Brain and cranial nerves (Chp.15) Flashcards by Rowan Sit

3 major proportions of brain:
_________, _________ & ___________

cerebrum; cerebellum; brainstem

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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

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Cerebellum (Blue area):
* inferior, posterior to
cerebrum
* Separated from cerebrum
by _____________________
* 10% of brain volume

transverse cerebral
fissure

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Brainstem (Green area):
* Essential for survival;
vital functions
* Consists sub-regions
* Continues as ____________
inferiorly

spinal cord

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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

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Three membranes
protect and provide
structures for the brain
* _____________, ____________ and _____________

dura mater; arachnoid mater; pia mater

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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

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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

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Hollow space in the brain, filled with _____________________

cerebrospinal fluid

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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

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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

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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

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II.2.1 Brainstem
Consists of
* ____________
* ____________
* __________________________

Midbrain; pons; medulla oblongata

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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

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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

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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

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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。

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Internal structures:
* _________________________: awareness of pain
* ___________________: motor center, improves motor performance by suppressing unwanted movements

Central /periaqueductal gray; Substantia nigra

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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

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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

* 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)