Neurosci Exam 1 definitions

Egyptians

Knew about brain damage but believed that the heart was where the memories are stored

Galvani

Showed that electricity can stimulate muscle movement; concept that nerves conduct electrical signals not fluid

Ablation

Destruction of cells or brain region, used to determine structure function relationships

Broca

Provided evidence for localization of a specific brain function: speech

Animal Welfare

Concept that animals are to be treated ethically and humanely

Hippocrates

Early Greek physician who believed that the brain was the center of intelligence and sensation and that epilepsy was a brain disease

White matter

Axons of neurons in the CNS

alzheimer's disease

Degeneration fo cholinergic neurons leading to dementia

Vesalius

produced detailed drawings of the brain during the 1500

Gyri

Ridges or bumps present in the cortex that increase surface area

Stimulation

Activating a region of the brain to determine its function

Plato

Early Greek who believed that the brain was the center of mental processes

Cerebral localization

Concept that specific brain regions are involved in specific functions

Darwin

Espoused the concept that nervous systems have evolved and are related

Gray matter

Cell bodies in the CNS

Sulci

Grooves or creases present in the cortex

Aristotle

Believed that the heart was the center of intelligence but that the brain cooled the blood

Fluid Mechanical Theory

Fluid pumped through the ventricles control the body

Animal Rights

Concept that animals have the same rights as humans

Bell and Magendie

Used ablation to show that dorsal roots carried sensory information into the spinal cord and that ventral roots carried motor information away, with spinal nerves there are axons conducting in each direction

Model animals

Animals such as worms, fruit flies, rats, and mice used to study various aspects of nervous system function and development

Evolution of the nervous system

Nervous systems are related; various animals are good models for studying specific aspects of the nervous system

Willis

Early comparative anatomist who noticed that animals behaved like humans in basic ways

Phrenology

Incorrect belief espoused by Gall that the bumps on the skull reflected certain personality traits

Galen

Early physician who studied brain anatomy; he believed the brain controlled the body, but that nerves were tubes carrying vital fluids

Parkinson's Disease

Degeneration of dopaminergic neurons leading to loss of voluntary movement

Descartes

Believed in the fluid mechanical theory but also that human abilities came from the mind

Ventricles

Cavities in the brain filled with CSF, were thought to control brain function

"Mind-Body" Problem

Idea that the human mind is separate from the brain, research shows that the physical basis of the mind is the brain

Nissl Stain

Stains Nissl bodies ( rough endoplasmic reticulum) can be used to count neurons but can't be used to determine neuronal shape

Dendrite

Branched structure of a neuron; many synapses formed here

Tripartite Synapse

Composed of presynaptic neurons, post synaptic neuron and astrocytes

Bipolar neruon

One dendrite and one axon

Dendritic spines

Often sites of synaptic input can change structure depending on the type and amount of input

Microtome

An instrument used to make thin slices of brain tissue

Oligodendrocyte

Myelinating glial cell in CNS

Type II Neuron

Local circuit neurons; short axons, ie. stellate cells

Motor neurons

Regulate motor function spinal motor neurons innervate muscle

Recurrent Collaterals

Axon branches which form synapses with the neuron from which they project

Interneurons

Make connections between neurons. Most neurons are in this group

Tissue fixation

Treatment with formaldehyde to make the brain easier to section

Neuron Doctrine

Concept that cell theory applies to the nervous system

Astrocyte

Most numerous glial cell; supports neuron function and release gliotransmitters

Neurofilaments

Space filling axons; mutations produce slower action potential speed

Stellate Cells

Major class of multipolar neurons; local circuit

Boutons en passant

Synapse formed by axon at a location other than the axon terminal

Gliotransmitter

Neurotransmitters released from astrocytes ie glutamate, D- serine, ATP

Wallerian Degeneration

Degeneration axon degeneration distal to the injury when cut

Slow axonal transport

1-10 mm/day ; microtubules and kinesin used cytosolic proteins moved

Type I Neurons

Projection neurons; log axons that can extend between brain regions ie pyramidal cells

Retrograde Transport

Transport from the terminal to the soma; uses dynein as the molecular motor

Soma

Cell body of neuron

Golgi Stain

Stains all parts of a neuron; can be used to determine neuronal shape

Kinesin

Molecular motor for anterograde transport

Microtubule

Composed of tubulin; involved in axoplasmic transport

Bouton

Specialized structure at the end of an axon; synaptic vesicles found here

Microfilaments

Composed of actin; part of transport system

Axon

Neuron structure through which neurons communicate and action potentials travel down

Characteristics of neurons

Large amount of mitochondria, and RER. Genome regulation is complex with a large amount of alternative mRNA splicing, complex transcriptional regulation for gene expression

Multipolar

One axon and multiple dendrites

Anterograde Transport

Transport from the soma to the terminal; uses kinesin as the molecular motor

Axon Hillock

Structure at the beginning of axon where action potential initiate

Unipolar

one neurite

Microglia

Macrophage-like glial cell; act as local immune system

Perikaryon

Another term for the soma

Primary sensory neurons

Have neurites extending into sensory organs such as the skin

Fast Axon Transport

400-1000mm/day; uses microtubules and kinesin, vesicles and membranous organelles moved

Schwann cell

Myelinating glia in the PNS

Dynein

Molecular motor for retrograde transport

Pyramidal Cell

Major class of multipolar neurons; projection

Anion

a negatively charged ion

Voltage

Force on a charged particle; electrical potential

Goldman Equation

Used to calculate the Vm

Cation

a positively charged ion

Diffusion

Movement of solutes from higher concentration to lower

Plasma Membrane

Lipid bilayer surrounding neurons with high resistance to current flow

K+ Channels

K+ selective ion channels; K+ leak channels se the neuronal resting potential

Conductance

Relative ability of charge movement; inverse of resistance

Hydrophilic

Polar molecules such as ion which interact with water

Equilibrium Potential

Electrical potential difference which balances diffusional force calculated for each ion

Blood Brian Barrier

Brain capillary structure which limits some substances from entering the brain

Na-K ATPase

Ion channel pump using active transport (ATP as energy source) to move K+ into cells and Na+ out, thus maintaining ionic gradients

Nernst Equation

Used to calculate the ionic equilibrium potential of an ion

Resistance

Relative inability of charge movement

Calcium pump

Enzyme that transports Ca2+ out of the cytoplasm using active transport

Ohm's Law

I=gV

Hydrophobic

Non-polar molecules which don't interact with water membranes lipid have this property and thus can separate the contents on the inside of neurons form those outside

Ionic Driving Force

Difference between the neuron's membrane potential and the equilibrium potential for any given ion

Electrical Current

Movement of charge, positive in the direction of positively charged particles

Resting Potential

Membrane voltage of a neuron at rest

Delayed Rectifier Channels

Voltage-gated K+ channels which open slowly and allow K+ efflux resulting in neuronal repolarization during an action potential

Action Potential Propagation

Movement of the action potential down the axon

Antidromic

Action potential moving from axon towards soma

Tetrodotoxin

Toxin form pufferfish which blocks voltage-gated Na+ channels and prevents action potentials

Rising Phase

Beginning of action potential when Na+ enters neuron through voltage-gated channels

Node of Ranvier

Gaps in myelin where voltage-gated Na+ channels are clustered, leading to fast action potential propagation via saltatory conduction

Patch Clamp

Used to record activity of individual ion channels

Spike Initiation Zone

Region of a neuron where action potentials are started often at the axon hillock; large density of voltage-gate Na+ channels here

Inactivation Gate

Structure of voltage-gated sodium channels which closes after about 1 msec; must re-open before next action potential begins

Generator Potentials

Changes in Voltage produced by positively charged ions entering the neuron