Chapter 14 Study Topics – The Brain and the Cranial Nerves

Question 1

Define Rostral and Caudal

Answer 1

Rostral—toward the forehead​
Caudal—toward the spinal cord​

Question 2

List the 3 major portions of the brain.

Answer 2

1. Cerebrum is largest part of forebrain
2. Cerebellum is second-largest part of brain
3. Brainstem is the rest of the brain

Question 3

Compare the cortex to the nuclei – are these found in the gray matter or white matter?

Answer 3

Cortex—surface layer of gray matter in cerebrum, cerebellum
​Nuclei—deeper masses of gray matter, surrounded by white matter​

Question 4

What is white matter composed of?

Answer 4

White matter composed of tracts—bundles of nerve fibers (axons)

Question 5

What is gray matter composed of?

Answer 5

Gray matter contains nerve cell bodies, dendrites, and synapses​

Question 6

What is meningitis? How is it diagnosed?

Answer 6

Meningitis—inflammation of the meninges​; Diagnosed by examining CSF obtained by lumbar puncture (spinal tap)​
Symptoms: High fever, stiff neck, drowsiness, intense headache
Diagnosis: Examination of CSF by lumbar puncture (spinal tap)

Question 7

What is CSF? Where is it found in the brain?

Answer 7

Cerebrospinal fluid (CSF)—clear, colorless liquid that fills the ventricles, canals of CNS and bathes its external surface

Question 8

What are the 3 functions of CSF?

Answer 8

Buoyancy​
Allows brain to attain considerable size without being impaired by its own weight​

Protection​
Protects brain from striking cranium when head is jolted​
Shaken child syndrome and concussions still occur from severe jolting​

Chemical stability​
Flow of CSF rinses away metabolic wastes from nervous tissue and homeostatically regulates chemical environment

Question 9

What type of molecules can pass the BBS?

Answer 9

Highly permeable: Water, glucose, and lipid-soluble substances such as oxygen, carbon dioxide, alcohol, caffeine, nicotine, anesthetics​
Slightly Permeable: Sodium, potassium, chloride, waste products, urea, and creatine

Question 10

What are the two points of entry into the brain the BBS guards?

Answer 10

Blood capillaries throughout the brain tissue; guarded by the blood-brain barrier​
Capillaries of the choroid plexus; guarded by the blood-CSF barrier​

Question 11

What is the clinical term for a stroke? What are the 2 types and what causes them?

Answer 11

Stroke (cerebral vascular accident, CVA)
Two kinds of stroke distinguished by cause:

Hemorrhagic stroke—rupture of a cerebral or subarachnoid blood vessel​

Ischemic stroke—obstruction of a blood vessel by blood clot or lipid deposit

Question 12

What are the 3 components of the brain stem. List the functions that the medulla oblongata oversees.

Answer 12

1. Midbrain​
2. Pons​
   Pontine respiratory group - helps maintain normal rhythm of breathing​
3. Medulla Oblongata​
   Autonomic reflex center​
   Cardiovascular center​
   Respiratory centers - Generate respiratory rhythm and Control rate and depth of breathing (with pontine centers)​
   Additional centers regulate vomiting, swallowing, coughing, sneezing

Question 13

What is the gray matter in the cerebellum called? What is the white matter called?

Answer 13

(folia) Superficial cortex of gray matter with folds,
(arbor vitae) branching white matter and deep nuclei​

Question 14

List the functions of the cerebellum.

Answer 14

Motor coordination and locomotor ability​
Sensory, linguistic, emotional, and other nonmotor functions including:
~ Comparing textures of objects​
~Perceiving space (as tested by pegboard puzzles)​
~Recognizing objects from different views​
~Keeping judge of elapsed time and maintaining tapping rhythm ​
~Directing eye movements to compensate for head movement​
~Judging pitch of tones; distinguishing between spoken words​
~Helping in verbal association tasks​
~Planning, scheduling, and emotion control​

Question 15

List the 2 portions of the forebrain.

Answer 15

1.Diencephalon
~Encloses third ventricle​
~Most rostral part of the brainstem
2.Telencephalon
~Develops chiefly into the cerebrum

Question 16

List the 3 components of the diencephalon

Answer 16

The Diencephalon has three major components:
~Thalamus: The gateway to the cerebral cortex that plays a key role in motor control and emotions
~Hypothalamus: Forms parts of walls and the floor of the third ventricle while maintaining the major control center of the autonomic nervous system, endocrine system, and homeostatic regulation of all body systems
~Epithalamus: A small mass composed of the pineal gland (endocrine gland) that secretes melatonin

Question 17

What does the thalamus mediate?

Answer 17

The thalamus mediates sensation, motor activities, cortical arousal, learning, and memory

Question 18

What are the 7 functions of the hypothalamus?

Answer 18

1.Hormone secretion​
2.Autonomic effects​
3. Thermoregulation
4. Food and water intake ​
5.Sleep and circadian rhythms​
6. Memory
7. Emotional behavior and sexual response

Question 19

What gland does the epithalamus include? What does this gland secrete?

Answer 19

pineal gland, an endocrine gland, secretes melatonin​
- Melatonin—helps regulate sleep-wake cycle​

Question 20

What does each lobe of the cerebrum control?

Answer 20

1. Frontal Lobe: Voluntary motor functions, motivation, foresight, planning, memory, mood, emotion, social judgment, and aggression
2. Parietal Lobe: Integrates general senses, taste, and some visual information
3. Occipital Lobe: The primary visual center of the brain
4. Temporal Lobe: Functions in hearing, smell, learning, memory, and some aspects of vision and emotion
5. Insula: Helps in understanding spoken language, taste, and integrating information from visceral receptors

Question 21

What are the 3 types of tracts found in cerebral white matter? Describe each one. Which type of tract is the corpus callosum?

Answer 21

Projection tracts ​
~Extend vertically between higher and lower brain and spinal cord centers​
Commissural tracts​
~Cross from one cerebral hemisphere to the other allowing communication between two sides of cerebrum​
~corpus callosum = largest​ commissural tract
Association tracts​
~Connect different regions within the same cerebral hemisphere​

Question 22

What does the limbic system control? List the 3 components present in the limbic system.

Answer 22

Important center of emotion and learning​
Cingulate gyrus—arches over corpus callosum in frontal and parietal lobes​
Hippocampus—in medial temporal lobe​
Amygdala—immediately rostral to hippocampus

Question 23

What does the cerebrum’s basal nuclei control?

Answer 23

-Masses of cerebral gray matter buried deep in the white matter, lateral to the thalamus​
-Involved in motor control​

Question 24

What does an EEG measure?

Answer 24

brain waves, rhythmic voltage changes in surface layers of cortex​

Question 25

What happens during REM sleep?

Answer 25

Rapid eye movement (REM) sleep:​-Occurs about five times a night ​ -Eyes oscillate back and forth​ -Sleeper is harder to arouse than during any other stage ​-Vivid and long dreams​ -Sleep paralysis is stronger, preventing dreams from being acted out

Question 26

Compare the 3 sleep disorders discussed in class. Which one includes the destruction of orexins?

Answer 26

Narcolepsy ​ ~Abrupt lapse into sleep from awake state​ ~Orexins ("wake-up" chemicals from hypothalamus) ​ ~destroyed by immune system​ Insomnia ​ ~Chronic inability to obtain amount or quality of sleep needed​ Sleep apnea ​ ~Temporary cessation of breathing during sleep​ ~Causes hypoxia

Question 27

Define cognition

Answer 27

the range of mental processes by which we acquire and use knowledge

Question 28

Compare anterograde amnesia to retrograde amnesia

Answer 28

~Anterograde amnesia—unable to store new information​ ~Retrograde amnesia—person cannot recall things known before the injury​

Question 29

How do the hippocampus, cerebellum, and amygdala each play a role in memory?

Answer 29

Hippocampus—important limbic system area for memory​ Cerebellum—is involved in learning motor skills​ Amygdala—plays a role in emotional memory

Question 30

What is the role of the prefrontal cortex?

Answer 30

prefrontal cortex-seat of judgment, intent, and control over expression of emotions

Question 31

What is the role of the primary sensory cortex? What is a multimodal association area?

Answer 31

~Primary sensory- sites where sensory input is first received, and one becomes conscious of the stimulus​ ~Multimodal association areas receive input from multiple senses and integrate this into an overall perception of our surroundings Example: orbitofrontal cortex receives taste, smell, and visual input to provide overall impression of desirability of a food

Question 32

Where in the brain are the areas for the special senses (vision, hearing, equilibrium, taste, smell)?

Answer 32

Vision: Occipital lobe Hearing: Temporal lobe Equilibrium: Signals from inner ear project to cerebellum and brainstem nuclei Taste: Inferior end of postcentral gyrus Smell: Medial cortex of the temporal lobe

Question 33

What 2 regions of the brain are involved in voluntary motor control? What is Dyskinesias?

Answer 33

Two principal brain regions are involved in voluntary motor control: ~Motor association (premotor) area—found in frontal lobes​ Program transmitted to neurons of the ~precentral gyrus (primary motor area—The neurons send signals to the brainstem and spinal cord leading ultimately to muscle contractions Dyskinesias—movement disorders caused by lesions in the basal nuclei involving abnormal movement initiation (example: Parkinson disease)​

Question 34

What are the 2 regions of the brain that aid in language? What is Aphasia?

Answer 34

~Posterior speech area (Wernicke area)—posterior to lateral sulcus, usually in left hemisphere; recognition of spoken and written language ​ ~Motor language are (Broca area)—inferior prefrontal cortex, usually in left hemisphere; generates motor program for the muscles of the larynx, tongue, cheeks, and lips for speaking and for hands when signing​

Question 35

List the cranial nerves in order including their classification (sensory/motor/both) and function.

Answer 35

I.Olfactory→ Sensory→Smell II.Optic→ Sensory→Vision III.Oculomotor→ Motor→Eye movement IV.Trochlear→ Motor→ Eye V.Trigeminal→ Both→ Face sensation and mandible movement VI. Abducens→Motor→Eye movement VII.Facial→Both→ Facial muscle movement and taste VIII. Vestibulocochlear→Sensory→ Hearing and equilibrium IX. Glossopharyngeal→Both→ Regulation of blood pressure respiration, swallowing, and salivation X.Vagus→Both→Taste, hunger, gastrointestinal secretion, heart deceleration XI.Accessory→Motor→ Swallowing and movement of head, neck, and shoulders XII.Hypoglossal→Motor→Tongue movements Sensory nerves (CN 1, 2, and 8)—carry signals only from outlying sense organs to the brain​ Motor nerves (CN 3, 4, 6, 11, and 12)—stimulate muscle but also contain fibers of proprioception​ Mixed nerves (CN 5, 7, 9,10)—sensory functions may be quite unrelated to their motor function; example: facial nerve (7) has sensory role in taste and motor role in facial expression

Question 36

What does each of the 4 EEG waves represent? (You do not need to know the wavelength values)

Answer 36

Alpha waves→ awake but resting, eyes closed, not mentally contracting on any one subject Beta waves→ receiving sensory stimulation or engaged in concentrated mental activity Theta→ Drowsy or sleepy state in adults; Common in children Delta waves→ deep sleep