Pages 239-252. Cerebrum: General Functions Speech, memory, logical/emotional response Consciousness,...

Functions of Major Brain Regions

Pages 239-252

Cerebrum: General FunctionsSpeech, memory, logical/emotional responseConsciousness, interpretation of sensationVoluntary movementSpeech

Cerebrum: Primary Somatic Sensory AreaReceives impulses from the body’s sensory

receptorsPain, temperature, light touchLocated in parietal lobe posterior to central

sulcusSensory homunculus is a spatial map

showing locations of specifics sensationsLeft side of the primary somatic sensory area

receives impulses from right side or body(and vice versa)

© 2015 Pearson Education, Inc.

Figure 7.13c Left lateral view of the brain.

Primary motor area

Premotor area

Anteriorassociation area•Workingmemory andjudgment

Broca’s area(motor speech)

Olfactoryarea

Central sulcusPrimary somaticsensory area

Gustatory area(taste)

Speech/language(outlined by dashes)

Posteriorassociationarea

Visual area

Auditory area

• Problemsolving• Language

comprehension

(c)

Figure 7.14 Sensory and motor areas of the cerebral cortex.

Hand

Swallowing

Tongue

Jaw

Lips

Face

Eye

Brow

Neck

Thumb

Fingers

Wrist

Elb

ow

Arm

Sh

ou

lder

Trun

kH

ipK

nee

Fo

ot

Toes

Genitals

Kn

ee Leg Hip

Tru

nk

Nec

kH

ead

Arm

Elb

owFo

rear

mH

and

Fing

ers

Thum

b

Eye

Nose

Face

Lips

Teeth

Gums

Jaw

Tongue

Pharynx

Intra-abdominal

Posterior

Motor SensoryAnteriorMotor map in

precentral gyrusSensory map in postcentral gyrus

Primary motorcortex(precentral gyrus)

Primary somaticsensory cortex(postcentral gyrus)

Special SensesSpecific lobes of the cerebral hemispheres

are responsible for impulses of specific senses:Visual area (occipital lobe)Auditory area (temporal lobe)Olfactory area (temporal lobe)


Cerebrum: Primary Motor AreaSends impulses to skeletal muscles (efferent

pathway)Located in frontal lobe anterior to central

sulcusMotor neurons form corticospinal (pyramidal)

tract, which descends to spinal cordMotor homunculus is a spatial map

showing specific locations responsible for respective body areas



Primary motor area

Premotor area



Olfactoryarea





Visual area

Auditory area


comprehension

(c)

Figure 7.14 Sensory and motor areas of the cerebral cortex.

Hand

Swallowing

Tongue

Jaw

Lips

Face

Eye

Brow

Neck

Thumb

Fingers

Wrist

Elb

ow

Arm

Sh

ou

lder

Trun

kH

ipK

nee

Fo

ot

Toes

Genitals

Kn

eeL

eg Hip

Tru

nk

Nec

kH

ead

Arm

Elb

owFo

rear

mH

and

Fing

ers

Thum

b

Eye

Nose

Face

Lips

Teeth

Gums

Jaw

Tongue

Pharynx

Intra-abdominal

Posterior

Motor SensoryAnteriorMotor map in

precentral gyrusSensory map in postcentral gyrus

Primary motorcortex(precentral gyrus)

Primary somaticsensory cortex(postcentral gyrus)

Cerebrum: Specialized AreasBroca’s area

Involved in our ability to speakUsually in left hemisphere

Anterior and posterior association areas Involved in multiple capabilities including:

Reasoning Behavior Visual recognition Speech



Primary motor area

Premotor area



Olfactoryarea





Visual area

Auditory area


comprehension

(c)

Figure 7.12b Development and regions of the human brain.

Cerebralhemisphere

Brain stem

Cerebellum

Diencephalon

(b) Adult brain

Structures of the Diencephalon

DiencephalonThalamus

Surrounds the third ventricleRelay station for sensory impulses

Sends impulses to cortex for interpretationDistinguishing pleasant vs. unpleasant

sensations begins here (pg. 246)Involved in memory


DiencephalonHypothalamus

Important autonomic nervous system center Helps regulate: body temperature, water balance,

metabolismHouses limbic center which is responsible

for: emotions (pleasure, fear, anger) drives (hunger, sex, parenting, dominance)

Regulates pituitary gland (which produces ADH and oxytocin)

Houses mammillary bodies for olfaction (smell) These are reflex centers for smell


DiencephalonEpithalamus

Houses the pineal body an endocrine gland which produces melatonin, a

hormone involved in regulating sleep cycles and reproductive behaviors

Includes the choroid plexus of the 3rd ventricle Capillaries within the ventricles which form CSF

Regulates motor pathways and emotions


Figure 7.16a Diencephalon and brain stem structures.

Third ventricle

Anteriorcommissure

Hypothalamus

Optic chiasma

Pituitary gland

Mammillary body

Pons

Medulla oblongataSpinal cord

(a)

Cerebral hemisphere

Corpus callosum

Choroid plexus of thirdventricle

Occipital lobe ofcerebral hemisphere

Thalamus(encloses third ventricle)

Pineal gland(part of epithalamus)

Corpora quadrigemina

Cerebral aqueduct

Cerebral peduncle

Fourth ventricleChoroid plexusCerebellum

Midbrain


Third ventricle

Anteriorcommissure

Hypothalamus

Optic chiasma

Pituitary gland

Mammillary body

Pons


(a)

Cerebral hemisphere

Corpus callosum






Cerebral aqueduct

Cerebral peduncle


Midbrain

Structures of the Brain Stem

Brain StemMidbrain

Composed mostly of tracts of nerve fibersTwo bulging fiber tracts, cerebral peduncles,

convey ascending and descending impulsesFour rounded protrusions, corpora

quadrigemina, are the visual and auditory reflex centers called “colliculi”


Brain StemPons

The anteriorly bulging center part of the brain stem

Mostly composed of fiber tractsIncludes nuclei involved in the control of

breathing


Brain StemMedulla oblongata

The lowest part of the brain stemMerges into the spinal cordIncludes important fiber tracts from the

cerebrum These tracts cross to opposite sides at this location

Contains important homeostatic control centers: Heart rate control Blood pressure regulation Breathing Swallowing Vomiting


Brain StemReticular formation

Diffuse mass of gray matter along the entire brain stem

Involved in motor control of visceral (internal) organs

Reticular activating system (RAS) Plays a role in awake/sleep cycles and

consciousness Filter for incoming sensory information


Figure 7.16b Diencephalon and brain stem structures.

Radiationsto cerebralcortex

Auditoryimpulses

Descendingmotor projectionsto spinal cord

Reticular formation

Ascending general sensorytracts (touch, pain, temperature)

(b)

Visual impulses

CerebellumTwo hemispheres with convoluted surfacesControls balance and equilibriumProvides precise timing for skeletal muscle

activity and coordination of body movementsBalance, posture

Alcohol affects coordination via the cerebellum



Third ventricle

Anteriorcommissure

Hypothalamus

Optic chiasma

Pituitary gland

Mammillary body

Pons


(a)

Cerebral hemisphere

Corpus callosum






Cerebral aqueduct

Cerebral peduncle


Midbrain

This midsagittal section shows the gray matter outlining the arbor vitae (white)

The Cerebellum

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