30 Questions
What is the main function of dendrites in a neuron?
Communication with other neurons
Which type of glial cell supports and protects neurons in the mammalian brain?
Astrocytes
What is the function of Schwann cells in the peripheral nervous system (PNS)?
Insulation of axons
What is the main function of satellite cells in the PNS?
Support and protection of neurons
What is the purpose of myelin sheath in the PNS?
Insulation of axons
Which type of fibers in the PNS are covered by a multilayered myelin sheath produced by Schwann cells?
Myelinated fibers
Which cells outnumber neurons by ten times in the mammalian brain?
Astrocytes
What covers the nerve fibers individually and connects them within the PNS?
Endoneurium
What is the composition of nerve endings in the PNS?
Bundles of nerve fibers individually surrounded by Schwann cells and connective tissue
What is the main function of peripheral nerves in the body?
Communication between CNS and sense organs and effectors
Which of the following is NOT a part of the Central Nervous System (CNS)?
Dorsal root (spinal or sensory) ganglia
Which type of ganglia is NOT part of the Peripheral Nervous System (PNS)?
Cranial nerves (those emerge from brain)
What is the main function of the Peripheral Nervous System (PNS)?
Receives stimuli
What is the function of synaptic boutons?
Conducts impulses away
What type of cells exhibit mitotic activity in nerve tissue?
Neuroglia cells
What is the purpose of the blood brain barrier?
Forms a wall that separates nerve cells from connective tissue
What differentiates nerve cells from connective tissue?
Blood brain barrier
Which part of the nervous tissue contains very few connective tissues?
Nerve cells (neurons)
What is the main function of dendrites in a neuron?
Receives stimuli
Which type of ganglion serves as a relay station to transmit nerve impulses?
Autonomic ganglia
Which component of the nervous system forms a network of many billion nerve cells(neurons)?
Central Nervous System (CNS)
What type of neurons receive afferent impulses that go to the Central Nervous System?
Pseudounipolar neurons
Which part of the autonomic nervous system is responsible for the fight-or-flight response?
Sympathetic division
Where are the nerve cell bodies of parasympathetic nerves located?
In small ganglia within the innervated organ
What do Meissner's plexus and Auerbach's plexus provide innervation to?
Smooth muscle cells
Which sensory receptors respond to mechanical pressure or distortion?
Pacinian corpuscles
Where are Pacinian corpuscles found?
Glabrous and hairy skin, as well as in the subcutaneous tissue
What are satellite cells in ganglia?
Glial cells arranged around the cell bodies of neurons
What is the role of autonomic nerves in the body?
Effect the activity of smooth muscle, the secretion of some glands, and heart rate
What do afferent fibers carry?
Information from internal body regions and environment to the CNS
Study Notes
- The cell body (perykarion) of a neuron contains a large, euchromatic nucleus with a prominent nucleolus and perinuclear cytoplasm rich in rough endoplasmic reticulum and free ribosomes.
- Dendrites are projection from the cell body that branch many times and provide locations for other neurons to communicate with the cell body. Dendrites receive information from other neurons at synapses.
- The axon is a single, long process that arises from the cell body, much thinner than the dendrites, and its diameter is related to conduction velocity. It is covered by myelin sheath in the Peripheral Nervous System (PNS) and Schwann cells.
- Glial cells support and protect neurons, outnumbering them by ten times in the mammalian brain. There are six major types of glial cells: astrocytes, oligodendrocytes, microglia, ependymal cells, Schwann cells, and satellite cells.
- In the Peripheral Nervous System (PNS), Schwann cells envelop nerve fibers, and they produce a myelin sheath that insulates the axon, allowing for faster action potential propagation and facilitating regeneration of damaged fibers.
- Satellite cells are cuboidal or squamous glial cells of ganglia that provide metabolic and mechanical support to the neurons.
- The peripheral nervous system (PNS) is composed of nerves, ganglia, and nerve endings, which are bundles of nerve fibers (axons) individually surrounded by Schwann cells and connective tissue.
- Myelinated fibers in the PNS are covered by a multilayered myelin sheath produced by Schwann cells, which insulates the axon and facilitates action potential propagation.
- Unmyelinated axons are surrounded by a single Schwann cell and do not form myelin sheaths and they use action potentials that do not require myelin sheath insulation.
- Axons and Schwann cells are enclosed within layers of connective tissue, with endoneurium surrounding each axon, perineurium surrounding nerve fascicles, and epineurium surrounding the entire nerve.
- Peripheral nerves provide communication between the CNS and sense organs and effectors (muscles, glands), and they generally contain both afferent (sensory) and efferent (motor) fibers.
Test your knowledge of the histology of the peripheral nervous system with this quiz. Quiz content covers the anatomical organization, ganglions, nerves, and autonomic ganglia of the peripheral nervous system.
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