Ch. 12 Neurons Flashcards

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Questions and Answers

What is another name for the Neural Cell Body?

Dendrite

Axon

Soma (correct)

Perikaryon

What is the term for the cytoplasm that surrounds the nucleus of a neuron?

Perikaryon

What are Neurofilaments?

Intermediate filaments of neuron cytoskeleton

What do Neurotubules resemble?

Intermediate microtubules of other types of cells Signup and view all the answers

What are Neurofibrils?

Bundles of neurofilaments that provide support for dendrites and axon Signup and view all the answers

What are Dendrites specialized to do?

Receive information Signup and view all the answers

What is an Axon?

A threadlike extension of a neuron that carries nerve impulses away from the cell body Signup and view all the answers

What is Axoplasm?

Cytoplasm of axon Signup and view all the answers

What is Axolemma?

Plasma membrane of axon Signup and view all the answers

What is the Initial Segment of an axon?

Base of the axon Signup and view all the answers

What is the Axon hillock?

Cone shaped region of an axon where it joins the cell body Signup and view all the answers

What are Collaterals?

Branches that may occur along an axon Signup and view all the answers

What are Telodendria?

Terminal branches of axons Signup and view all the answers

What are Axon Terminals?

Branches at the end of the axon that contain synaptic vesicles Signup and view all the answers

What is a Synapse?

A specialized site where the neuron communicates with another cell Signup and view all the answers

What are Neurotransmitters?

Chemical messengers that cross synaptic gaps Signup and view all the answers

What is a Neuromuscular Junction?

Point of contact between a motor neuron and a skeletal muscle cell Signup and view all the answers

What is a Neuroglandular Junction?

Synapse between a neuron and a gland Signup and view all the answers

What is the Presynaptic Membrane?

A synaptic surface where neurotransmitter release occurs Signup and view all the answers

What is the Postsynaptic Membrane?

Portion of the plasma membrane of a postsynaptic cell part of a synapse Signup and view all the answers

What is Axoplasmic Transport?

Movement of materials between the cell body and the synaptic terminals Signup and view all the answers

_____ neurons have multiple dendrites but no axon.

Anaxonic Signup and view all the answers

What do Bipolar Neurons have?

Two distinct processes: one dendrite and one axon Signup and view all the answers

What characterizes a Unipolar Neuron?

The dendrites and axon are continuous Signup and view all the answers

What are Multipolar Neurons?

Neurons with one axon and two or more dendrites Signup and view all the answers

What are Sensory Neurons also known as?

Afferent Neurons Signup and view all the answers

What is a Ganglion?

A collection of neuron cell bodies in the PNS Signup and view all the answers

The axons of sensory neurons are called _________ and extend between a sensory receptor and the spinal cord or brain.

Afferent fibers Signup and view all the answers

What do Somatic Sensory Neurons do?

Receive information about the outside world via receptors in the skin, skeletal muscle, and joints Signup and view all the answers

What do Visceral Sensory Neurons monitor?

Internal conditions within organs Signup and view all the answers

What are Interoceptors?

Receptors that monitor internal systems and provide sensations of distension and pain Signup and view all the answers

What do Exteroceptors provide?

Information about the external environment Signup and view all the answers

What are Proprioceptors?

Sensory receptors that provide information about body position and movement Signup and view all the answers

What do Motor Neurons do?

Carry impulses from the brain and spinal cord to muscles and glands Signup and view all the answers

What are Efferent Fibers?

Axons traveling away from the CNS Signup and view all the answers

___________ innervate skeletal muscle to produce conscious, voluntary movements.

Somatic Motor Neurons Signup and view all the answers

What do Visceral Motor Neurons innervate?

Peripheral effectors other than skeletal muscles Signup and view all the answers

Where are Interneurons located?

Between sensory and motor neurons Signup and view all the answers

Study Notes

Neurons and Their Structures

Neural cell body (soma) houses a prominent nucleus and nucleolus.
Perikaryon refers to the cytoplasm surrounding the nucleus in a neuron.
Neurofilaments are intermediate filaments that make up the neuron cytoskeleton.
Neurotubules are similar to microtubules and are present in the perikaryon.
Neurofibrils consist of bundles of neurofilaments that support dendrites and axons.

Types of Neuron Extensions

Dendrites are branch-like structures responsible for receiving information.
Axons are threadlike extensions that transmit nerve impulses away from the soma.
Axoplasm is the cytoplasm within an axon, while the axolemma is its specialized plasma membrane.
The initial segment is the base of the axon, and the axon hillock is the cone-shaped area where the axon connects to the cell body.

Axon Termination and Communication

Collaterals are branches that may emerge along an axon.
Telodendria are terminal branches at the axon's end, leading to axon terminals.
Axon terminals house synaptic vesicles that contain neurotransmitters, facilitating communication across synapses.

Synapses and Neurotransmitters

Synapse is a specialized junction where a neuron communicates with another cell.
Neurotransmitters are chemical messengers that cross the synaptic gap and influence either the sending or receiving neuron.
Neuromuscular junction is where a motor neuron meets a skeletal muscle cell, while neuroglandular junction refers to a synapse between a neuron and a gland.

Membrane Structures

Presynaptic membrane is the site of neurotransmitter release, while the postsynaptic membrane is part of the receiving cell's plasma membrane involved in the synapse.

Axoplasmic Transport

Axoplasmic transport refers to the movement of materials between the neuron cell body and synaptic terminals, functioning bidirectionally.

Types of Neurons

Anaxonic neurons lack axons but have multiple dendrites, primarily communicating through dendrites.
Bipolar neurons consist of one axon and one dendrite, with the cell body situated between them; they are rare and found in special senses.
Unipolar neurons have a continuous dendrite and axon structure, with the cell body situated off to one side.
Multipolar neurons have one axon and multiple dendrites; they are the most common neurons in the CNS, including motor neurons for skeletal muscle.

Sensory Neurons and Functions

Sensory (afferent) neurons transmit information from sensory receptors to the CNS.
Ganglia are collections of neuron cell bodies located in the PNS.
Afferent fibers are axons of sensory neurons leading to the CNS.

Types of Sensory Neurons

Somatic sensory neurons monitor the external environment via sensory receptors in the skin and muscles.
Visceral sensory neurons observe internal conditions within organs.
Interoceptors detect sensations such as distension and pain from the internal systems.
Exteroceptors provide information on external stimuli like touch and pressure.
Proprioceptors are sensory receptors in muscles and joints that inform on body position and movement.

Motor Neurons and Their Pathways

Motor (efferent) neurons carry impulses from the brain and spinal cord to muscles and glands, forming the efferent division of the PNS.
Efferent fibers are those axons that travel away from the CNS.
Somatic motor neurons stimulate voluntary movements in skeletal muscles.
Visceral motor neurons innervate smooth muscle, cardiac muscle, glands, and adipose tissue throughout the body.

Interneurons

Interneurons act as connectors between sensory and motor neurons, facilitating communication within the CNS.

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Description

These flashcards cover essential terminology related to neurons, including key components such as the neural cell body and various cytoskeletal elements. Each card provides definitions that are crucial for understanding neuronal structure and function. Perfect for students looking to reinforce their knowledge of neurobiology.