Nervous System Overview and Divisions

False (B)

Schwann cells

<p>oligodendrocytes, Schwann cells</p> Signup and view all the answers

<p>Myelin sheath = A fatty, insulating substance surrounding axons Oligodendrocytes = Glial cells that form myelin in the CNS Schwann cells = Glial cells that form myelin in the PNS Neurilemma = The outer collar of perinuclear cytoplasm in Schwann cells Node of Ranvier = Gaps between segments of myelin where the axon is exposed</p> Signup and view all the answers

<p>Form myelin sheaths around axons (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>The three functional zones of a neuron are the receptive zone, the integrating zone, and the transmitting zone. The receptive zone receives input from other neurons, the integrating zone sums up the input and decides whether to send a signal, and the transmitting zone sends a signal to other cells.</p> Signup and view all the answers

<p>astrocytes</p> Signup and view all the answers

<p>Astrocytes = Support and brace neurons Microglial cells = Phagocytize microorganisms and debris Ependymal cells = Form myelin sheaths around axons Oligodendrocytes = Line central cavities of the brain and spinal cord Satellite cells = Surround neuron cell bodies in the PNS Schwann cells = Surround peripheral nerve fibers and form myelin sheaths</p> Signup and view all the answers

<p>A nerve is a bundle of axons in the PNS, while a tract is a bundle of axons in the CNS. (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>A nucleus is a cluster of neuron cell bodies located in the CNS, while a ganglion is a cluster of neuron cell bodies located in the PNS.</p> Signup and view all the answers

<p>Cause depolarization of the postsynaptic membrane (C)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>The two main inhibitory neurotransmitters are GABA (gamma-aminobutyric acid) and glycine. They cause hyperpolarization of the postsynaptic membrane, making it less likely to generate an action potential.</p> Signup and view all the answers

<p>acetylcholine</p> Signup and view all the answers

<p>Acetylcholine = Excitatory Glutamate = Excitatory GABA = Inhibitory Glycine = Inhibitory</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>three, two</p> Signup and view all the answers

<p>They propagate over long distances without decrement. (E)</p> Signup and view all the answers

<p>Graded potential = A localized change in membrane potential that can vary in magnitude and duration. Action potential = A rapid, all-or-none electrical signal that travels down the axon of a neuron. Resting membrane potential = The difference in electrical charge across the plasma membrane of a cell at rest.</p> Signup and view all the answers

<p>The four steps involved in generating an action potential are: 1) <strong>Resting State:</strong> The neuron is at its resting membrane potential. 2) <strong>Depolarization:</strong> The neuron is stimulated, causing sodium channels to open, allowing sodium ions to flow into the cell, making it more positive. 3) <strong>Repolarization:</strong> Sodium channels close, while potassium channels open, allowing potassium ions to flow out of the cell, making it more negative. 4) <strong>Hyperpolarization:</strong> Potassium channels remain open for a brief period, leading to a more negative charge than the resting potential. The membrane then returns to its resting state.</p> Signup and view all the answers

<p>The minimum stimulus required to trigger an action potential. (D)</p> Signup and view all the answers

<p>Action potentials are propagated along neurons by a process called saltatory conduction. The signal jumps from one node of Ranvier to the next, skipping over the myelin-covered sections of the axon. This process ensures that the signal is transmitted quickly and efficiently, without losing strength.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Causes a graded depolarization of the postsynaptic membrane. (C)</p> Signup and view all the answers

<p>spatial summation</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Excitatory postsynaptic potentials (EPSPs) cause depolarization of the postsynaptic membrane, making it more likely for an action potential to occur. Inhibitory postsynaptic potentials (IPSPs) cause hyperpolarization of the postsynaptic membrane, making it less likely for an action potential to occur.</p> Signup and view all the answers

<p>Synapse = A junction between two neurons where information is transmitted. Chemical synapse = A synapse where a chemical messenger is transmitted across the junction. Excitatory postsynaptic potential (EPSP) = A graded depolarization of the postsynaptic membrane. Inhibitory postsynaptic potential (IPSP) = A graded hyperpolarization of the postsynaptic membrane.</p> Signup and view all the answers

<p>When the EPSPs are stronger than the IPSPs, allowing the neuron to fire an action potential. (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>temporal summation</p> Signup and view all the answers

<p>Calcium influx through voltage-gated channels (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Hyperpolarization</p> Signup and view all the answers

<p>cAMP</p> Signup and view all the answers

<p>Norepinephrine (NE) = Excitatory Adrenergic effect GABA = Inhibitory effect Acetylcholine (ACh) = Excitatory Cholinergic effect</p> Signup and view all the answers

Support cells in the nervous system that surround neurons.

Most abundant neuroglia that supports and braces neurons.

Small cells that monitor neurons and clean up debris.

Line brain cavities and help circulate cerebrospinal fluid (CSF).

Neuroglia that wrap nerve fibers in the CNS with myelin.

Cells that form myelin sheaths in the PNS and help in nerve regeneration.

Excitable cell that transmits electrical signals in the nervous system.

A nerve is a bundle of nerve fibers in the PNS, while a tract is in the CNS.

Chemical substances that enable communication between cells.

Neurotransmitters that cause depolarization and promote action potentials (AP).

Neurotransmitters that cause hyperpolarization and suppress action potentials (AP).

Neurotransmitter binds to a receptor, directly opening ion channels.

Neurotransmitter triggers second messengers which eventually open channels.

Action potential is initiated through direct signaling via acetylcholine (ACh) release.

Voltage-gated calcium channels open in the synaptic knob, triggering neurotransmitter release.

Norepinephrine (NE) activates second messenger cAMP for indirect signaling.

GABA neurotransmitter causes hyperpolarization, making it harder for the postsynaptic neuron to reach threshold.

Patterns of neuronal organization and processing are key to understanding neural integration.

A junction between two presynaptic and postsynaptic neurons.

A synapse where neurotransmitters are transmitted across the gap between neurons.

Graded depolarization that helps generate an action potential in the postsynaptic neuron.

Graded hyperpolarization that makes the postsynaptic membrane less likely to generate an action potential.

The process of combining multiple EPSPs and/or IPSPs to trigger an action potential.

The combined effect of simultaneous inputs from different synapses on a single neuron.

The combined effect of repeated inputs from the same synapse on a single neuron.

Behavior occurs when EPSP overcomes IPSP, leading to action potential generation.

Voltage across a cell's membrane when not sending signals, typically -50 to -90 mV.

Movement of ions through specific channels to maintain RMP.

The cell membrane is more permeable to K+ than Na+.

Transport mechanism that moves 3 Na+ out and 2 K+ in, maintaining RMP.

Short-lived signals that can be depolarizing or hyperpolarizing, varying in strength.

Excitatory postsynaptic potential, a type of graded potential that depolarizes the membrane.

Inhibitory postsynaptic potential, a type of graded potential that hyperpolarizes the membrane.

A rapid change in membrane potential that propagates along neurons.

A protective layer around axons that speeds up nerve impulses.

Oligodendrocytes form myelin in the CNS, coiling around multiple axons.

Schwann cells wrap around axons in a jelly-roll manner to form myelin in the PNS.

The electric charge difference across the cell membrane when a neuron is not transmitting signals.

Myelinated fibers transmit impulses faster than nonmyelinated fibers.