ANATOMY - Term Test 2 (CNS/PNS) Flashcards
What are the main divisions of the CNS?
brain and spinal cord
Layers of the meninges
Dura mater - strong white fibrous; outer layer of meninges and as inner periosteum of cranial bones
Arachnoid mater - delicate, spider web-like layer between dura and pia mater
Pia mater - innermost layer; transparent and adheres to outer surface of the brain and spinal cord; contains blood vessels
The meningeal layer that serves as the inner periosteum of the cranial bone is
dura mater
What is the innermost layer of the meninges?
pia mater
Meningitis refers to the inflammation of what?
Meninges
CSF is formed by filtration of blood (separation between blood and fluid). Where does this take place?
choroid plexuses
The vomiting reflex is mediated by what part of the brain?
medulla oblongata
Which part of the brain receives impulses from the labyrinth of the ear and thus plays a role in equilibrium?
cerebellum
Functions of the hypothalamus
- link between psyche (mind) and soma (body)
- links nervous system to endocrin system
- certain areas function as pleasure/reward centers for primary drives (eating, drinking, sex)
- regulator and coordinator of autonomic activities (controlling and integrating responses made by autonomic/viscera effectors)
- MAJOR relay stations between cerebral cortex and lower autonomic centers
- maintaining water balanced (neurons in supraoptic and paraventicular nuclei of hypothalamus synthesize hormones released by posterior pituitary gland)
- endocrine functions - hormones that control hormone secretion by sex glands, thyroid, and adrenal cortex
- involved in arousal/alerting mechanism
- regulating appetitie/food intake
- maintaining normal body temperature
The areas specializing in language functions are found in the left cerebral hemisphere in ____% of the population.
90
What part of the cerebrum is associated with anger, fear, and sorrow?
limbic system
Parts of the brainstem
Midbrain, pons, medulla oblongata
The body’s biological clock is controlled by what gland?
pineal gland
Besides protection, CSF helps regulate what?
serves as a reservoir of circulating fluid that monitors for changes in internal environment (CO2 and pH)
The layer of meninges least likely to be involved in meningitis is which?
Dura mater
The nervous system is divided into two major divisions. What are they?
CNS and PNS
What is the epidural space and where is it found?
- Space between dura mater and vertebral wall containing a supportve cushion of fat and other connective tissues
- typically not present around the brain because the dura mater is continuous with periosteum in inside face of cranial bones
Structures of the diencephalon
Main structures: thalamus, hypothalamus, optic chiasma, pineal gland
*epithalamus is also part of diencephalon and is a group of many smaller structures; pineal gland is an epithalamic structure
What part of the brain can produce a hormone?
- hypothalamus (produces hormones that control hormone release from pituitary)
- pituitary gland
- pineal gland
William was recently involved in a serious automobile accident. As a result, he has had difficulty controlling skeletal muscles and maintaining his balance. What part of the nervous system was most likely damaged?
cerebellum
Explain how the lack of dopamine physiologically affects those individuals suffering from Parkinson’s disease.
In normal healthy individuals:
- neurons that lead from substantia nigra to basal nuclei secrete dopamine
- Dopamine inhibits the excitatory effects of ACh produced by other neurons in the basal nuclei ⇒ produces a balanced, restrained output of muscle-regulating signals from basal nuclei
In Parkinson Disease (PD):
- neurons leading to substantia nigra degenerate and thus do not release normal amounts of dopamine
- Excitatory effects of ACh thus not restrained ⇒ basal nuclei produces excess of signals that affect voluntary muscles in several areas of the body
- Over stimulation of postural muscles in neck, trunk, and upper limbs produce: tremors of head and limbs; abnormal shuffling gait; absence of relaxed arm-swinging while walking; forward tilting of the trunk
Since her fall several weeks ago, Juanita has slipped in and out of consciousness. Her arousal or alerting mechanisms are apparently not functioning properly. What specific area of the brain is most likely responsible?
reticular activating system (RAS) - consists of centers in brainstem’s reticular formation that receive impulses from spinal cord and relay them to thalamus; thalamus ⇒ cerebral cortex areas
When someone close to you dies, you feel a sense of sorrow. Your ability to experience this emotion is the result of which body system?
limbic system
During your life time, you are capable of remembering such things as telephone numbers, SIN, and song lyrics from many years ago. Your ability to perform these LT memory tasks is because:
repeated impulse conduction over a given neuronal circuit produces synaptic changes (increase in number of presynaptic axon terminals OR increase in number of receptor proteins in postsynaptic neuron’s membrane) - all of it increases synaptic strength which allow for memory storage
Jeffrey contracted poliomyelitis. It has affected the medulla oblongata. Doctors warn that death is imminent. What function of the medulla oblongata has warranted such a dire prognosis?
the medulla oblongata contains vital centers that control heart action, blood vessel diameter, and respiration
The nerve commonly called the vagus nerve is in which cranial nerve?
CN X
Damage to the _____ nerve could cause the diaphragm unable to function.
phrenic
The phrenic nerve is found in which plexus?
cervical plexus
All of the following are examples of parasympathetic stimulation except for which one:
a) contraction of the urinary bladder
b) relaxation of the sphincters of the digestive tract
c) increased HR
d) none of the above
increased HR
What physiological changes occur with the fight or flight response?
- increased HR
- increased strength of cardiac muscle contraction
- Dilation of coronary vessels of the heart
- dilation of blood vessels in skeletal muscles
- increased stimulation at NMJs and increased ion pump activity in skeletal muscles
- constriction of blood vessels in digestive and other organs
- contraction of spleen and other blood reservoirs
- dilation of respiratory airways
- increased rate and depth of breathing
- increased sweating
- increased conversion of glycogen into glucose
- increased breakdown of stored fats
A child was frightened by a large dog. The pupil of the child become dilated. HR and RR increased. These symptoms were caused by the stimulation of what system?
sympathetic nervous system
Parts of the peripheral nervous system
Fibers present in the cranial nerves (12 pairs of cranial nerves), the spinal nerves (31 pairs of spinal nerves, and all their individual branches.
Functionally: PNS divided into sensory (afferent) division and motor (efferent) division
- Motor division is further broken down into: somatic nervous system, autonomic nervous system
Where is the cauda equine found?
End of spinal cord - below the conus medullaris
Norepinephrine can stimulate which receptors
Adrenergic receptors (alpha and beta receptors)
A gymnast is experiencing problems with balance and equilibrium. Which cranial nerves may be causing this?
vestibulocochlear nerve (CN VIII)
Danielle has sustained an injury that has reduced her ability to complete simple tasks (like lifting a pencil and brushing her hair). The injury has affected which motor pathway?
somatic motor pathway
How is herpes zoster (shingles) a result of the reactivation of the varicella zoster virus?
- virus most likely travels through a cutaneous nerve and remains dormant in a dorsal root ganglion for years after an initial episode of chicken pox
- reactivate with body’s immunological protective mechanisms becomes diminished (in elderly or as a result of stress, radiation therapy, immunosuppressive drugs)
- if reactivated, virus will travel over sensory nerve to the skin of a single dermatome
- S/S: painful eruption of red swollen plaques or vesicles that eventually rupture and crust before clearing in 2-3 weeks
After radiation treatment, jake experienced a painful eruption of red swollen plaques/sores that later ruptured and crusted over. Soon after, jake complained of burning and itching in the affected dermatome. These Sx are most likely a result a what condition?
Herpes Zoster (shingles)
Judy has sustained an injury that damaged the vestibulocochlear nerve. This injury will have an effect on her ability to do what?
hearing and/or equillibrium
A patient complains of numbness in the skin of buttocks and posterior surface of thigh and leg. The spinal nerve/peripheral branch most likely involved with this condition is what?
coccygeal branch
What are the two protective coverings for the CNS?
Outer covering: bone (cranial bones, vertebrae)
inner covering: meninges
The following are all inward extensions of dura mater except:
a) falx cerebri
b) falx cerebelli
c) tentorium cerebelli
d) all of the above are inward extensions of dura mater
d) all of the above are inward extensions of dura mater
Falx cerebri: projects downward into longitudinal fissure to form partition between two cerebral hemipheres
Falx cerebelli: sickle shaped extension that separates the two halves/hemispheres of cerbellum
Tentorium cerebelli: separates cerebellu, from cerebrum; tent-like covering over cerebellum
Superior sagittal sinus
one of the dural sinues; the space where falx cerebri begins to descend between L and R cerebral hemispheres
Subdural space
“under the dura” - the space between dura mater and arachnoid mater
*normally a potential space but can be a real space if blood leaked into it forming a subdural hematoma
Subarachnoid space
between arachnoid and pia mater (contains sig amount of CSF)
Filum terminale
delicate, fibrous strand of tissue formed by pia mater that blends with dura mater and extends down to the end of the spinal cord into periosteum of the coccyx
Where is CSF found?
- CSF found in the subarachnoid space around the brain and spinal cord, and within the cavities and canals of brain and spinal cord
There are ___ ventricles within the brain. What are they?
4
two lateral ventricles - one oin each hemisphere of cerebrum
third ventricle - thin, verticle pocket of fluid below and medial to lateral ventricles
fourth ventricle: tiny, diamond shaped space where cerebellum attaches to the back of the brainstem
Choroid plexuses
- network of capillaries that project from pia mater into lateral ventricles and into roofs of third and fourth ventricles
- each plexus is covered with a sheet of special type of glial cell that releases CSF into fluid spaces
Pathway of CSF circulating into the blood
CSF formed as fluid separated from blood (in choroid plexuses) ⇒ flow into ventricles of brain and circulates through ⇒ central canal + subarachnoid spaces ⇒ absorbed back into blood
Avg amount of CSF (in adult)
140 mL
Withdrawal of some of the CSF from subarachnoid space in the lumbar region of the vertebral column (above/below 4th lumbar vertebra) is known as:
lumbar puncture/spinal tap
What does the spinal cavity contain?
spinal cord, meninges, CSF, adipose tissue, and blood vessels
The two deep grooves that incompletely divide the spinal cord into separate symmetrical halves are known as:
anterior median fissure and posterior median sulcus
What are nerve roots? What are the two types?
Nerve roots: two bundles of nerve fibers that project from each side of the spinal cord
- Doral (posterior) nerve root: carry sensory information into the spinal cord; cell bodies are in the dorsal root ganglion (small swelling)
- Ventral (anterior) nerve root: carry motor information out of spinal cord; cell bodies are multipolar and found in gray matter that makes up inner spinal cord
Dorsal and ventral roots join together on each side of the spinal cord to form a spinal nerve (single mixed nerve)
Spinal cord ends at vertebra ____ in a tapered cone called ______.
L1; conus medullaris
The conus medullaris has many nerve roots extending from it to make a “horse tail” of spinal nerve roots known as:
cauda equina
In the middle of the gray matter is _________________ where the central canal carries CSF through the spinal cord.
a) anterior gray column
b) posterior gray column
c) funiculi
d) gray commissure
d) gray commissure
anterior and posterior gray columns (along with lateral gray columns) forms the H shape of grya matter; the gray commissure resides in the middle of all this
funiculi is part of white matter
Where do spinal tracts exist in the spinal cord?
In white matter - separated into three white columns (anterior, posterior and lateral funiculi) and each column has large bundles of axonx divided into smaller bundles (spinal tract)
What are the two general functions of the spinal cord?
1) conduction routes to and from the brain
2) serves as the integrator (reflex center) for all spinal reflexes
Ascending vs descending tracts
Ascending tracts: conduct sensory impulses up the cord to the brain
Descending tracts: conduct motor impulses down cord from brain
What are the 6 major divisions of the brain (from inferior to superior):
1) medulla oblongata
2) pons
3) midbrain
4) cerebellum
5) diencephalon
6) cerebrum
How many pairs of cranial nerves arise from the brainstem?
10
Medulla oblongata
Part of the brain that attaches to the spinal cord (located just above the foramen magnum)
What vital centers does the medulla oblongata contain?
cardiac (controls heart action)
vasomotor (controls blood vessel diamater)
respiration
The mesencephalon is also known as the:
midbrain
Midbrain
midsection of brain (lies above pons, below cerebrum); composed of both white matter (tracts) and reticular formation
Non-vital reflexes controlled by medulla include:
vomiting
coughing
sneezing
hiccuping
swallowing
The two ropelike masses of white matter that extend from the midbrain is called
cerebral peduncles
Pons contains centers for reflexes mediated by which cranial nerves?
CN V, VI, VII, and VIII
The structure that is composed of two inferior colliculi and two superior colliculi is known as
corpora quadrigemina
Red nucleus and substantia nigra are also structures that are part of which brain structure?
midbrain
they contain clusters of neuron cell bodies involved in muscular control
True or False. The cerebellum is the second largest part of the brain and has more neurons than all other parts of the nervous system combined.
True. (Largest part of the brain is cerebrum)
The cerebellum contains a structure known as the “tree of life” made up of white matter. What structure is this?
Arbor vitae
Function of the cerebellum
- Performs a variety of functions that complement/assist cerebrum (planning and coordination of skeletal muscle activity and maintaining balance in the body)
- basically to ensure that muscle activity is smooth, steady, efficient, and coordinated
A patient with signs and symptoms of ataxia (slow scanning speech, gait and balance disturbances, tremors) is likely to have disease/injury to what brain structure?
Cerebellum
Location of diencephalon
Between cerebrum and midbrain
All of the following cranial nerves have a functional classification of motor except:
a. vestibulocochlear
b. trochlear
c. accessory
d. oculomotor
a. vestibulocochlear
The lumbar plexus gives rise to the _____ nerve.
femoral
Which part of the vertebral column has one more pair of nerves coming from it than it has vertebra?
cervical
Which is not true of the dorsal nerve root?
a. It is also called the posterior root
b. It includes the spinal ganglion
c. It includes sensory fibers
d. All of the above are true
d. All of the above are true
Which of the following cranial nerves is not associated with eye movement?
a. Oculomotor
b. Abducens
c. Trochlear
d. Trigeminal
d. Trigeminal
In a healthy adult, a well-placed tap on the knee will result in what? What is this called?
stretch of the tendon, the quadriceps femoris, and thereby stimulation of the muscle spindles.
known as the knee jerk/patellar reflex
When responding to stimulation of the outer margin of the sole of the foot, a 1-year-old infant extends her great toe without fanning of the other toes. This is known as:
Babinski sign
Which of the following is not an example of sympathetic stimulation?
a. Dilation of skeletal muscle blood vessels
b. Constriction of the urinary sphincters
c. Decreased secretion of the pancreas
d. Constriction of the bronchioles
d. Constriction of the bronchioles
Ventral nerve root
nerve root that carries motor nerves away from the spinal cord
Dermatome
skin surface area that is supplied by one spinal nerve
Dorsal nerve root
nerve root carries sensory neurons into the spinal cord
Myotome
group of skeletal muscles that receive axon from one spinal nerve
Where is the 4th ventricle located?
where the cerebellum attaches to the brainstem
What structure drains cerebrospinal fluid into the fourth ventricle?
cerebral aqueduct (Sylvius aqueduct)
The spinal cord ends at vertebral L1 in a narrowed area called the:
conus medullaris
