NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
1. Review the anatomy of the brain. Which portion is responsible for keeping
you awake, controlling thought, speech, emotions and behavior, maintaining
balance and posture? CH 15 pg 440: The three major structural divisions of the brain are 1) the
forebrain (prosencephalon) which includes the telencephalon and diencephalon. 2) the midbrain (the mesencephalon,
which connects the pons to the diencephalic;pn and the includes the corpora quadrigemina, tegmenjtum and cerebral
peduncles; and 3). the hind brain (rhombencephalon), which connects the hemispheres of the brain, cerebellum and
spinal cord.
Reticular formation: is collection of nuclei within the brainstem collectively, and is a large network of diffuse nuclei that
connect the brainstem to the cortex and control vital reflexes, such as CV function and respiration. It is essential for
maintains wakefulness and attention and thus us referred to as the reticular activating system.
Cerebral hemisphere: Part frontal lobe: prefrontal area is responsible for goal oriented behavior/ the ability to
concentrate, short term memory recall, and the elaboration of thought and inhibition on the limbic (emotional) areas
of the CNS.
The premotor area is involved in programming motor movements.
The Broca area in the inferior frontal lobe is an important center for speech and language processing. Injury to this
area results in difficulty to form words (expressive aphasia/ or dysphasia)
The hind brain: the cerebellum is responsible for reflexive, involuntary fine tuning of motor control and for maintaining
balance and posture through extensive neural connections with the medulla and with the midbrain
2. What nerves are capable of regeneration? CH 15 pg 435-437: Myelinated axons ONLY
in the PNS.
When an axon is severed wallerian degeneration occurs in the portion of the axon distal to the cut:
1) a characteristic swelling appears
2) the neurofilaments hypertrophy
3) the myelin sheath shrinks and disintegrates
4) this axon portion degenerates and disappears.
The myelin sheaths reform into Schwann cells that line up in a column between the cut and the effector organ. At the
, NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
proximal end of the injured axon, similar changes occur but only as far back as the next node of Ranvier. The cell body
responds to trauma by swelling and then dispersing the Nissl substance (chrmatolysis). During the repair process the
cell increases in metabolic activity, protein synthesis, and mitochondrial activity. This process is limited to myelinated
fibers and generally doesn't occur outside of the PNS. The regeneration of axonal constituents in the CNS is limited
by increased scar formation and the different nature of myelin formation by the oligodendrocyte. Nerve regeneration
depends on many factors, such as location of injury, type of injury, the inflammatory responses, and the process of
scarring. The closer the cell body of the nerve, the greater the chances that the nerve cell will die and not regenerate.
A crushing injury allows recovery more fully than a cut. Crushed nerves sometimes recover whereas, cut nerves often
form connective tissue scars that block or slow regenerating axonal branches.
3. Know the function of the arachnoid villi. CH 15 pg 451: CSF is reabsorbed in venous
circulation through a pressure gradient between the arachnoid villi and the cerebral venous sinuses. The arachnoid villi
protrude from the arachnoid space, through the dura mater, and lie within the blood flow of the venous sinuses. The
vili function as one way valves directing CSF outflow into the blood but preventing blood flow into the subarachnoid
space.
4. What is the function of the CSF? Where is it produced? Where is it absorbed?
CH 15 pg 450: Is a clear colorless fluid. the intracranial and spinal cord structures float in CSF and are thus
protected by this fluid from jolts and blows. The buoyant properties of CSF also prevent the brain from tugging on the
meninges , nerve roots, and blood vessels. Aprox 600 ml of CSF is produced daily.
The choroid plexus in the lateral, third and fourth ventricles produce the major portion of CSF.
The CSF exerts pressure within the brain and spinal cord. CSF flor results from the pressure gradient between the arterial
system and the CSF filled cavities.
Beginning in the lateral ventricles the CSF flows through the intraventricular foramen into the third ventricle and then
pass through the cerebral aqueduct into the fourth ventricle. From the ventricle , the CSF may pass through either the
paired lateral apertures or the median aperture before communicating with the subarachnoid spaces of the brain and
spinal cord. CSF is produced continually but does not accumulate. Instead it is reabsorbed in the venous circulation
through a pressure gradient between the arachnoid villi and the cerebral venous sinuses. Thus the CSF is formed from
the blood and, after circulating throughout the CNS it returns to the blood.
5. Review blood flow to the brain. pg 452 Ch 15: The brain derives its arterial supply from two
systems: the internal carotid arteries (anterior circulation) and the vertebral arteries (posterior circulation) The internal
, NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
carotid arteries supply a proportionaly greater amount of blood flow. They originate at the common carotid arteries,
enter the cranium through the base of the skull and pass through the cavernous sinus. After entering the skull, these
arteries divide into the anterior and middle cereal arteries. The vertebral arteries originate at the subclavian arteries and
pass through the transverse foramina of the cervical vertebrae, entering the cranium through the foramen magnum.
They join at the junction of the ins and medulla omblongata to form the basilar artery, the basil artery divides at the
level of the midbrain to form paired posterior cerebral arteries.
Three major paired arteries perfuse the cerebellum and brainstem: the posterior inferior cerebella artery, the anterior
inferior cerbeller artery, and the superior cerebella arteries. They originate from the basilar artery. The basilar artery
also gives rise to small pontine arteries. The large arteries on the surface of the brain and their branches are called
superficial arteries. Small branches that project into the brain are term projecting arteries.
The circle of willis provides an alternate route for blood flow when one the contributing arteries is obstructed. The circle
of willis is formed by the posterior cerebral arteries , posterior communicating arteries, internal carotid arteries, anterior
cerebral arteries, and anterior communicating artery. The anterior cerebral , middle cerebral, and posterior cerebral
arteries leave the arterial circle and extend to various brain structures.
Brain blood flow (p.467-469) The brain receives about 20% of the cardiac output. Carbon dioxide serves as a primary
regulator for blood flow within the CNS as it is a potent vasodilator. The brain derives its arterial supply from two systems:
the internal carotid arteries and the vertebral arteries.• Internal Carotid Arteries:
o The ICAs supply blood to the anterior portion of the brain. They originate from the common carotid arteries, enter
the cranium through the base of the skull, and pass through the cavernous sinus; after giving off some small branches,
they divide into the anterior and middle cerebral arteries.
• Vertebral Arteries:o The VAs supplies the posterior portion of the brain. They originate as branches off the subclavian
arteries, pass through the transverse foramina of the cervical vertebrae, and enter the cranium through the foramen
magnum. They join at the junction of the pons and medulla oblongata to form the basilar artery.
• Basilar Artery:
o Divides at the level of the midbrain to form paired posterior cerebral arteries. Three major paired arteries perfuse
the cerebellum and brainstem and originate from the posterior arterial supply: the posterior inferior cerebellar artery,
, NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
off the vertebral artery; and the anterior inferior cerebellar and superior cerebellar arteries, off the basilar artery. The
basilar artery also gives arise to small pontine arteries. The large arteries on the surface of the brain and their branches
are called superficial arteries. The small branches that project into the brain are termed projecting arteries.
• Circle of Willis:
o A structure credited with the ability to compensate for reduced blood flow from any one of the major contributors.
Formed by the posterior cerebral arteries, posterior communicating arteries, internal carotid arteries, anterior cerebral
arteries, and anterior communicating artery.
*Cerebral venous drainage does NOT parallel its arterial blood supply; whereas the venous drainage of the brainstem
and the cerebellum DOES parallel the arterial supply of the structures. The veins drain into the venous plexuses and
dural sinus and eventually join the internal jugular veins at the base of the skull.
6. What is the gate control theory of pain? CH 16 pg 469: Pain transmission is modulated
by a balance of impulses conducted to the spinal cord where cells in the substantial gelatinous function as a "gate".
The spinal gate regulates pain transmission to higher centers in the CNS. Large myenlated A-delta fibers and small
unmyenlated C fibers respond to a brave range of painful stimuli (mechanical, thermal, and chemical). These fibers
terminate on interneurons in the substantia gelatinosa (lamine in the dorsal horn of the spinal cord) and "open"
the spinal gate to transmit the perception of pain. Closure or partial closure of the spinal gates can occur from
nonnociceptive stimulation (i.e from touch sensors on the skin) carried on large A-beta fibers decreasing pain
perception. This is why rubbing a pain area may alleviate some of the discomfort. The CNS, through efferent pathways
may also close, partially close, or open the "gate".
7. Know the type of nerve fibers that transmit pain impulses. CH 16 pg 469-470)-
: The processing of potentially harmful (noxious) stimuli through a normally functioning nervous system is called
nociception. Nociceptors are free nerve endings in the afferent peripheral nervous system that selectively respond
to different chemical, mechanical and thermal stimuli. When stimulated they cause nociceptive pain. Nociceptors are
unevenly distributed throughout the body, so the relative sensitivity to pain differs according to their location. For
example fingertips have more nociceptors than the skin fo the back, and all skin has many more nociceptors than
internal organs. Primary nociceptive afferents have the ability to detect a wide range of stimuli. To do this, nociceptors
are equipped with an array of transduction channels that can sense different forms of noxious stimulation and at
different intensities.
Nociceptors are categorized according to the stimulus to which they respond and by the properties of the axons
Study online at https://quizlet.com/_7061ng
1. Review the anatomy of the brain. Which portion is responsible for keeping
you awake, controlling thought, speech, emotions and behavior, maintaining
balance and posture? CH 15 pg 440: The three major structural divisions of the brain are 1) the
forebrain (prosencephalon) which includes the telencephalon and diencephalon. 2) the midbrain (the mesencephalon,
which connects the pons to the diencephalic;pn and the includes the corpora quadrigemina, tegmenjtum and cerebral
peduncles; and 3). the hind brain (rhombencephalon), which connects the hemispheres of the brain, cerebellum and
spinal cord.
Reticular formation: is collection of nuclei within the brainstem collectively, and is a large network of diffuse nuclei that
connect the brainstem to the cortex and control vital reflexes, such as CV function and respiration. It is essential for
maintains wakefulness and attention and thus us referred to as the reticular activating system.
Cerebral hemisphere: Part frontal lobe: prefrontal area is responsible for goal oriented behavior/ the ability to
concentrate, short term memory recall, and the elaboration of thought and inhibition on the limbic (emotional) areas
of the CNS.
The premotor area is involved in programming motor movements.
The Broca area in the inferior frontal lobe is an important center for speech and language processing. Injury to this
area results in difficulty to form words (expressive aphasia/ or dysphasia)
The hind brain: the cerebellum is responsible for reflexive, involuntary fine tuning of motor control and for maintaining
balance and posture through extensive neural connections with the medulla and with the midbrain
2. What nerves are capable of regeneration? CH 15 pg 435-437: Myelinated axons ONLY
in the PNS.
When an axon is severed wallerian degeneration occurs in the portion of the axon distal to the cut:
1) a characteristic swelling appears
2) the neurofilaments hypertrophy
3) the myelin sheath shrinks and disintegrates
4) this axon portion degenerates and disappears.
The myelin sheaths reform into Schwann cells that line up in a column between the cut and the effector organ. At the
, NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
proximal end of the injured axon, similar changes occur but only as far back as the next node of Ranvier. The cell body
responds to trauma by swelling and then dispersing the Nissl substance (chrmatolysis). During the repair process the
cell increases in metabolic activity, protein synthesis, and mitochondrial activity. This process is limited to myelinated
fibers and generally doesn't occur outside of the PNS. The regeneration of axonal constituents in the CNS is limited
by increased scar formation and the different nature of myelin formation by the oligodendrocyte. Nerve regeneration
depends on many factors, such as location of injury, type of injury, the inflammatory responses, and the process of
scarring. The closer the cell body of the nerve, the greater the chances that the nerve cell will die and not regenerate.
A crushing injury allows recovery more fully than a cut. Crushed nerves sometimes recover whereas, cut nerves often
form connective tissue scars that block or slow regenerating axonal branches.
3. Know the function of the arachnoid villi. CH 15 pg 451: CSF is reabsorbed in venous
circulation through a pressure gradient between the arachnoid villi and the cerebral venous sinuses. The arachnoid villi
protrude from the arachnoid space, through the dura mater, and lie within the blood flow of the venous sinuses. The
vili function as one way valves directing CSF outflow into the blood but preventing blood flow into the subarachnoid
space.
4. What is the function of the CSF? Where is it produced? Where is it absorbed?
CH 15 pg 450: Is a clear colorless fluid. the intracranial and spinal cord structures float in CSF and are thus
protected by this fluid from jolts and blows. The buoyant properties of CSF also prevent the brain from tugging on the
meninges , nerve roots, and blood vessels. Aprox 600 ml of CSF is produced daily.
The choroid plexus in the lateral, third and fourth ventricles produce the major portion of CSF.
The CSF exerts pressure within the brain and spinal cord. CSF flor results from the pressure gradient between the arterial
system and the CSF filled cavities.
Beginning in the lateral ventricles the CSF flows through the intraventricular foramen into the third ventricle and then
pass through the cerebral aqueduct into the fourth ventricle. From the ventricle , the CSF may pass through either the
paired lateral apertures or the median aperture before communicating with the subarachnoid spaces of the brain and
spinal cord. CSF is produced continually but does not accumulate. Instead it is reabsorbed in the venous circulation
through a pressure gradient between the arachnoid villi and the cerebral venous sinuses. Thus the CSF is formed from
the blood and, after circulating throughout the CNS it returns to the blood.
5. Review blood flow to the brain. pg 452 Ch 15: The brain derives its arterial supply from two
systems: the internal carotid arteries (anterior circulation) and the vertebral arteries (posterior circulation) The internal
, NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
carotid arteries supply a proportionaly greater amount of blood flow. They originate at the common carotid arteries,
enter the cranium through the base of the skull and pass through the cavernous sinus. After entering the skull, these
arteries divide into the anterior and middle cereal arteries. The vertebral arteries originate at the subclavian arteries and
pass through the transverse foramina of the cervical vertebrae, entering the cranium through the foramen magnum.
They join at the junction of the ins and medulla omblongata to form the basilar artery, the basil artery divides at the
level of the midbrain to form paired posterior cerebral arteries.
Three major paired arteries perfuse the cerebellum and brainstem: the posterior inferior cerebella artery, the anterior
inferior cerbeller artery, and the superior cerebella arteries. They originate from the basilar artery. The basilar artery
also gives rise to small pontine arteries. The large arteries on the surface of the brain and their branches are called
superficial arteries. Small branches that project into the brain are term projecting arteries.
The circle of willis provides an alternate route for blood flow when one the contributing arteries is obstructed. The circle
of willis is formed by the posterior cerebral arteries , posterior communicating arteries, internal carotid arteries, anterior
cerebral arteries, and anterior communicating artery. The anterior cerebral , middle cerebral, and posterior cerebral
arteries leave the arterial circle and extend to various brain structures.
Brain blood flow (p.467-469) The brain receives about 20% of the cardiac output. Carbon dioxide serves as a primary
regulator for blood flow within the CNS as it is a potent vasodilator. The brain derives its arterial supply from two systems:
the internal carotid arteries and the vertebral arteries.• Internal Carotid Arteries:
o The ICAs supply blood to the anterior portion of the brain. They originate from the common carotid arteries, enter
the cranium through the base of the skull, and pass through the cavernous sinus; after giving off some small branches,
they divide into the anterior and middle cerebral arteries.
• Vertebral Arteries:o The VAs supplies the posterior portion of the brain. They originate as branches off the subclavian
arteries, pass through the transverse foramina of the cervical vertebrae, and enter the cranium through the foramen
magnum. They join at the junction of the pons and medulla oblongata to form the basilar artery.
• Basilar Artery:
o Divides at the level of the midbrain to form paired posterior cerebral arteries. Three major paired arteries perfuse
the cerebellum and brainstem and originate from the posterior arterial supply: the posterior inferior cerebellar artery,
, NU 545 Unit 2 Study Guide
Study online at https://quizlet.com/_7061ng
off the vertebral artery; and the anterior inferior cerebellar and superior cerebellar arteries, off the basilar artery. The
basilar artery also gives arise to small pontine arteries. The large arteries on the surface of the brain and their branches
are called superficial arteries. The small branches that project into the brain are termed projecting arteries.
• Circle of Willis:
o A structure credited with the ability to compensate for reduced blood flow from any one of the major contributors.
Formed by the posterior cerebral arteries, posterior communicating arteries, internal carotid arteries, anterior cerebral
arteries, and anterior communicating artery.
*Cerebral venous drainage does NOT parallel its arterial blood supply; whereas the venous drainage of the brainstem
and the cerebellum DOES parallel the arterial supply of the structures. The veins drain into the venous plexuses and
dural sinus and eventually join the internal jugular veins at the base of the skull.
6. What is the gate control theory of pain? CH 16 pg 469: Pain transmission is modulated
by a balance of impulses conducted to the spinal cord where cells in the substantial gelatinous function as a "gate".
The spinal gate regulates pain transmission to higher centers in the CNS. Large myenlated A-delta fibers and small
unmyenlated C fibers respond to a brave range of painful stimuli (mechanical, thermal, and chemical). These fibers
terminate on interneurons in the substantia gelatinosa (lamine in the dorsal horn of the spinal cord) and "open"
the spinal gate to transmit the perception of pain. Closure or partial closure of the spinal gates can occur from
nonnociceptive stimulation (i.e from touch sensors on the skin) carried on large A-beta fibers decreasing pain
perception. This is why rubbing a pain area may alleviate some of the discomfort. The CNS, through efferent pathways
may also close, partially close, or open the "gate".
7. Know the type of nerve fibers that transmit pain impulses. CH 16 pg 469-470)-
: The processing of potentially harmful (noxious) stimuli through a normally functioning nervous system is called
nociception. Nociceptors are free nerve endings in the afferent peripheral nervous system that selectively respond
to different chemical, mechanical and thermal stimuli. When stimulated they cause nociceptive pain. Nociceptors are
unevenly distributed throughout the body, so the relative sensitivity to pain differs according to their location. For
example fingertips have more nociceptors than the skin fo the back, and all skin has many more nociceptors than
internal organs. Primary nociceptive afferents have the ability to detect a wide range of stimuli. To do this, nociceptors
are equipped with an array of transduction channels that can sense different forms of noxious stimulation and at
different intensities.
Nociceptors are categorized according to the stimulus to which they respond and by the properties of the axons
