Tutorial 8 - Spinal Cord & Nerves Flashcards
What are the two anatomical divisions of the nervous system?
Central Nervous System
Peripheral Nervous System
What are the four structural components of a neuron?
- Dendrite
- Soma
- Axon
- Axon terminal
What does it mean to be myelinated?
Surrounded by fats (faster)
What does it mean to be non-myelinated?
No myelin sheaths (slower)
What are the four types of CNS neuroglia?
- Astrocytes
- Ependymal cells
- Oligodendrocytes
- Microglia
What are the two types of PNS neuroglia?
- Schwann cells
- Satellite cells
What are astrocytes?
Neuroglia in the CNS that support neurons and connect them to capillaries
- most abundant in the CNS
What are ependymal cells?
Cells that line cavities and ventricles and produce CSF in the CNS
What are oligodendrocytes?
Create myelin sheaths in the CNS (increases conduction velocity)
What are microglia?
Involved in immune system support
What are schwann cells?
PNS neuroglia that insulates and produces myelin sheaths (nodes of ranvier = gaps)
What are satellite cells?
cells that support neurons, maintain homeostasis, and regulate exchanges
Describe the structure of the spinal cord
- formed by bundles of neurons and neuroglia
- protected by meninges and enclosed in vertebral column
- transmits signals between the brain and the rest of the body
- controls reflexes
What are spinal nerves?
Nerves that transfer signals between the body and spinal cord
- connected to the spinal cord via the dorsal and ventral root
What is the dorsal root?
Carries sensory signals (has ganglion)
What is the ventral root?
Relays motor signals
What is gray matter?
The darker, unmyelinated matter of the spinal cord
- integration and reflex processing center
- made of neuronal cell bodies, dendrites, unmyelinated axons, and neuroglia
What is the posterior horn?
Sensory relay neurons conveying touch, temperature, pain, etc.
What is the anterior horn?
Somatic motor neuron cell bodies that facilitate skeletal muscle movement
What is the lateral horn?
Present in thoracic and superior lumbar spinal cord segments and contain autonomic motor cell bodies that innervate visceral organs
What is white matter?
Myelinated matter in the spinal cord (can be unmyelinated as well)
- forms columns that pass information up and down the spinal cord
- travels in ascending and descending tracts
What is the ascending column?
Sensory signals up to the brain
What is the descending column?
Motor signals down spinal cord to periphery
What are sensory signals?
Passed into spinal cord through dorsal root of each spinal nerve
What are dorsal root ganglion?
Bundles of cell bodies of spinal nerves
What are motor commands?
Passed from spinal cord through ventral root of each spinal nerve and out to the body to trigger an action
- action is either skeletal muscle contraction or gland secretion
What is a plexus?
Networks of spinal nerves that innervate a specific region
What is dermatome?
Region of skin innervated by the sensory fibers from a single spinal nerve
What is the one dermatome exception?
C1
All spinal nerves innervate dermatomes except C1
- C1 does not contain any sensory axons
- sensory skin info from the skin in racial region is conveyed by cranial nerve V (the trigeminal nerve)
What are cranial nerves?
Nerves that do not intersect with spinal cord but connect muscles and organs of the head and body directly to the brain