Neuroscience Ch. 1 PowerPoint

8/21/2019 Neuroscience Ch. 1 PowerPoint

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Neuroscience

is a field devoted to the scientific study of the nervous system.

It spans the structure, function, evolutionary, development,genetic, biochemistry, physiology, pharmacology, informatics,

computational, and pathology study of the nervous system.

Traditionally it is a branch of the biological sciences.

Subdivisions/Disciplines

Molecular and Cellular neuroscience

Behavioral neuroscience

Systems neuroscience

Developmental neuroscience

Cognitive neuroscience

Theoretical and computational neuroscience

Neural engineering


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Nervous System Function

In all animals

Obtains information from the environment

Processes information

Stores information Generates behavior

Additional functions in humans

Feeling Abstract thought


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Genes

Proteins are encoded by genes

Genes consist of sequences of DNA nucleotides

Adenine (A)

Thymine (T) Cytosine (C)

Guanine (G)

Genes have coding (exons) and non-coding(introns) regions

Each amino acid is specified by three nucleotides(codon)

General Intro to Systems Biology


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Figure 1.1 Estimated number of genes in four animal genomes

Genome- collective set of genes in an

organism

~25K


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Nervous System Functions are Distributed

Majority of Genes expressed in brain

Genes associated with

Neurodisease- SNPs

(introns+exons)

CNS: Encompasses sensory, motor,and association processing systems

PNS: sensory and motor

communication with CNS


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Figure 1.3 The major light and electron microscopical features of neurons (Part 1)

Neurons are

specialized cells in NSNeurons

communicate via

synapses-specialized

points of

chemical/electrical

contact

Electrical signals are

transferred between

neuronsNeurons have

organelles found in

other cells


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Neurons

Neurons have organelles found in allcells

Mitochondria for energy

Nucleus containing chromasomes,site of transcription, production of

mRNA

Endoplasmic reticulum and Golgifor protein synthesis

Cytoskeleton proteins such as

actin, tubulin and myosin


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Neuronal Soma Organelles

Nucleus

Contains DNA - genetic material

High level of transcription in neurons

Rough Endoplasmic Reticulum

Ribosomes attached Functions in Protein Translation


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Ribosomes

Structures for rotein translation

Golgi apparatus

Post-translation modification of

proteins

Packaging of proteins for transport


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Neuronal Soma Organelles

Mitochondria

Energy Production

Calcium storage

Apoptosis - programmed cell

death

Smooth Endoplasmic Reticulum

Calcium storage and release


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Ramon y Cajal

Histological (Golgi) Staining of human brain

tissue

Neuronal Tracing/Morphology

Neuron Doctrine: Neurons are basic FN units

Camillo Golgi

Developed Golgi Technique

Impregnation of cells with

Silver salts to resolve subcellular

structures.


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Neuron Morphology and Diversity

Major Components ofNeurons

Soma= Cell body

Differ in size/shape Site of most Protein

synthesis

Dendrites(input)

Differ in branchingpattern/complexity

Signal Integration

Protein Synthesis

Axon(output) Differ in length and

projection

Incoming SignalIntegration

AP source


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Neuron Morphology and Diversity

Input

of Information

Output of Information

Directionality to Information Processing


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Major Features of Neurons

Branching Nucleus Myelin

Electron Micrograph (EM)


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Plasma MembranePlasma membrane

Phospholipid Bilayer

Separates intracellular and

extracellular contents

Maintains a concentration

gradient of ions

Anchors proteins embedded

within the membrane

Enzymes

Channels

Site ofExocytosis/Endocytosis

Release of neurotransmitter

vesicles

Internalization of membrane

associated molecules


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Major Features of Axons

B: axon hillock / initial segment- non-myelinated, site of many

ion channels, site of initiation of AP

G: nodes of Ranvier-non-myelinated regions along axon,

enhance and electrical signal conduction

C: synaptic terminals- subcellular structures for

neurotransmission- electrical/chemical


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Major Features of Axons

Myelin produced by

oligodendrocyte

(glia)

Terminals Vesicles of

neurotransmitter


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EM of Dendritic Spine and

synapse

AT: Axon terminal

Post-synaptic density

Dendrite

ine


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Immunohistochemistryrefers to the process of localizing proteins in

cells based on the principle of antibodies binding specifically to their

protein antigens in tissue.

Visualizing the

antibody-antigen

interaction can be

accomplished in 2

primary ways:

1. conjugating the

antibody to an enzyme

aka peroxidase staining

2. Conjugating theantibody to a

fluorophore aka

immunofluorescence

staining

Primary antibody

Secondary antibody

fluorophore

visualized

intracellular protein

visualizedcell surface

protein


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Cytoskeletal Elements

Green= Tubulin, theprotein constituent ofmicrotubules

(A) Red= microtubulebinding protein (tau),only in axons

(B) Red= actin, only intips of growing axonsand dendrites

Fluorescent Immunostaining to

Visualize Cells and Proteins-


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Neuroglial cells (Dividing cells)-

Glia--glue

No significant electrical signaling

Outnumber neurons in brain by 3:1

3 types-

Astrocytes

Star like shape

Modulate neural signaling

Neurotransmitter uptake/Ion Buffering Release Growth Factors and Cytokines

Neural Development + Repair

Glia


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Glia

Myelin producing CellsOligodendroctyesin CNS

Schwann cellsin PNS

Microglial cells

Related to immune macrophages

Scavenge cell debris from injury or

death

Secrete cytokines modulate

inflammation

Myelin


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Myelin

Myelin

Lipid rich wrapping of cell membrane aroundaxons

On average 20 wraps/axon segment

Results in- Electrical Insulation of the segment,1. Increases electrical potential of axons 2.Enhances neurotransmission

Seen as alternating light and dark bands on EM

Myelin


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Myelin

Figure 1 5 Varieties of neuroglial cells


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Figure 1.5 Varieties of neuroglial cells

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Neuroscience Ch. 1 PowerPoint