Brain and cranial nerves (Chp.15) Flashcards
3 major proportions of brain:
_________, _________ & ___________
cerebrum; cerebellum; brainstem
- Cerebrum:
- 83% of brain volume
- Has pair of half globes called
______________ - Separated by longitudinal ___________
- Connected by ____________________
(bundle of nerve fibers) - ________: thick folds/elevations on
cerebrum - __________: deep groove/depression
hemisphere; fissure; Corpus callosum; Gyrus; Sulcus
Cerebellum (Blue area):
* inferior, posterior to
cerebrum
* Separated from cerebrum
by _____________________
* 10% of brain volume
transverse cerebral
fissure
Brainstem (Green area):
* Essential for survival;
vital functions
* Consists sub-regions
* Continues as ____________
inferiorly
spinal cord
Gray matter in the brain:
* At outer surface of cerebrum (cortex)
* Nuclei: deeper masses, collection of ________________
* White matter in the brain:
* Bundle of axons
* Connecting brain to spinal cord, or within the cerebrums
neuronal soma
Three membranes
protect and provide
structures for the brain
* _____________, ____________ and _____________
dura mater; arachnoid mater; pia mater
Dura mater:
* Dense fibrous connective tissue
* Has two layers: ________ & ____________
* Periosteal layer: attached to _____________
* Meningeal layer: inner layer
Dural sinuses:
* space between the two dural layers (e.g. _____________________)
* Collect blood and empties into ______
periosteal ; meningeal; cranial bones; superior sagittal sinus; veins
- In some areas, dura mater fold
inward to separate major parts of
brain - E.g. ___________ and ______________
Arachnoid & pia mater: - Similar to spinal cord
- Arachnoid mater:
- Transparent
- Over ____________ space, filled with CSF
- Pia mater:
- Delicate
- Cover cerebrum
Falx cerebri; Falx cerebrelli; subarachnoid
Hollow space in the brain, filled with _____________________
cerebrospinal fluid
- Ventricular system: 4 chambers (ventricles)
- Lateral ventricles X 2: in each cerebral hemisphere
- Third ventricle: connect to lateral ventricles via ______________________
- Fourth ventricle: connect to third ventricle via
______________________ - Fourth ventricle continues as central canal in
spinal cord - On floor of ventricles, spongy mass of
blood capillaries form _____________________,
producing CSF
interventricular foramen; cerebral aqueduct; choroid plexus
Functions of CSF:
1. Provide ______________: prevent brain from collapse due to own weight
2. Protection: prevent brain from striking the cranium
3. Chemical stability: remove metabolic wastes, maintain chemical environment
buoyancy
Brain Barrier system (BBS)
* Gives protection to the brain by regulating substances
from blood stream into the brain
1. Blood-Brain barrier (BBB):
* _____________ contact blood capillaries, stimulates _______________________
between ____________________________
2. Blood-CSF barrier:
* Formed at ____________________ by ____________________ cells
Astrocytes; tight junctions; endothelial cells; choroid plexus; ependymal cells
II.2.1 Brainstem
Consists of
* ____________
* ____________
* __________________________
Midbrain; pons; medulla oblongata
The Medulla Oblongata
* Contains all nerve fibers travel between brain
and spinal cord
* ___________ pairs of cranial nerves (nerves directly
arise from the brain to peripheries)
* Several nuclei with basic physiological functions:
* ________________: regulate rate and force of heartbeat
* _________________: regulate blood pressure and vasoconstriction;
* _______________ centers: regulate rate and depth of breathing
* Others: speech, cough, sneezing, swallowing, etc
Four; cardiac centre; vasomotor centre; respiratory centre
On the surface:
* _____________: clublike ridges
* _________________________: separates
pyramids
Internal structures:
* Ascending and descending tracts:
e.g. _______________ and ________________ tracts
Nucleus
* E.g. ___________________________
* Fourth ventricle
Pyramids; Anterior median fissure; tectospinal; corticospinal; inferior olivary nucleus
The Pons:
* Rostral（吻端） to the medulla
* Has pair of __________________, connecting to the cerebellum
* 4 pairs of cranial nerves begin/end here
Internal structures:
* Continuation of ascending/descending tracts
e.g. ______________________
* Part of fourth ventricles
cerebellar peduncles; tectospinal tract
The midbrain
* ___________________________ passes through
* Colliculus:
* Superior: visual reflex (e.g. blinking) and visual attention (tracking moving objects)
* Inferior: transduce auditory info to the brain; auditory reflexes (e.g. _________________)
Cerebral aqueduct; startle reflex
當變換嬰兒的位置或姿勢時，便會出現出雙手迅速向外伸張，然後再復原作擁抱狀。
Internal structures:
* _________________________: awareness of pain
* ___________________: motor center, improves motor performance by suppressing unwanted movements
Central /periaqueductal gray; Substantia nigra
Cerebellum
* Motor coordination center
* Consists two hemispheres,
connected by _________ (narrow
wormlike bridge)
* _______ = gyri (腦迴) on cerebrum
* Connect to:
* Medulla via ________ peduncles
* Pons via _________ peduncles
* Midbrain via _________ peduncles
* Internal structures:
* _________________: white matter
* Specific types of neurons: ____________ cells
and ____________ cells
vermis; folia; inferior; middle; superior; Arbor vitae; granule; Purkinje
- Highly important in motor coordination
- Involved in:
- Learning motor skills
- Maintain muscle tone and posture
- Coordinates eye and body movement
- Coordinate complex actions
- Received info from ___________ and _______________; compare planned and actual movement, send feedback to
_______________
cerebrum; joints; cerebrum
Thalamus
* Oval shape, separate into right and left
parts
* Consists of 23 nuclei
* Gateway to the _____________: almost all
sensory input passes by
* E.g. vision, hearing, somatosensory function
* Relays signals from _____________ to
cerebrum
* Also involved in memory and emotion as
_______ system
cerebral cortex; cerebellum; limbic
Reticular formation
* Loosely organized gray matter, runs vertically through brainstem
* Functions:
* Somatic motor control: adjust muscle tone, balance, posture via _________________________
* Work with cerebellum for motor
coordination
* Cardiovascular control
* _______________________: regulate/block pain signal to the brain
* Sleep and consciousness: control
state of consciousness
* ___________________: ignore repetitive, inconsequential stimuli
reticulospinal tract; pain modulation （疼痛調節）; Habituation (習慣化）
- ______________: most _________ (吻端) part of brainstem; part of forebrain
- Consists: Thalamus, hypothalamus and epithalamus
Diencephalon; rostral
The epithalamus
* Epithalamus: _______________ + ____________
* ______________: secrets melatonin, regulate sleep and consciousness
Pineal gland; habenula; Pineal gland
The Hypothalamus
* Walls and floor of the ______ ventricle
* Connected to the thalamus via _____________
* Very important in regulation of endocrine system and autonomic nervous system
* Functions:
* Produce and secret hormones:
* Regulate growth, metabolism, reproduction, etc.
* Autonomic effects:
* Influence brainstem functions
e.g. heart rate, blood pressure, digestive function, etc
* Thermoregulation
* Regulate appetite
* Emotion, reproductive response, memory, etc.
third; infundibulum;
Functions of the 5 lobes:
* ___________: For higher cognitive functions
* ___________: For sensation
* ___________: For vision
* ___________: For hearing, smell, etc
* ___________: for taste, visceral sensation.
Frontal; Parietal; Occipital; Temporal; Insula
Gross anatomy of cerebrum
* Extensive folding (gyri) to greatly increase surface area to house neurons
* Surface of cerebrum divided into 5 lobes:
* Frontal: anterior, superior part of the
brain.
* Parietal: separate from frontal by central
sulcus.
* Occipital: caudal part. Separated from parietal lobe by ________________________.
* Temporal: lateral, separated from parietal lobe by ________________________.
* Insula: deep to the __________.
parieto-occipital sulcus; lateral sulcus
White matter in the cerebrum
* Projection tracts:
* Extend vertically, between brain and spinal cord centers
* Examples: _________________ tract: carry motor commands to spinal cord
* _________________ tracts:
* Cross from one hemisphere to the other
* E.g.
* _________________: largest tract
* Anterior and posterior commissures
* Association tracts:
* Connect different regions in same
hemisphere
Corticospinal; Commissural; Corpus callosum;
- Limbic system:
- Center of _________ and __________
- Consists:
- Hippocampus
- Amygdala
- Cingulate gyrus
- _______________:
- Receives input from vision, taste,
smell, etc - Important for association of
sensation to emotion - Sense of fear: no __________, no fear
emotion; learning; Amygdalal; amygdala
Basal nuclei:
* Later to thalamus, a.k.a. basal ganglia
* Consists:
* Caudate nucleus
* Putamen
* Globus pallidus
* Involved in ________________
* Planning and execution of movement
* Sends feedback of action to _____________
motor control; motor cortex
- Primary cortex:
- Cerebrum regions connect directly with sensory or motor neurons
- i.e. with third order neurons or upper motor neurons
- Association cortex:
- Regions involved in integrative functions
- E.g. interpretation of sensory input
- Planning motor output
- Cognitive processes, etc
- May receive input from multiple senses and integrate these
- E.g. ____________
prefrontal cortex
Higher functions and structures of the cerebrum
* Special senses:
* Include taste, smell, hearing, equilibrium and vision
* Signals from sense organs/receptors are firstly sent to ______________________________
* Then signals are relayed to nearby association area, where sensation is integrated with memory and interpreted
primary sensory cortex
General/somatosensory senses
* General senses include touch, pressure,
stretch, temperature, pain, which are
received by skin receptors
* Sensory signals sent via ascending tracts
to ______________ side of thalamus, then
to _______________________, a.k.a. primary
somatosensory cortex
* Signals relayed to association area, for
interpretation
contralateral; postcentral gyrus
- ____________________________:
- A diagram showing which cortex
receive general sensation from
particular body areas - The more ______________ for a body
part, the much _______________________ - i.e. _____ and ______ are much
sensitive than _____ and _________________.
Sensory homunculus; cortex area; innervated and
sensitive; hand and face; trunk and lower
limbs
Motor control
* Intention to move begins in ____________________________ area
* Neurons compile a program for the muscle
movement for an action
* Then the program transmitted to
_________________________ /__________________ area
* Motor commands then being sent to
brainstem and spinal cord for carrying out
motor association; precentral gyrus; primary motor area;
- Motor _______________ shows amount and
region of cortex for motor action of body
parts - Amount of cortex in proportion to
number of muscles/motor units; more
innervation, more complex movement
can be made - I.e. action of _______ is much complex than
____________________________
homunculus; hand; the trunk and feet
Language
* Integration of sensory and motor functions
*_________________:
* _________________________; receive auditory, visual and
other sense information
* recognition of spoken and written language
* Formulate phrases; send to _____________
* Broca’s area:
* Motor association area: generate motor program for
muscles of larynx, tongue, cheeks and lips
* Transduce signal to _____________________________________ for execution
Wernicke’s area; sensory association area; Broca’s area; primary motor cortex
Cranial Nerves
* The brain mainly communicates with other body
parts via spinal cord and spinal nerves
* Cranial nerves:
* Directly arise from the brain and brainstem
* _____ pairs in total
12
- To remember the order and name of cranial nerves,
a useful mnemonic: - Take initial letter from the nerve
- OOO TT A Fa Ve Glo Va AH
- Olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, vestibulocochlear, glossopharyngeal,
vagus, accessory, hypoglossal
- To remember function of Cranial nerves, better classify
first - Cranial nerves classified as Predominantly
- Sensory (_____________),
- Motor (_____________________) or
- Mixed (_______________)
I, II, VIII; III, IV, VI, Xi, XII; V, VII, IX, X
Cranial nerves: Sensory nerves I, II, VIII
* Name: _____________________:
* Function: sense of smell
* Nerve with olfactory receptors
* Origin/termination:
* Olfactory __________ to olfactory _________
Olfactory nerve (I); mucosa; bulbs
- Name: _____________
- Function: Vision
- Origin/termination: ________ Thalamus/midbrain
Optic Nerve (II); Retina
- Name: ____________________________
- Function: (sensory): hearing & equilibrium
- Origins: cochlea, vestibule and semicircular ducts of inner ear
- Termination: medulla and pons (sensory); outer hair cells (motor)
Vestibulocochlear Nerve (VIII);
Cranial nerves: Motor III, IV, VI
* CN III, IV and VI are for eye movements
* Origin:
* III: Midbrain
* IV: midbrain
* VI: pons
* Termination (extra orbital muscles):
* III: extra orbital muscles (superior, midal and inferior rectus,
inferior oblique)
* IV: superior oblique
* VI: lateral rectus
Cranial nerves: Motor XI, XII
* Name: Accessory Nerve (XI); Hypoglossal Nerve (XII)
* Functions:
* XI: _________________; __________________________________
* XII: Tongue movement for ___________, food ______________________ and _________________
* Origins:
* Medulla Oblongata
(XI: also with spinal nerves __________)
* Terminations:
* XI: Palate; pharynx; trapezius and ____________________ muscles (head and neck muscles)
* XII: muscles of tongues
Swallowing; head/neck/shoulder movements; speech; manipulation; swallowing; C1 – C6; sternocleidomastoid
Cranial Nerves: Mixed (V, VII, IX, X)
* Name: _______________
* Divisions: V1, V2, V3
* Functions:
* V1: General sensation from ____________
* V2: General sensation from ____________
* V3: Same as V1 and V2, lower on face; ____________
* Origins;
* V1: ________ region of face; nasal mucosa, etc
* V2: ________ region of face; nasal mucosa etc
* V3: ________ region of face; tongue (sensory); Pons(motor)
* Terminations:
* V1 and V2: Pons
* V3: Pons (sensory); muscles for mastication
Trigeminal Nerve (V); upper face; lower face; mastication; Superior; middle; Inferior
- Name: _________________
- Functions:
- Sensory: taste
- Motor: facial expression; secrete tears saliva, nasal/oral mucus
- Origins:
- Sensory: taste buds, anterior two-thirds of tongue
- Motor: pons
- Termination:
- Sensory: thalamus
- Motor: muscles for mastication, facial expression, glands for saliva/tear/mucus secretion
Facial Nerve (VII)
- Name: ___________________________
- Functions:
- Sensory: general senses of tongue and outer ear,
gagging (______________) - Motor: salivation, swallowing
- Origins:
- Sensory: pharynx, ear, tongue
- Motor: medulla
- Termination:
- Sensory: medulla
- Motor: salivary gland; muscle dilates pharynx
Glossopharyngeal Nerve (IX); afferent fiber
- Name: ________________
- Function:
- Sensory: taste, sense of hunger, gastrointestinal discomfort
- Motor: swallowing, speech, heart rate regulation, broncho constriction
- Origins:
- Sensory: internal organs; tongue; pharynx, etc
- Motor: medulla
- Termination:
- Sensory: medulla
- Motor: tongue, pharynx and larynx, internal
Vagus Nerve (X)
