Nervous system 2 Flashcards
What is the myelin-providing glial cells in the CNS?
Oligodendrocytes
What is the myelin-providing glial cells in the PNS?
Schwann cells
What are the collections of cell bodies in the CNS called?
Nuclei (singular nucleus)
What are the collections of cell bodies in the PNS called?
ganglia (singular ganglion)
what are the bundles of axons in the CNS called?
Tracts
what are the bundles of axons in the PNS called?
nerves
what are axons?
long, slender projections of neurons that transmit electrical signals
what are axons responsible for in the PNS?
connecting the CNS to muscles, glands and sensory organs
What do axons in the periphery cluster together to form?
Nerves, which are collections of thousands of individual axons within a common external connective tissue sheath called the epineurium.
What connective tissue sheath surrounds an entire nerve?
The epineurium.
How are axons within a nerve organized?
They are sub-grouped into fascicles.
What connective tissue sheath surrounds each fascicle within a nerve?
The perineurial sheath.
what is the simple pathway of nerves?
sensory neuron (afferent) -> interneuron -> motor neuron (efferent)
What are the two types of peripheral nerve axons based on their function?
Efferent (motor) axons, which carry signals from the CNS, and afferent (sensory) axons, which carry signals to the CNS.
What is the function of efferent axons in the peripheral nervous system?
To carry motor signals from the CNS to the periphery.
What is the function of afferent axons in the peripheral nervous system?
To carry sensory signals from the periphery to the CNS.
How are efferent and afferent axons connected to the CNS?
Through separate spinal roots.
What are the two main types of nerves involved?
Spinal nerves and cranial nerves.
What is the relationship between sensory neurons, interneurons, and motor neurons in this diagram?
Sensory neurons transmit signals from receptor endings to the CNS, interneurons process these signals within the CNS, and motor neurons carry the response signals from the CNS to the muscles or glands.
Through which root do sensory axons enter the CNS?
The dorsal (posterior) root.
How do efferent (motor) and afferent (sensory) axons segregate before entering the CNS?
Sensory axons join the CNS via the dorsal (posterior) root, while motor axons join via the ventral (anterior) root.
Through which root do motor axons connect to the CNS?
The ventral (anterior) root.
where do cell bodies reside in a spinal segment?
dorsal root ganglion (DRG)
What structures of the CNS do the dorsal and ventral roots connect to?
The spinal cord or brainstem.