Nervous System

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