Brain and Cranial Nerves Flashcards
deep groove that separates cerebral hemispheres
Longitudinal fissure
thick folds on brain surface
Gyri
shallow grooves between gyri
Sulci
thick nerve bundle at bottom of longitudinal fissure that connects hemispheres
Corpus Callosum
surface layer (cortex) over cerebrum and cerebellum that contains cell bodies, dendrites, and synapses.
Gray matter
Called “tracts” in the CNS, “nerves” in the PNS. Made up of bundles axons
White matter
Four major portions of the brain
cerebrum
cerebellum
diencephalon
brainstem
largest part of the brain
cerebrum
largest part of hindbrain
Cerebellum
second largest part of the brain
Cerebellum
what is apart of the Diencephalon
Thalamus
Epithalamus
Hypothalamus.
- “Gateway to the cerebral cortex”
Thalamus
screens out most of the information it receives and des not pass it along to the cerebral cortex.
Thalamus
what does the thalamus play a major role in?
Plays key role in motor control. Relays signals from cerebellum to cerebrum and provides feedback loops between the cerebral cortex and the basal nuclei.
Involved in memory and emotion because the limbic system includes some of the anterior thalamic nuclei.
Thalamus
is a major control center of autonomic nervous system and endocrine system.
Hypothalamus
what does the Hypothalamus play a role in
Plays an essential role in homeostatic regulation of all body systems.
Functions of hypothalamus
Hormone secretion
Autonomic effects
Thermoregulation
Food and water intake
Sleep and circadian rhythms
Memory
Emotional behavior
Anger, aggression, fear, pleasure, contentment, sexual drive
connect the limbic system to other parts of the brain
Epithalamus
what makes up the Epithalamus
Habernula
Pineal Gland
Parts of the brainstem
midbrain
pons
medulla oblongata
the smallest portion of the brainstem
Midbrain
between the pons and diencephalon
Midbrain
the part of the brainstem that links the medulla oblongata and the thalamus.
Pons
forming the lowest part of the brainstem and containing control centers for the heart and lungs.
Medulla Oblongata
what embryonic development of the nervous tissue is found in the third week
Neuroectoderm
Neural Plate
Neural Groove
Neural folds
what happens in the third week of development
Dorsal midline of embryo thickens to form neural plate
Neural plate sinks and its edges thicken and forms neural groove with a raised
neural fold on each side.
what embryonic development of the nervous tissue is found in the fourth week
Neural tube
Forebrain
Midbrain
Hindbrain
what embryonic development of the nervous tissue is found in the fifth week
Forebrain
-Telencephalon
-Diencephalon
Midbrain
-Mesencephalon
Hindbrain
-Metencephalon
-Myelencephalon
Meninges layers from outermost (superficial) to innermost (deep)
Dura mater
Arachnoid mater
Pia mater
Transparent membrane over brain surface
separates pia mater below
Arachnoid Mater
presses closely against cranial bones
Not directly attached to bone except around foramen magnum, sella turcica, crista galli, and sutures of the skull
Dura Mater
Very thin membrane, not usually visible without microscope
Follows arteries as they penetrate into cerebrum
Pia Mater
ventricles and flow of cerebrospinal fluid
spongy mass of blood capillaries on the floor of each ventricle produces CSF
choroid plexus
type of neuroglia that lines ventricles and covers choroid plexus
ependyma
what is the function of the cerebrospinal fluid
assists the brain by providing protection, nourishment, and waste removal
what are the factors that play a role in establishing and maintaining the blood brain barrier
Anything leaving the blood must pass through the cells and not the gaps between them and endothelial cells can be selective (unlike simple gaps) excluding harmful substances, while allowing necessary ones to pass through to brain tissue.
function of the blood brain barrier
what substances can get from bloodstream into tissue fluid of the brain to prevent pathogens from entering the brain.
where the barrier is absent allows blood direct access to the brain and enables the brain to monitor and respond to fluctuations in blood glucose, pH, osmolarity, and other variables.
circumventricular organs
where are circumventricular organs found?
places in the third and fourth ventricles
function of the reticular formation
Somatic motor control
Gaze centers
Central pattern generators
Cardiovascular control
Pain modulation
Sleep and consciousness
Habituation
function of the thalamus
Plays key role in motor control
They are located at the ends of the anterior arches of the fornix.
mammillary nuclei
function of the pineal gland
to receive information about the state of the light-dark cycle from the environment and convey this information by the production and secretion of the hormone melatonin
is the largest, most conspicuous part of human brain
cerebrum
function of the cerebrum
sensory perception, memory, thought, judgment, and voluntary motor actions
parts of cerebrum
-Frontal lobe
-Parietal lobe
-Occipital lobe
-Temporal lobe
-Insula
function of Frontal lobe
Voluntary motor functions, motivation, foresight, planning, memory, mood, emotion, social judgment, and aggression.
function of Parietal lobe
Integrates general senses, taste, and some visual information.
function of Occipital lobe
Primary visual center of brain.
function of Temporal lobe
Functions in hearing, smell, learning, memory, and some aspects of vision and
emotion
function of Insula
Helps in understanding spoken language, taste and integrating information from visceral receptors
name the tracts of the cerebral white matter
-Association tracts
-Commissural tracts
-Projection tracts
Connect different regions within the same cerebral hemisphere. Long fibers connect different lobes; short fibers connect gyri within a lobe.
Association tracts
Cross from one cerebral hemisphere to the other allowing communication between two sides of cerebrum
Commissural tracts
Extend vertically between higher and lower brain and spinal cord centers
Projection tracts
two principal types of neurons found in the cerebral cortex
Stellate cells
Pyramidal cells
Spheroid somas with dendrites projecting in all directions.
Receive sensory input, process information locally.
Stellate cells
Tall and conical, with apex toward the brain surface. A thick dendrite with many branches with small, knobby dendritic spines. Include the output neurons of the cerebrum which are axons that leave the cortex and connect with other parts of the CNS.
Pyramidal cells
what is the function of the basal nuclei and brain centers
helping to control:
Onset and cessation of intentional movements
Repetitive hip and shoulder movements in walking
Highly practiced, learned behaviors such as writing, typing, driving a car
what are the three brain centers that form the basal nuclei?
- Caudate nucleus
- Putamen
- Globus pallidus
what are the three brain centers that form the basal nuclei called collectively
corpus striatum
what are the putamen and globus pallidus together called
Lentiform nucleus
function of Caudate Nucleus
planning the execution of movement, but also in learning, memory, reward, motivation, emotion, and romantic interaction.
function of Putamen
learning and motor control, including speech articulation, language functions, reward, cognitive functioning, and addiction.
function of Globus Pallidus
control conscious and proprioceptive movements
function of Lentiform nucleus
working memory, executive function, reward, and learning
function of Corpus Striatum
reward and reinforcement circuit of the brain
what are the limbic system components
Cingulate gyrus
Hippocampus
Amygdala
function of limbic system
to process and regulate emotion and memory while also dealing with sexual stimulation and learning
[Gratification and Aversion]
function of Cingulate gyrus
helps regulate emotions and pain
function of Hippocampus
important limbic system area for memory
Functions in memory consolidation
organizes cognitive information into a unified long-term memory but does not hold the memory itself.
function of Amygdala
contains emotional memory
name the waves of the electroencephalogram (EEG)
-Alpha waves
-Beta waves
-Theta waves
-Delta waves
- Awake and resting with eyes closed and
mind wandering - Suppressed when eyes open or
performing a mental task.
Alpha waves
Eyes open and performing mental
tasks.
Accentuated during mental activity and sensory stimulation.
Beta waves
Drowsy or sleeping adults
If awake and under emotional stress.
Theta waves
High amplitude observed during deep sleepin adults.
Delta waves
temporary state of unconsciousness from which one can awaken when stimulated
sleep
Stage 1 sleep
Lasts 1 to 7 minutes. The individual feels drowsy, closes eyes, begins to relax but awakens easily if stimulated. EEG transitions: alpha waves to waves of mixed frequency.
Stage 2 sleep
Lasts 10 to 25 minutes in the initial sleep cycle. Light sleep, EEG frequency decreases but amplitude increases. 1 or 2 seconds of sleep spindles (high spikes) due to interactions between thalamus and cerebral cortex.
Stage 3 sleep
Typically begins about 20 minutes after Stage 1. Moderate to deep sleep, muscles relax, vital signs fall. Theta and delta EEG waves appear.
Stage 4 sleep
Usually occurs only in the first one-third of the night. Muscles very relaxed, vitals very low, difficult to awaken. EEG dominated by low- frequency, high-amplitude delta EEG waves (slow wave sleep).
Rapid eye movement sleep (paradoxical sleep)
Occurs about five times a night. Sleeper backtracks from Stage 3 or 4 to Stage 2
- 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
- Parasympathetic activation causes penile/clitoral erection and constriction of pupils
function of the prefrontal cortex
seat of judgment, intent, and control over expression of emotions
function of the Primary sensory (somesthetic) cortex
Provides awareness of stimulus.
function of Sensory (somesthetic) association area
Makes cognitive sense of stimulus.
function of the Primary visual cortex
to receive, segment, and integrate visual information
function of Visual association area
deals with recognizing faces and familiar objects
function of Primary auditory cortex
processes auditory information
function of Auditory association area
Recognizes spoken words, a familiar piece of music, or a voice on the phone
function of Primary gustatory cortex
responsible for the perception of taste
function of Primary olfactory cortex
is involved with the learning and memory of odors, and encodes representations of odor quality, identity, familiarity, and hedonics.
function of Primary motor cortex
generate signals to direct the movement of the body
function of Motor association (premotor) area
involved in the selection of appropriate motor plans for voluntary movements
Diagram of sensory inputs to the primary somesthetic cortex in parietal lobe. Resembles upside-down sensory map of contralateral side of the body.
sensory homunculus
has a distorted look because the amount of cortex devoted to a given body region is proportional to the number of muscles and motor units in that body region (not body region size)
motor homunculus
first-order neurons which are responsible for carrying the electrical impulses that initiate and modulate movement.
upper motor neuron
responsible for transmitting the signal from the upper motor neuron to the effector muscle to perform a movement
lower motor neuron
what are the two language areas
Wernicke area
Broca area
a language deficit from lesions to hemisphere with Wernicke and Broca areas
Aphasia
Slow speech, difficulty in choosing words, using words that only approximate the correct word
Non fluent (Broca) aphasia
- Speech normal and excessive, but uses
senseless jargon - Cannot comprehend written and spoken
words
Fluent (Wernicke) Aphasia
Can speak and understand speech, cannot identify written words or pictures
Anomic aphasia
usually the categorical hemisphere
- Specialized for spoken and written
language - Sequential and analytical reasoning (math
and science) - Breaks information into fragments and
analyzes it
Left hemisphere
usually the representational hemisphere
- Perceives information in a more
integrated way - Seat of imagination and insight
- Musical and artistic skill
- Perception of patterns and spatial
relationships - Comparison of sights, sounds, smells, and taste
Right hemisphere
which cranial nerves are sensory
I, II, and VIII
which cranial nerves are motor
III, IV, VI, XI, and XII
which cranial nerves are mixed
V, VII, IX, and X
Cranial nerve I
The Olfactory Nerve (I)
function: (Sensory) Sense of smell
Cranial nerve II
The Optic Nerve (II)
function:
(Senory): Provides vision
Cranial nerve III
The Oculomotor Nerve (III)
function: Motor: Controls muscles that turn the eyeball up, down, and medially, as
well as controlling the iris, lens, and upper eyelid
Cranial nerve IV
The Trochlear Nerve
function: Motor: Eye movement
Cranial nerve V
Trigeminal Nerve
function: Motor: Muscles of Mastication
Cranial nerve VI
The Abducens Nerve (VI)
function: Motor: Provides eye movement (lateral rectus m.)
Cranial nerve VII
The Facial Nerve (VII)
function:
- Motor—major motor nerve of facial muscles: facial expressions; salivary glands and tear, nasal, and palatine glands
- Sensory—taste on anterior two-thirds of tongue
Cranial nerve VIII
The Vestibulocochlear Nerve
function: Sensory: Nerve of hearing and equilibrium
Cranial nerve IX
The Glossopharyngeal Nerve
function: Swallowing, salivation, gagging, control of BP and respiration
Cranial nerve X
The Vagus Nerve (X)
function: Major role in the control of cardiac, pulmonary, digestive, and urinary function
Swallowing, speech, regulation of viscera
Cranial nerve XI
The Accessory Nerve (XI)
Motor: Swallowing; head, neck, and shoulder movement
Cranial nerve XII
The Hypoglossal Nerve (XII)
functions: Tongue movements for speech, food manipulation, and
swallowing
causes, symptoms and diagnosis of meningitis
inflammation of the meninges due to bacterial or viral invasion of CNS through nose and throat. Pia mater and arachnoid are most often affected. It can cause swelling of the brain, enlargment of the ventricles, and hemorrhage.
Signs: include high fever, stiff neck, drowsiness, intense headache
Diagnosed: by examining CSF obtained by lumbar puncture (spinal tap)
causes, symptoms and diagnosis of Trigeminal Neuralgia
Recurring episodes of intense stabbing pain in trigeminal nerve area (near mouth or nose)
Pain triggered by touch, drinking, washing face
Treatment may require cutting nerve
causes, symptoms and diagnosis of Bell Palsy
- Degenerative disorder of facial nerve causes paralysis of facial
muscles on one side - May appear abruptly with full recovery within 3 to 5 weeks
