Lecture 1 - 8/19

Introduction and cells!

The Nervous System is a major

System of communication

The Central Nervous System (CNS) integrates function of

The entire nervous system

The CNS consists of

Brain and spinal cord (SC)

The Peripheral Nervous System (PNS) connects

CNS to the peripheral targets

The PNS consists of

Nerves and ganglia

Ganglia

Clusters of nerve cell bodies, or swellings, found of roots of dorsal nerves

Neuron

Basic functional unit of the nervous system

What are some features of a neuron?

Vary in shape, conduct impulses, and are great communicators

Anatomy of a Neuron

Soma

Cell body

Anatomy of a Neuron

Dendrites

Extension of soma that transmits impulses toward the cell body

Anatomy of a Neuron

Axon

Transmits impulses away from the cell body; vary in length depending on one’s height

Anatomy of a Neuron

Axon Terminals

End of axon that contain vesicles with neurotransmitters

Anatomy of a Neuron

Synapse

Site of neurotransmitter release

Spines

Spiky pieces located on dendrites; the more spines on a dendrite, the better it can communicate

What are the three shapes of a neuron?

Multipolar, Bipolar, and Pseudo-unipolar

Multipolar Neuron

Most common; contains multiple neurites

Biolar Neuron

Rare; contains 2 neurite connections; found in organs of special sensations

Pseudo-unipolar Neuron

One neurite connection; found in PNS

What are the common locations of a neuron?

Gray matter, white matter, nuclei, and tracts

Gray Matter

Concentration of cell bodies and dendrites; unmyelinated axons

White Matter

Myelinated-covered axons

Nuclei

Chunks of gray matter

Tracts

Strips of white matter

Myelin

Phospholipids within glial cells. This insulates axons and increases velocity of impulses

Sensory Neurons

From sensory receptors to CNS; located in ganglion; pseudo-unipolar neurons

Motor Neurons

From CNS to periphery; located in gray matter; multipolar neurons

Interneurons

Middlemen

Projection Neurons

From gray matter in SC to the brain or brain to SC; stays in the CNS; multipolar neurons

Supporting cells

Facilitate but do not conduct impulses

What are five types of supporting cells?

Schwann Cells, Oligodendrocytes, Astrocytes, Ependymal Cells, and Microglia

Schwann Cells

Produce myelin in the PNS; myelinates portion of only ONE axon

Oligodendrocytes

Produce myelin in CNS; can myelinate several axons

Multiple Sclerosis is an autoimmune disease where antibodies attack

Oligodendrocytes

Multiple Sclerosis (MS) reduces

Myelination of axons in CNS, causing decreased velocity of impulses

What is the most numerous cells in the CNS?

Astrocytes

List some features of Astrocytes

Surround capillaries to form blood-brain barrier, soak up excess material to remove toxins, rapidly proliferate, but highly susceptible to neoplasms

Ependymal Cells

Line ventricles of brain, central canal, and spinal cord

Microglia

First responders of nervous system; phagocytosis

What is helpful in axonal transport?

Microtubules

Anterograde Axonal Transport

New nutrients and neurotransmitters move from a cell body to the axon terminal

Retrograde Axonal Transport

Transfer of material from PNS to CNS (soma) for recycling

List the four amines

Acetylcholine, Catecholamines, Serotonin, Histamine

Acetylcholine is used to

Excite muscles

Which neurotransmitter is used for mood?

Serotonin

List the three amino acids

Glutamate, GABA, Gly

Which amino acid is inhibitory?

GABA

Neuropeptides are

Modifiers of ongoing signals

List four neuropeptides

B-endorphin, Enkephalin, Orexin, Substance P

Clinical Considerations

Lambert-Eaton Syndrome

The body attacks the calcium antibodies, which ultimately destroys them

Clinical Considerations

Guillain-Barre Syndrome

Autoimmune disease causing damage to the myelin sheath. Can recover

Clinical Considerations

Charcot-Marie-Tooth

Structural concern to microtubules, causing inability to signal

Clinical Considerations

Myasthenia Gravis

Autoimmune disease caused by blocked release of ACh. This leads to inability to stimulate

Clinical Considerations

Botulism

Toxin blocks release of ACh. Leads to paralysis

Clinical Considerations

Tetanus

Toxin blocks release of Gly. Leads to paralysis