1. Human Physiology Unit Four

2. Nervous System Function
The general purpose of the nervous system is to coordinate the function of all body cells and maintain homeostasis using electrical and chemical means

3. Nervous System Function
Integrating
Center
Sensor
Effectors
Stimulus
Response

4. Anatomy of the Human Nervous System

5. Anatomy of the Human Nervous System

6. Anatomy of the Human Nervous System
Neuron – a nerve cell
Nerve – a bundle of neuron axons
wrapped in fibrous connective
tissue
Ganglion – a mass of neuron cell
bodies found in the PNS

7. Anatomy of the Human Nervous System

8. Anatomy of a Neuron

9. Myelin Sheath Formation

10. Anatomy of a Neuron

11. Anatomy of a Synapse

12. Neuron Cell Types

13. Neuroglia
Neuroglia - support cells that aid in the functions of neurons found in the CNS

14. The Spinal Cord

15. The Spinal Cord Nucleus – a cluster of neuron cell bodies in the CNS
Remember – a ganglion is a cluster of neuron cell bodies in the PNS

16. The Spinal Cord
Ascending tract – a bundle of associated nerve fibers that send sensory impulses to the brain
Descending tract – a bundle of associated nerve fibers that send motor impulses to effectors

17. Unmyelinated vs. Myelinated Conduction

18. Unmyelinated vs. Myelinated Conduction

19. Nerve Impulse Propagation
Action Potentials are
“all or nothing”!

20. Nerve Impulse Propagation

21. Nerve Impulse Propagation

22. The Neural Synapse

23. Cholinergic receptors
The Neural Synapse
Cholinergic receptors

24. Cholinergic receptors
The Neural Synapse
Cholinergic receptors

25. The Neural Synapse
Adrenergic receptors

26. Postsynaptic Response
As has been noted, postsynaptic responses can be excitatory or inhibitory
Neurotransmitters that elicit an excitatory response do so by producing excitatory postsynaptic potentials (EPSPs)

27. Postsynaptic Response
Neurotransmitters that elicit an inhibitory response do so by producing inhibitory postsynaptic potentials (IPSPs)
Both EPSPs and IPSPs are necessary for proper function in the nervous system

28. Postsynaptic Response

29. Postsynaptic Response

30. Postsynaptic Response

31. Postsynaptic Response

32. Postsynaptic Response

33. Postsynaptic Response

34. Postsynaptic Response

35. Postsynaptic Response
Summation is the process of adding up postsynaptic potentials & responding to their net effect

36. Postsynaptic Response

37. Postsynaptic Response
Summation can occur in two ways:
~ temporal
~ spatial

38. Postsynaptic Response

39. Postsynaptic Response EPSPs & Motor End Plates

40. Presynaptic and Postsynaptic Inhibition

41. The Autonomic Nervous System Functions
Innervates smooth & cardiac muscle and glands
Maintains homeostasis by varying rates, constriction, dilation, etc.

42. The Autonomic Nervous System

43. The Autonomic Nervous System

44. Autonomic Nervous System
The
Autonomic Nervous System

45. Sympathetic Chain Ganglia

46. Autonomic Nervous System
The
Autonomic Nervous System

47. The Autonomic Nervous System

48. The Autonomic Nervous System Receptors
Adrenergic receptors
# found on effectors
# respond to epinephrine &
norepinephrine
# can be excitatory or inhibitory
# two forms – alpha & beta

49. The Autonomic Nervous System Receptors
Adrenergic receptors
# alpha receptors are usually
excitatory
# beta receptors are usually
inhibitory, but can be excitatory

50. The Autonomic Nervous System Receptors
Cholinergic receptors
# found on postganglionic neurons
and effectors
# respond to acetylcholine
# can be excitatory or inhibitory
# two forms – nicotinic &
muscarinic

51. The Autonomic Nervous System Receptors
Cholinergic receptors
# nicotinic receptors are always
excitatory and are found in the
postganglionic neurons, adrenal
medulla & myoneural junctions

52. The Autonomic Nervous System Receptors
Cholinergic receptors
# muscarinic receptors can be
either inhibitory or excitatory,
work by way of a second
messenger and are found in
effectors

53. The Autonomic Nervous System Functions
Certain drugs can be used to block these receptors so they cannot be stimulated
These drugs are called blockers

54. The Autonomic Nervous System Functions
Sympatholytics are drugs that block adrenergic receptors
Propranolol is a beta blocker that blocks beta receptors in the heart & arteries

55. The Autonomic Nervous System Functions
Parasympatholytics are drugs that block cholinergic receptors
Atropine blocks muscarinic receptors, such as in the eyes & respiratory tubes

56. The Autonomic Nervous System

57. ANS Receptor Effects

58. Receptors
Receptors are dendrite endings that transduce energy from the external and internal environment into the energy of action potentials
Receptors are grouped by the type of energy they transduce
Chemoreceptors
Nociceptors
Photoreceptors
Mechanoreceptors
Thermoreceptors
Proprioceptors

59. Receptor Action

60. Cutaneous Receptors
Pacinian corpuscles - mechanoreceptors used in touch & pressure
Temperature receptors - respond to temperature change
Pain receptors (nociceptors) chemoreceptors that respond to tissue damage

61. Cutaneous Receptors

62. Taste Receptors

63. Olfactory Receptors

64. Ear Anatomy

65. Inner Ear Anatomy

66. Hair Cell Receptors

67. Hair Cells & Otoliths

68. Inner Ear Anatomy

69. Organ of Corti

70. Eye Anatomy

71. Rods & Cones