Ch. 43 Review Warm-Up

1. Ch. 43 Review Warm-Up • Contrast the functions of B cells and T cells. • What are memory cells? • How do vaccines work? • How does HIV affect the immune system?

2. Warm-Up • Draw and label the parts of a neuron. • Describe saltatory conduction. • Explain how a nerve impulse is transmitted across a neuron.

3. Warm-Up • What happens at the synapse? • Choose 1 neurotransmitter. Describe its action. • What is the role of the following structures in the human brain? • Brainstem • Cerebellum • Cerebrum • Corpus callosum

4. Chapters 48 & 49 Campbell Biology – 9th ed. Nervous Systems

5. You must know • The anatomy of a neuron. • The mechanisms of impulsetransmission in a neuron. • The process that leads to release of neurotransmitters, and what happens at the synapse. • How the vertebratebrain integrates information, which leads to an appropriate response. • Different regions of the brain have different functions.

6. Organization of the Nervous System • Central nervous system (CNS) = brain + spinal cord • Peripheral nervous system (PNS) = nerves throughout body • Sensory receptors: collect info • Sensory neurons: body  CNS • Motor neurons: CNS  body (muscles, glands) • Interneurons: connect sensory & motor neurons • Nerves = bundles of neurons • Contains motor neurons +/or sensory neurons

11. Peripheral Nervous System Peripheral nervous system Somatic nervous system Autonomic nervous system Parasympathetic division Enteric division Sympathetic division

13. Neuron = dendrite + cell body + axon

14. Neuron • cell body: contains nucleus & organelles • dendrites: receive incoming messages • axons: transmit messages away to other cells • myelin sheath: fatty insulation covering axon, speeds up nerve impulses • synapse: junction between 2 neurons • neurotransmitter: chemical messengers sent across synapse • Glia: cells that support neurons • Eg. Schwann cells (forms myelin sheath)

15. Schwann cells and the myelin sheath

16. BioFlix: How Neurons Work

17. Membrane Potential: difference in electrical charge across cell membrane Microelectrode –70 mV Voltage recorder Reference electrode

18. The Na+/K+ pump (using ATP) maintains a negative potential inside the neuron. Voltage-Gated Ion Channels

19. Action potentials (nerve impulses) are the signals conducted by axons • Resting potential: membrane potential at rest; polarized • Na+outside, K+inside cell • Voltage-gated Na+ channel = CLOSED • Nerve impulse: stimulus causes a change in membrane potential • Action potential: neuron membrane depolarizes • All-or-nothing response K+ channels open Na+ channels open Na+ enters cell K+ leaves cell Inside of neuron axon becomes more - again (= repolarized) Inside of neuron axon becomes more + (=polarized)

26. Conduction of an action potential

27. Action Potential The resting potential of a neuron is -70 mV Stimulus (and depolarization) must reach the Threshold of -55 mV in order for an action potential to occur = “all or none” response

28. Nerve Impulse Animation

29. Saltatory conduction: nerve impulse jumps between nodes of Ranvier(unmyelinated gaps)  speeds up impulse Saltatory conduction speed: 120 m/sec

30. Cell communication: neurotransmitter released at synapsesAxon (presynaptic cell)  Dendrite (postsynaptic cell)

31. Neurotransmitters • Chemicals released from vesicles by exocytosis into synaptic cleft • Diffuse across synapse • Bind to receptors on neurons, muscle cells, or gland cells • Broken down by enzymes or taken back up into surrounding cells • Types of neurotransmitters: • Excitatory: speed up impulses by causing depolarization of postsynaptic membrane • Inhibitory: slow impulses by causing hyperpolarization of postsynaptic membrane

33. Examples of Neurotransmitters • Acetylcholine (ACh): stimulates muscles, memory formation, learning • Epinephrine: (adrenaline) fight-or-flight • Norepinephrine: fight-or-flight • Dopamine: reward, pleasure (“high”) • Loss of dopamine  Parkinson’s Disease • Serotonin: well-being, happiness • Low levels  Depression • GABA: inhibitory NT • Affected by alcohol

34. TGIF! • Have out your “Endocrine System” Homework Reading + Questions for me to check. • Complete the Warm-up (use your notes!) • Read the board for tonight’s HW assignment. We MAY have important visitors today so do not be out of your seat, on your phone, or working on things for other classes.

35. WARM-UP GRADE Each group should discuss the assigned warm-up question below and come to a consensus on the best answer choice. Be ready to explain to class. You may NOT discuss with other groups. Today’s warm-up grade will be whole-class determined. If your group is not 100% confident, you may ask permission to “phone a friend” BUT we will be docked ½ point from overall score.

36. Let’s Visualize • Nerve Cell Communication Animation (from Life Sciences Learning Center)

37. Nerve Cell Communication • “Lab” Activity • Work in Pairs • Each pair needs: • 1 Sending AND 1 Receiving neuron • Baggie of White card labels & Blue card labels • Baggie of beads and pink +/1 strips • Lab sheet for each person Read and follow directions. Raise your hand when you reach the “Teacher Checks.”

38. When you Finish • Turn in Activity to Tray • Return bags to box on front table • Return Sending and Receiving Neurons to Correct Pile • Pick up: • HW POGIL • Notes sheet

39. POGIL: Neuron Structure • This is for Homework! • Due Monday

40. BioFlix: How Synapses Work

41. Evolution of Nervous Systems

42. Vertebrate brain is regionally specialized Major Regions: forebrain, midbrain, hindbrain

43. Forebrain  cerebrum • Midbrain  brainstem • Hindbrain  cerebellum

44. Human Brain

45. Human Brain

46. Human Brain

47. Human Brain

48. Grey matter: neuron cell bodies, unmyelinated axonsWhite matter: fatty, myelinated axons

49. Reflexes • Simple, automatic response to a stimulus • Conscious thought not required • Reflex arc: • Stimulus detected by receptor • Sensory neuron • Interneuron (spinal cord or brain stem) • Motor neuron • Response by effector organ (muscles, glands)

50. Reflex Arc • Reflex Arc (from Life Sciences Learning Center)