1. BIO 210 Chapter 13 Supplement 3 The Central Nervous System
PowerPoint by John McGill
Supplemental Notes by Beth Wyatt

2. CEREBRUM Largest, Uppermost Division STRUCTURE CEREBRAL HEMISHPERES
LOBES

3. CEREBRAL HEMISHPERES
2 Halves of the Cerebrum That are Joined

4. Sheep Brain: Cerebral Hemispheres

5. 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

6. LOBES of the CEREBRUM: Insula
Lies Hidden in the Lateral Fissure (a.k.a. lateral sulcus)

7. Insula Photos

8. Cerebral Fissures FISSURES (4 Major) LONGITUDINAL FISSURE (next slide)
CENTRAL SULCUS (aka central fissure)
LATERAL FISSURE
PARIETALOCCIPITAL FISSURE

9. Cerebral Fissures: Longitudinal
Deepest; Divides Cerebrum into 2 Hemispheres

10. Cerebral Fissures: Central Sulcus

11. Cerebral Fissures: Lateral Fissures

12. Cerebral Fissures: Parietaloccipital

13. CEREBRAL CORTEX
CONVOLUTIONS (GYRI) are Folds
SULCI are Grooves

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

15. Cerebral Tracts White Matter of the Cerebrum Lies Below the Cortex
Cerebrum Has 3 Major Kinds of Tracts
PROJECTION TRACTS
ASSOCIATION TRACTS
COMMISSURAL TRACTS

16. PROJECTION TRACTS are
Extensions of Tracts of Spinal Cord & Brainstem, ascending & descending.
Example of Ascending (Sensory)
spinothalamic
Example of Descending (Motor)
corticospinal

17. Projection Tracts: Sensory/Ascending-spinothalamic

18. Projection Tracts: Motor/Descending-corticospinal

19. ASSOCIATION TRACTS
Tracts That Extend From 1 Convolution to Another Convolution in the SAME Hemisphere
Most Numerous

20. COMMISSURAL TRACTS
Tracts That Extend From 1 Convolution to a Corresponding Convolution in the OPPOSITE Hemisphere
Compose the Corpus Callosum

21. Additional Cerebral Structures
CEREBRAL NUCLEI (BASAL GANGLIA)
CORPUS CALLOSUM
SEPTUM PELLUCIDUM

22. CEREBRAL NUCLEI (BASAL GANGLIA)
Gray Matter Located Deep Within the Cerebrum’s White Matter

23. CEREBRAL NUCLEI (BASAL GANGLIA)

24. CORPUS CALLOSUM
White Curved Structure That Joins the 2 Cerebral Hemispheres
Composed of Commissural Tracts

25. SEPTUM PELLUCIDUM Membrane That Lies Below the Corpus Callosum
Covers the Lateral Ventricles

26. FUNCTIONS OF THE CEREBRAL CORTEX
Organized Into 3 Groups
SENSORY, MOTOR, & INTEGRATIVE.

27. FUNCTIONS OF THE CEREBRAL CORTEX

28. SENSORY FUNCTIONS OF THE CEREBRAL CORTEX
Cortex Involved in the Interpretation of Sensations

31. 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

32. 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

33. VISUAL CORTEX (OCCIPITAL LOBE)
Major Area Involved in the Interpretation of Vision
Located in the Occipital Lobe

34. PRIMARY AUDITORY AREA (TRANSVERSE GYRUS)
Major Area Involved in the Interpretation of Hearing
Located in the Transverse Gyrus (Temporal Lobe)

35. PRIMARY TASTE AREA Major Area Involved in the Interpretation of Taste
Located in the Postcentral Gyrus

36. 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)

37. MOTOR FUNCTIONS OF THE CEREBRAL CORTEX
Cortex also Involved the Producing Normal Voluntary Movements of Skeletal Muscles

38. 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

41. Sensory & Motor Maps

42. 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)

43. Integrative Functions
3 cerebral functions:
Sensory
Motor
Integrative
Integrative Functions
Reticular Activating System-awareness
Language-understanding & speech
Limbic System-emotions
Memory

44. INTEGRATIVE FUNCTIONS: Awareness
CONSCIOUSNESS
RETICULAR ACTIVATING SYSTEM
Awareness of One's Self, the Environment, Others

45. 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

46. 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

47. 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

48. 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

49. Memory Formation

50. 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

51. 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

52. 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)

53. 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

54. SENSORY PATHWAYS

55. 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

56. Motor Pathways

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