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Diencephalon

SlideCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Sits on top of the brain stem

Enclosed by the cerebral heispheres

Made of three partsThalamus

Hypothalamus

Epithalamus

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Diencephalon

SlideCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.15

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Figure 4.8 The human brain stem This composite structure extends from the top of the spinal cord into the

center of the forebrain. The pons, pineal gland, and colliculi

are ordinarily surrounded by the cerebral cortex.

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The Brainstem : Medulla oblongata

Most inferior portion, functions asa conduction pathway (descendingmotor neuron pathways decussate here)

Reflex centers for:

regulating heart rate

blood vessel diameter

coughing, sneezing

breathing

swallowing

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The Brainstem : Pons

Superior to Medullaoblongata.

Contains more ascendingand descending pathways.

Relays information fromcerebrum to cerebellum.

Also includes sleep andrespiratory centers.

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The Brainstem : Midbrain

Small section superior tothe pons.

Part of the auditory pathways and visualreflexes

Also involved in regulating

muscle tone/activity andcoordination

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The Brain : Reticular formation

2 types of nuclei:Cranial nerves III-XIIandReticular Formation nuclei whichare scattered throughout

brainstem

Many pathways from RF projectdirectly to cerebrum to modulateactivity

Habituation (repetitive stimuli)

Reticular Activating System

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The Diencephalon : Thalamus

Gateway to cerebral cortex

Most sensory stimuli project tothe thalamus, which in turn

projects to the cerebrum.

Thalamus also influencesmoods and activities associatedwith strong emotion.

(Two concepts: Sensoryintegration and Mood )

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The Diencephalon : Hypothalamus

Major control center ofautonomic nervous systemand endocrine system.

Centers associated with:

* Food/H2O intake * Thermoregulation

* Cardiovascular regulation * Hormone secretion * Sleep/waking

* Emotional behavior

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Thalamus

Slide 7.35 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Surrounds the third ventricle

The relay station for sensory impulsesTransfers impulses to the correct part ofthe cortex for localization andinterpretation

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Hypothalamus

SlideCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Under the thalamus

Important autonomic nervous systemcenter

Helps regulate body temperature

Controls water balance

Regulates metabolism

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Hypothalamus

SlideCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

An important part of the limbic system(emotions)The pituitary gland is attached to thehypothalamus

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Epithalamus

Slide 7.37 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Forms the roof of the third ventricle

Houses the pineal body (an endocrinegland)

Includes the choroid plexus formscerebrospinal fluid

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Brain Stem

SlideCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Attaches to the spinal cord

Parts of the brain stemMidbrain

Pons

Medulla oblongata

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Brain Stem

SlideCopyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Figure 7.15a

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Midbrain

Slide 7.39 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Mostly composed of tracts of nervefibers

Reflex centers for vision and hearingCerebral aquaduct 3 rd-4 th ventricles

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Pons

Slide 7.40 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

The bulging center part of the brain

stemMostly composed of fiber tracts

Includes nuclei involved in the control ofbreathing

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Medulla Oblongata

Slide 7.41 Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings

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

Contains important control centersHeart rate controlBlood pressure regulation

BreathingSwallowingVomiting

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