1. 1.What is the difference between a neuron and other cells? Where does it start and end? 2.What is the interaction that neurons have with muscles?

2. 1.Draw a neuron and label it. Try not to look back and cheat. 2.What is an action potential?

3. Explain this graph. What are the three most important numbers?

4. Draw the axon of neuron so that you can see the inside and the outside. Now label which side starts out positive and negative. Also, label the placement of the sodium and potassium ions at resting potential.

6. 1.How do you think your body registers different amounts of pain or pressure? How does it separate out the difference. Explain your answer.

7. Neural Control of Exercising Muscle

8. Neuron has three major regions: Cell body –Contains nucleus Dendrites –Receiver cell processes Axon –Sender cell process, starts at axon hillock –End branches, axon terminals store neurotransmitters in vesicles.

9. Nervous System Structure and Function: Nerve Impulse Electrical signal for communication between periphery and brain Must be generated by a stimulus Must be propagated down an axon Must be transmitted to next cell in line

10. Resting Membrane Potential Difference in electrical charges between outside and inside of cell −70 mV Caused by uneven separation of charged ions Polarized

11. 1.What is depolarizing mean? What causes it? 2.Why does hyperpolarization happen? What does it mean?

12. Resting Membrane Potential Why −70 mV? –High [Na + ] outside cell, medium [K + ] inside cell –Inside more negative relative to outside Na + channels closed –Na + wants to enter cell but can’t K + channels open –K + leaves cell (concentration gradient) –Offset by Na + −K + pumps

13. Depolarization and Hyperpolarization Depolarization –Occurs when inside of cell becomes less negative, -70 mV  0 mV –More Na + channels open, Na + enters cell Hyperpolarization –Occurs when inside of cell becomes more negative, -70 mV  −90 mV –More K + channels open, K + leaves cell

14. Graded and Action Potentials Depolarization and hyperpolarization contribute to nervous system function via –Graded potentials (GPs) Help cell body decide whether to pass signal to axon Can excite or inhibit a neuron –Action potentials (APs) Pass signal down axon Only excitatory

15. Graded Potentials Localized changes in membrane potential –Generated by incoming signals from dendrites –Inhibitory signal = K + efflux = hyperpolarization –Excitatory signal = Na + influx = depolarization Strong GP  AP –How strong? Must depolarize to threshold mV –AP will be propagated down axon –AP will be transmitted to next cell

16. Action Potentials: Generating an AP If GP reaches threshold mV, AP will occur –~−55 mV –Threshold mV not reached = no action potential –All-or-none principle − 70 mV  +30 mV  − 70 mV again –− 70 to −55 mV: depolarizing GP, Na + influx –− 55 to +30 mV: depolarizing AP, Na + influx –+30 to −70 mV: repolarizing AP, K + efflux

17. Figure 3.3

18. Action Potentials: Refractory Periods Absolute refractory period –During depolarization –Neuron unable to respond to another stimulus –Na + channels already open, can’t open more Relative refractory period –During repolarization –Neuron responds only to very strong stimulus –K + channels open (Na + closed, could open again)

19. Action Potentials: Propagation Down Axon Myelin: speeds up signal –Not continuous (nodes of Ranvier) –Multiple sclerosis: degeneration of myelin Axon diameter: larger = faster

20. Synapse: Transmitting APs Junction or gap between neurons –Site of neuron-to-neuron communication –AP must jump across synapse Axon  synapse  dendrites –Presynaptic cell  synaptic cleft  postsynaptic cell –Signal changes form across synapse –Electrical  chemical  electrical

21. Figure 3.4

22. Synapse: Transmitting APs AP can only move in one direction Axon terminals contain neurotransmitters –Chemical messengers –Carry electrical AP signal across synaptic cleft –Bind to receptor on postsynaptic surface –Stimulate GPs in postsynaptic neuron

23. Neuromuscular Junction: A Specialized Synapse Site of neuron-to-muscle communication –Uses acetylcholine (ACh) as its neurotransmitter –Excitatory: passes AP along to muscle Postsynaptic cell = muscle fiber –ACh binds to receptor at motor end plate –Causes depolarization

24. Figure 3.5

25. Neurotransmitters 50+ known or suspected Two major categories –Small molecule, rapid acting –Large molecule neuropeptides, slow acting

26. 1.Draw the graph in you notebook and explain the major steps. 2.How many neurotransmitters do we know of? Which is used for muscle contraction?

27. 1.What is the difference between gray and white matter in the brain? What do you think causes the different coloration? 2.Why do you think our brain is the part of our body we know least about?

28. 1.What is your opinion of Logan’s Drake impression?

29. I am going to show you a clip and then give you the warm-up questions. clip Get your notebook ready.

30. 1.What causes a concussion? What are the symptoms? 2.What sports do you think have the highest concussion rate? Trailer

31. 1.What did you think of the results we saw yesterday with the distractions? Did you think it would make that big of a difference? Why or why not? 2.This is a homunculus, what do you think it is representing?

32. 1.This is different a homunculus, what do you think it is representing?

33. 1.What did you think was the cause of you being able to feel the two points closer together? 2.What was your most sensitive area and what was your least?

34. Figure 3.1

35. Brain: Cerebrum Left and right hemispheres –Connected by corpus callosum, which allows interhemisphere communication Cerebral cortex –Outermost layer of cerebrum –Gray matter (nonmyelinated) –Conscious brain (mind, intellect, awareness)

36. Cerebrum: Five Lobes Four superficial (outer) lobes –Frontal: general intellect, motor control –Temporal: auditory input, interpretation –Parietal: general sensory input, interpretation –Occipital: visual input, interpretation

37. Cerebrum: Regions of Interest for Exercise Physiology Primary motor cortex (frontal lobe) –Conscious control of skeletal muscle movement Basal ganglia (cerebral white matter) –Help initiate sustained or repetitive movements –Walking, running, posture, muscle tone Primary sensory cortex (parietal lobe)

38. Brain: Cerebellum Coordinates timing, sequence of movements Compares actual to intended movements and initiates correction Accounts for body position, muscle status Receives input from primary motor cortex

39. Figure 3.6

40. Spinal Cord Tracts of nerve fibers permit two-way conduction of nerve impulses –Ascending afferent (sensory) fibers –Descending efferent (motor) fibers

41. Peripheral Nervous System Connects to brain and spinal cord –Both types directly supply skeletal muscles Two major divisions –Sensory (afferent) division –Motor (efferent) division

42. Sensory Division Transmits information from periphery to brain Major families of sensory receptors –Mechanoreceptors: physical forces –Thermoreceptors: temperature –Nociceptors: pain –Photoreceptors: light –Chemoreceptors: chemical stimuli

43. Motor Division Transmits information from brain to periphery Two divisions –Autonomic: regulates visceral activity –Somatic: stimulates skeletal muscle activity

44. Motor Division: Autonomic Nervous System Controls involuntary internal functions Exercise-related autonomic regulation –Heart rate, blood pressure –Lung function Two complementary divisions –Sympathetic nervous system –Parasympathetic nervous system

45. Autonomic Nervous System: Sympathetic Fight or flight: Prepares body for exercise Sympathetic stimulation –  Heart rate, blood pressure –  Blood flow to muscles –  Airway diameter –  Metabolic rate, glucose levels, FFA levels –  Mental activity

46. Autonomic Nervous System: Parasympathetic Rest and digest –Active at rest –Opposes sympathetic effects Parasympathetic stimulation includes –  Digestion, urination –Conservation of energy –  Heart rate –  Diameter of vessels and airways

47. 1.What is the difference between gray and white matter in the brain? What do you think causes the different coloration? 2.Why do you think our brain is the part of our body we know least about?

48. Sensory-Motor Integration Process of communication and interaction Five sequential steps 1. Stimulus sensed by sensory receptor 2. Sensory AP sent on sensory neurons to CNS 3. CNS interprets sensory information, sends out response 4. Motor AP sent out on  -motor neurons 5. Motor AP arrives at skeletal muscle, response occurs

49. Figure 3.7

50. Sensory-Motor Integration: Sensory Input Can be integrated at many points in CNS Complexity of integration increases with ascent through CNS –Spinal cord –Lower brain stem –Cerebellum –Thalamus –Cerebral cortex (primary sensory cortex)

51. Figure 3.8

52. Sensory-Motor Integration: Motor Control Sensory input can evoke motor response regardless of point of integration –Spinal cord –Lower region of brain –Motor area of cerebral cortex As level of control moves from spinal cord to cerebral cortex, movement complexity 

53. Sensory-Motor Integration: Reflex Activity Motor reflex –Instant, preprogrammed response to a given stimulus –Response to stimulus identical each time –Occurs before conscious awareness Impulse integrated at lower, simple levels

54. Sensory-Motor Integration: Muscle Spindles When stretched, muscle spindle sensory neuron –Synapses in spinal cord with an  -motor neuron –Triggers reflex muscle contraction –Prevents further (damaging) stretch –Stretch reflex

55. Sensory-Motor Integration: Golgi Tendon Organs Sensory receptor embedded in tendon –Associated with 5 to 25 muscle fibers –Sensitive to tension in tendon (strain gauge) When stimulated by excessive tension, Golgi tendon organs –Prevent excessive tension in muscle/tendon –Reduce potential for injury

56. Figure 3.9

57. Motor Response  -Motor neuron carries AP to muscle AP spreads to muscle fibers of motor unit –Fine motor control: fewer fibers per motor unit –Gross motor control: more fibers per motor unit Homogeneity of motor units –Fiber types not mixed within a given motor unit –Either type I fibers or type II fibers –Motor neuron may actually determine fiber type