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