Physiological Psychology Exam 1

Golgi Stain

Soaking brain tissues in silver chromate solution stains a small number of neurons in their entirety (developed by Camillo Golgi in 1873)

Neuron Doctrine

Neurons communicate by contact, not continuity (Santiago Romon y Cajal Father of Neuroscience)

Axon

root, or single fiber of a neuron that carries messages

Dendrites

Collect information

Spines

Protrusion from a dendrite that greatly increases surface area. usually point of contact with axon

Soma

the region of the neuron that is defined by the presence of the cell nucleus

Axon Hillock

junction of soma and axon where action potential begins

Synapse

junction between one neuron and another. Usually between a terminal button of an axon of one neuron and a dendritic spine of another

Axonal Transport

the transportation of materials between neuronal cell body and axon terminals

Sensory Neurons

Carries info from sensory receptors into spinal cord into brain. Afferent → outside to inside

Motor Neurons

carries info from brain and spinal cord to muscles. Efferent → inside to outside (brain to muscle)

Interneurons

link sensory and motor neurons, make up most neurons in the brain. Most are inhibitory (GABA), larger brains have more, cell bodies are located in the central nervous system

Glial Cells

Support cells constantly replace themselves, may transmit information

Ependymal Cells

line the walls of the ventricles in the CNS. Make and secrete cerebrospinal fluid

Microglia

Originate in the blood, small defensive function, aid in cell repair, scavenge debris in the nervous system (phagocytosis), multiply when the brain is injured

Oligodendrocytes

cell with a few branches, only found in the CNS, insulate axons with myelin, 1 can insulate 50 axons

Resting Potential

electrical charge across a neuronal membrane in the absence of stimulation. Store of energy produced by greater negative charge on intracellular side relative to extracellular side, -70mV = inside membrane relative to outside

Cations

positively charged (Na+ and K+)

Anions

negatively charged (Cl- and A-)

Concentration Gradient

if could move wherever they want they would move to more equal

Excitatory Postsynaptic Potential (EPSP)

brief depolarization in response to stimulation, more positive inside, neurons more likely to produce an action potential

Excitatory Postsynaptic Potential (EPSP) Caused By

Inward movement of sodium (Na+) (Na+ influx)

Inhibitory Postsynaptic Potential (IPSP)

brief hyperpolarization of a response to stimulation, more negative side, neuron less likely to fire an action potential

Inhibitory Postsynaptic Potential (IPSP) Caused By

K+ channels open and K+ moves to outside (Efflux) (lose positive charge on inside). Cl- channels open and Cl- moves to inside (Influx) (gains more negative charges on inside)

CTX

Blocks K+ channels. Causes: hyperexcitability and paralysis

TTX

Blocks Na+ channel, blocks depolarization, death in 4-6 hours

Aconitine

neurotoxin opens Na+ channels. Causes: respiratory paralysis, cardiac arrest, death

Action Potential

large, brief reversal in polarity of neuronal membranes, intracellular side positive relative to extracellular side, polarity reverse again to return to resting potential

Absolute Refractory Periods

during depolarizing and repolarizing period during which a new action potential can’t be elicited

Relative Refractory Periods

later phase of action potential during which increased electrical current is required to produce another action potential

Myelin

Glial coating that surrounds an insulates axons, allows for info to be sent quickly over long distances, neurons with more of this can send info faster and over long distances, to conduct impulses quickly axons need to be very thick or covered in this, axons of huma neurons are thin so we have this

Saltatory Conduction

Action potentials can’t occur where myelin covers an axon, barrier doesn’t allow ions to pass, few channels, gaps are close enough so voltage-sensitive gates can be triggered on next node

Nodes of Ranvier

Part of axon not covered in myelin form tiny gaps

Temporal Summation

graded potentials (depolarizing or hyperpolarizing) that occur at approximately the same time on membrane are summated

Spatial Summation

Graded potentials that occur at approximately the same location and time on membrane are summed

Graded Potentials

small voltage fluctuations restricted to the vicinity of axon where ion concentrations charge to cause brief change in electrical charge, axon must be stimulated and decay quickly, takes place on soma or dendrites

Action Potentials

large, brief reversal in polarity of neuronal membrane, intracellular side positive relative to extracellular side, polarity reverse yet again to return to resting potential, last ~1 millisecond (ms) an axon can produce up to 200 a second

Presynaptic Membrane

membrane on output side (axon)

Postsynaptic Membrane

membrane on input side (dendrite)

Synaptic Cleft

Gap that separates presynaptic membrane from postsynaptic membrane

Mitochondria

organelle that supplies energy (powerhouse of the cell)

Microtubules

Transport proteins and NT’s to terminal

Storage Granule

membranous compartment that holds several vesicles containing NT

Synaptic Vesicles

Organelle consisting of membrane structure that encloses quantum of NT

Botulinum Toxin effect on neurotransmission

Cleaves SNARE proteins, prevents vesicle fusion, no NT release = no action potential

Tetanus affect on neurotransmission

Cleaves SNARE proteins, prevents vesicle fusion in inhibitory neurons, produces hyperexcitability of motor neurons

Glutamate

Excitatory, increases Na+ conductance

GABA

Inhibitory, increase Cl- conductance

Acetyl Coenzyme A (Acetyl CoA)

brings acetate to synthesis site

Choline Acetyltraaansferasee (ChAT)

transfers acetate to cholne = ACh

Functions of ACh

Attention, learning, memory, pain, sensory input, REM sleep, reward

Dopamine (DA)

Motor initiation and movement, reinforcement and addiction, error prediction, and working memory and planning

Norepinephrine (NE)

alertness, arousal, influences reward system

Serotonin (5-HT)

varying excitatory and inhibitory behavioral effects, mood, eating, sleep, dreaming, arousal, pain aggression

Function of peptide NT’s (Neuropeptide)

Multifunctional chair of amino acids that act as NT, synthesized from instructions from DNA, process of synthesis and transport is slow, indirectly influence cel structure and function, play a role in motivation, food intake and response to stress and pain, endorphin rush (“runner’s high”)

Anandamide functions

Produced and released on demand, not stored in vesicles, forgetting, prevents brain from being overwhelmed by stimuli and information

Adenosine functions

Vasodilation, mostly inhibitory, build up is a precursor to sleep

Equilibrium Potential

the voltage across a permeable membrane that exactly counteracts the movement of ions from the side with high concentration to the side with a low concentration

Nernst Equation

an equation predicting the equilibrium potential for a given ion based on the concentrations of the ion on opposite sides of a permeable membrane

Goldman Equation

an equation predicting the potential difference across a membrane based on the concentrations of multiple ions on opposite sides of the membrane, as well as its relative permeability to each ion