Chapter 14 Study Topics – The Brain and the Cranial Nerves Flashcards
Question #21, #23 & #5 I couldn't get on here with the pictures
Define Rostral and Caudal
Rostral—toward the forehead
Caudal—toward the spinal cord
List the 3 major portions of the brain.
- Cerebrum is largest part of forebrain
- Cerebellum is second-largest part of brain
- Brainstem is the rest of the brain
Compare the cortex to the nuclei – are these found in the gray matter or white matter?
Cortex—surface layer of gray matter in cerebrum, cerebellum
Nuclei—deeper masses of gray matter, surrounded by white matter
What is white matter composed of?
White matter composed of tracts—bundles of nerve fibers (axons)
What is gray matter composed of?
Gray matter contains nerve cell bodies, dendrites, and synapses
What is meningitis? How is it diagnosed?
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)
What is CSF? Where is it found in the brain?
Cerebrospinal fluid (CSF)—clear, colorless liquid that fills the ventricles, canals of CNS and bathes its external surface
What are the 3 functions of CSF?
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
What type of molecules can pass the BBS?
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
What are the two points of entry into the brain the BBS guards?
Blood capillaries throughout the brain tissue; guarded by the blood-brain barrier
Capillaries of the choroid plexus; guarded by the blood-CSF barrier
What is the clinical term for a stroke? What are the 2 types and what causes them?
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
What are the 3 components of the brain stem. List the functions that the medulla oblongata oversees.
- Midbrain
- Pons
Pontine respiratory group - helps maintain normal rhythm of breathing - 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
What is the gray matter in the cerebellum called? What is the white matter called?
(folia) Superficial cortex of gray matter with folds,
(arbor vitae) branching white matter and deep nuclei
List the functions of the cerebellum.
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
List the 2 portions of the forebrain.
1.Diencephalon
~Encloses third ventricle
~Most rostral part of the brainstem
2.Telencephalon
~Develops chiefly into the cerebrum
List the 3 components of the diencephalon
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
What does the thalamus mediate?
The thalamus mediates sensation, motor activities, cortical arousal, learning, and memory
What are the 7 functions of the hypothalamus?
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
What gland does the epithalamus include? What does this gland secrete?
pineal gland, an endocrine gland, secretes melatonin
- Melatonin—helps regulate sleep-wake cycle
What does each lobe of the cerebrum control?
- Frontal Lobe: Voluntary motor functions, motivation, foresight, planning, memory, mood, emotion, social judgment, and aggression
- Parietal Lobe: Integrates general senses, taste, and some visual information
- Occipital Lobe: The primary visual center of the brain
- Temporal Lobe: Functions in hearing, smell, learning, memory, and some aspects of vision and emotion
- Insula: Helps in understanding spoken language, taste, and integrating information from visceral receptors
What are the 3 types of tracts found in cerebral white matter? Describe each one. Which type of tract is the corpus callosum?
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
What does the limbic system control? List the 3 components present in the limbic system.
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
What does the cerebrum’s basal nuclei control?
-Masses of cerebral gray matter buried deep in the white matter, lateral to the thalamus
-Involved in motor control
What does an EEG measure?
brain waves, rhythmic voltage changes in surface layers of cortex
What happens during REM sleep?
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
Compare the 3 sleep disorders discussed in class. Which one includes the destruction of orexins?
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
Define cognition
the range of mental processes by which we acquire and use knowledge
Compare anterograde amnesia to retrograde amnesia
~Anterograde amnesia—unable to store new information
~Retrograde amnesia—person cannot recall things known before the injury
How do the hippocampus, cerebellum, and amygdala each play a role in memory?
Hippocampus—important limbic system area for memory
Cerebellum—is involved in learning motor skills
Amygdala—plays a role in emotional memory
What is the role of the prefrontal cortex?
prefrontal cortex-seat of judgment, intent, and control over expression of emotions
What is the role of the primary sensory cortex? What is a multimodal association area?
~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
Where in the brain are the areas for the special senses (vision, hearing, equilibrium, taste, smell)?
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
What 2 regions of the brain are involved in voluntary motor control? What is Dyskinesias?
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)
What are the 2 regions of the brain that aid in language? What is Aphasia?
~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
List the cranial nerves in order including their classification (sensory/motor/both) and function.
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
What does each of the 4 EEG waves represent? (You do not need to know the wavelength values)
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
