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Levels of analysis to study nervous system
- Cellular level
- Synaptic level
- Molecular level
- Social Level
- Organ level
- Neural systems level
- Brain region level
- Circuit level
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Central Nervous System
- Brain and Spinal Cord
- Encased within the skull and spinal colum
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Peripheral Nervous System
Made of nerve tissue located outside of brain and spinal cord
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Blood vessels
Provide nutrients and proteins
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Neurons (nerve cell)
- Basic unit of nervous system
- Perform info processing and communication functions of nervous system
- 100,000,000,000 neurons in the brain
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Glial Cells
- Provide structural, nutritional, and other types of support to the brain
- "Glue" in Greek
- 1/10 size of neurons
- Not capable of electrochemical signal
- Provide support and nutrients to neurons
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Santiago Ramon y Cajal (1906)
- Neurons and other cells of brain are structurally, metabolically, and functionally independent
- Information is transmitted from neuron to neuron across tiny gaps (synapses)
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Visualizing Cells
Golgi stain
- Nissl stain
- Certain cells pick up stain
- Cells densely packed
- Immunocytochemistry
- Antibodies with fluorescent tag allows you to see particular parts of cells
- Expression of c-fos in activated cells
- Stains tissue dark
- Shows cells recently active
- Would show where cocaine would take affect
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What kind of information do neurons process?
Pain perception and reflexes
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Dendrites
- Input zone
- Receives info from other neurons
- transmits toward cell body (soma)
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Soma
- Integration zone
- Processes info
- Initiates electrical signal (action potential)
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Axon or nerve fiber
- Conduction zone
- transmits info (action potential) away from cell body towards terminal button
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Axon terminal or synaptic bouton
- Output zone
- end of axon
- forms synapse on another cell
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Cytoplasm
semi-water fluid that fill inside of cell and contain organelles
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Cell membrane
- Separates cytoplasm from outside of cell
- Controls flow of substances into and out of neuron
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Nucleus
- Membrane enclosed structure
- Contains genetic material (DNA)
- Involved in protein synthesis
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Ion Channels
channels for passage of substances from one side of the membrane to the other
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Receptor proteins
recognize and bind to neurotransmitters or other chemicals
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Pump proteins
exchange one type of substance for another
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Proteins
- Made up of string of amino acids folded up to form specific shapes
- Sequence obtained from genetic material
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Nucleus contains __________ of Chromosomes.
23 pairs
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Gene
- segment of DNA encodes for specific proteins
- 23,000 genes
- 1.5% of genome
- 98.5% "Junk"
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Protein synthesis
- Make proteins: DNA has to be TRANSCRIBED into RNA
- RNA is then TRANSLATED into protein by ribosomes
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pairs with Thymine
pairs with Cytosine
- Adenine pairs with Thymine
- Guanine pairs with Cytosine
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Peptide
50 amino acids of less
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Golgi apparatus
Package proteins for transport
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Mitochondira
- Stored energt
- Takes in pyruvic acid (from sugar, proteins, and fats) and oxygen
- Produces adenosine triphosphate (ATP)
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Lysosomes
Degrade products that are not needed by the cell (waste material)
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Axons branch out and are called __________.
axon collaterals
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Information transfer is chemical (_____________) which is packaged in ______________.
Information transfer is chemical (neurotransmitter) which is packaged in synaptic vesicles.
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Information Processing
- 1. Electrical
- 2. Chemical
- 3. Electrical
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Cytoskeleton
- "Bones" found throughout the cytoplasm
- Microtubules
- Microfilaments
- Neurofilaments
- Maintain structure/shape
- Allow for movement of substances across neuron (axoplasmic transport)
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Microtubules
hollow pipe runs longitudinally down neurites (axon and dendrites)
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Microfilaments and Neurofilaments
Protein strands found throughout neurons
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__________________-->new proteins
- Anterograde transport-->new proteins
- away from soma
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Waste<--________________
- Waste<--Retrograde transportreturn to soma
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Sensory neurons
Carry sensory info to CNS
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Interneurons
Connect sensory and motor neurons or communicate with other neurons
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Motor neurons
Carry into from CNS to muscles to control their functioning
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Astrocytes
- Most numerous of glial cells
- Star-shaped
- Provide physical support to neurons, nourishment, and other functions:
- Increase blood flow
- formation of synapses
- neural plasticity
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Microglia cells
- Smallest of glial cells
- Support neurons by removing debris
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Oligodendrocytes
- Produce myelin
- Myelin: fatty insulation that surrounds axons of neurons IN the CNS
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Schwann Cells
- Produce myelin
- Myelin: fatty insulation that surrounds axons of neurons OUTSIDE the CNS (in the PNS)
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Nodes of Ranvier
Gaps in myelin sheath
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Multiple sclerosis
Demyelinating disease
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