Nervous System Introduction

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Questions and Answers

Where is the olfactory epithelium located?

Spinal cord

Cranial nerves

Nasal cavity (correct)

Hippocampus

Which part of the nervous system includes the brain and spinal cord?

Central Nervous System (CNS) (correct)

Somatic Nervous System (SNS)

Autonomic Nervous System (ANS)

Peripheral Nervous System (PNS)

What is the main function of neurons?

To store nutrients

To release hormones

To respond to physical and chemical stimuli (correct)

To divide by mitosis

What is the function of the dendrites in a neuron?

To receive information Signup and view all the answers

What is the cell body of a neuron responsible for?

Receiving and integrating information Signup and view all the answers

Where are cell bodies of neurons located in the PNS?

In ganglia Signup and view all the answers

What is the function of the axon in a neuron?

To transmit nerve impulses Signup and view all the answers

What is a neuron unable to do?

Divide by mitosis Signup and view all the answers

What is the typical direction of electrical impulses conducted by an axon?

Away from the cell body Signup and view all the answers

What is the name of the projection of a nerve cell that conducts electrical impulses?

Axon Signup and view all the answers

How many axons do most neurons have?

Only one axon Signup and view all the answers

What is the function of the axon?

To transmit electrical impulses Signup and view all the answers

What are the structures at the end of an axon?

Telodendria Signup and view all the answers

What is the process of transporting proteins and other molecules to nerve endings?

Axoplasmic flow Signup and view all the answers

What is the direction of axonal transport?

Either orthograde or retrograde Signup and view all the answers

What is a bundle of axons located outside the CNS?

Nerve Signup and view all the answers

What is the primary function of Nerve Growth Factor?

To regulate the growth, maintenance, and survival of target neurons Signup and view all the answers

What is the role of neurotrophin-3 in fetal development?

It facilitates the embryonic development of sensory neurons and sympathetic ganglia Signup and view all the answers

What is the function of Glial-Derived Neurotrophic Factors (GDNF)?

To maintain spinal neurons and sustain neurons that use dopamine Signup and view all the answers

What are the two types of supporting cells in the Peripheral Nervous System (PNS)?

Schwann cells and neurolemmocytes Signup and view all the answers

What is the role of Nerve Growth Factor (NGF) in adults?

It maintains sympathetic ganglia Signup and view all the answers

What do neurotrophins promote?

The growth of neurons Signup and view all the answers

What is the function of myelin-associated inhibitory proteins?

They inhibit axon regeneration Signup and view all the answers

What is the role of neurotrophins in the development of the nervous system?

They facilitate the growth and maintenance of neurons Signup and view all the answers

What is the primary function of interneurons?

To integrate groups of afferent and efferent neurons into reflex circuits Signup and view all the answers

Where are interneurons located in the body?

In the central nervous system Signup and view all the answers

What percentage of all neurons are interneurons?

99% Signup and view all the answers

What determines the number of interneurons involved in a reflex action?

The complexity of the action Signup and view all the answers

Which of the following reflexes does not involve interneurons?

Knee-jerk reflex Signup and view all the answers

What is an example of a complex action that may involve millions of interneurons?

Stimuli invoking memory or language Signup and view all the answers

What role can interneurons serve as in neural circuits?

Only as signal changers or gatekeepers Signup and view all the answers

What is an example of an interneuron's function as a signal changer?

Converting an excitatory input into an inhibitory output Signup and view all the answers

What is the primary function of unipolar neurons?

To transmit impulses for pain, touch, temperature, taste, proprioception, and visceral organ activity Signup and view all the answers

What is unique about the dendritic branching of bipolar neurons?

It is typically limited Signup and view all the answers

Which type of neuron is specialized for transmitting impulses related to smell?

Bipolar neuron Signup and view all the answers

What is the main function of glial cells?

To support and protect neurons Signup and view all the answers

Where are bipolar neurons mainly found?

In the retina of the eye, roof of the nasal cavity, and inner ear Signup and view all the answers

What type of senses do bipolar neurons transmit impulses for?

Special senses like smell, sight, taste, hearing, and vestibular functions Signup and view all the answers

How many processes do bipolar neurons have extending from the cell body?

Two Signup and view all the answers

What is the characteristic of the axons of bipolar neurons?

They are short in length Signup and view all the answers

Study Notes

Olfactory Epithelium

Located in the nasal cavity, containing olfactory receptor cells with specialized cilia extensions
Except in the hippocampus, where the olfactory epithelium is not found

Introduction to Nervous System

Divided into Central Nervous System (CNS) and Peripheral Nervous System (PNS)
CNS consists of brain and spinal cord
PNS consists of cranial nerves and spinal nerves

Neurons

Basic structural and functional units of the nervous system
Cannot divide by mitosis
Functions: respond to physical and chemical stimuli, produce and conduct electrochemical impulses, and release chemical regulators

Neuron Structure

Cell body (perikaryon, soma): receives information, integrates, and transmits nerve impulses
Components: plasma membrane, cytoplasm, and neurotrophic factors (e.g., nerve growth factor)
Located in CNS (clustered into nuclei) and PNS (in ganglia)

Neuron Growth Factor

Neurotrophic factor (neuropeptide) involved in growth, maintenance, and proliferation of target neurons
Functions: promote neuron growth, survival, and differentiation

Neurotrophins

Include nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and glial-derived neurotrophic factor (GDNF)
Functions: promote neuron growth, survival, and differentiation during fetal development and in adult maintenance

Glial Cells

Supporting cells in the PNS, including Schwann cells (neurolemmocytes) and axon
Functions: provide nutrients, remove waste, and provide structural support to neurons

Axon

Long, slender projection of a neuron that conducts electrical impulses away from the cell body
Structures: collaterals, telodendria (axon terminals), and synaptic knobs (terminal boutons)
Functions: transmits nerve impulse away from the cell body toward other neurons, muscles, and glands

Functional Classification of Neurons

Interneurons/association neurons: integrate and signal change, lie entirely within the CNS, and account for 99% of all neurons
Unipolar neurons: transmit impulses for pain, touch, temperature, taste, proprioception, and visceral organ activity
Bipolar neurons: specialized sensory neurons for transmission of special senses, found in retina, nasal cavity, and inner ear

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Description

This quiz covers the basics of the nervous system, including the olfactory epithelium and its location in the nasal cavity. It also touches on the physiology of the nervous system.