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What is the primary function of astrocytes in the nervous system?
What is the primary function of astrocytes in the nervous system?
What distinguishes a multipolar neuron from other types of neurons?
What distinguishes a multipolar neuron from other types of neurons?
Which type of neuroglia is responsible for myelinating neurons in the central nervous system?
Which type of neuroglia is responsible for myelinating neurons in the central nervous system?
What role do microglia serve in the nervous system?
What role do microglia serve in the nervous system?
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What percentage of the total cell population in the nervous system is made up of neuroglia?
What percentage of the total cell population in the nervous system is made up of neuroglia?
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What is the main function of dendrites in a neuron?
What is the main function of dendrites in a neuron?
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What distinguishes the structure of a unipolar neuron from other neuron types?
What distinguishes the structure of a unipolar neuron from other neuron types?
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What does the long axon of a neuron primarily do?
What does the long axon of a neuron primarily do?
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Which of the following is NOT a component of a neuron's structure?
Which of the following is NOT a component of a neuron's structure?
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Which type of neuron is commonly found in the central nervous system (CNS)?
Which type of neuron is commonly found in the central nervous system (CNS)?
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What aspect of neurons is crucial for their ability to transmit information?
What aspect of neurons is crucial for their ability to transmit information?
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In the structure of a bipolar neuron, how is the arrangement of processes characterized?
In the structure of a bipolar neuron, how is the arrangement of processes characterized?
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Which term best describes the overall function of neurons within the nervous system?
Which term best describes the overall function of neurons within the nervous system?
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What does the NatK pump primarily do?
What does the NatK pump primarily do?
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What is the equilibrium potential for potassium ($E_{k+}$)?
What is the equilibrium potential for potassium ($E_{k+}$)?
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Which ion exerts a dominant effect on the resting membrane potential?
Which ion exerts a dominant effect on the resting membrane potential?
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What primarily regulates the membrane channels?
What primarily regulates the membrane channels?
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What could cause the membrane to open or close?
What could cause the membrane to open or close?
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What is the primary effect of ion movement across the plasma membrane?
What is the primary effect of ion movement across the plasma membrane?
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What is the status of sodium concentration inside the cell compared to outside?
What is the status of sodium concentration inside the cell compared to outside?
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What does the concentration difference of Na+ and K+ primarily create?
What does the concentration difference of Na+ and K+ primarily create?
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What type of conduction is characterized by action potentials jumping from node to node?
What type of conduction is characterized by action potentials jumping from node to node?
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What is the primary mechanism by which sodium ions are transported into the cell?
What is the primary mechanism by which sodium ions are transported into the cell?
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What is a characteristic of electrical synapses in neurons?
What is a characteristic of electrical synapses in neurons?
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How many high-affinity sites for sodium does the sodium-potassium pump have?
How many high-affinity sites for sodium does the sodium-potassium pump have?
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Which type of conduction is slower due to propagation through segments?
Which type of conduction is slower due to propagation through segments?
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What happens to ion distribution after an action potential (AP) is restored?
What happens to ion distribution after an action potential (AP) is restored?
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In chemical synapses, how is information transmitted between neurons?
In chemical synapses, how is information transmitted between neurons?
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How many low-affinity sites for potassium does the sodium-potassium pump have?
How many low-affinity sites for potassium does the sodium-potassium pump have?
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What is the role of voltage-gated calcium channels in synaptic transmission?
What is the role of voltage-gated calcium channels in synaptic transmission?
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Which structure connects the axon of the presynaptic neuron to the dendrite of the postsynaptic neuron?
Which structure connects the axon of the presynaptic neuron to the dendrite of the postsynaptic neuron?
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What initiates the release of neurotransmitters from the presynaptic neuron?
What initiates the release of neurotransmitters from the presynaptic neuron?
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Which calcium ion (Ca2+) role is critical in the process of synaptic transmission?
Which calcium ion (Ca2+) role is critical in the process of synaptic transmission?
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What is the first step that occurs in the presynaptic terminal during synaptic transmission?
What is the first step that occurs in the presynaptic terminal during synaptic transmission?
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What role do neurotransmitters play in synaptic transmission?
What role do neurotransmitters play in synaptic transmission?
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How do excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) affect the postsynaptic neuron?
How do excitatory and inhibitory postsynaptic potentials (EPSPs and IPSPs) affect the postsynaptic neuron?
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What mechanism is involved in terminating the action of acetylcholine in the synaptic cleft?
What mechanism is involved in terminating the action of acetylcholine in the synaptic cleft?
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What type of ion channel is primarily involved in the action of EPSPs?
What type of ion channel is primarily involved in the action of EPSPs?
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What is a key feature of synaptic integration in the neuronal pathways?
What is a key feature of synaptic integration in the neuronal pathways?
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What effect does the breakdown of acetylcholine by acetylcholinesterase have on synaptic activity?
What effect does the breakdown of acetylcholine by acetylcholinesterase have on synaptic activity?
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What is the primary function of graded potentials in synaptic transmission?
What is the primary function of graded potentials in synaptic transmission?
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What determines whether a postsynaptic neuron will reach threshold?
What determines whether a postsynaptic neuron will reach threshold?
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Study Notes
Neurons
- Neurons are conducting cells in the nervous system, transmitting information electrically and chemically.
- Structure:
- Soma (cell body): Contains organelles essential for survival.
- Dendrites: Short, highly branched; receive information from other neurons.
- Axon: Long, single axon; carries electrical signals (action potentials) to target.
- Types:
- Bipolar neuron: One long dendrite, one long axon.
- Unipolar neuron: Dendrites and axon continuous; soma to one side.
- Multipolar neuron: Multiple short dendrites, one long axon.
Neuroglia
- Supports neuronal function and is ~50% of total nervous system (NS) cells.
- Types:
- Astrocytes: Regulate chemical environment; surround neurons.
- Myelinating glia:
- Oligodendrocytes (CNS): Myelinate neurons.
- Schwann cells (PNS): Myelinate neurons.
- Microglia: Phagocytic role (engulf cell debris and waste).
- Ependymal: Produce cerebrospinal fluid (CSF) in brain ventricles.
Neural Communication
- Nerve and muscle cells are excitable tissues.
- Neurons produce, process, transmit, and receive electrical and/or chemical signals.
Resting Membrane Potential
- Membrane potential: -70 mV (polarized).
- Resting potential established due to unequal distribution of ions (sodium (Na+), potassium (K+), chloride (Cl-), and negatively charged proteins) inside and outside the cell.
- Na+/K+ pump moves 3 Na+ out and 2 K+ in (maintains concentration gradients).
- Membrane more permeable to K+, which diffuses out and causes net negative charge inside.
Membrane Channels
- Leaky channels: Channels always open, allowing ions to pass through.
- Gated channels: Open/close in response to stimuli (voltage, chemicals, physical force, temperature).
Graded Potentials
- Local changes in membrane potential, varying in magnitude.
- Only spreads throughout dendrites and soma.
Action Potentials
- Brief, rapid, large change in membrane potential (all-or-none).
- Changes membrane permeability; ion movement across membrane.
- Propagated from axon hillock to axon terminals.
Voltage-gated Na+ and K+ Channels
- Voltage-gated Na+ channels: Open rapidly in response to depolarization; inactivation gates close.
- Voltage-gated K+ channels: Open slowly after depolarization; K+ diffuses out of the cell, returning the membrane to resting potential.
Synaptic Transmission
- Synapses: Junctions between neurons or between neurons and muscle/gland cells.
- Electrical synapses: Direct connections; fast.
- Chemical synapses: Transmit signals via neurotransmitters.
- Transmission steps:
- Action potential arrives at pre-synaptic axon terminal.
- Depolarization opens voltage-gated calcium channels, allowing calcium influx.
- Calcium influx causes synaptic vesicles to release neurotransmitters into the synaptic cleft.
- Neurotransmitters bind to receptors on post-synaptic membrane, initiating changes in membrane potential.
- Neurotransmitters are removed from the synapse(e.g., enzymatic degradation or reuptake).
Myelination
- Myelin sheath: Fatty insulation around some axons; formed by Schwann cells (PNS) or oligodendrocytes (CNS).
- Myelination speeds up action potential propagation through saltatory conduction (jumps between Nodes of Ranvier).
Types of Conduction
- Contiguous conduction: Slower; propagation of AP along entire axon.
- Saltatory conduction: Faster; AP "jumps" between Nodes of Ranvier; more efficient.
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Description
This quiz covers the essential concepts of neurons and neuroglia in the nervous system. You'll learn about the structure and types of neurons, as well as the different types of neuroglial cells and their functions. Perfect for students wanting to deepen their understanding of neurobiology.
