Nervous Nervous SystemSystem

Functions of Nervous SystemFunctions of Nervous System

• The body’s control and communication The body’s control and communication centercenter

• Responds to stimuli in environmentResponds to stimuli in environment• Initiates nerve impulses in muscles and Initiates nerve impulses in muscles and

glandsglands

Response to StimuliResponse to Stimuli

• Sensory Input – (int. or ext.)Sensory Input – (int. or ext.)–Sensory receptorsSensory receptors

• IntegrationIntegration– ProcessingProcessing– Control – coordination - communicationControl – coordination - communication

• Motor OutputMotor Output–MusclesMuscles–GlandsGlands

Parts of Nervous SystemParts of Nervous System• CCentral entral NNervous ervous SSystem - Association ystem - Association

or interneuronsor interneurons

–BrainBrain

–Spinal CordSpinal Cord

• PPeripheral eripheral NNervous ervous SSystem - Nervesystem - Nerves– Sensory – coming inSensory – coming in

– Motor – going outMotor – going out

Cells of Nervous SystemCells of Nervous System

NeuronsGlialCells

Sensory

Motor

InterMicroglial

Oligodendrocytes

Astrocytes

Satellite

Schwann

Ependymal

NeuronsNeurons

• Conduct action potential (nerve Conduct action potential (nerve impulse)impulse)

• Electrically excitableElectrically excitable

• Have 2 types of processes (axons & Have 2 types of processes (axons & dendrites)dendrites)

• Neurons HAVE synapses that use Neurons HAVE synapses that use neurotransmittersneurotransmitters

Neurotransmitters

• Chemicals release from axon terminals (presynaptic knobs) [~pitchers]

• Diffuse across synapse• Land on receptors on dendrites

(~catchers)

Glial CellsGlial Cells

1.1. Glial cells do NOT have chemical Glial cells do NOT have chemical synapses. synapses.

2.2. Glial cells have a resting potential, but Glial cells have a resting potential, but they cannot generate an action potentialthey cannot generate an action potential

3.3. There are many MORE (10-50 times There are many MORE (10-50 times more) glial cells in the brain compared to more) glial cells in the brain compared to the number of neurons.the number of neurons.

4.4. ~slaves~slaves

Schwann Schwann CellsCells

• PNSPNS

• Insulation for neurons of PNSInsulation for neurons of PNS

Satellite CellsSatellite Cells

• PNSPNS

• Physical supportPhysical support

• CNSCNS• Star shapedStar shaped• Physical & nutritional supportPhysical & nutritional support• Anchors neuronsAnchors neurons• Transports nutrients to neuronsTransports nutrients to neurons• Digests parts of dead neuronsDigests parts of dead neurons• Cleans up brain debrisCleans up brain debris• Regulates contents of extracellular Regulates contents of extracellular

spacespace

AstrocytesAstrocytes

Microglial CellsMicroglial Cells

• Similar to astrocytesSimilar to astrocytes

• Digests dead neuronsDigests dead neurons

OligodendrocytesOligodendrocytes

• CNSCNS

• Provide insulation to neurons Provide insulation to neurons of CNS – myelin sheath of CNS – myelin sheath

• (analogous to Schwann Cells)(analogous to Schwann Cells)

Ependymal CellsEpendymal Cells

• CNSCNS

• Line cavities of CNSLine cavities of CNS

• Ciliated – help circulated Ciliated – help circulated cerebrospinal fluidcerebrospinal fluid

• Similar in fx to oligodendrocytesSimilar in fx to oligodendrocytes

Nervous System DivisionsNervous System Divisions

Parasympathetic

• Autonomic • Normal operating mode • Your “at rest & repair” state

SympatheticSympathetic

• Autonomic

• Emergency overdrive- “fight or flight”

• “save the brain”–Send oxygen

–Send glucose (ATP)

• Slows heart rate

Sympathetic or Parasympathetic?Parasympathetic?

• Dilates bronchi

SympatheticSympathetic or Parasympathetic?

• Inhibits peristalsis & digestion

Sympathetic Sympathetic or Parasympathetic?or Parasympathetic?

• Stimulates the release of bile from the liver/gall bladder

Sympathetic or Sympathetic or Parasympathetic?Parasympathetic?

Sympathetic Sympathetic or Parasympathetic?or Parasympathetic?

• Stimulates the liver to Stimulates the liver to convert glycogen to glucoseconvert glycogen to glucose

• Secretion of adrenaline from the adrenal medulla

SympatheticSympathetic or Parasympathetic?

• Inhibits Inhibits the the external external unrinary unrinary bladder bladder sphincterssphincters

Sympathetic Sympathetic or Parasympathetic?

Cranial Nerves

• PNS

• 12 pairs

• Come off brain

• #’d anterior to posterior

“On Old Olympus Towering Tops

A Finn And German

Viewed Some Hops"

Sheep Brain

• Olfactory bulb (I)

• Optic nerve II.Oculomotor nerve III.Trochlear nerve IV.Trigeminal nerve V.Abducens nerve VI.

I - Olfactory

• Sensory

• Smell

II – Optic

• Vision

• Sensory

III - Oculomotor

• Eye movement

• Eyelid movement

• Pupil Dilation

• Motor

IV - Trochlear

• Eye Movement

• Superior oblique

• Downward & laterally

V - Trigeminal

• Somatosenosory info (touch, pain) from face and head

• Muscles for chewing

VI - Abducens

• Eye movement

• Laterally

VII - Facial

• Taste – anterior 2/3• Somatosensory from

ears• Controls muscles

used in facial expressions

• Secretion of tears & saliva

VIII – Vestibulocochlear (Auditory)

• Hearing

• Balance

Glossopharyngeal - IX

• Taste – posterior 1/3• Somatosensory from

tongue, tonsil, pharynx

• Controls some muscles used in swallowing

• Senses carotid blood pressure

X – Vagus

• Sensory, motor, & autonomic fxs of viscera

• Glands• Stimulates

digestion• Slows heart rate• Senses aortic blood

pressure

Spinal Accessory - XI

• Controls muscles used in head movement–Trapezius

–Sternocleidomastoid

• Swallowing

XII - Hypoglossal

• Controls tongue movement

Spinal Nerves

• PNS

• 31 pr

• Come off spinal cord

• #’d superior to inferior

• 1. Cerebrum• 2. Corpus callosum• 3. Cerebellum• 4. Reticular Activating System• 5. Spinal Cord• 6. Brain Stem• 7. Hypothalamus• 8. Thalamus

Eight small bones of the wrist:

Never Lower Tilly's Pants; Mother Might Come Home.

Navicular, Lunate, triquetrum, pisiform, greater Multongular, lesser

Multongular, Capitate, Hamate.

The ten essential amino acids: These Ten Valuable Amino Acids

Have Long Preserved Life In Man. Threonine, Tryptophan, Valine, Arginine, Histidyine,

Lysine, Phenylalanine, Leucine, Isoleucine, Methionine.

Functions of the blood: Old Charlie Foster Hates Women Having Dull Clothes. Oxygen (transport), Carbon Dioxide

(transport), Food, Heat, Waste, Hormones, Disease, Clotting

The excretory organs of the body. SKILL. Skin, Kidneys, Intestines,

Liver and Lungs.