40 Questions
Where is the olfactory epithelium located?
Nasal cavity
Which part of the nervous system includes the brain and spinal cord?
Central Nervous System (CNS)
What is the main function of neurons?
To respond to physical and chemical stimuli
What is the function of the dendrites in a neuron?
To receive information
What is the cell body of a neuron responsible for?
Receiving and integrating information
Where are cell bodies of neurons located in the PNS?
In ganglia
What is the function of the axon in a neuron?
To transmit nerve impulses
What is a neuron unable to do?
Divide by mitosis
What is the typical direction of electrical impulses conducted by an axon?
Away from the cell body
What is the name of the projection of a nerve cell that conducts electrical impulses?
Axon
How many axons do most neurons have?
Only one axon
What is the function of the axon?
To transmit electrical impulses
What are the structures at the end of an axon?
Telodendria
What is the process of transporting proteins and other molecules to nerve endings?
Axoplasmic flow
What is the direction of axonal transport?
Either orthograde or retrograde
What is a bundle of axons located outside the CNS?
Nerve
What is the primary function of Nerve Growth Factor?
To regulate the growth, maintenance, and survival of target neurons
What is the role of neurotrophin-3 in fetal development?
It facilitates the embryonic development of sensory neurons and sympathetic ganglia
What is the function of Glial-Derived Neurotrophic Factors (GDNF)?
To maintain spinal neurons and sustain neurons that use dopamine
What are the two types of supporting cells in the Peripheral Nervous System (PNS)?
Schwann cells and neurolemmocytes
What is the role of Nerve Growth Factor (NGF) in adults?
It maintains sympathetic ganglia
What do neurotrophins promote?
The growth of neurons
What is the function of myelin-associated inhibitory proteins?
They inhibit axon regeneration
What is the role of neurotrophins in the development of the nervous system?
They facilitate the growth and maintenance of neurons
What is the primary function of interneurons?
To integrate groups of afferent and efferent neurons into reflex circuits
Where are interneurons located in the body?
In the central nervous system
What percentage of all neurons are interneurons?
99%
What determines the number of interneurons involved in a reflex action?
The complexity of the action
Which of the following reflexes does not involve interneurons?
Knee-jerk reflex
What is an example of a complex action that may involve millions of interneurons?
Stimuli invoking memory or language
What role can interneurons serve as in neural circuits?
Only as signal changers or gatekeepers
What is an example of an interneuron's function as a signal changer?
Converting an excitatory input into an inhibitory output
What is the primary function of unipolar neurons?
To transmit impulses for pain, touch, temperature, taste, proprioception, and visceral organ activity
What is unique about the dendritic branching of bipolar neurons?
It is typically limited
Which type of neuron is specialized for transmitting impulses related to smell?
Bipolar neuron
What is the main function of glial cells?
To support and protect neurons
Where are bipolar neurons mainly found?
In the retina of the eye, roof of the nasal cavity, and inner ear
What type of senses do bipolar neurons transmit impulses for?
Special senses like smell, sight, taste, hearing, and vestibular functions
How many processes do bipolar neurons have extending from the cell body?
Two
What is the characteristic of the axons of bipolar neurons?
They are short in length
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
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.
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