1. Chapter Two The Anatomy and Evolution of the Nervous System

2. CHAPTER 2 THE ANATOMY AND EVOLUTION OF THE NERVOUS SYSTEM

3. Anatomical Directions Rostral or anterior – Head end of four legged animal Caudal or posterior – Tail end of four legged animal Inferior or ventral – Towards the belly Superior or dorsal – Towards the back

4. Planes of Section Coronal (frontal) Sagittal Horizontal (axial)

5. Figure 2.1 Anatomical Directions

6. Figure 2.2 Planes of Section

7. Protecting and Supplying the Nervous System Meninges – Three layers of meninges provide protection Cerebrospinal Fluid – Secreted in hollow spaces in the brain known as ventricles – Circulates through ventricles, subarachnoid space, and central canal of the spinal cord Blood Supply – Brain receives nutrients through the carotid arteries and vertebral arteries

8. Figure 2.3 The Skull and Three Layers of Membrane Protect the Brain

9. Figure 2.5 Cerebrospinal Fluid Circulates Through the Ventricles, Spinal Cord and Subarachnoid Space

10. Figure 2.7 The Brain Has a Generous Supply of Blood

11. Figure 2.8 The Organization of the Nervous System

12. The Central Nervous System The Spinal Cord – Extends from medulla to the first lumbar vertebra The Hindbrain – The myelencephalon (medulla) – The metencephalon (pons and cerebellum) The Midbrain – The mesencephalon

13. Figure 2.9 The Anatomy of the Spinal Cord

14. Figure 2.10 Structures of the Brain Stem

15. Table 2.1 Some Important Structures of the Brainstem

16. Figure 2.11 The Internal Structure of the Midbrain

17. The Central Nervous System The Forebrain – The Thalamus and Hypothalamus of the Diencephalon – The Basal Ganglia – The Limbic System – The Cortex Lobes of the cortex Localization of function in the cortex

18. Figure 2.12 The Thalamus and Hypothalamus of the Diencephalon

19. Figure 2.13 The Basal Ganglia Are Located Deep Within the Cerebral Hemispheres

20. Figure 2.14 The Limbic System Participates in Learning and Emotion

21. Table 2.2 Structures of The Limbic System

22. Figure 2.16 Comparative Convolutions of the Cortex

23. Figure 2.17 The Layers of the Cerebral Cortex

24. Figure 2.19 The Lobes of the Cerebral Cortex

25. Figure 2.20 The Corpus Callosum and the Anterior Commissure

26. The Peripheral Nervous System The Cranial Nerves – Enter and exit the brain directly to serve the region of the head and neck The Spinal Nerves – 31 pairs of spinal nerves exit the spinal cord to provide sensory and motor pathways to the torso, arms, and legs – Mixed nerve (containing an afferent and efferent nerve) The Autonomic Nervous System – Manages the vital functions of the body without conscious effort or awareness

27. Figure 2.22 The 12 Pairs of Cranial Nerves

28. Figure 2.23 The Structure of the Spinal Cord

29. The Autonomic Nervous System The Sympathetic Nervous System – Fight-or-flight system The Parasympathetic Nervous System – Provides rest, repair, and energy storage Central Control of the Autonomic Nervous System – Hypothalamus, midbrain tegmentum, and reticular formation

30. Figure 2.24 The Autonomic Nervous System

31. The Evolution of the Human Brain and Nervous System Natural Selection and Evolution – Natural selection favors the organism with highest degree of fitness Evolution of the Nervous System – Fairly recent development – Vertebrates or chordates = animals with spinal columns and real brains Evolution of the Human Brain – Outstanding feature of modern humans is brain size – Brain development occurred very quickly

32. Figure 2.25 Timeline for the Evolution of the Brain

33. Figure 2.26 True Brains Are Found in Chordates

34. Figure 2.27 Chordate Brains Continued to Evolve