1. The Nervous System

2. Major division - Central vs. Peripheral Central or CNS- brain and spinal cord Peripheral- nerves connecting CNS to muscles and organs Central Nervous System Peripheral Nervous System

3. Autonomic Nervous System (ANS) Involuntary Regulates the activity of: –Cardiac Muscle, Smooth Muscle, and Glands

4. ANS Divisions Sympathetic: “Fight or Flight” Activated during emergencies, exercise or vigorous physical activity Revs up body to respond to situations that upset homeostasis Parasympathetic: “Rest & Digest” Reduces energy use Promotes: –digestion of food –storage of energy –elimination of wastes –homeostasis

5. Peripheral Nervous System Skeletal (Somatic) SympatheticParasympathetic Autonomic Peripheral Nervous System

6. 3 kinds of neurons connect CNS to the body –sensory –motor –interneurons Motor - CNS to muscles and organs Sensory - sensory receptors to CNS Interneurons: Connections Within CNS Spinal Cord Brain Nerves

7. Somatic System Nerves to/from spinal cord –control muscle movements –somatosensory inputs Both Voluntary and reflex movements Skeletal Reflexes –simplest is spinal reflex arc Muscle Motor Neuron Interneuron Skin receptors Sensory Neuron Brain

8. Autonomic System Two divisions: –sympathetic –Parasympathetic Control involuntary functions –heartbeat –blood pressure –respiration –perspiration –digestion Can be influenced by thought and emotion

9. Sympathetic “ Fight or flight” response Release adrenaline and noradrenaline Increases heart rate and blood pressure Increases blood flow to skeletal muscles Inhibits digestive functions CENTRAL NERVOUS SYSTEM Brain Spinal cord SYMPATHETIC Dilates pupil Stimulates salivation Relaxes bronchi Accelerates heartbeat Inhibits activity Stimulates glucose Secretion of adrenaline, nonadrenaline Relaxes bladder Stimulates ejaculation in male Sympathetic ganglia Salivary glands Lungs Heart Stomach Pancreas Liver Adrenal gland Kidney

10. Parasympathetic “ Rest and digest ” system Calms body to conserve and maintain energy Lowers heartbeat, breathing rate, blood pressure CENTRAL NERVOUS SYSTEM Brain PARASYMPATHETIC Spinal cord Stimulates salivation Constricts bronchi Slows heartbeat Stimulates activity Contracts bladder Stimulates erection of sex organs Stimulates gallbladder Gallbladder Contracts pupil

11. Summary of autonomic differences Autonomic nervous system controls physiological arousal Sympathetic division (arousing) Parasympathetic division (calming) Pupils dilate EYES Pupils contract Decreases SALVATION Increases Perspires SKIN Dries Increases RESPERATION Decreases Accelerates HEART Slows Inhibits DIGESTION Activates Secrete stress hormones ADRENAL GLANDS Decrease secretion of stress hormones

12. Central Nervous System Brain and Spinal Cord Spinal Cord Brain

13. Left & Right sides are separate Corpus Callosum : major pathway between hemispheres Some functions are ‘lateralized’ –language on left –math, music on right Lateralization is never 100% Brain has 2 Hemispheres Left Hemisphere Corpus Callosum Right Hemisphere

14. Each hemisphere is divided into 4 lobes Frontal Parietal Occipital Temporal

15. Sensory Information sent to opposite hemisphere Principle is Contralateral Organization Sensory data crosses over in pathways leading to the cortex Visual Crossover –left visual field to right hemisphere –right field to left Other senses similar Left visual field Right visual field Optic nerves Corpus Callosum Left Visual Cortex Right Visual Cortex

16. Contralateral Motor Control Movements controled by motor area Right hemisphere controls left side of body Left hemisphere controls right side Motor nerves cross sides in spinal cord Somatosensory CortexMotor Cortex

17. Corpus Callosum Major ( but not only) pathway between sides Connects comparable structures on each side Permits data received on one side to be processed in both hemispheres Aids motor coordination of left and right side Corpus Callosum Medial surface of right hemisphere

18. Corpus Callosum What happens when the corpus callosum is cut? Sensory inputs are still crossed Motor outputs are still crossed Hemispheres can’t exchange data

19. Localization of function Frontal Parietal Occipital Temporal

20. Occipital Lobe Input from Optic nerve Contains primary visual cortex –most is on surface inside central fissure Outputs to parietal and temporal lobes Occipital Lobe Visual Lobe

21. Temporal Lobe Inputs are auditory, visual patterns –speech recognition –face recognition –word recognition –memory formation Outputs to limbic System, basal Ganglia, and brainstem z Contains primary auditory cortex Temporal Lobe Temporal Lobe Auditory Cortex

22. Parietal Lobe Somatosensory Cortex Parietal Lobe Inputs from multiple senses z contains primary somatosensory cortex z borders visual & auditory cortex z Outputs to Frontal lobe z hand-eye coordination z eye movements z attention

23. Frontal Lobe Frontal Lobe Contains primary motor cortex Motor Cortex Motor Cortex Broca’s Area Motor Cortex Working Memory No direct sensory input Important planning and sequencing areas Broca’s area for speech Prefrontal area for working memory

24. Conjunctiva The Eye

25. Conjunctiva Covers the inner surface of the eyelids and the anterior surface of the eye. Membrane which produces mucous that lubricates the eye and prevents dryness. Protects the eye.

26. Fibrous Tunic

27. Sclera Functions: Protects eye Shapes eye Anchors eye muscles Cornea Functions: Transparent window for light entry Refracts light

28. Vascular Tunic

29. Choroid Functions: Provides nutrients to all eye tunics. Absorbs light preventing reflecting & scattering of light within the eye. Ciliary Body Functions: Ciliary processes secrete aqueous humor. Suspensory ligaments hold lens in place. Ciliary muscles pull on the ligaments to change the thickness of the lens. Iris Functions: Constricts or dilates to adjust the amount of light entering the eye.

30. Vascular Tunic Ciliary Processes Ciliary Muscles

32. Aqueous Humor Helps support the eye internally due to the intraocular pressure it produces inside the eye. Supplies nutrients & oxygen to the cornea, lens and portions of the retina. Carries away metabolic wastes from the cornea, lens and portions of the retina.

33. Vitreous Humor Transmits light within the posterior segment. Supports the lens posteriorly. Holds the retina in place. Contributes to intraocular pressure.

34. Retina Pigmented Layer Absorbs light Carries out phagocytosis Stores Vitamin A Neural Layer Contains photoreceptors (rods and cones) for visual perception Contains bipolar cells & ganglion cells for visual impulse transmission

35. Optic Disc Retina

36. Cones Are located in macula lutea but are most highly concentrated in the fovea centralis. Are sensitive to bright light (daylight) situations in which light is very intense. Each cone synapses with a single bipolar cell which synapses with a single ganglion cell. The axons of ganglion cells form the optic nerve to conduct visual images to the brain. Provide acute (sharp) color images (vision).

37. Rods Most highly concentrated in the retina outside the macula lutea Many rods synapse with a single bipolar cell Many bipolar cells may synapse with a single ganglion cell which carries stimuli to brain More sensitive & function only in dim light, night and peripheral vision Images are blurry and only in shades of gray

38. Visual Pigments: Cones Retinal + Red, Green or Blue Opsin = Red, Green or Blue visual pigments Each Opsin absorbs light only in the area of the visible light spectrum it is sensitive to, ie, red cones, green cones & blue cones Function only in bright light (daylight) Provide sharp color images RedCone Red Opsin RETINAL (Light) Impulse GreenCone Green Opsin RETINAL Impulse

39. Myopia (Nearsighted) Eyeball too long Distant objects focused in front of retina Image striking retina is blurred Correction: Concave lens or laser surgery to slightly flatten the cornea

40. Hyperopia (Farsighted) Eyeball too short, lens too thin or too stiff. Nearby objects are focused behind retina. Image striking the fovea is blurred. Correction: Convex lens

41. Astigmatism Irregular Curvature in parts of the cornea or lens Causes blurry image This may be corrected by specially ground lenses which compensate for the irregularity or laser surgery.

42. Cararact Clouding of lens due to aging, diabetes mellitus, heavy smoking, frequent exposure to intense sunlight or congenital factors Treatment: Lens Implant

43. Conjunctivitis Inflammation of the conjunctiva by: Bacteria, fungi or viruses Trauma “Pink Eye”

44. Glaucoma Most common cause of blindness. Increasing intraocular pressure compresses retina, optic nerve & blood vessels. Late symptoms include blurred vision & halos around bright objects Canal of Schlemn

45. Glaucoma

46. Color Blindness Congenital lack of one or more cone types Deficit or absence of red or green cones most common Sex-linked trait Most common in males What numbers can you see in each of these?

47. Night Blindness Impaired vision at night or in dim light situations Rhodopsin deficiency affecting rods Most common cause - prolonged Vitamin A deficiency Rods degenerate

48. Macular Degeneration Most common cause of vision loss after 65. Progressive deterioration of macula causing loss of central vision Dry Form - due to accumulation of pigments in macula due to reduced phagocytosis of cone debris by pigmented layer Wet Form - due to invasion of macula with new blood vessels from choroid causing scarring & retinal detachment

49. The Ear

50. Inner Ear Vestibule

51. Saccule Utricle

52. Inner Ear Semicircular Canals

53. Inner Ear Oval Window

54. Inner Ear Cochlea

55. Maculae Monitors position of head in space Responds to straight-line changes in speed & direction Receptors for static equilibrium

56. Macula Receptor for Static Equilibrium

57. Cochlea Unrolled Sprial Organ of Corti

58. Spiral Organ of Corti Receptor organ of hearing Different frequencies of vibrations (compression waves) in cochlea stimulate different areas of Organ of Corti Interpreted as differences in pitch

59. Inner Ear Round Window

60. Cochlea Oval Window Round Window

61. The Nervous System: Summary Major structures of the nervous –CNS, Somatic, Autonomic –Two hemispheres & 4 lobes Localization of functions Central Nervous System Peripheral Nervous System

62. Modified from Robert F. Allen