Quiz 1 Biological basis of behavior

Neurons and glia-

Neurons- Cells specialized for communication and information processing

Glial cells- cells that support, protect, and maintain neruons

Types of glial cells- Macroglia and microglia

Astrocytes- help form the blood brain barrier and regulate synapses and support neurons

Oligodendrocytes- produce myelin around axons in the CNS

Schwann cells- produce myelin around axons in the PNS

Microglia- immune defense cells that remove damaged cells and debris in the CNS

Dendrites- branches that receive information from other neurons

Dendritic spine- projection that can receive synaptic input

Axon- extension that carries action potentials away from the cell body

Axon Hillock- integration zone where inputs are summed and an action potential may begin

Axon Terminals- endings of an axon that release neurotransmitters

Synaptic vesicle- sac that stores neurotransmitter in the axon terminal

Neurotransmitter- chemical messenger released by neurons to communicate with other cells

Synaptic gap- gap between communicating neurons

Myelin- fatty insulating sheath around axons that speeds up conduction

Nodes of Ranvier- gaps between myelin segments where action potentials are regenerated

Microtubules- cytoskeleton fibers that transport materials along neurons

Sodium potassium pump job- uses ATP to move 3 Na+ out and 2 K+ into the neuron

Neuron types by structure- Unipolar, bipolar, multipolar

Unipolar- one process extending from soma

Bipolar- two processes extending from soma

Multipolar- multipolar, one axon and many dendrites

Sensory neurons afferent- carries information from sensory receptors to the CNS

Motor neurons efferent- carry commands from CNS to muscles and glands

Interneurons- connects and process information between the neurons in the CNS

The cell-

Nucleus- stores cells DNA

Chromosome- structure of DNA and proteins containing genetic information

Mitochondria- produces ATP the cells energy

ATP- cells main useable energy molecule

Endoplasmic reticulum- membrane involved in making and processing proteins and lipids

Rough ER- contains ribosomes and makes proteins for membranes or export

Smooth ER- makes lipids and helps transport and process cellular materials

Ribosomes- build protein

Golgi apparatus- "UPS" modifies, sorts, and packages proteins for transport

Cytoskeleton- fibers that give cell support, shape, and transport pathways

Cytoplasm- Everything inside the cell membrane, not including the nucleus

Cytosol- fluid portion of the cytoplasm

Resting and action potentials-

Resting potential- electrical charge in a resting neuron's membrane -70mV

Diffusion- movement of particles from high to low concentration

Electrical force- force that attracts opposite and repels like charges

Driving force- combined influence of diffusion and electrical force on ion movement

Potassium is more concentrated…- inside the neuron

Sodium and chloride are more concentrated…-outside the neuron

How does sodium potassium pump use ATP- moves 3 Na+ out and 2 K+ in to maintain ion concentration gradients

How is resting potential maintained?- active transport of ions through SP pump and passive diffusion of potassium through leak channels

Action potential- rapid, all of none change in the membrane voltage that travels along the axon

Threshold- membrane voltage needed to trigger action potential -55mV

All or none- action potential either happens or does not

Depolarization- inside of neuron becomes less negative or more positive

What happens during depolarization- voltage gated sodium channels open and Na+ enters the neuron

Repolarization- membrane voltage returns towards its negative resting level -70mV

What happens during repolarization- potassium channels open and K+ leaves the neuron

Hyperpolarization- inside of neuron becomes more negative than its resting potential

What is the cause of hyperpolariation- potassium channels remain open briefly allowing K+ to leave

Absolute refractory period- period when another action potential cannot be generated

Relative refractory period- when action potential is possible but it needs a stronger stimulus

Why are refractory periods important- they limit firing frequency and help action potentials travel in one direction

Conduction velocity- speed at which an action potential travels along the axon

How does axon diameter affect conduction speed- larger diameter= faster conduction because the resistance is lower

Passive conduction- local electrical current spreads along an axon and weakens with distance

saltatory conduction- action potentials regenerate at nodes of ranvier, jumping between them

Why is saltatory conduction faster- myelin insulates so signal is regenerated mainly at the nodes

Propagation- process when action potential is regenerated along the axon

Synapses-

Synapse- junction where one neuron communicates with another cell

Chemical synapse- neurotransmitters carry the message across a gap can be both excitatory or inhibitory depending on receptors or ions involved

Electrical synapse- faster because ion pass directly between cells through gap junctions

Presynaptic neuron- sending neuron that releasing neurotransmitters

Postsynaptic neuron- receieving neuron that has receptors for neurotransmitters

What happens when an action potential reaches the axon terminal- voltage gated calcium channels open and Ca2+ enters

What does calcium do at a chemical synapse- triggers synaptic vesicles to fuse with the membrane and release neurotransmitters

Exocytosis- releasing substances when vesicles fuse with the cell membrane

Ionotropic receptor- receptor that opens or closes an ion channel fast

Metabotropic receptor- activates G proteins and indirect signaling slower

G protein- protein that relays signals inside the cell after receptor activation

Reuptake- presynaptic neuron reabsorbs neurotransmitters from synaptic cleft

Enzymatic breakdown- enzymes breakdown neurotransmitters into inactive substances

Diffusion at a synapse- neurotransmitters move away from synaptic cleft

Excitatory postsynaptic potential EPSP- makes action potential likely

Inhibitatory postsynaptic potential IPSP- makes action potential less likely

EPSP affect on membrane voltage- depolarizes the neuron, brings it closes to threshold

IPSP affect on membrane voltage- hyperpolarizes neuron or stabilizes, moving it away from threshold Cl- chloride entering or K+ potassium leaving the neuron

Neural integration- combining EPSP and IPSP inputs to determine if threshold was reached

Spatial summation-inputs from multiple synapses combine at the same time

Temporal summation- inputs from one synapse combine over a short period

Neuromodulation- changing how strongly neurons communicate with each other

Presynaptic inhibition- decrease in neurotransmitter release from the presynaptic neuron

Presynaptic facilitation- increase in neurotransmitter release from the presynaptic neuron

Autorecptors- detect a neurons own neurotransmitters and regulate further release

Calcium pumps after neurotransmitter release- remove Ca2+ from the presynaptic terminal

Vesicle recycling- vesicle membrane is retrieved by endocytosis and reused

Tetanospasmin- toxin produced by tetanus bacteria that blocks inhibitory neurotransmitter release

Retrograde transport- movement along and axon towards the soma

How does tetanus cause muscle spasms- it blocks GABA and glycine release, removing inhibition and over activating motor neurons

How is brain acivtity measured?-

EEG electroencephalography- records brains electrical activity on the scalp by measuring voltage changes caused by ions traveling across the cells membrane