EXSC 2150 Human Anatomy Ch 15&16
gray matter
-houses motor neuron and interneuron cell bodies, dendrites, terminal arborizations, unmyelinated axons -forms cerebral cortex, which covers surface of most of adult brain -cerebral nuclei
longitudinal fasciculi
-longer -connect gyri in different lobes of the same hemisphere
spinal nerves
-made up of motor and sensory axons -thousands of axons wrapped together -extend from spinal cord to effector organs (motor) and from sensory receptors to spinal cord (sensory)
white matter
-made up of myelinated axons -deep to the gray matter of the cortex
Blood Brain Barrier (BBB)
-nervous tissue protected from general circulation -BBB regulates what substances can enter interstitial fluid of brain -maintains consistent, protected environment for sensitive nervous tissue
The _____ protects nervous tissue from chemical fluctuations that would disrupt neuron function.
CSF
______ acts as cushioning fluid that floats the brain.
CSF
______ is continuously removed from the subarachnoid space so that it will not accumulate.
CSF
functions of hypothalamus
Master control of the autonomic nervous system Master control of the endocrine system Regulation of body temperature Control of emotional behavior Control of food intake Control of water intake Regulation of sleep-wake (circadian) rhythms
The spinal cord extends inferiorly from the brain through the ______ and then through the vertebral canal and ends at the level of the ____ vertebra.
foramen magnum; L1
The _______ matter houses cell bodies, dendrites and unmyelinated axons.
gray
______ matter lies on the surface of the brain and in internal clusters.
gray
cerebral cortex is
gray matter
In the cerebrum, the outer layer is made of ______ matter and the inner layer is made mostly of ______ matter.
gray; white
elevated fold
gyrus
The cerebellum is composed of left and right cerebellar ______.
hemispheres
The _____ is in the anterior and inferior region of the diencephalon.
hypothalamus
anterior ramus
innervates the anterior and lateral skin and muscles of the trunk and gives rise to nerves of the limbs
posterior ramus
innervates the deep muscles and skin of the back
association areas
integrate and interpret/store information
The left and right sides of the thalamus are connected by which structures?
inter thalamic adhesion & intermediate mass
sensory nuclei in posterior horns contain
interneuron cell bodies of somatic sensory nuclei and visceral sensory nuclei
Each anterior root and its corresponding posterior root unite within the _______ to become a spinal nerve.
intervertebral foramen
The autonomic motor nuclei in the _______ horns innervate smooth muscle, cardiac muscle, and glands.`
lateral
autonomic motor nuclei are in the
lateral horns
hemispheres are divided by
longitudinal fissure
visual and auditory reflex centers
midbrain
anterior roots contain ____ axons ONLY
motor
A spinal nerve contains ______ axons.
motor and sensory
three categories of functional areas
motor areas, sensory areas, association areas
The central white matter lies deep to cerebral cortex and is composed of _____.
myelinated axons
nerve plexus
network of interweaving anterior rami of spinal nerves
Ventricles of the brain are cavities that are derived from the lumen of the embryonic ______.
neural tube
within the gray matter are functional groups of neuron cell bodies called
nuclei
CSF transports ______ and chemicals to the brain.
nutrients
The cranial nerves found in the midbrain are ______.
oculomotor (CN III) & trochlear (CN IV)
pons
peduncles - transverse fibers - connect pons to cerebellum -nuclei of 3 cranial nerves
Deep to the subarachnoid space, is a delicate, innermost meningeal layer composed of elastic and collagen fibers. This layer is known as the ______.
pia mater
The ______ is a bulging region on the anterior side of the brainstem.
pons
Additional rami, called the ______, are also associated with spinal nerves.
rami communicates
tight junctions further
reduce endothelial cell permeability
A phenomenon in which pain or discomfort from one organ is mistakenly referred to a dermatome is called ______.
referred visceral pain
The spinal cord and spinal nerves are responsible for ______, which are our quickest reactions to a stimulus.
reflexes
cardiac center
regulates heart rate & strength of contraction
medullary respiratory center
regulates respiratory rate
dermatome
segment of skin supplied by a single spinal nerve
The cell bodies of ______ neurons are found in the posterior horns of the spinal cord.
sensory
posterior roots contain _____ axons ONLY
sensory
The spinal cord and its attached spinal nerves are a pathway for ______ impulses.
sensory and motor
anterior funiculus
sensory and motor tracts
lateral funiculus
sensory and motor tracts
posterior funiculus
sensory tracts
The axons of ______ neurons and the cell bodies of ______ are located in the posterior horns.
sensory; interneurons
arcuate fibers
short - connect neighboring gyro within a lobe
epidural space
sits between dura and periosteum of vertebra
The cerebellum coordinates and "fine-tunes" ______.
skeletal muscle movements
A dermatome is a specific segment of ______ supplied by a single spinal nerve.
skin
lateral horns
somas of autonomic motor neurons
anterior horns
somas of somatic motor neurons
motor nuclei in the anterior horns contain
somatic motor nuclei
The thalamus will process incoming information and project it to the ______.
somatosensory cortex
CSF from the choroid plexus eventually leaves the ventricles and enters the ______ space.
subarachnoid
Deep to the arachnoid mater is the ______ space, which is a real space filled with ______ fluid.
subarachnoid; cerebrospinal
A narrow space separates the dura mater from the arachnoid mater. This space is called the _____ space.
subdural
shallow groove
sulcus
The _____ lets the cerebrum know where the sensory information came from such as when a nerve impulse comes from the eye.
thalamus
The ______ refers to paired oval masses that lie on each side of the third ventricle between the anterior commissure and the pineal gland.
thalamus
diencephalon
thalamus and hypothalamus -provides relay & switching center for some sensory & motor pathways & control of visceral activites
multiple anterior rootlets arise from
the spinal cord and merge to form a single anterior root
The cerebral nuclei are also called the basal nuclei and sometimes are incorrectly called the basal ganglia. Why is this incorrect?
the term ganglia refers to clusters of cell bodies in the PNS
hypothalamus
thin, stalk like infundibulum extends inferiorly from hypothalamus to attach to pituitary gland
Most of the central white matter is grouped into bundles called _____.
tracts
The axons within each white matter funiculus are organized into smaller structural units called ______.
tracts
environmental stability
transports nutrients & chemicals & removes waste from brain; protects from chemical fluctuations that would disrupt function
True or false: The ventricles of the brain are continuous with one another as well as with the central canal of the spinal cord.
true
gray commissure
unmyelinated axons for communication between right & left side -houses narrow central canal
The gray commissure primarily contains ______ axons and serves as a communication route between the right and left sides of the ______ matter.
unmyelinated; gray
Along the midline, between the cerebellar hemispheres is a narrow band of cortex known as the
vermis
Longitudinal fasciculi are parts of ______ tracts.
association
The type of tract that connects the primary motor cortex to the premotor area is a(n) _______ tract.
association
The rami communicantes contain axons associated with the ______ nervous system.
autonomic
The lateral horns contain the cell bodies of ______ neurons.
autonomic motor
posterior horns
axons of sensory neurons and cell bodies of interneurons
how is CSF formed?
choroid plexus -composed of ependymal cells & capillaries that lie within Pia mater
cerebrospinal fluid (CSF)
clear liquid that circulates in ventricles and subarachnoid space
The ______ tracts extend between the cerebral hemispheres through axon bridges.
commissural
The corpus callosum is an example of a(n) ______ tract.
commissural
projection tracts
connect cerebral cortex to inferior brain regions and spinal cord
association tracts
connect regions of cortex within a hemisphere -arcuate fibers -longitudinal fasciculi
cranial meninges
connective tissue coverings of brain
cerebrum
contains large number of neurons needed for complex analytical & integrative functions performed in cerebrum
motor areas
control voluntary motor functions
vasomotor center
controls blood pressure by regulating contraction & relaxation of smooth muscle in walls of arterioles
What are the white matter tracts that connect the cerebral hemispheres?
corpus callosum
largest tract that connects two hemispheres
corpus callosum
neuron function is brain may be adversely affected by
drugs, waste products, some normal substances in circulation, fluctuations of substances (hormones, ions)
BBB is formed by
endothelial cells & astrocyte perivascular feet
perivascular feet wrap around completely
enveloping brain capillaries
CSF is produced by secretion of a fluid from the _____ cells.
ependymal cells
The ______ partially forms the posterior roof of the diencephalon and covers the third ventricle.
epithalamus
commissural tracts
extend between the right and left cerebral hemispheres
The white matter of the spinal cord is ______ to the gray matter.
external
deep grooves
fissures
All spinal nerves except _____ innervate a segment of skin, and so each of these nerves is associated with a dermatome.
C1
distribution of white matter
-external to gray matter axons within each funiculus are organized into tracts
functions of cranial meninges
- Separate brain from bones of cranium - Protect blood vessels of brain; form some large veins that drain blood from brain - Contain and circulate cerebrospinal fluid
medulla oblongata contains several autonomic nuclei
-cardiac center -vasomotor center -medullary respiratory center
distribution of gray matter
-centrally located in spinal cord -Sectioned shape resembles butterfly
The diameter of a typical adult spinal cord is about ______.
3/4 of an inch
How many spinal nerves are there?
31 pairs
Spinal Nerve Distribution
After leaving the intervertebral foramen, a typical spinal nerve splits into branches termed rami
Multiple posterior rootlets derive from
a single posterior root
The ______ horns primarily house the cell bodies of somatic motor neurons.
anterior
The ______ ramus is the larger of the two main branches of a spinal nerve.
anterior
Motor nuclei in the ______ horns contain motor neuron cell bodies that send nerve impulses to muscles and glands.
anterior and lateral
gray matter is subdivided into
anterior horns, lateral horns, posterior horns, gray commissure
There is a ______ brain barrier that prevents harmful materials from the brain.
blood
capillaries filter ________ then _______ modify
blood plasma; ependymal cells
The brain is protected by
bony cranium meninges cerebral spinal fluid blood-brain barrier
decussation
both hemispheres generally receive sensory information from & project motor commands to the opposite sides of body -tracts cross over to the other side of the body
buoyancy
brain floats in CSF supporting most of its weight prevents being crushed from own weight
The ______ connects the cerebrum and cerebellum to the spinal cord.
brainstem
functions of CSF
buoyancy, protection, environmental stability
ventricles
cavities within the brain -produce, circulate, reabsorb CSF -continuous with with one another & central canal of spinal cord
Motor axons arise from
cell bodies in the anterior and lateral horns of the spinal cord
sensory axons arise from
cell bodies in the posterior root ganglion, which is attached to the posterior root
The gray commissure is a horizontal bar of gray matter that surrounds a narrow ______ in the spinal cord.
central canal
The ______ connects the third and fourth ventricles and is found in the mesencephalon (midbrain).
cerebral aqueduct
The ______ are paired, irregular masses of gray matter buried deep within the central white matter in the basal region of the cerebral hemispheres.
cerebral nuclei
Within the white matter, the brain contains clusters of gray matter called ______ ______.
cerebral nuclei
regions of gray matter in deeper white matter
cerebral nuclei
______ is a clear, colorless liquid that circulates in the ventricles.
cerebrospinal fluid
The _____ is the location of conscious thought processes and the origin of all complex intellectual functions.
cerebrum
The location of conscious thought processes and the origin of all complex intellectual functions is the
cerebrum
four major regions of the brain
cerebrum, diencephalon, brainstem, cerebellum
Most of the motor neurons cross to the opposite side of the brain at a point called the ______ of the pyramids.
decussation
As a result of ______, each cerebral hemisphere controls the voluntary movements of the opposite side of the body.
decussation of the pryamids
cerebral nuclei
deep clusters of neuron cell bodies -paired irregular masses of gray matter
The gray matter of the spinal cord is dominated by the ______ and ______ of neurons.
dendrites; cell bodies
Some individual fasciculi conduct motor impulses as ______ from the brain to the spinal cord.
descending tracts
Which region of the brain is often referred to as the 'in-between" brain.
diencephalon
A posterior funiculus lies between the ______ gray horns on the posterior side of the cord and the posterior median sulcus.
posterior
Three regions of white matter
posterior funiculus, lateral funiculus, anterior funiculus
Which spinal nerve rami do not form plexuses?
posterior rami
The cell bodies of the sensory neurons of the posterior root are located in a ______, which is attached to the posterior root.
posterior root ganglion
central white matter
primarily myelinated axons bundled into tracts
An example of ______ tracts are corticospinal tracts that carry motor signals from the cerebrum to the brainstem and spinal cord.
projection
The internal capsule is made of ______ tracts.
projection
sensory areas
provide conscious awareness of sensation
protection (CSF)
provides a liquid cushion protecting delicate neural structures from sudden movements
continuous basement membrane
provides barrier
The blood-brain barrier keeps the neurons in the brain from being exposed to ______?
waste products in the blood variations in the levels of ions drugs
The anterior funiculi are interconnected by the ______.
white commissure
The ______ matter lies deep to the ______ matter of the cortex of the brain.
white; gray
functions of cerebellum
~ Coordinate skeletal muscle activity ~ Maintains balance (equilibrium) ~Maintains muscle tone and controls postural muscles