Essay Question #2

1. Essay Question #2 Scoring Guidelines: http://apcentral.collegeboard.com/apc/public/repository/ap07_biology_q3.pdf

2. Chapter 48 and 49 Neurons and the vertebrate brain

3. The Vertebrate Brain

4. Forebrain • Midbrain • Hindbrain Embryonic Brain Regions

5. Fig. 49-9 Cerebrum (includes cerebral cortex, white matter, basal nuclei) Telencephalon Forebrain Diencephalon Diencephalon (thalamus, hypothalamus, epithalamus) Midbrain Mesencephalon Midbrain (part of brainstem) Metencephalon Pons (part of brainstem), cerebellum Hindbrain Myelencephalon Medulla oblongata (part of brainstem) Diencephalon: Cerebrum Mesencephalon Hypothalamus Metencephalon Thalamus Midbrain Pineal gland (part of epithalamus) Myelencephalon Hindbrain Diencephalon Brainstem: Midbrain Pons Spinal cord Pituitary gland Forebrain Medulla oblongata Telencephalon Spinal cord Cerebellum Central canal (c) Adult (a) Embryo at 1 month (b) Embryo at 5 weeks

6. Oldest: brain stem • Middle: Cerebellum • Newest: Cerebral cortex/cerebrum Human Brain is like 3 brains in one.

7. Clear • Colorless • Surrounds CNS • Functions: • Buffers brain from skull • Buoys brain on spine • Waste products • Transport of hormones Cerebrospinal Fluid

8. Consists of: • Midbrain • Pons • Medulla Oblongatta • Functions: • Regulation of homeostasis – breathing, heart rate • Swallowing • Startle response • Autonomic nervous system • Coordination of body movement/balance The Brainstem

9. Develops from hindbrain • Coordination of movement and balance • Equilibrium • Receives sensory signals – voluntary movement • Joints • Muscle length, extension • Auditory, visual Cerebellum

10. Part of the forebrain • Develops into: • Thalamus • Hypothalamus (homeostasis, posterior pituitary gland) • Epithalamus (pineal gland, generates cerebrospinal fluid) Diencephalon

11. Develops from forebrain • Information processing • Olfaction, auditory, visual processing • 2 hemispheres • Grey matter – cerebral cortex • White matter – internal • Basal nuclei – within white matter Cerebrum

12. Large in mammals • Controls: • Perception • Voluntary movement • Learning • Highly convoluted • High surface area but can still fit in the skull Cerebral Cortex

13. Right and left sides control opposite side of the body • Connected by the corpus collosum • Thick band of neurons Cerebral Cortex

14. Frontal Lobe • Parietal Lobe • Occipital Lobe • Temporal Lobe Divisions of Human Cerebral Cortex

15. Fig. 49-15 Frontal lobe Parietal lobe Somatosensory cortex Motor cortex Somatosensory association area Speech Frontal association area Taste Reading Speech Hearing Visual association area Smell Auditory association area Vision Temporal lobe Occipital lobe

16. Consciousness • Goal setting • Inhibition • Attention • Time perception • Judgment • Control of emotional response • Internalization of language • Memory for habits & motor activities Frontal Lobe

17. Visual attention • Touch perception • Goal oriented voluntary movements • Manipulation of objects • Integration of different senses to allow for understanding of a single concept. Parietal Lobe

18. Vision • Visual perception • Recognition of printed words Occipital Lobe

19. Hearing ability • Memory acquisition • Some visual • Categorization • Emotion • Language Temporal Lobe

20. Chapter 48: Neuron Structure and Function

21. Nerve cells • Brain: group of nerve cells specialized for control of body systems • Ganglia (simpler nerve clusters) Neurons

22. Motor Neurons • From brain to muscle cells • Sensory Neurons • Transmit outside signals (from external stimuli, senses, muscle tension, stimuli within the body ie. Blood pressure) to brain • Interneurons • Short, carry signals very short distances • Mostly within the brain Types of Neurons

23. Fig. 48-3 Sensory input Integration Sensor Motor output Central nervous system (CNS) Effector Peripheral nervous system (PNS)

24. Central Nervous System • Brain • Spinal cord • Peripheral Nervous System • Carry information to and from the CNS Divisions of the Nervous System

25. Cell body • Dendrites • Axon • Axon hillock Neuron Structure

26. Fig. 48-4 Dendrites Stimulus Presynaptic cell Nucleus Axon hillock Cell body Axon Synapse Synaptic terminals Postsynaptic cell Neurotransmitter

27. Junction between an axon and another cell • Can be another nerve, muscle cell • Synaptic terminal • Neurotransmitters Synapse

28. Presynaptic cell • Postsynaptic cell Synapse

29. Support cells for neurons • Nourish • Insulate • Regulate extracellular fluid Glial Cells

30. Action potential • Utilize ions, electrical signals to propagate signal down an axon • Neurons are semi-permeable Neuron Signaling

31. Neurons are not sending a signal • Inside is negatively charged • Potassium can pass freely (K+) • Sodium (Na+) and Chloride (Cl-) cannot At rest

32. Pumps: • Na+, K+ ions • Resting potential -70mV Pumps within the Neuron Membrane

33. Action Potential Graph

34. Cell becomes depolarized • “spike” in current • Causes resting potential to change from -70mV to closer to 0mV • MUST reach the critical threshold level to fire • All or nothing Creation of an Action Potential

35. Resting • Depolarization • Repolarization • Hyperpolarization Major Steps in Action Potentials

37. Na+ channels CLOSED • K+ channels maintain resting potential • Passive Resting

38. Na+ channels OPENed by stimulus • If potential reaches threshold, will trigger action potential • K+ channels CLOSED • Increases internal charge (causes spike) Depolarization

39. Na+ channels CLOSE • K+ channels OPEN to stabilize membrane potential Repolarization

40. Na+ become unblocked • K+ remain open and return membrane to resting potential Hyperpolarization

41. Steps of polarization occur down the neuron Propagation of the Action Potential

42. Fig. 48-11-3 Axon Plasma membrane Action potential Cytosol Na+ Action potential K+ Na+ K+ Action potential K+ Na+ K+

43. Fig. 48-12a Node of Ranvier Layers of myelin Axon Schwann cell Schwann cell Nodes of Ranvier Nucleus of Schwann cell Axon Myelin sheath

44. Review of Chapter 48 and 49