Chapter 40

1. Chapter 40 Neural Regulation

2. Nerve nets • Radially symmetrical invertebrates • Nerve cells scattered throughout the body

3. Hydra’s nerve net

4. Radial nervous systems • Radially symmetrical invertebrates • Nerve ring and nerves that extend to various parts of the body

5. Bilateral nervous systems • Bilaterally symmetrical animals • Nerve cells form nerves, nerve cords, ganglia, and brain • Sense organs concentrated in the head region

6. Bilateral nervous systems • Wide range of responses • Increased number of association neurons • More complex synaptic contacts permit a planarian flatworms

7. Planarian flatworms • Cerebral ganglia • Two solid ventral nerve cords connected by transverse nerves

8. Ladder-type nervous system in flatworms

9. Annelids and arthropods • Ventral nerve cord • Numerous ganglia • Cerebral ganglia of arthropods have specialized regions • Cephalopod mollusks • Complex nervous systems • Neurons in a central region

10. Annelid and arthropod nervous systems

11. Evolutionary trends • Increased numbers and concentration of nerve cells • Specialization of function • Increased number of association neurons • More complex synaptic contacts • Formation of a head

12. Vertebrate nervous system • Central nervous system (CNS) • Brain • Dorsal, tubular spinal cord • Peripheral nervous system (PNS) • Sensory receptors • Nerves

13. Vertebrate brain development • Brain and spinal cord arise from the neural tube • Anterior end of the tube differentiates into • Forebrain • Midbrain • Hindbrain

14. Early development of the vertebrate nervous system

15. Section through the human brain

16. Hindbrain subdivides into • Metencephalon • Myelencephalon

17. Myelencephalon develops into the medulla • Vital centers • Other reflex centers • Fourth ventricle • Communicates with the central canal of the spinal cord

18. Metencephalon gives rise to the cerebellum • Muscle tone • Posture • Equilibrium • Pons • Connects various parts of the brain

19. Midbrain • Largest part of the brain in fishes and amphibians • Main association area, linking sensory input and motor output • Center for visual and auditory reflexes in reptiles, birds, and mammals

20. Brain stem • Medulla • Pons • Midbrain

21. Forebrain differentiates to form the diencephalon and telencephalon • Diencephalon develops into the thalamus and hypothalamus • Thalamus • Relay center for motor and sensory information

22. Hypothalamus • Controls autonomic functions • Links nervous and endocrine systems • Controls temperature, appetite, and fluid balance • Emotional and sexual responses

23. Telencephalon develops into the cerebrum and olfactory bulbs • Cerebrum • Divided into right and left hemispheres • In fishes and amphibians, integrates sensory information

24. In birds, the corpus striatum controls complex behavior patterns, such as flying and singing • In mammals, the neocortex accounts for a large part of the cerebral cortex

25. Human brain and spinal cord • Protected by bone and three meninges • Dura mater • Arachnoid • Pia mater • Cushioned by cerebrospinal fluid (CSF)

26. Spinal cord • Transmits impulses to and from the brain • Controls many reflex actions • Gray matter contains nuclei that serve as reflex centers

27. Structure of the spinal cord

28. Ascending tracts • Transmit information to the brain • Descending tracts • Transmit information from the brain

29. Withdrawal reflex • Sensory receptors • Sensory neurons • Interneurons • Motor neurons • Effectors

30. Reflex action

31. Human cerebral cortex • Gray matter • Forms folds or convolutions • Fissures • Deep furrows between the folds

32. Cerebrum • Sensory areas • Receive incoming sensory information • Motor areas • Control voluntary movement

33. Association areas • Link sensory and motor areas • Learning • Language • Thought • Judgment

34. The cerebrum consists of lobes • Frontal lobes • Parietal lobes • Temporal lobes • Occipital lobes

35. Human brain

36. White matter of the cerebrum • Lies beneath the cerebral cortex • Corpus callosum • Large band of white matter • Connects right and left hemispheres

37. Basal ganglia • Cluster of nuclei within the white matter • Important centers for motor function

38. Sleep–wake pattern • Regulated by the hypothalamus and brain stem

39. Alpha wave patterns • Relaxed states • Beta wave patterns • Accompany heightened mental activity

40. Theta and delta waves • Slower frequency • Higher-amplitude • Non-REM sleep

41. EEGs showing electrical activity in the brain

42. Reticular activating system (RAS) • Arousal system • Neurons filter sensory input • Selects which information is transmitted to the cerebrum

43. Non-REM sleep • Electrical activity of the cerebral cortex slows • Metabolic rate slows • REM sleep • Dreaming

44. Suprachiasmatic nucleus • Main biological clock • Receives information about light and dark • Transmits it to other nuclei that regulate sleep

45. Limbic system • Emotional aspects of behavior • Motivation • Sexual behavior • Autonomic responses • Biological rhythms

46. Hippocampus • Categorizes information • Consolidated memories • Amygdala • Evaluates incoming information • Signals danger

47. Learning • Acquiring information as a result of experience • Memory • Information is encoded, stored, and retrieved

48. Implicit memory • Unconscious memory for perceptual and motor skills • Explicit memory • Factual memory of people, places, or objects

49. Short-term memory • Recall information for a few minutes • Information can be transferred to long-term memory

50. Synaptic plasticity • Ability of the nervous system to modify synapses during learning and remembering • Long-term memory storage • Gene activation • Long-term functional changes at synapses