BIO 210 Chapter 13Supplement 3

The Central Nervous System

PowerPoint by John McGillSupplemental Notes by Beth

Wyatt

CEREBRUM

Largest, Uppermost Division STRUCTURE

CEREBRAL HEMISHPERES LOBES

CEREBRAL HEMISHPERES

2 Halves of the Cerebrum That are Joined

Sheep Brain: Cerebral Hemispheres

LOBES of the CEREBRUM LOBES

Cerebrum is Divided into Lobes by Fissures

Majority of Lobes Named After Bones FRONTAL LOBE PARIETAL LOBE TEMPORAL LOBE OCCIPITAL LOBE INSULA

Lies Hidden in the Lateral Fissure

LOBES of the CEREBRUM: Insula

Lies Hidden in the Lateral Fissure (a.k.a. lateral sulcus)

Insula Photos

Cerebral Fissures FISSURES (4 Major)

LONGITUDINAL FISSURE (next slide)

CENTRAL SULCUS (aka central fissure)

LATERAL FISSURE PARIETALOCCIPITAL

FISSURE

Cerebral Fissures: Longitudinal

Deepest; Divides Cerebrum into 2 Hemispheres

Cerebral Fissures: Central Sulcus

Cerebral Fissures: Lateral Fissures

Cerebral Fissures: Parietaloccipital

CEREBRAL CORTEX

CONVOLUTIONS (GYRI) are Folds SULCI are Grooves

Cerebrum vs. Cerebellum

Cerebral Cortex has Convolutions and Sulci as Cerebellum, Both Larger in Cerebrum

Cerebral Tracts White Matter of the

Cerebrum Lies Below the Cortex Cerebrum Has 3

Major Kinds of Tracts PROJECTION TRACTS ASSOCIATION TRACTS COMMISSURAL TRACTS

PROJECTIONTRACTS are

Extensions of Tracts of Spinal Cord & Brainstem, ascending & descending. Example of Ascending

(Sensory) spinothalamic

Example of Descending (Motor) corticospinal

Projection Tracts: Sensory/Ascending-spinothalamic

Projection Tracts: Motor/Descending-corticospinal

ASSOCIATION TRACTS

Tracts That Extend From 1 Convolution to Another Convolution in the SAME Hemisphere

Most Numerous

COMMISSURAL TRACTS

Tracts That Extend From 1 Convolution to a Corresponding Convolution in the OPPOSITE Hemisphere

Compose the Corpus Callosum

Additional Cerebral Structures

CEREBRAL NUCLEI (BASAL GANGLIA) CORPUS CALLOSUM SEPTUM PELLUCIDUM

CEREBRAL NUCLEI (BASAL GANGLIA)

Gray Matter Located Deep Within the Cerebrum’s White Matter

CEREBRAL NUCLEI (BASAL GANGLIA)

CORPUS CALLOSUM

White Curved Structure That Joins the 2 Cerebral Hemispheres

Composed of Commissural Tracts

SEPTUM PELLUCIDUM

Membrane That Lies Below the Corpus Callosum Covers the Lateral Ventricles

FUNCTIONS OF THE CEREBRAL CORTEX

Organized Into 3 Groups SENSORY, MOTOR, & INTEGRATIVE.

FUNCTIONS OF THE CEREBRAL CORTEX

SENSORY FUNCTIONS OF THE CEREBRAL CORTEX

Cortex Involved in the Interpretation of Sensations

MAJOR SENSORY AREAS OF THE CEREBRAL CORTEX

PRIMARY SOMATIC SENSORY AREA (POSTCENTRAL GYRUS): CONTAINS SOMATIC SENSORY MAP

VISUAL CORTEX (OCCIPITAL LOBE)

PRIMARY AUDITORY AREA (TRANSVERSE GYRUS)

PRIMARY TASTE AREA

MAJOR SENSORY AREAS

PRIMARY SOMATIC SENSORY AREA POSTCENTRAL GYRUS

CONTAINS SOMATIC SENSORY MAP Major Area Involved in the Interpretation of

General Sensations Located in the Postcentral Gyrus (Parietal Lobe) Contains a Somatic Sensory (General Sense) Map

VISUAL CORTEX (OCCIPITAL LOBE)

Major Area Involved in the Interpretation of Vision Located in the Occipital Lobe

PRIMARY AUDITORY AREA (TRANSVERSE GYRUS)

Major Area Involved in the Interpretation of Hearing Located in the Transverse Gyrus (Temporal Lobe)

PRIMARY TASTE AREA

Major Area Involved in the Interpretation of Taste

Located in the Postcentral Gyrus

ASSOCIATION AREAS

Areas that Assist the Major Sensory Areas in the Interpretation of Sensations

In Addition, Other Areas of the Brain are Also Involved in the Interpretation of Sensation (i.e., Mamillary Bodies, Corpora Quadrigemina, Thalamus)

MOTOR FUNCTIONS OF THE CEREBRAL CORTEX

Cortex also Involved the Producing Normal Voluntary Movements of Skeletal Muscles

MOTOR FUNCTIONS OF THE CEREBRAL CORTEX

Movements of Skeletal Muscles PRIMARY SOMATIC MOTOR AREA (PRECENTRAL GYRUS): CONTAINS

SOMATIC MOTOR MAP Major Area Responsible for Producing Voluntary Movements (Nerve Impulses

Begin Here) Located in the Precentral Gyrus (Frontal Lobe) Contains a Somatic Motor (Skeletal Muscle) Map

Sensory & Motor Maps

Motor Functions continued… PREMOTOR AREA

Assists the Major Motor Area in Producing Voluntary Movements

Located in the Frontal Lobe

In Addition, Other Areas of the Brain are Also Involved in Producing Normal Voluntary Movements (i.e., Cerebellum, Cerebral Nuclei, Thalamus)

Integrative Functions

3 cerebral functions: Sensory Motor Integrative

Integrative Functions Reticular Activating System-awareness Language-understanding & speech Limbic System-emotions Memory

INTEGRATIVE FUNCTIONS: Awareness

CONSCIOUSNESS RETICULAR ACTIVATING SYSTEM Awareness of One's Self, the Environment, Others

INTEGRATIVE FUNCTIONS: Awareness

Involves the Reticular Activating System (RAS) RAS = Neuron Pathways of the Reticular Formation, Brainstem,

Hypothalamus, Thalamus, Areas of the Cerebral Cortex Mechanism: As NI are Continuously Conducted Over the RAS and

Excite Key Areas of the Cerebral Cortex, Consciousness Results RAS Functions as the Arousal (Alerting) Mechanism

Integrative functions: LANGUAGE (SPEECH

CENTERS) The 2 major

Speech Centers Include: Wernicke's Area:

Sensory Speech Area (Understanding Language)

Broca's Area: Motor Speech Area (Use of Language) Speech Centers Are

Usually Located in the Left Cerebral Hemisphere

Integrative functions: EMOTIONS (LIMBIC SYSTEM)

Limbic System Structures Form a Curving Border Around the Corpus Callosum E.g. Cingulate gyrus & Hippocampus

Involved in Both the Experience and the Expression of Emotions

There Are Other Areas of the Cerebral Cortex Important in the Expression of Emotions

Integrative functions: Memory

Considered a Major Function of the Cerebral Cortex Involves Many Areas of the Cerebral Cortex Also Appears to Involve the Limbic System

Memory Formation

Memory Involves Many Brain Areas

Most activities involve multiple brain areas Consider hearing and then repeating

words: impulses start in the ear and end in the precentral gyrus

GENERALIZATIONS ABOUT CEREBRAL FUNCTIONS

LEFT AND RIGHT HEMISPHERES SPECIALIZE IN DIFFERENT FUNCTIONS Left: Language, Right: Nonlanguage (i.e., Images or Nonspeech

Sounds) Both Hemispheres Work Together to Accomplish Functions

CEREBRAL ACTIVITY GOES ON AS LONG AS LIFE ITSELF (EEG)

Cerebral Activity: Nerve Impulses (Measured as Brain Waves)

Absence of Brain Waves = Death (Brain Death) Evidence Comes From EEG Electroencephalogram:

Measures Brain Waves)

SENSORY PATHWAYS

FOR THE CEREBRAL CORTEX TO PERFORM ITS SENSORY FUNCTIONS, IMPULSES MUST BE CONDUCTED TO ITS SENSORY AREAS ALONG SENSORY PATHWAYS Example: Spinothalamic Sensory Pathways: See Handout & Next

Slide Sensory Pathways Are Crossed

SENSORY PATHWAYS

Motor Pathways

FOR THE CEREBRAL CORTEX TO PERFORM ITS MOTOR FUNCTIONS, IMPULSES MUST BE CONDUCTED FROM ITS MOTOR AREAS TO SKELETAL MUSCLES ALONG SOMATIC MOTOR PATHWAYS Example: Corticospinal Somatic Motor Pathways: See Handout & Next

Slide Most (Though Not All) Somatic Motor Pathways

Are Crossed

Motor Pathways

LEFT BRAIN & RIGHT BRAIN

LEFT AND RIGHT HEMISPHERES SPECIALIZE IN DIFFERENT FUNCTIONS due to ascending and descending pathways being crossed.