AP Notes, Outlines, Study Guides, Vocabulary, Practice Exams and more!

AP Biology Chapter 37 Flashcards

Terms : Hide Images
6363489749Neurons- Nerve cells that transfer information within the body. - Communication→long distance electrical signals & short distance chemical signals.0
6363489750Cell body- Consists if a neuron's organelles (including nucleus)1
6363489751Dendrites- Branchlike parts of a neuron that are specialized to receive information. - Receive signals from other neurons.2
6363489752Axon- An extension of the neuron that transmits signals to other cells. - Axon hillock →where cells signals that ravel down the axon are generated.3
6363489753Synapse- A junction where information is transmitted from one neuron to the next.4
6363489754Synaptic terminal- The part of each axon branch that forms the synapse5
6363489755neurotransmitters- Chemical messengers that pass information from the transmitting neuron to the receiving cell.6
6363489756Presynaptic cell- The transmitting neuron7
6363489757Postsynaptic cell- The neuron, muscle or gland cell that receives the signal.8
6363489758glia- Cells in the nervous system that support, nourish, and protect neurons. - Sometimes function in replenishing certain groups of neurons and in transmitting information.9
63634897593 stages of Information processing1. Sensory input, 2. Integration, and 3. motor output.10
6363489760Sensory neurons- Transmit information to processing centers in the brain or ganglia. - Detect external stimuli (light, touch) & internal stimuli (blood pressure). - They integrate the sensory input.11
6363489761Interneurons- Neurons which form the local circuits connecting neurons in the brain. - Majority of neurons in the brain.12
6363489762Motor neurons- Transmit signals to muscle cells & cause them to contract.13
6363489763Central Nervous System- Includes the brain and a longitudinal nerve cord.14
6363489764Peripheral nervous system- A division of the nervous system consisting of all nerves that are not part of the brain or spinal cord.15
6363489765Nerves- Bundles of neurons.16
6363489766Membrane potential- A measurable difference in electrical charge between the cytoplasm (negative ions) and extracellular fluid (positive ions) - Inputs from other neurons or specific stimuli cause changes in the neuron's membrane potential that act as signals, transmitting information. - Largely due to ion channels.17
6363489767Resting potential- Membrane potential for a resting neuron. - Usually between -60 and -80 mV. - Net flow of each ion across the membrane →K+ & Na+ currents are equal and opposite.18
6363489768Sodium-potassium pump- Na+ and K+ gradient are maintained. - Uses energy from ATP hydrolysis→ 3 Na+ out and 2 K+ in (resulting voltage only a difference of a few millivolts).19
6363489769Ion Channels- Pores formed by clusters of specialized proteins that span the membrane. - Ions diffuse through channels & carry with them units of electrical charge→net movement of positive/negative charge generates a membrane potential.20
6363489770Potassium Channel- Have selective permeability→allow only certain ions to pass and thus convert chemical potential energy from concentration gradients of K+ and Na+ to electrical potential energy. - Allows K+→140 mM inside and 5mM outside (favors outflow of K+ ) - Resting neuron →many open potassium channels but few sodium, K+ outflow →net negative charge.21
6363489771Equilibrium potential- The magnitude of the membrane voltage at equilibrium for a particular ion.22
6363489772Gated ion channels- Ion channels that open or close in response to stimuli. - Responsible for changes in the membrane potential →Alters the membranes permeability to particular ions and thus alters the membrane potential.23
6363489773Hyperpolarization- Increase in the magnitude of the membrane potential that makes the inside of the membrane more negative. -Resting neuron →this results from any stimulus that increases the outflow of positive ions or inflow of negative ions.24
6363489774Depolarization- A reduction in the magnitude of the membrane potential. - Often involves gated sodium channels →if they open in a resting neuron, the membrane's permeability to Na+ increases & Na+ diffuses in which causes a depolarization.25
6363489775Graded potential- Response to hyper polarization or depolarization that causes a shift in the membrane potential. - large stimulus → greater change in membrane potential. - Induce a small electrical current that leaks out of the neuron as it flows along the membrane. - Decay with distance from their source.26
6363489776Action potential- A massive change in membrane voltage caused by depolarization. - Constant magnitude & can regenerate (can spread along axons). - All-or-none response to a stimuli. - Rate at which they are produced conveys information about the strength of the input signal.27
6363489777Voltage-gated ion channels- Ion channels in neurons that open or close when the membrane potential passes a particular level. - If depolarization opens→ flow of Na+ into the neuron results in further depolarization (result: positive feedback that triggers rapid opening of many voltage-gated sodium channels & change in membrane potential that defines an action potential).28
6363489778Threshold- The level of stimulation required to trigger a neural impulse. - Many mammalian neurons →threshold is -55 mV29
6363489779Refractory period- The downtime when a second action potential cannot be initiated is called. - Limits the maximum frequency at which the action potentials can be generated. - Ensures that ensures that all singles in an anon travel in one direction ,from the cell body to the axon terminals. - Due to the inactivation of sodium channels.30
6363489780Axon hillock- Site where an action potential is initiated. - Action potential that starts here moves along the axon toward the synaptic terminals. - Neuron's integrating center →region where the membrane potential at any instant represents the summed effect of all EPSPs and IPSPs.31
6363489781Conduction of an action potential1. An action potential is generated as Na+ flows inward across the membrane at one location. 2. Depolarization of an action potential spreads to neighboring region of the membrane (reinitiating the action potential there). To the left of this region, the membrane is repolarizing as K+ flows outward. 3. Depolarization-repolarization process is repeated in the next region. Local currents of ions across the plasma membrane cause the actin potential to be propagated along the length of the axon.32
6363489782Evolutionary adaptations- Axon structure- Wider axon →provides less resistance to the current associated with an action potential than does a narrow axon. - Electrical insulation →causes the depolarization current associated with an action potential to spread farther along the axon interior, bringing more distant regions to the threshold sooner.33
6363489783Myelin Sheath-Electrical insulation that surrounds vertebrate axons. - Produced by 2 types of glia: *oligodendrocytes* in the CNS & *Schwann cells* in the PNS (wrap axons in layers of membrane).34
6363489784Nodes of Ranvier- Gaps in the myelin sheath to which voltage-gated sodium channels are confined.35
6363489785Saltatory conduction- Rapid transmission of a nerve impulse along an axon, resulting from the action potential jumping from one node of Ranvier to another, skipping the myelin-sheathed regions of membrane. - Action potentials are not generated at nodes of ranvier & inward occurrent produced during rising phase of action potential at a node travels to the next node, where it depolarizes the membrane & regenerates the action potential.36
6363489786Myelination- The process by which axons become coated with myelin, a fatty substance that speeds the transmission of nerve impulses from neuron to neuron. - Advantage: space efficiency37
6363489787Electrical synapses- Contain gap junctions which allow electrical current to flow from one neuron to another. - Synchronize the activity of neurons responsible for rapid, unvarying behaviors.38
6363489788Chemical synapses- Involve the release of a chemical neurotransmitter by the synaptic neuron. - At each terminal, presynaptic neuron synthesizes the neurotransmitter and packs it into synaptic vesicles. - Action potential at a synaptic terminal →depolarizes plasma membrane, allowing Ca2+ to diffuse in thru channels and synaptic vesicle fuse with the terminal membrane releasing a neurotransmitter which diffuses across *Synaptic cleft*39
6363489789Ligand-gated ion channel- Type of membrane receptor that has a region that can act as a "gate" when the receptor changes shape. - Inotropic receptor - Clustered in the membrane of the postynaptic cell, opposite the synaptic terminal.40
6363489790Excitatory postsynaptic potential- Membrane potential that occurs because of the influx of Na+ through chemically gated channels in the receptive region of a neuron. - Brings the membrane potential towards threshold.41
6363489791Inhibitory postsynaptic potential- A postsynaptic potential that hyperpolarizes the neuronal membrane, making a cell less likely to fire an action potential. - Moves the membrane farther from threshold.42
6363489792Temporal summation- Two ESPSPS occur at a single synapse in such rapid succession that the postsynaptic neuron's membrane potential has not returned to the resting potential before the arrival of the second EPSPS. - EPSPS add together43
6363489793Spatial summation- EPSPs produced nearly simultaneously by different synapses on the same postsynaptic neuron can add together and create this.44
6363489794Modulate Signaling at Synapses- Neurotransmitter binds to a metabotropic receptor which activates a signal transduction pathway in the postsynaptic cell involving a second messenger. - SEcond messengers modulate the responsiveness of postsynaptic neurons to inputs in diverse ways. - Signal transduction pathways play a role in modulating synaptic transmission.45
6363489795Acetylcholine- A common neurotransmitter in both invertebrates and vertebrates. - Vital for nervous system functions that include muscle stimulation, memory formation and learning. - A metabotropic acetylcholine receptor is found alt locations that include the vertebrate CNS and heart. - Toxins disrupt neurotransmission by acetylcholine →sarin inhibits acetylcholinesterase and causes a buildup of acetylcholine to levels that trigger paralysis & death.46
6363489796Neuromuscular junction- The site where a motor neuron forms a synapse with a skeletal muscle cell. - Acetylcholine released by motor neurons binds this receptor, ion channel opens producing an EPSP. - Excitatory activity is terminated by acetylcholinesterase.47
6363489797Glutamate- Amino acid that acts as a neurotransmitter. - In invertebrates →neurotransmitter at neuromuscular junction.48
6363489798gamma-aminobutyric acid- Amino acid that is a neurotransmitter at most inhibitory synapses in the brain. - Binding of GABA to receptors in postsynaptic cells →increases membrane permeability to Cl-→IPSP. - Valium reduces anxiety through binding to a site on a GABA receptor.49
6363489799Biogenic amines- Neurotransmittes that are synthesized from amino acids and include norepinephrine (made of tyrosine). - Role in many nervous system disorders and treatments.50
6363489800Dopamine- Biogenic amine made from tyrosine. - Parkinson's is associated with a lack of dopamine in the brain.51
6363489801Serotonin- Biogenic amine made from tryptophan. - Prozac enhances the effect of serotonin by inhibiting its repute after release.52
6363489802Neuropeptides- Relatively short chains of amino acids. - Many serve as neurotransmitters that operate via metabotropic receptors.53
6363489803Endorphins- Neuropeptides that function as natural analgesics, decreasing pain perception. - Produced during times of stress. - Reduce urine output, decrease respiration and produce euphoria.54
6363489804Gases- Some vertebrate neurons release dissolved gases that act as local regulators. - Human males →certain neurons release NO into the erectile tissue of the penis during sexual arousal.55

Need Help?

We hope your visit has been a productive one. If you're having any problems, or would like to give some feedback, we'd love to hear from you.

For general help, questions, and suggestions, try our dedicated support forums.

If you need to contact the Course-Notes.Org web experience team, please use our contact form.

Need Notes?

While we strive to provide the most comprehensive notes for as many high school textbooks as possible, there are certainly going to be some that we miss. Drop us a note and let us know which textbooks you need. Be sure to include which edition of the textbook you are using! If we see enough demand, we'll do whatever we can to get those notes up on the site for you!