Questions and Answers
What does PNS stand for?
What are the components of the PNS?
Nerves, ganglia, enteric plexuses, and sensory receptors.
What are ganglia?
Small masses of nervous tissue, primarily consisting of neuron cell bodies, located outside of the brain and spinal cord.
What are enteric plexuses?
Signup and view all the answers
What does SNS consist of?
Signup and view all the answers
What does ANS consist of?
Signup and view all the answers
What are the two divisions of the motor part of the ANS?
Signup and view all the answers
Neurons undergo mitotic division.
Signup and view all the answers
What is the difference between neuroglia and neurons?
Signup and view all the answers
What does the neuron cell body contain?
Signup and view all the answers
What are Nissl bodies?
Signup and view all the answers
What is the function of newly synthesized proteins produced by Nissl bodies?
Signup and view all the answers
What does the cytoskeleton include?
Signup and view all the answers
What is lipofuscin?
Signup and view all the answers
What is the general term for any neuronal process that emerges from the cell body?
Signup and view all the answers
What is the axon hillock?
Signup and view all the answers
What is the initial segment of the axon?
Signup and view all the answers
What is the trigger zone?
Signup and view all the answers
What does the axon contain?
Signup and view all the answers
What does the dendrite cytoplasm contain?
Signup and view all the answers
What is axoplasm?
Signup and view all the answers
What is the axolemma?
Signup and view all the answers
What are axon collaterals?
Signup and view all the answers
What are synaptic end bulbs?
Signup and view all the answers
What are varicosities?
Signup and view all the answers
What stores neurotransmitters?
Signup and view all the answers
What is slow axonal transport?
Signup and view all the answers
What is fast axonal transport?
Signup and view all the answers
What is anterograde transport?
Signup and view all the answers
What is retrograde transport?
Signup and view all the answers
What are multipolar neurons?
Signup and view all the answers
What are bipolar neurons?
Signup and view all the answers
What are unipolar neurons?
Signup and view all the answers
Where is the trigger zone for nerve impulses in a unipolar neuron?
Signup and view all the answers
What are Purkinje cells?
Signup and view all the answers
What are pyramidal cells?
Signup and view all the answers
What are the functional classifications of neurons?
Signup and view all the answers
What are gliomas?
Signup and view all the answers
What neuroglia are found in the CNS?
Signup and view all the answers
What neuroglia are found in the PNS?
Signup and view all the answers
What are the functions of astrocytes?
Signup and view all the answers
What are protoplasmic astrocytes?
Signup and view all the answers
What are fibrous astrocytes?
Signup and view all the answers
What do the processes of astrocytes contact?
Signup and view all the answers
What is the role of oligodendrocytes?
Signup and view all the answers
What do microglial cells function as?
Signup and view all the answers
Where are ependymal cells located?
Signup and view all the answers
What do ependymal cells produce?
Signup and view all the answers
What are Schwann cells responsible for?
Signup and view all the answers
What does each Schwann cell myelinate?
Signup and view all the answers
What are satellite cells?
Signup and view all the answers
What two types of neuroglia produce myelin sheaths?
Signup and view all the answers
What is neurolemma?
Signup and view all the answers
How does the neurolemma aid regeneration when an axon is injured?
Signup and view all the answers
What are nodes of Ranvier?
Signup and view all the answers
What is a tract?
Signup and view all the answers
What is white matter composed of?
Signup and view all the answers
What does grey matter contain?
Signup and view all the answers
Study Notes
Peripheral Nervous System (PNS)
- PNS includes all nervous tissue outside the central nervous system (CNS).
- It is categorized into three divisions: Somatic Nervous System (SNS), Autonomic Nervous System (ANS), and Enteric Nervous System (ENS).
Components of the PNS
- Major components are nerves, ganglia, enteric plexuses, and sensory receptors.
Ganglia
- Small clusters of neuron cell bodies situated outside the brain and spinal cord.
Enteric Plexuses
- Networks of neurons located within the gastrointestinal tract, aiding in digestive regulation.
Somatic Nervous System (SNS)
- Composed of sensory neurons that transmit information from somatic receptors to the CNS and motor neurons that direct voluntary movement to skeletal muscles.
Autonomic Nervous System (ANS)
- Contains sensory neurons that relay information from autonomic sensory receptors; motor neurons control involuntary actions in smooth muscle, cardiac muscle, and glands.
Sensory Neurons of the ENS
- Monitor chemical changes and stretching in the GI tract, regulating contractions and secretions for digestion.
Neuroglia vs. Neurons
- Neuroglia are smaller but significantly outnumber neurons, providing support and protection. Unlike neurons, they can divide throughout life.
Neuron Structure
- Neuron cell bodies house a nucleus, cytoplasm, and organelles like lysosomes and mitochondria.
- Nissl bodies are clusters of ribosomes and rough endoplasmic reticulum in the cell bodies, involved in protein synthesis.
Neuron Processes
- Axon hillock is where the axon joins the cell body, serving as a critical site for impulse generation.
- Axons can have collaterals, which are side branches, and they terminate in synaptic end bulbs or varicosities that store neurotransmitters.
Axonal Transport
- Slow axonal transport moves materials from the cell body towards axon terminals at a rate of 1-5 mm/day.
- Fast axonal transport can move materials at speeds of 200-400 mm/day and occurs in both anterograde (cell body to axon terminal) and retrograde (axon terminal to cell body) directions.
Neuron Types
- Multipolar neurons possess multiple dendrites and an axon, mostly found in the CNS.
- Bipolar neurons have one axon and one main dendrite, located in sensory structures such as the retina.
- Unipolar neurons have fused dendrites and an axon; their trigger zone is where dendrites meet the axon.
Glial Cells
- Gliomas are tumors originating from glial cells.
- CNS glial cells include astrocytes, oligodendrocytes, microglia, and ependymal cells.
- PNS glial cells consist of Schwann and satellite cells.
Astrocytes
- Largest glial cells with star-like shapes, they create a blood-brain barrier to protect neurons and maintain the chemical environment.
Oligodendrocytes
- Form and maintain the myelin sheath around CNS axons; crucial for insulating and speeding up neural impulses.
Microglial Cells
- Act as immune defense in the CNS, removing debris and responding to injury.
Ependymal Cells
- Line the brain's ventricles and the central canal of the spinal cord, involved in cerebrospinal fluid production and circulation.
Schwann Cells
- Form myelin sheaths around PNS axons and facilitate regeneration after nerve injury.
Nodes of Ranvier
- Gaps in the myelin sheath crucial for the rapid conduction of nerve impulses.
CNS vs. PNS Structure
- White matter is primarily composed of myelinated axons, while gray matter consists of neuronal cell bodies and unmyelinated axons, giving it a grayish appearance due to the presence of Nissl bodies.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Explore the key components and functions of the Peripheral Nervous System (PNS). This quiz covers the divisions of the PNS, including the Somatic, Autonomic, and Enteric Nervous Systems, as well as the roles of various components like ganglia and sensory receptors.