BIO 201 Chapter 14, Part 2 Lecture

8/14/2019 BIO 201 Chapter 14, Part 2 Lecture

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Chapter 14: Part 2The Brain and Cranial


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The Cerebrum

seat of intelligenceCerebral cortex- gray matter.

Gyri-Sulci-Longitudinal fissure-Cerebral hemispheres-


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The Cerebrum


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The Cerebrum


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Lobes of the Cerebrum

Four lobes: frontal lobe, parietal lobe,temporal lobe and occipital lobe.

Central sulcus- separates the frontaland parietal lobes.Precentral gyrus- primary motor area.Postcentral gyrus- primary

somatosensory area.


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Cerebral white matter

Commissural tracts- Corpus callosum: Association tracts- Projection tracts-


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Basal Ganglia

Three nuclei deep within eachcerebral hemisphere make up basal

ganglia.They are globus pallidus, putamen,and caudate nucleus.

Help initiate and terminate

movements, suppress unwantedmovements and regulate muscletone.


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Basal Ganglia


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The Limbic System

A ring of structures on the innerborder of the cerebrum and floor ofthe diencephalon.

Includes cingulate gyrus,hippocampus, dentate gyrus,amygdala, mammillary bodies,

thalamus, and the olfactory bulb.emotional brain as it governsemotional aspects of behavior.

Also involved in olfaction and


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The Limbic System


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Functional Organization ofthe Cerebral Cortex: Sensory

Primary somatosensory area-postcentral gyrus.

Primary visual area- occipital lobe.Primary auditory area- temporal lobe.Primary gustatory area- base of the

postcentral gyrus.Primary olfactory area- temporal

lobe.


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Functional Organization ofthe Cerebral Cortex:


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Functional Organization ofthe Cerebral Cortex: Motor

Primary motor area- precentral gyrus. Brocas speech area- left cerebral

hemisphere.


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Functional Organization ofthe Cerebral Cortex:

Somatosensory association area-posterior to primary somatosensory

area.Visual association area- occipitallobe.

Auditory association area- temporal

lobe.Wernickes area- left temporal and

parietal lobes.


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Brain Waves

Electroencephalogram: Recording ofthe electrical

activity within thebrain. Alpha waves Beta waves

Theta waves Delta waves


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Cranial Nerves

12 pairs.

Sensory, motor and mixed nerves.

Name as well as roman numericnumbers to identify the nerves.


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Olfactory (I) Nerve

Sensory nerve. Sense of smell. Olfactory cells

converge to

become olfactory


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Optic (II) Nerve

Sensory nerve. Ganglion cells in

the retina of eacheye join to form anoptic nerve.

Nerve of vision.


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Oculomotor (III) Nerve


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Trochlear (IV) Nerve

Motor cranialnerve.

Smallest of the 12

cranial nerves. Origin: midbrain. Controls movement

of the eyeball.


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Trigeminal (V) nerve

Largest cranialnerve.

Mixed nerve.

Three branches:opthalmic,maxillary andmandibular. Dealwith sensation oftouch, pain andtemperature.

Motor axons supplymuscles of


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Abducens (VI) Nerve

Motor cranialnerve.

Originates from the

pons. Cause abduction of

the eyeball (lateralrotation).


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Facial (VII) Nerve

Mixed cranialnerve.

Sensory portion

extends fromthe taste budsof the anteriortwo-thirds of the

tongue. Motor portionarises from thepons and dealwith facial


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Vestibulocochlear (VIII)Nerve

Sensory cranialnerve.

Originates in

the inner ear. Vestibular

branch carriesimpulses for

equilibrium. Cochlear

branch carriesimpulses for


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Glossopharyngeal (IX)Nerve

Mixed cranialnerve.

Sensory axonscarry signals

from the tastebuds of theposterior one-third of thetongue.

Motor neuronsarise from themedulla anddeal with therelease of


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Vagus (X) Nerve


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Vagus (X) Nerve

Mixed cranial nerve.Distributed from the head and neck

into the thorax and abdomen.

Sensory neurons deal with a varietyof sensations such as proprioception,and stretching.

Motor neurons arise from the medulla

and supply muscles of the pharynx,larynx, and soft palate that areinvolved in swallowing andvocalization.


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Accessory (XI) Nerve

Motor cranialnerve.

Divided into

cranialaccessory andspinal accessorynerves.

Supplies

sternocleidomastoid andtrapeziusmuscles tocoordinate head


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End of Chapter 14, Part2

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BIO 201 Chapter 14, Part 2 Lecture