Chapter 13 Questions Based on Objectives Flashcards
The first layer of protection for the central nervous system is the_________
Hard bony skull and vertebral column.
The second protective layer of the brain is the ________
meninges
What are meninges?
three distinct protective, connective tissue coverings that encircle the spinal cord and brain.
The spinal cord is also protected by a cushion of fat and connective tissue located in the _____
epidural space
What is the epidural space?
a space between the dura mater and the wall of the vertebral canal
What are the three types of Meningeal layers?
Dura Mater
Arachnoid Mater
Pia Mater
What is Dura Mater?
The most superficial of the three spinal meninges is a thick strong layer composed of dense irregular connective tissue.
What is Arachnoid Mater?
This layer, the middle of the meningeal membranes, is a thin, avascular covering comprised of cells and thin, loosely arranged collagen and elastic fibres.
What is the subdural space?
the space between the Dura mater and Arachnoid mater, which contains interstitial fluid.
What is Pia Mater?
Innermost layer of the meninx; thin transparent connective tissue that adheres to the surface of the spinal cord and brain.
What is the Subarachnoid space?
Is the space between the Arachnoid mater and Pia mater consisting of shock-absorbing cerebrospinal fluid.
Which of the three mater layers contains blood vessels that supply oxygen and nutrients to the spinal cord?
Pia Mater
In External Anatomy of the Spinal Cord What is Cervical enlargement?
Enlargements extending from the 4th cervical vertebra (C4) to the 1st thoracic vertebra (T1).
What nerves are in the Cervical Enlargement?
Nerves to and from the upper limbs are from the cervical enlargement.
In External Anatomy of the Spinal Cord, What is Lumbar enlargement?
Inferior enlargement, extends from the 9th (T9) to twelfth (12th) thoracic vertebra.
What nerves are in the Lumbar Enlargement?
Nerves to and from the lower limbs are from the lumbar enlargement
In External Anatomy of the Spinal Cord, What is Conus medullaris?
Inferior to cervical and lumbar enlargement, the spinal cord terminates as a conical structure called conus medullaris.
In External Anatomy of the Spinal Cord, What is Filum Terminal?
Extension of pia mater that extends inferiorly (down) fuses with arachnoid mater and dura mater. And anchors the spinal cord to the coccyx.
In External Anatomy of the Spinal Cord, What is Cauda equina?
The roots of nerves are collectively called Cauda equina (horse’s tail).
In Internal Anatomy of the Spinal Cord, What is Anterior median fissure?
Wide groove on the anterior side, penetrating the white matter.
In Internal Anatomy of the Spinal Cord, What is Posterior median sulcus?
Narrow furrow on the posterior side, penetrating the white matter.
In Internal Anatomy of the Spinal Cord, What is Gray commissure?
Forms the crossbar of the H (grey matter).
In Internal Anatomy of the Spinal Cord, What is the Central canal?
Small space in the center of the Gray commissure.
-Extends the length of the spinal cord filled with cerebrospinal fluid.
In Internal Anatomy of the Spinal Cord, What is
Anterior or White commissure?
Anterior to gray commissure; connects the white matter of the left and right sides of the spinal cord.
In Internal Anatomy of the Spinal Cord, What are Nuclei?
Clusters of cell bodies form functional groups.
What do Sensory nuclei do?
Receive input from sensory neurons, and motor nuclei provide output via motor neurons.
In Internal Anatomy of the Spinal Cord, What is
Posterior (dorsal) gray horns?
Contain cell bodies and axons of interneurons as well as axons of incoming sensory neurons.
In Internal Anatomy of the Spinal Cord, What is Anterior (ventral) gray horns?
Contain somatic motor nuclei which provide nerve impulses for contraction of skeletal muscles.
In Internal Anatomy of the Spinal Cord, What is Lateral gray horns?
Between posterior and anterior gray horns; present only in thoracic and upper lumbar segments.
What do Lateral gray horns contain?
autonomic motor nuclei
What do autonomic motor nuclei do?
It regulates the activity of cardiac muscles, smooth muscles, and glands.
The white matter of the spinal cord is organized into 3 regions called?
Funiculi of Columns
What are the three regions of the spinal cord’s white matter?
(1) anterior white funiculi
(2) posterior white funiculi
(3) lateral white funiculi
Each funiculus, in turn, contains distinct bundles of axons having a funiculus origin or destination and carrying similar information. What are these bundles called?
Tracts
Recall that tracts are bundles of axons in the ______, whereas nerves are bundles of axons in the ______
CNS
&
PNS
_________tracts consist of axons that conduct nerve impulses toward the brain.
Sensory (ascending)
Tracts consisting of axons that carry nerve impulses from the brain are called ____________tracts
motor (descending)
How the Spinal Nerve is connected to the Spinal Cord. Define Roots
Two bundles of axons connect each spinal nerve to a segment of the cord.
How the Spinal Nerve is connected to the Spinal Cord. Define Rootlets
are smaller bundles of axons that connects the roots to the cord.
How the Spinal Nerve is connected to the Spinal Cord. Define Posterior (dorsal) root
Contain sensory axons which conduct nerve impulses from skin, muscles, and internal organs to the CNS.
How the Spinal Nerve is connected to the Spinal Cord. Define Posterior (dorsal) root ganglion
A swelling of the posterior root containing cell bodies of sensory neurons.
How the Spinal Nerve is connected to the Spinal Cord. Define Anterior (ventral) root
Contains axons of motor neurons, conduct nerve impulses from CNS to effectors.
What are Spinal Nerves?
Parallel bundles of axons and their associated neurological cells wrapped in several layers of connective tissue.
How do spinal nerves connect to the spinal cord?
It has two connections to the cord: posterior and anterior root
The posterior and anterior roots unite to form a spinal nerve at the _____________ ______________
intervertebral foramen.
Because the posterior root contains sensory axons and the anterior root contains motor axons, a spinal nerve is classified as a ______
mixed nerve
The ______________ root contains a spinal ganglion in which cell bodies of sensory neurons are located.
Posterior
How are the spinal nerves named and numbered?
The 31 pairs of spinal nerves are named and numbered according to the region and level of the vertebral column from which they emerge.
Individual axons within a nerve, whether myelinated or unmyelinated, are wrapped in _______
endoneurium, the innermost layer
What are individual axons within a nerve wrapped in?
endoneurium
What makes up endoneurium?
A mesh of collagen fibres, fibroblasts, and macrophages.
Groups of axons with their endoneurium are held together in bundles called _______
nerve fascicles
What are nerve fascicles wrapped in?
perineurium
The perineurium is a thicker layer of what type of tissue?
Connective tissue.
The outermost covering over the entire nerve is the ________
epineurium
What makes up the epineurium?
fibroblasts and thick collagen fibers.