Chapter 14
Using the mnemonic device "Oh, Once One Takes The Anatomy Final, Very Good Vacations Are Heavenly," list the names of the 12 pairs of cranial nerves.
I: olfactory nerve *II: optic nerve *III: oculomotor nerve *IV: trochlear nerve *V: trigeminal nerve *VI: abducens nerve *VII: facial nerve *VIII: vestibulocochlear nerve *IX: glossopharyngeal nerve *X: vagus nerve *XI: accessory nerve *XII: hypoglossal nerve
If symptoms characteristic of Parkinson disease appear, which part of the mesencephalon is inhibited from secreting a neurotransmitter? Which neurotransmitter is it?
In Parkinson disease, the substantia nigra is inhibited from secreting the neurotransmitter, dopamine, at the basal nuclei.
Cerebral meningitis is a condition in which the meninges of the brain become inflamed as the result of viral or bacterial infection. This condition can be life threatening. Why?
In any inflamed tissue, edema occurs in the area of inflammation. The accumulation of fluid in the subarachnoid space can cause damage by pressing against neurons. If the intracranial pressure is excessive, brain damage can occur, and if the pressure involves vital autonomic reflex areas, death could occur.
List in order the 12 cranial nerves.
Olfactory *optic *oculomotor *trochlear *trigeminal *abducens *facial *vestibulocochlear *glossopharyngeal *vagus *accessory *hypoglossal
Describe the three layers of the cranial meninges.
Pia mater: the closest appressed to the surface of the brain; anchored to the brain by astrocytes and extends into every fold of the brain *Arachnoid: covers the brain providing a smooth surface that does not follow the folds of the brain *Dura Mater: consists of outer and inner fibrous layers; fuses into the cranial bones with the periosteum
Which structure in the brain would your A & P instructor be referring to when talking about a nucleus that resembles a sea horse and that appears to be important in the storage and retrieval of long-term memories? In which functional system of the brain is it located?
This nucleus is the hippocampus, which is part of the limbic system
What is an EEG?
a printed report of the electrical activity in the brain
What are the two primary functions of the cerebellum?
adjusting the postural muscles of the body *programming and fine tuning movements controlling at the subconscious levels
What are the four commonly seen types of brainwaves in an EEG and in whom is each typically seen?
alpha waves: healthy adults *beta waves: individuals who are concentrating or under stress *theta waves: sleeping adults and frustrated children and adults *delta waves: deeply sleeping adults and children and adults with brain damage
The centers in the pons that modify the activity of the respiratory rhythmicity centers in the medulla oblongata are the
apneustic and pneumotaxic centers
Describe the classification and function of axons found in the white matter of the cerebrum.
association fibers: interconnect areas of neural cortex within a single cerebral hemisphere *commissural fibers: interconnect and permit communication between the cerebral hemispheres *projection fibers: link the cerebral cortex to the diencephalon, brain stem, and spinal cord
List and describe the function of the three important nuclei found in the medulla oblongata.
autonomic nuclei: controls visceral activities *sensory and motor nuclei: control motor commands to the muscles of the pharynx, neck and back *Relay stations along Sensory and Motor Pathways
What isolates neural tissue from general blood circulation?
by the blood-brain barrier
List the four principle basal nuclei of the cerebrum.
caudate nucleus *lentiform nucleus *globus palidus *putamen
What are the six major regions of the brain?
cerebrum, diencephalon, mesencephalon, pons, cerebellum, and medulla oblongata
Which of the following is the site of cerebrospinal fluid production
choroid plexus
Describe the functions of The primary sensor cortex:
conscious perception of touch, pressure, pain, vibration, taste, and temperature
List and describe the 8 functions of the hypothalamus.
controls somatic motor activities at the subconscious level *controls autonomic function *coordinates activities of the endocrine and nervous systems *secretes hormones *produces emotions and behavioral drives *coordinates voluntary and autonomic functions *regulates body temperature *coordinates circadian cycles of activity
What are the two major functions of the cerebrum?
coordinates complex somatic motor patterns *adjusts output of other somatic motor centers in brain and spinal cord
The prefrontal cortex:
coordinates information relayed from the association areas of he entire cortex
The mesencephalon contains two pairs of sensory nuclei; what are they called and what is their function?
corpora quadrigemina: process visual and auditory sensation respectively and control movement of the eyes, head, and neck in response to those stimuli
What are the three important functions of the CSF?
cushioning delicate neural structures *supporting the brain *transporting nutrients, chemical messengers, and waste products
What are the three functions of CSF?
cushioning the neural structures, supporting the brain, and transporting nutrients, chemical messengers, and waste products
Damage to the vestibular nucleus would lead to
difficulty in maintaining balance
Cerebrospinal fluid is produced and secreted by
ependymal cells
List the three components of the diencephalon.
epithalamus, hypothalamus, thalamus
What are the functions of the limbic system?
establishing emotional states *linking the conscious functions of the cerebral cortex with the unconscious functions of the brain stem *facilitating memory retrieval and storage
The dural fold that divides the two cerebellar hemispheres in the
falx cerebelli
List the three largest folds in the dura mater (dural folds).
falx cerebri, tentorium cerebelli, falx cerebelli
The primary purpose of the blood-brain barrier (BBB) is to
isolate neural tissue in the CNS from the general circulation
Describe the function(s) of the thalamus.
it is the final relay point for ascending sensory information that will be projected to the sensory cortex; acts as a filter, passing only a small portion of the arriving information
The establishment of emotional states in a function of the
limbic system
The auditory association area:
monitors sensory activity in the auditory cortex
The visual association area:
monitors the patterns of activity in the visual cortex and interprets the results
What varied roles does the hypothalamus play in the body?
subconscious control of skeletal muscle contractions *control of autonomic functions *coordination of nervous and endocrine systems *secretion of hormones *production of emotions and drives *coordination of autonomic and voluntary functions *regulation of body temperature *control of circadian rhythms
The final relay point for ascending sensory information that will be projected to the primary sensory cortex is the
thalamus
A cerebrovascular accident occurs when
the blood supply to a portion of the brain is cut off
What protects the brain from mechanical stresses?
the bones of the cranium, the cranial meninges, the cerebrospinal fluid
Coordination of learned movement patterns at the subconscious level is performed by
the cerebellum
The term higher brain centers refers to those areas of the brain involved in higher-order functions. These centers would probably include nuclei, centers, and cortical areas of
the cerebellum *the cerebrum *the diencephalon
Describe hemispheric lateralization of the brain.
the left hemisphere contains the general interpretive and speech centers responsible for language based skills and analytical skills; the right hemisphere analyzes spatial relationships and allows the recognition of familiar objects
The pons
tracts that link the cerebellum with the brain stem
The two cerebral hemispheres are functionally different, even though anatomically they appear the same.
true
Colleen falls down a flight of stairs and bumps her head several times. Soon after, she develops a headache and blurred vision. Diagnostic tests at the hospital reveal an epidural hematoma in the temporoparietal area. The hematoma is pressing against the brain stem. What other signs and symptoms might she experience as a result of the injury?
Increasing pressure in the cranium could compress important blood vessels, leading to further brain damage in areas not directly affected by the hematoma. Pressure of the brain stem could disrupt vital respiratory, cardiovascular, and vasomotor functions and possibly cause death. Pressure on the motor nuclei of the cranial nerves would lead to drooping eyelids and dilated pupils. Pressure on descending motor tracts would impair muscle function and decrease muscle tone in the affected areas on the body.
Describe CSF circulation and production.
Inside the brain there are ependymal cells in the choroid plexus that produces about 500ml per day; it reaches the subarachnoid space via 2 lateral apertures and one medial aperture in the 4th ventricle; it surrounds the brain and is replaced every 8 hours
What kinds of problems are associated with the presence of lesions in the Wernicke area and the Broca area?
Lesions in the general interpretive area (Wernicke area, sensory) produce defective visual and auditory comprehension of language, repetition of spoken sentences, and defective naming of objects. Lesions in the speech center (Broca area, motor) result in hesitant and distorted speech.
Infants have little to no control of the movements of their head. One of the consequences of this is that they are susceptible to shaken baby syndrome, caused by vigorous shaking of an infant or young child by the arms, legs, chest, or shoulders. Forceful shaking can cause brain damage leading to mental retardation, speech and learning disabilities, paralysis, seizures, hearing loss, and even death. Damage to which areas of the brain would account for the clinical signs observed in this syndrome?
Most of the functional problems observed in shaken baby syndrome are the result of trauma to the cerebral hemispheres due to contact between the brain and the inside of the skull. Damage to and distortion of the brain stem and medulla oblongata can cause death.
Smelling salts can sometimes help restore consciousness after a person has fainted. The active ingredient of smelling salts is ammonia, and it acts by irritating the lining of the nasal cavity. Propose a mechanism by which smelling salts would raise a person from the unconscious state to the conscious state.
Sensory innervation of the nasal mucosa is via the maxillary branch of the trigeminal nerve (V). Irritation of the nasal lining by ammonia increases the frequency of action potentials along the maxillary branch of the trigeminal nerve through the semilunar ganglion to reach centers in the mesencephalon, which in turn excite the neurons of the reticular activating system (RAS). Increases activity by the RAS can raise the cerebrum back to consciousness.
Stimulation of which part of the brain would produce sensations of hunger and thirst?
Stimulation of the feeding and thirst centers of the hypothalamus.
Why can the brain respond to stimuli with greater versatility when the spinal cord?
The brain can respond with greater versatility because is includes many more interneurons, pathways, and connections than the tracts of the spinal cord.
Briefly summarize the overall functions of the cerebellum.
The cerebellum adjusts voluntary and involuntary motor activities based on sensory information and stored memories of previous experiences
What are the principle functional differences between the right and left hemispheres of the cerebrum?
The left hemisphere contains the general interpretive and speech centers and is responsible for performing analytical tasks, for logical decision-making, and for language-based skills. The right hemisphere analyzes sensory information and relates the body to sensory environment. Interpretive centers in this hemisphere permit the identification of familiar objects by touch, smell, sight, taste, or feel. The right hemisphere is also important in understanding three-dimensional relationships and in analyzing the emotional context of a conversation.
A police officer has just stopped Bill on suspicion of driving while intoxicated. The officer asks Bill to walk the yellow line on the road and when to place the tip of his index finger on the tip of his nose. How would these activities indicate Bill's level of sobriety? Which part of the brain is being tested by these activities?
The officer is testing the function of Bill's cerebellum. Many drugs, including alcohol, have pronounced effects on the function of the cerebellum. A person who is under the influence of alcohol cannot properly anticipate the range and speed of limb movement, because processing and correction by the cerebellum are slow.
Why is it incomplete at those points?
They are very permeable and allow the flow of hormones
The only cranial nerves that are attached to the cerebrum are the _________ nerves.
olfactory
List the points at which the blood-brain barrier is incomplete.
parts of the hypothalamus, pituitary gland, pineal gland, choroid plexus
Which three areas in the brain are not isolated from the general circulation by the blood-brain barrier?
portions of the hypothalamus where the capillary endothelium is extremely permeable *capillaries in the pineal gland *capillaries at the choroid plexus
Wernicke's area:
receives information from all the sensory association areas
The speech center:
regulates patterns of breathing and vocalization needed for normal speech
The somatic motor association area:
responsible for the coordination of learned movements
List the four principle functional components of the pons and functions associated with those components.
sensory and motor nuclei of cranial nerves *nuclei involved with the control of respiration *nuclei and tracts that process and relay information to/from the cerebellum *ascending, descending and transverse tracts
