Nervous System Overview

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Questions and Answers

What are the two major anatomical subdivisions of the nervous system?

Autonomic Nervous System

Peripheral Nervous System (PNS) (correct)

Central Nervous System (CNS) (correct)

Somatic Nervous System

What does the CNS consist of?

Brain and Spinal Cord

What are the primary functions of the nervous system?

Providing sensation of the internal and external environments, integrating sensory information, regulating and controlling peripheral structures and systems

What are neurons responsible for?

Information transfer and processing in the nervous system Signup and view all the answers

Where are voltage-gated sodium channels located in a neuron?

Axon Hillock Signup and view all the answers

How are neurons classified based on their structure?

Anaxonic, Unipolar, Bipolar, Multipolar Signup and view all the answers

How are neurons classified based on their function?

Motor, sensory, association Signup and view all the answers

What are the two major cell populations of neural tissue?

Neurons and neuroglia Signup and view all the answers

What types of glial cells are found in the CNS?

Astrocytes, oligodendrocytes, microglia, ependymal cells Signup and view all the answers

What does the white matter of the CNS primarily consist of?

Oligodendrocytes Signup and view all the answers

What does depolarization of the membrane shift it toward?

0 mV Signup and view all the answers

What is the resting membrane potential (RMP) of a typical neuron?

-70 mV Signup and view all the answers

If the resting membrane potential is -70 mV and the threshold is -60 mV, what happens at -62 mV?

Not produce an action potential Signup and view all the answers

What does the membrane contain at the site of an action potential?

An excess of positive ions inside and an excess of negative ions outside Signup and view all the answers

If the resting membrane potential is -70 mV, what is a hyperpolarized membrane?

-80 mV Signup and view all the answers

What does a node along the axon represent?

An absence of myelin Signup and view all the answers

What happens as the diameter of the axon increases?

The faster an action potential will be conducted Signup and view all the answers

What are the two most important factors that determine the rate of action potential conduction?

The presence or absence of a myelin sheath and the diameter of the axon Signup and view all the answers

What connects the presynaptic and postsynaptic membranes at an electrical synapse?

Gap junctions Signup and view all the answers

What distinguishes chemical synapses from electric synapses?

Involve a neurotransmitter Signup and view all the answers

What does the effect of a neurotransmitter on the postsynaptic membrane depend on?

Properties of the receptor Signup and view all the answers

What triggers exocytosis and the release of acetylcholine in the synaptic cleft?

Calcium ions flooding into the axoplasm Signup and view all the answers

What is the normal stimulus for neurotransmitter release?

Arrival of an action potential Signup and view all the answers

What are inhibitory or hyperpolarizing CNS neurotransmitters?

Dopamine and Serotonin Signup and view all the answers

What is an excitatory postsynaptic potential (EPSP)?

A depolarization produced by the arrival of a neurotransmitter Signup and view all the answers

What is an inhibitory postsynaptic potential (IPSP)?

Transient hyperpolarization of the postsynaptic membrane Signup and view all the answers

What are the most important determinants of neural activity?

EPSP-IPSP interactions Signup and view all the answers

Why do active neurons need ATP?

To support the synthesis, release, and recycling of neurotransmitter molecules, the recovery from action potentials, the movement of materials to and from the soma via axoplasmic flow Signup and view all the answers

What are sensory neurons responsible for?

Carrying impulses to the CNS Signup and view all the answers

How do interneurons differ from sensory and motor neurons?

Exclusive location in the brain and spinal cord Signup and view all the answers

What do efferent pathways consist of?

Axons that carry impulses away from the CNS Signup and view all the answers

What are graded potentials that develop in the postsynaptic membrane in response to a neurotransmitter?

Postsynaptic Potentials Signup and view all the answers

What is the addition of stimuli occurring in rapid succession called?

Temporal Summation Signup and view all the answers

Study Notes

Nervous System Subdivisions

Two major subdivisions: Central Nervous System (CNS) and Peripheral Nervous System (PNS).
CNS comprises the brain and spinal cord.

Functions of the Nervous System

Provides sensory information about internal and external environments.
Integrates sensory information for processing.
Regulates and controls peripheral structures and systems.

Neurons and Their Functions

Neurons transfer and process information in the nervous system.
Types of neurons based on structure: Anaxonic, Unipolar, Bipolar, Multipolar.
Types of neurons based on function: Motor, Sensory, Association.

Glial Cells

Two major cell populations in neural tissue: Neurons and Neuroglia.
Glial cell types in CNS: Astrocytes, Oligodendrocytes, Microglia, Ependymal cells.
White matter in CNS is dominated by oligodendrocytes.

Membrane Potentials

Resting membrane potential (RMP) is typically -70 mV.
Depolarization shifts membrane potential towards 0 mV.
Hyperpolarization occurs when RMP is below -70 mV (e.g., -80 mV).

Action Potentials

Action potential requires threshold of -60 mV; -62 mV will not generate one.
Node along the axon indicates absence of myelin; larger axon diameter increases conduction speed.
Rate of action potential conduction depends on myelin sheath presence and axon diameter.

Synapses

Electrical synapses connect presynaptic and postsynaptic membranes at gap junctions.
Chemical synapses utilize neurotransmitters for communication.
Effect of neurotransmitter depends on receptor properties.

Neurotransmitter Release

Acetylcholine release triggered by calcium ions in axoplasm.
Arrival of an action potential depolarizes the synaptic knob, stimulating neurotransmitter release.

Postsynaptic Potentials

Inhibitory neurotransmitters (e.g., Dopamine, Serotonin) induce hyperpolarization (IPSP).
Excitatory postsynaptic potential (EPSP) results from depolarization by neurotransmitter arrival.
Neural activity is primarily determined by EPSP-IPSP interactions.

Energy Requirements of Neurons

Active neurons require ATP for neurotransmitter synthesis, release, recycling, recovering from action potentials, and axoplasmic flow.

Sensory and Interneurons

Sensory neurons send impulses to the CNS.
Interneurons are located exclusively within the CNS (brain and spinal cord).
Efferent pathways transport impulses away from the CNS.

Summation

Graded potentials from postsynaptic membranes in response to neurotransmitters are termed Postsynaptic Potentials.
Temporal summation involves the rapid succession of stimuli.

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Description

Explore the major subdivisions of the nervous system, including the Central and Peripheral Nervous Systems. Understand the functions of neurons, types of glial cells, and membrane potentials. This quiz covers crucial concepts for anyone studying the nervous system.