Chapter 8.1 CNS Flashcards
How does the CNS contribute to homeostasis?
The CNS maintains homeostasis by receiving input from sensory neurons, integrating new and old info, making decisions, and causing motor activity
What are some functions of the CNS?
Processes sensory info
Generates thought
Emotions
Memories
Stimulates muscles and glands to secrete
What are the protective coverings of the spinal cord?
The meninges and the vertebrate
Spinal Cord
A cylinder of nervous tissue that extends from the brain.
How long is the spinal cord in adults?
45cm in length and 2cm in diameter
Where is the spinal cord located?
w/in the vertebral canal of the vertebral column.
Meninges
Tough, connective tissue coverings that encircle the spinal cord and brain
What are the 3 spinal meninges?
Dura mater
arachnoid mater
pia mater
Subarachnoid space
B/w the arachnoid mater and the pia mater which contains cerebrospinal fluid
Meningitis
Bacterial or viral infection that causes inflammation of the meninges
Bacterial or viral is worse for meningitis
bacterial is worse, but there are vaccines. Viral goes away on its own in a couple of days
How are spinal nerves named?
They are named based on the region of the vertebral column from which they emerge
How many pairs of spinal nerves are there?
31
_ cervical nerves
_ thoracic nerves
_ lumbar “
_ sacral “
_ coccygeal “
8
12
5
5
1
How is a spinal nerve connected to the spinal cord?
By two bundles of axons called roots
Dorsal root
Contains only sensory axons, which conduct action potentials from sensory receptors in the skin, muscles, and organs to the CNS
What does each dorsal root have?
A swelling called the dorsal root ganglion
Dorsal Root Ganglion (DRG)
The swelling of a dorsal root that contains the primary sensory neurons that transmit pain signals from the peripheral nerve to the CNS. Contains thousands of cell bodies
Ventral root
axons of motor neurons
Which root contains sensory neurons and which contains motor neurons?
DRG contains sensory neurons
Ventral root contains motor neurons
Mixed nerve
DRG contains sensory neurons and Ventral root contains motor neurons
White matter surrounds ___
inner core of grey matter
White matter
bundles of myelinated axons of neurons
Gray matter
unmyelinated axons of neurons, neuroglia, dendrites and cell bodies of neurons
Neuroglia
supporting nerve cells
Central Canal
Space in the center of gray matter that is filled with cerebrospinal fluid and extends the length of the spinal cord
The gray matter is subdivided into ___
horns
What are the 3 horns
dorsal
ventral
lateral
Dorsal gray horn
axons of incoming sensory neurons as well as cell bodies and axons of interneurons
Ventral gray horns
cell bodies of somatic motor neurons that convey action potentials to skeletal muscles
Where are the lateral gray horns located only?
Only in thoracic and and upper lumbar segments of the spinal cord
What kind of cell bodies do the lateral gray horns hold?
LGH contain cell bodies of autonomic motor neurons that convey action potentials to cardiac muscle, smooth muscle, and glands
How is white matter subdivided?
Into 3 areas called columns
Dorsal
Ventral
Lateral
How does the spinal cord maintain homeostasis?
Two principal functions
Action potential propagation and integration of information
What are the highways of the spinal cord?
White matter
Which matter receives and integrates
incoming and outgoing information
