1. Warm-Up 1.Name the 2 main organs of the nervous system. 2.Draw and label the parts of a neuron.

2. Warm-Up Label the parts of the neuron below. A B E F C G D

3. Warm-Up 1.One neuron transmits a nerve impulse at 40 m/s. Another conducts at the rate of 1 m/s. Which neuron has a myelinated axon? 2.List the following in order: A.K + channels open and K + floods out of cell B.Membrane is polarized (resting potential) C.Neurotransmitters are released from vesicles into synaptic cleft D.Na + channels open and Na + floods into cell E.Stimulus triggers membrane depolarization 3.What restores the resting potential of a neuron?

4. The Nervous System

5. Nervous System Master controlling and communicating system

6. Basic Functions 1.Sensory input 1.Sensory input – gather information 2.Integration 2.Integration – process and interpret sensory input 3.Motor output 3.Motor output – response by muscles and glands

7. Organization A.Central Nervous System (CNS) ▫Brain & spinal cord ▫Integrative and control centers B.Peripheral Nervous System (PNS) ▫Nerves (spinal nerves, cranial nerves) ▫Communication lines between CNS and rest of body ▫Two Divisions: 1.Sensory (afferent) Division 1.Sensory (afferent) Division: Sensory receptors  CNS 2.Motor (efferent) Division 2.Motor (efferent) Division: CNS  effectors (muscles & glands)

8. Motor Division Somatic nervous systemSomatic nervous system (voluntary) – control skeletal muscles Autonomic nervous systemAutonomic nervous system (ANS) (involuntary) – regulate smooth muscles, cardiac, glands sympatheticparasympathetic ▫Subdivisions: sympathetic & parasympathetic

10. Nervous Tissue 1.Neurons 1.Neurons (nerve cells) - transmit message Anatomy: ▫Cell body ▫Cell body – contains nucleus; metabolic center ▫Dendrite ▫Dendrite – fiber that conveys messages toward cell body ▫Axon ▫Axon – conduct nerve impulses away from the cell body ▫Axon terminals ▫Axon terminals – end of axon; contain neurotransmitters & release them ▫Synaptic cleft/synapse ▫Synaptic cleft/synapse – gap between neurons

12. Nervous Tissue Neuroglia 2.Supporting cells (Neuroglia) CNS: astrocytes, microglia, ependymal cells, oligodendrocytes  barrier between capillaries and neurons  protect neurons  immune/defense  line brain and spinal cord cavities  wrap nerve fibers  produces myelin sheaths (covering) PNS: Schwann cells, satellite cells  surround large neurons  protect & cushion

14. Myelin:Myelin: whitish, fatty material that covers nerve fibers to speed up nerve impulses Schwann cells:Schwann cells: surround axons and form myelin sheath Myelin sheath:Myelin sheath: tight coil of wrapped membranes Nodes of RanvierNodes of Ranvier: gaps between Schwann cells

15. GangliaGanglia: collections of cell bodies tracts nervesBundles of nerve fibers = tracts (CNS) or nerves (PNS) White matterWhite matter: dense collections of myelinated fibers Gray matterGray matter: unmyelinated fibers & cell bodies

16. It’s a Mad, Mad, Mad Neuron

17. Classification of Neurons

18. 1.Functional Classification: direction nerve impulse is traveling Sensory neurons Motor neurons Interneurons carry impulses from sensory receptors to CNS carry impulses from CNS to muscles & glands connect sensory & motor neurons Vision, hearing, equilibrium, taste, smell, pain, pressure, heat

20. 2.Structural Classification: # processes extending from cell body MultipolarBipolarUnipolar 1 axon, several dendrites 1 axon, 1 dendrite1 process Most common (99%) Rare Short with 2 branches (sensory, CNS) Eg. Motor neurons, interneurons Eg. retina, nose, ear Eg. PNS ganglia

22. Nerve Impulses

23. Neuron Function 1.Irritability 1.Irritability: ability to respond to stimulus & convert to nerve impulse 2.Conductivity 2.Conductivity: transmit impulse to other neurons, muscles, or glands

24. Exciting a Neuron: polarizedCell membrane at rest = polarized ▫Na + outside cell, K + inside cell ▫Inside is (-) compared to outside depolarizedStimulus  excited neuron (Na + rushes in)  becomes depolarized action potentialDepolarization activates neuron to transmit an action potential (nerve impulse) ▫All-or-none response ▫Impulse conducts down entire axon repolarizationK+ diffuses out  repolarization of membrane sodium- potassium pumpNa+/K+ ion concentrations restored by sodium- potassium pump (uses ATP)

25. Resting membrane potential (-70mV)

26. Gated Ion Channels (Na + and K + )

27. Depolarization

30. Saltatory conductionSaltatory conduction: electrical signal jumps from node to node along myelinated axon (30x faster!)

31. Multiple Sclerosis (MS) Autoimmune disease Myelin sheaths destroyed  reduced to hardened lesions (scleroses) Blindness, muscle weakness, speech disturbance, urinary incontinence Treatment: interferons, glatiramer (hold off attacks)

33. Nerve Conduction neurotransmitters (NT) synaptic cleftAction potential reaches axon terminal  vesicles release neurotransmitters (NT) into synaptic cleft NT diffuse across synapse  bind to receptors of next neuron electrochemical eventTransmission of a nerve impulse = electrochemical event

34. Neuron Talk

35. Neurotransmitters 50+ identified ExcitatoryExcitatory: cause depolarization InhibitoryInhibitory: reduce ability to cause action potential Eg. acetylcholine, serotonin, endorphins

36. Mouse Party

37. Neurotransmitters Neurotransmitter Action Affected by: Acetylcholinemuscle contractionbotulism, curare (paralytic), nicotine Dopamine“feeling good”cocaine, amphetamines Serotoninsleep, appetite, nausea, mood, migraines Prozac, LSD, ecstasy Endorphinsinhibit painmorphine, heroin, methadone GABAmain inhibitory NTalcohol, Valium, barbiturates

39. Reflexes Rapid, predictable, involuntary responses to stimuli 1.Somatic Reflexes: stimulate skeletal muscles ▫Eg. jerking away hand from hot object 2.Autonomic Reflexes: regulate smooth muscles, heart, glands ▫Eg. salivation, digestion, blood pressure, sweating

40. Reflex Arc (neural pathway) Five elements: 1.Receptor – reacts to stimulus 2.Sensory neuron 3.CNS integration center 4.Motor neuron 5.Effector organ – muscle or gland

43. Reflex Activities Patellar (Knee-jerk) Reflex Pupillary Reflex

44. Patellar (Knee-jerk) Reflex Pupillary Reflex Stretch reflex Tapping patellar ligament causes quadriceps to contract  knee extends Help maintain muscle tone, posture, & balance Optic nerve  brain stem  muscles constrict pupil Useful for checking brain stem function and drug use

45. Flexor (withdrawal) reflex: painful stimulus  withdrawal of threatened body part ▫Pin prick Plantar reflex: draw object down sole of foot  curling of toes ▫Babinski’s sign: check to see if motor cortex or corticospinal tract is damaged

46. Voluntary Reactions More neurons and synapses are involved  longer response times Reflex = Involuntary ReactionVoluntary Reaction

48. Warm-Up 1.List and describe the 5 elements of a reflex arc. 2.List an example of a reflex. 3.What is the difference between a reflex and a voluntary reaction?

49. Human Brain

50. 4 Major Regions 1.Cerebral Hemispheres 2.Diencephalon 3.Brain stem 4.Cerebellum

51. 1. Cerebral Hemispheres (Cerebrum)  L & R hemispheres  Corpus callosum: large fiber tract; connects 2 hemispheres  Lobes: major regions (named for cranial bones)  Parietalfrontaloccipitaltemporal  Parietal, frontal, occipital, temporal  Gyri (gyrus) = elevated ridges of tissue  Sulci (sulcus) = shallow grooves  Fissures = deeper grooves, separate large regions of brain  Motor & sensory function: opposite hemispheres

55. Cerebral Cortex Grey matter “Executive suite”  conscious mind

57. Functions of the Major Lobes

59. 2. Diencephalon (interbrain) 3 main structures: 1.Thalamus: relay station for incoming info 2.Hypothalamus: A.Autonomic control center (heart rate, BP, digestion) B.Emotional response (limbic system) C.Body temperature regulation D.Regulate food intake E.Sleep-wake cycles F.Control endocrine system  pituitary gland at base 3.Epithalamus: pineal gland (sleep-wake cycle)

60. Diencephalon

62. 3. Brain Stem Programmed, automatic behaviors for survival 3 regions: 1.Midbrain: vision, hearing, reflex 2.Pons: breathing 3.Medulla oblongata: heart rate, BP, breathing, swallowing, vomiting, coughing, sneezing

63. Brain Stem

65. 4. Cerebellum Balance, equilibrium, timing of skeletal muscle activity

66. Protection of CNS Meninges: connective tissue covering CNS structures ▫Dura mater (leathery outer), arachnoid mater (web-like middle), pia mater (surface of brain) ▫Meningitis: inflammation of meninges; bacterial or viral infection Cerebrospinal fluid (CSF): watery cushion to protect NS from trauma ▫Lumbar (spinal) tap – test for infection, tumors, multiple sclerosis

68. Meningitis

69. Symptoms of Meningitis

70. Treatment for Meningitis Bacterial  antibiotics Herpes meningitis  antiviral meds IV fluids Prevention: vaccines for bacterial infections (HiB)

71. Blood-Brain Barrier: endothelial cells in capillaries prevent substances from crossing into brain NO: Urea Toxins Proteins White blood cells Bacteria Most drugs YES: Water Glucose Amino acids Gases Fat-soluble substances Some drugs: anesthetics, alcohol, nicotine

73. The Senses

74. Special senses Smell Taste Sight Hearing “Touch” = temperature + pressure + pain of skin, muscles, & joints Equilibrium (in the ear)

75. Sensory Receptors Large complex organs (eyes, ears) Localized clusters of receptors (taste buds, olfactory epithelium)

76. Vision Tests

77. Are the squares inside the blue and yellow squares all the same color?

78. Bezold effect The smaller squares inside the blue and yellow squares are all the same color. They seem different (magenta and orange) because a color is perceived differently depending on its relation to adjacent colors (here blue or yellow depending on the outer square).

79. Are the horizontal lines straight or crooked?

80. Café Wall Illusion The horizontal lines are straight, even though they do not seem straight. In this illusion, the vertical zigzag patterns disrupt our horizontal perception.

81. Does Lincoln’s face look normal?

82. Some neurons in the brain seem specialized in processing faces. Faces are usually seen upright. When presented upside down, the brain no longer recognizes a picture of a face as a face but rather as an object. Neurons processing objects are different from those processing faces and not as specialized. As a consequence these neurons do not respond to face distortions as well. This explains why we miss the weird eyes when the face is inverted.

83. Can you see a baby?

84. Illusory Contour The baby’s head is on the left, the baby’s feet are against the trunk of the tree on the right. Illusory Contour: a form of visual illusion where contours are perceived without a luminance or color change across the contour

85. How quickly can you say the color of the words below?

87. Taste Tests

88. Jellybean Test

90. Flavor = taste + smell

91. 5 Types of Taste Receptors

92. Aging After age 50, ability to smell and taste decrease Membranes lining nose become thinner & drier  olfactory nerve deteriorate # taste buds decrease with age  more difficult to detect sweet/salty  foods taste more bitter As people age, their food tastes more bland  eat less  possible malnutrition

93. Genetics of Taste

94. PTC = phenylthiocarbamide Discovered in 1931 by when a DuPont chemist named Arthur Fox accidentally released a cloud of fine crystalline PTC in the lab. A nearby colleague complained of the bitter taste, while Dr. Fox tasted nothing. Fox continued to test the taste buds of family and friends, setting the groundwork for future genetic studies.

95. Genetics of PTC Tasting Gene for tasting PTC (Tas2r38) is located on Chromosome 7. PAV = taster (T), AVI = nontaster (t), AAV = another allele ▫PAV-PAV = TT = very bitter ▫PAV-AVI = Tt = somewhat bitter ▫AVI-AVI = tt = nontaster General Population: 70% Tasters, 30% Nontasters TAS2R38

96. Bitter tastes = Result of selection pressures? Thiocynate Compounds (bitter taste) found in broccoli, cauliflower, mustard family ▫Tasters: avoid these foods in diet ▫Nontasters: more varied diet, include green leafy veggies Thiocynates might inhibit thyroid function  tasters may have protection against thyroid diseases

97. Bitter tastes = Result of selection pressures? Poisons = bitter taste ▫Tasters: part of hunter-gatherer societies? Genetic Drift ▫Europeans: all 3 alleles (PAV, AVI, AAV) ▫Asians: AAV allele rare ▫Native Americans: 98% have PAV allele only

98. Denver Museum of Nature and Science Expedition Health: Genetics of Taste Study Purpose of Study: ▫Is ability to taste bitter compounds related to what foods you eat, your % body fat, and BMI? ▫Is your ability to taste bitter compounds related to your genetic ancestry?

99. Substances related to PTC Thiourea (thiocarbamide) – very bitter!!! Sodium benzoate – sweet, salty, bitter, no taste ▫Food preservative

100. Family Pedigree Tasters: ▫Supertasters (TT) ▫Tasters (Tt) Non-tasters (tt)