2. I.Neuron Structure and Function II.Relationship between Stimuli  Input III.Nervous System Organization IV.Brains V.Preparation for next lecture Lecture 14 – Ch. 48 & 49: Nervous Systems

3. Specialized “excitable” cells: receive input, integrate, send output Neurons synapse dendrite synaptic terminal 1 Synaptic terminals: Bring signals from other neurons. 2 Dendrites: Receive signals from other neurons. 3 Cell body: Integrates signals; Coordinates. 4 Action potential starts here. 5 Axon: Conducts the action potential. 6 Synaptic terminals: Transmit signals to other neurons. 7 Dendrites (of other neurons).

4. 4

5. What parts of neurons are OUTSIDE the CNS? 1.All sensory, motor, and interneurons neurons 2.Sensory neuron dendrites & cell bodies AND motor neuron axons 3.Interneurons only 4.Motor neuron dendrites and interneuron axons

6. Neurons are electrical: At rest, neurons maintain an electrical difference across their membrane (-) inside cell; (+) outside cell Neurons charge = about -70 mV Na + pumped out, K + pumped in, but K + can leak out

7. gap dendrite of postsynaptic neuron neurotransmitter synaptic vesicle synaptic terminal Neurotransmitter signals next neuron. Signal reaches end of axon. Synaptic vesicles release neurotransmitter. Receptor binds neurotransmitter. Neurons Synapse: Region connecting two neurons or neuron and muscle Neurotransmitter may excite or inhibit the next neuron

8. Neurons Transmit Signals via Action Potentials: Action Potential (AP): The electrical signal passed along the length of a neuron During action potential, Na+ channels open, flows in (extracellular fluid) Na + (axon) action potential (+) inside cell; (-) outside cell (extracellular fluid) Na + (axon) action potential K+K+ Neuron membrane polarized = charge difference Triggers K+ channels to open, flows out Charge difference lost = depolarized Action Potentials Repolarized

9. Action Potentials Na+ channels open K+ channels open Before K+ channels close, greater charge difference = hyperpolarized

10. Action Potentials Action potentials are propagated down the length of the neuron – after the AP, neuron resets itself (Na+ out, K+ in) Na+ and K+ channels are voltage gated – as first Na+ channels open, more triggered to open (i.e. positive feedback)

11. Action potentials can be measured electrically: Action Potentials IPSP time (milliseconds) potential (millivolts) resting potential threshold EPSP Stimulation from a neighbor neuron excites the cell (brief increase in voltage = EPSP) Inhibition from another neuron causes a brief decrease in voltage (IPSP)

12. dendrite of Post-synaptic neuron neurotransmitter synaptic vesicle Pre-synaptic terminal Action Potentials IPSP time (milliseconds) potential (millivolts) EPSP EPSP = excitatory post-synaptic potential IPSP = inhibitory post- synaptic potential (+) Neurotransmitter (-) Neurotransmitter Individual EPSP & IPSP weak

13. Action Potentials

14. Sum of all excitatory & inhibitory ‘blips’ = summation Action Potentials action potential potential (millivolts) Less (-) time (milliseconds) resting potential threshold More (-) If threshold voltage is reached, an action potential occurs

15. Information Coding in the Nervous System: 1) Determine stimulus type (e.g. light / sound / touch) All neurons use same basic signal Wiring pattern in brain distinguishes stimuli 2) Signal intensity of stimulus All signals similar in size (all-or-none response) Intensity coded by: 1) Frequency of action potentials 2) # of neurons responding Stimuli  Input

16. Information Coding in the Nervous System: Stimuli  Input fires slowly silent 1 2 fires moderately silent 1 2 fires rapidly fires slowly 1 2

17. Information Coding in the Nervous System: 3)Integrate/coordinate signals 4) Determine Output Stimuli  Input Neural Pathways Direct Behavior: 1) Receptor: Detects stimulus 2) Sensory neuron: Sends stimulus message 3) Interneuron(s): Integrates stimuli 4) Motor neuron: Activates effector 5) Effectors: Performs function (muscle / gland)

18. Spinal Cord: Myelin = Insulation around axons Increases AP conduction rate Nervous System Organization

19. Spinal Cord: Nervous System Organization

20. What part of the spinal cord contains motorneuron cell bodies? 1.White matter 2.Dorsal root ganglia 3.Gray matter 4.Ventral roots

21. PNS CNS Brain and Spinal Cord Sympathetic nervous system "fight or flight" Parasympathetic nervous system "rest and repose" Somatic nervous system (voluntary) Sensory neurons registering external stimuli Autonomic nervous system (involuntary) Sensory Pathways Motor Pathways Sensory neurons registering external stimuli Nervous System Organization

23. If you are surprised by a “predator”, what happens in your nervous system? 1.Sympathetic nervous system increases heart rate 2.Somatic nervous system increases heart rate 3.Autonomic nervous system increases saliva 4.Parasympathetic NS increases saliva secretion

24. The Brain: 1) Hindbrain: Automatic Behaviors A) Medulla: Controls breathing, heart rate, blood pressure B) Pons: Controls wake/sleep transitions; sleep stages C) Cerebellum: Coordinates movement spinal cord meninges skull cerebellum pons medulla hindbrain Human Brain

25. The Brain: 2) Midbrain: Relay / “Screening” Center A) Reticular Formation: Controls arousal of brain Filters sensory input from body B) Visual / Auditory Reflex Centers pituitary gland pineal gland midbrain - Reticular Formation Human Brain

26. The Brain: 3) Forebrain (Cerebrum): “Seat of Consciousness” A) Cerebral Cortex Two hemispheres (Connection = Corpus Callosum) Left hemisphere controls right side of body (and vise versa) cerebral cortex corpus callosum Human Brain

27. The Brain: 3)Forebrain (Cerebrum) A) Cerebral Cortex Four regions: 1) Frontal: Primary motor area; complex reasoning 2) Parietal: Primary sensory area 3) Temporal: Primary auditory and olfactory areas 4) Occipital: Primary visual area Human Brain Occipital Lobe Parietal Lobe Frontal Lobe Temporal Lobe

28. Occipital Lobe primary sensory area sensory association area sensory association area primary visual area primary visual area visual association area visual association area auditory association area: language comprehension auditory association area: language comprehension memory speech motor area speech motor area higher intellectual functions higher intellectual functions primary auditory area primary auditory area premotor area premotor area primary motor area primary motor area leg trunk arm hand face tongue Parietal Lobe Frontal Lobe Temporal Lobe Human Brain

29. Motor and Sensory areas Human Brain

30. Which is a correct match between brain region and function: 1.Parietal lobe : visual processing 2.Reticular formation : filters sensory input 3.Cerebellum : controls sleep stages 4.Cerebrum : dictates breathing rate

31. Cortical Regions Involved in Different Tasks: Human Brain Seeing Words max0 Reading WordsGenerating Verbs Hearing Words

32. The Brain: hypothalamus thalamus B) Limbic System Produce emotions; form memories C) Thalamus Relays information from body to limbic system / cerebral cortex 3) Forebrain (Cerebrum) Human Brain

33. The Brain: B) Limbic System Hypothalamus: Homeostatic control center Amygdala: Produces sensations of pleasure, fear, or sexual arousal Hippocampus: Formation of long-term memory C) Thalamus Relays to limbic system / cerebral cortex Human Brain hypothalamus corpus callosum limbic region of cortex cerebral cortex amygdala hippocampus thalamus

34. Damage to the hippocampus could result in: 1.Failure to understand speech 2.Reduced fear response 3.Lack of homeostatic control 4.Loss of long-term memory formation

35. Things To Do After Lecture 14… Reading and Preparation: 1.Re-read today’s lecture, highlight all vocabulary you do not understand, and look up terms. 2.Self-Quiz: Ch. 48 #1-3, 5; Ch. 49 #1, 2, 4, 5, 6 (correct answers in back of book) 3.Read chapters 48 & 49, focus on material covered in lecture (terms, concepts, and figures!) 4.Skim next lecture. “HOMEWORK” (NOT COLLECTED – but things to think about for studying): 1.Explain the difference between the somatic and autonomic nervous systems. 2.Diagram a basic neuron – for sensory, motor, and interneurons explain the location of each region with respect to peripheral or central nervous system. 3.Compare and contrast the embryonic vertebrate brain with that of adults. 4.List the regions of the brain (with functions) from the “outside” of the brain, inward.