Nervous System
Central vs. Peripheral Nervous System 1. Central Nervous
System (CNS): brain and spinal cord
Central vs. Peripheral Nervous System 2. Peripheral Nervous
System (PNS): cranial nerves, spinal nerves and ganglia * (Ganglion=group of
neuron cell bodies located outside CNS)
Sensory division vs. Motor division 1. Sensory Division: receives information FROM
body and transmits it TO the CNS for processing a) Somatic Sensory component – receives sensory
information from skin, joints, muscle, special senses b) Visceral Sensory component – receives sensory info
from blood vessels and viscera 2. Motor Division: transmits info FROM the CNS TO
muscles and glands a. Somatic motor component: innervates skeletal muscle b. Autonomic motor (Autonomic Nervous System):
innervates smooth muscle, cardiac muscle, and glands of viscera (organs)
NERVOUS TISSUE CELLS
A. Neurons: respond to stimuli and conduct nerve impulses
NERVOUS TISSUE CELLS
B. Glial Cells: support and protect neurons (maintenance)
NEURON COMPOSITION (p 104) A. Cell Body:
B. Nucleus:
C. Dendrites:
D. Axon:
E. Synapse:
NEURON CLASSIFICATION 1. Sensory (Afferent) Neuron: brings information TO the CNS
2. Motor (Efferent) Neuron: takes information FROM CNS to other parts of the
body, cell body located in CNS
3. Interneuron (Association Neurons): helps coordinate and integrate info between sensory and motor neurons, cell body located in CNS
GLIAL CELLS - PNS
A. Satellite Cells: surround neuron cell bodies in spinal ganglia * (Ganglion=group of neuron cell bodies located outside CNS)
B. Schwann cells: myelinate axons in PNS
Glial Cells - CNS
C. Astrocytes: regulate transfer of materials from blood to the brain - help the workings of "blood -brain barrier"
D. Oligodendrocytes: myelinate axons in CNS
E. Microglia: phagocytize damaged neurons
F. Ependymal Cells: line central canal and ventricles -
help circulate cerebrospinal fluid (CSF)
MYELINATION OF AXONS
wrapping an axon with myelin
The Brain
4 Regions Cerebrum
R & L Hemispheres Diencephalon Brain Stem Cerebellum
Brain – Cerebrum
Largest Region Gyri (twisters) & Sulcus
(grooves) Fissures (deep
grooves) Longitudinal
(hemispheres) Divide Lobes
Brain – Cerebrum (lobes)
Parietal Lobe Somatic sensory area “homunculus”
Brain – Cerebrum (lobes)
Occipital Lobe Visual area
Brain – Cerebrum (lobes)
Temporal Lobe Olfactory
Deep inside
Brain – Cerebrum (lobes)
Frontal Lobe Primary Motor Area Speech Language
Cerebrum
Cerebral Gray Matter (Cortex) superficial
Cerebral White Matter deeper
Corpus Callosum connects hemispheres
Diencephalon (interbrain)
Sits atop brain stem Enclosed by cerebrum Structures
Thalamus Hypothalamus Epithalamus
Diencephalon
Thalamus Relay station from spinal
cord Crude impulse
Pleasant vs. Unpleasant
Diencephalon
Hypothalmus (“under the thalmus”) ANS (Emotional Visceral
Brain) Body Temp, H2O
balance, Metabolism Appetites (thirst, hunger) Pleasure & Pain
Diencephalon
Epithalamus Pineal body (endocrine
system) Choroid plexus
(cerebrospinal fluid)
Brain Stem
About size of thumb Areas
Midbrain Convey impulses
Pons Controls breathing
Medulla Oblongata Heart rate, BP, Swallowing, Vomiting, etc.
Cerebellum
Convoluted surface Precise timing of
Skeletal muscles Balance “Auto-Pilot”
Protection of Brain
Meninges dura mater (tough
mother) arachnoid mater pia mater (gentle mother)
Cerebrospinal Fluid Eliminate waste
Blood-Brain Barrier Least-permeable
membrane in body
Spinal Cord
Aprox. 17 in long Continuation of Brain
Stem Ends Below ribs
Spinal Cord
Gray Matter Posterior Horns (dorsal) Anterior Horns (ventral)
CSF Central Canal
Protection Vertebrae Dura mater Arachnoid Pia mater
Spinal Cord
Cervical Thoracic Lumbar Sacral Coccygeal
Spinal Cord - Cervical
8 Cervical Nerves C1-C8
Diaphragm, Shoulders, Neck
Damage may result in: Respiratory Paralysis
Spinal Cord - Thoracic
T1-T12 Intercostal
Spinal Cord - Lumbar
L1-L5 Lower abdomen,
buttocks, anterior & medial thigh, hip muscles, skin of thigh
Damage: Inability to flex hip Loss of cutaneous
sensation Inability to adduct thigh
Spinal Cord – Sacral & Coccygeal S1-S5 + Coccygeal
Nerve Lateral & posterior
leg/foot, gluteus, lower trunk
Damage: Inability to extend hip Inability to flex knee