Nervous System

1. Nervous System Textbook Reference: chapter 7

2. Objectives Unit 7 7.1 Name the organs of the nervous system and their functions within each classification of the nervous system 7.2 Describe the anatomy of a neuron and each part’s function 7.3 Differentiate between the 3 types of neurons and their functions 7.4 Describe the changes in a neuron when it is polarized, depolarized & re-polarized 7.5 Name the 4 main regions of the brain and their subdivisions 7.6 Name the purpose and structure of the spinal cord 7.7 Describe a reflex arc, its purpose and the anatomy of the process 7.8 Compare how different neuroglial cells work to support neurons

3. Objectives Unit 7 7.9 Explain how an action potential is transmitted 7.10 Describe the unique functions of the anatomy of a brain 7.11 Identify the parts of a sheep brain 7.12 Identify the homeostatic mechanisms of the nervous system

4. The Function • To act as the master controlling and communicating system for the body http://www.agen.ufl.edu/~chyn/age2062/lect/lect_20/nervsys.gif

5. Central Nervous System (CNS) Includes brain and spinal cord Acts as integrating and command center Peripheral Nervous System (PNS) Includes nerves outside of CNS Spinal nerves Cranial nerves Links all parts of body by carrying impulses Structural Classifications

6. PNS Assignment • There are 12 cranial nerves (pgs. 231-232) LOOK THEM UP!! You are responsible for knowing their number, name and function. For example: Cranial nerve I: olfactory, sense of smell Quiz to be announced!!

7. I. Olfactory II. Optic III. Oculomotor IV. Trochlear V. Trigeminal VI. Abducens VII. Facial VIII. Vestibulocochlear IX. Glossopharyngeal X. Vagus XI. Accessory XII Hypoglossal PNS: Cranial Nerves12 pairs “Oh, oh, oh, to touch and feel very good velvet, ah!”

10. Subdivisions of PNS • 1.) Somatic system:voluntary nervous system • Contains sensory and motor nerves • Makes you aware of the world around you & allows you conscious control

11. Subdivisions of PNS • 2.) Autonomic System:involuntary nervous system • Consists of motor nerves that carry impulses to organs, blood vessels and glands • The unconscious or “automatic control”

12. A. Sympathetic Division Active during stress  heart rate, respiratory rate and rate of ATP breakdown B. Parasympa-thetic Division Active during conditions of normal organ functioning Subdivisions of Autonomic System

13. Cells of the Nervous System • 1. Neuroglia • Acts to supportneurons • Makes up ~ 90% of brain and spinal cord (s.c.) • There are 5 different types of neuroglial cells

14. Assignment • Spilt your paper into 4 grids-1 grid for each cell type • Using pages 204-207 in your text, draw the different types of neuroglia and list their location and function within the nervous system below each drawing • DO NOT draw Schwann cells but do list its location and function

15. Cells of the Nervous System • 2. Neurons • The conducting nerve cell • Senses changes in environment, integrates information, carries out motor responses • Structure: each neuron varies in shape and size, but all have 3 main parts (dendrite, axon and cell body)

16. Neuron Anatomy • Dendrite: a process off of the cell body; receives impulses from adjacent neurons & conducts electrical impulses TOWARD the cell body; ~1000/neuron

17. Neuron Anatomy B. Axon: aka nerve fiber; acts to transmit impulses AWAY from the cell body; 1 axon/neuron C. Cell Body: contains the nucleus and metabolic center of the cell

18. Neuron Anatomy D. Myelin sheath: Lipid covering on some neurons. It encloses the axon & speeds up the rate of nervous conduction i. Gray matter: non-myelinated nerve fiber ii. White matter: myelinated nerve fiber

19. Myelinated Non myelinatedNeuron Neuron

20. Multiple Sclerosis

21. Neuron Anatomy E. Nodes of Ranvier: gaps in myelin sheath @ regular intervals; aids in increasing speed of nervous conduction See separate notes for how to conduct nervous impulses

23. How neurons communicate at synapses

25. Nerve ConductionPolarized – Nerve at Rest

26. Nerve ConductionStimulus initiates neurotransmitter

27. NERVE CONDUCTIONDepolarization & generation of the action potential

28. NERVE CONDUCTIONPropagation of the action potential

29. Nerve ConductionRepolarization

30. Once impulse stops, the Na – K pump restores the neuron to its resting state.

31. Impulse Conduction • Unmyelinated neurons slower than myelinated • Impulses on myelinated neurons seem to jump from one node of Ranvier to the next

32. 3 Types of Neurons 1. Afferent (sensory) Neurons: transmit impulses from PNS to CNS i.e. pain receptors and proprioceptors 2. Efferent (motor) Neurons: transmit impulses from CNS to muscles or glands

33. 3 Types of Neurons 3. Interneurons (association neurons): located within CNS and conducts impulses between sensory and motor neurons

34. Neurons Classified by Function

35. Reflex Arc

36. Reflex Center • Reflex: an extremely rapid response to an emergency situation • Occurs in spinal cord or lower brain; does not require thinking • The Reflex Arc: • Receptor: at end of sensory neuron; can generate an action potential to CNS • Association neurons: receive info. from sensory neuron and routes response to motor neuron • Motor neurons: conduct impulses to effectors

37. Think About This • A finger comes in contact with a hot stove. Draw and explain the reflex arc, involved in this emergency situation. • Label the 3 different neurons in your picture • Include the stove, finger, arm and spinal column in your drawing/explanation

38. 5 basic elements of all reflex arcs

39. Left Brain Language Logic Analytical thought Scientific Skill Numbers R hand control Right Brain Visual/spatial info. Imagination Insight 3-D forms Musical Awareness L hand control Central Nervous System But does this theory still hold true?

40. 'Right Brain' or 'Left Brain' - Myth Or Reality?By John McCrone • The 2 sides are actually more complementary…. • Left: more detail oriented • Right: concentrates on the broad background picture • Example: when listening to speech, the left brain concentrates on the vocabulary and grammar, while the right brain picks up the intonation and emotion • Example: right side strokes

41. Boy Brain vs. Girl Brain??Structural Differences • Males: • more white matter • larger hypothalamus • Girls: • more gray matter • larger corpus callosum

42. Females Better verbally Memory fluency Color id Written tests Un-timed tests Better grades More nurturing More accurate/detail oriented Navigation by landmarks More subdued/passive Interpreting emotions & hidden meanings More intuitive Males Visual-spatial activities Aiming at moving or stationary objects Throwing and intercepting projectiles Navigation by distance, time or spatial clues Better at multiple choice tests More aggressive-enjoys rough-housing Excel in higher levels of math Boy Brain vs. Girl Brain??Functional Differences

43. Central Nervous System • Brain and Spinal Cord • Brain will be learned in inquiry assignment

44. CNS: The Brain • 4 major portions: • Cerebrum: largest; sensory & motor function, higher thought, memory & reasoning • Cerebellum: coordination of skeletal muscles • Diencephalon: sensory information • Brain stem: connects parts of nervous system; controls visceral activities

45. CNS: Cerebral Lobes • Frontal Lobe: anterior portion • Primary motor area • Concentration, planning, problem solving • Broca’s Area: motor speech • Temporal Lobe: lateral lobe • Interpretation of sensory impulses, memory, visual & auditory patterns • Auditory area • Olfactory area

46. External Brain Diagram

47. CNS: Cerebral Lobes • Parietal Lobe: superior, lateral lobe • Sensory area • Understanding speech; using words • Occipital Lobe: posterior lobe • Vision • Combining visual images; visual recognition

48. Internal Brain Structures

49. Internal Brain Structures