Chapter 12-Part 1 Flashcards
(18 cards)
What are the general functions of the nervous system?
- Collect information
- Process and evaluate information
- Initiate response to information
These functions are essential for the nervous system to control various body systems effectively.
What are the two primary divisions of the nervous system?
- Structural
- Functional
The structural division includes the central and peripheral nervous systems, while the functional division includes sensory and motor systems.
What does the sensory nervous system do?
Receives sensory information from receptors and transmits it to CNS
It is also known as the afferent nervous system.
What is the difference between the somatic sensory system and the visceral sensory system?
- Somatic sensory system: detects stimuli we consciously perceive
- Visceral sensory system: detects stimuli we typically do not perceive
Examples of visceral sensory stimuli include signals from the heart and kidneys.
What is the function of the motor nervous system?
Initiates motor output and transmits it from CNS to effectors
It is also referred to as the efferent nervous system.
What are the two types of motor systems?
- Somatic motor system: sends voluntary signals to skeletal muscles
- Autonomic motor system: sends involuntary commands to heart, smooth muscle, and glands
The autonomic motor system has sympathetic and parasympathetic divisions.
What is a nerve?
A bundle of parallel axons in the PNS
Nerves are surrounded by connective tissue wrappings.
What are the three connective tissue wrappings in a nerve?
- Epineurium: encloses entire nerve
- Perineurium: wraps fascicles (bundles of axons)
- Endoneurium: wraps an individual axon
These wrappings provide structural support and protection to the nerve fibers.
What is a ganglion?
A cluster of neuron cell bodies in the PNS
Ganglia serve as relay points for transmitting signals in the nervous system.
What are the general characteristics of neurons?
- Excitability: responsiveness to a stimulus
- Conductivity: ability to propagate electrical signal
- Secretion: release of neurotransmitter in response to conductive activity
- Extreme longevity
- Amitotic: most neurons lose mitotic activity after fetal development
These characteristics are crucial for neuron function and communication.
What are the main parts of a neuron?
- Cell body (soma)
- Dendrites
- Axon
Each part plays a specific role in the neuron’s function and communication.
What is the role of dendrites in a neuron?
Receive input and transfer it to the cell body
Dendrites are short, unmyelinated processes that branch off the cell body.
What is the axon hillock?
The region where the axon attaches to the cell body
It is a triangular region that plays a crucial role in the initiation of action potentials.
What are synaptic knobs?
Tips of telodendria that house synaptic vesicles containing neurotransmitter
They are critical for neurotransmitter release at synapses.
What are the two types of axonal transport?
- Anterograde transport: moves material from cell body to synaptic knobs
- Retrograde transport: moves used materials from axon to cell body
These transport mechanisms are essential for maintaining neuron function.
What are the types of neurons based on structural classification?
- Multipolar neurons: many dendrites, one axon
- Bipolar neurons: one dendrite and one axon
- Unipolar neurons (pseudounipolar): one process extends from cell body, splits into two processes
- Anaxonic neurons: have dendrites but no axons
Multipolar neurons are the most common type.
What is the functional classification of neurons?
- Sensory neurons (afferent): conduct input to CNS
- Motor neurons (efferent): conduct output from CNS
- Interneurons: receive, process, and integrate information
Interneurons make up about 99% of our neurons.
True or False: Most sensory neurons are unipolar.
True
A few sensory neurons are bipolar, but the majority are unipolar.
