emergency, fear, excitement)
(Fight or Flight mode)
Arises from thorax and lumbar regions (thoraco-lumbar)
Adrenergic (Norepinephrine)
Parasympathetic system ( Restores back to resting conditions,
(visceral activity)
Arise from brain stem and sacrum (cranio-sacral)
Cholinergic (Acetylcholine)
Pain: Acute pain conducted through A Delta fibers : Thick Myelinated (faster)
Chronic pain conducted through C fibers : Thin, Unmyelinated (slower)
Referred Pain: Feeling of pain at a different location than from the real source (visceral organs)