The Biology of Psychology

1. The Biology of Psychology Neuroscience and Biology Neurons, Brain, CNS Myers, Chapter 2

2. Will Explain Why We FEEL…… Neural and Hormonal Systems Nervous Strong Sick Pain

3. Body’s 2 Major Systems • Nervous system • Endocrine system

4. Nervous System Has 2 Systems • Central Nervous System (CNS) - composed of brain and spinal cord; involved in making decisions about behavior • Peripheral Nervous System (PNS) includes every nerve outside the central nervous system, it carries information to and from CNS

5. Brain & Spinal Cord=CNS • Central Nervous System (CNS) • Made up of neurons • 100 billion in the brain

6. Neuron Structure (Soma) Nucleus Axon hillock (trapdoor) One-way door Protects DNA from electrical charge (surge protector) Direction of Action Potential

7. Structures of Neuron • Cell body (Soma): • Contains the cell nucleus (DNA)

8. Structures of Neuron • Dendrites: • Tiny fibers extending from the nucleus which receive information

9. Structures of Neuron • Axon: • 1 long fiber exiting the nucleus. Between 1-2 inches (up to 3 feet long) • Function is to secrete messengers or directly affect a muscle or gland

10. Structures of Neuron • Axon hillock: • The place at which the axon leaves the cell body, a one-way trap door that allows electrical impulses to leave but never to come back and harm the cell’s DNA

11. Structures of Neuron • Terminal Buttons: • Release neurotransmitter chemicals, (which are stored in synaptic vesicles) • These chemicals will travel across the synapse, to communicate with other neurons

12. Structures of Neuron • Synapse: • Area composed of the axon terminal, synaptic space, and the dendrite • The gap between the dendritic spine and terminal button, (called the cleft) filled with cerebral spine fluid

13. Neurons do NOT touch each other-the space in between is call the synapse. Synapse Cerebral Spinal Fluid 1 millionth of inch Neurotransmitters cross the gap in 1/10,000 sec.

14. 2 Types of Insulation • Glial Cells: • Carry messages between neurons • They connect some axons and speed the transmission of information

15. 2 Types of Insulation • Myelin Sheath: • Fatty covering surrounding the axon, accelerates speed. • White matter in the brain has this fatty tissue covering. • Gray matter is unmyelinated Pronounced: “My-Yellin”

16. Neuron Structure 1800s Discovered fatty tissue protecting axon Pronounced: “My-Yellin” 1922 Ranvier discovered “message centers” Nodes of Ranvier (Ron-vee-eh) Unmyelinated: gray matter, moves very slow Myelinated: (sausage links) white matter, fast Functions of sheath: 1. Insulator (protection) 2. Greater speed

17. Which one is faster? Local train makes constant stops Unmyelinated: slower Passive Cable Properties (slow) Supersonic train gets to destination much faster Nodes of Ranvier: quick info centers Myelinated: faster! .001 sec (1 nano) Saltatory Conduction: jumps from node to node, speed and efficiency

18. 3 Types of Neurons 1. Sensory Neurons (Afferent) 2. Motor Neurons (Efferent) 3. Inter Neurons (Association) 99%

19. Sensory Neurons(Afferent Neurons) • Take (pick-up) information from the senses (sense organs) to the brain (CNS)

20. Motor Neurons(Efferent Neurons) • Take information from the spinal cord to the muscles or glands (output from brain to the body). E=Effect, Efferent, Motor Movements are the Effect

21. Inter Neurons (Association) • Connect neurons to other neurons in the CNS. Carry messages from one neuron to another • 99% of all neurons

22. Interconnected Neurons Make Up The CNS (Nerves) Nerve Engram (Memory)

23. Memories: Neural Connections • True/false, the brain believes what you tell it • Lie/truth, Hypnosis, planted memories • “I am fat,” “Mommy likes you best” • Paranoia “They’re out to get me” • Smell, senses can trigger memories • Homemade cookies, “grandma” • Poodle, “dog bite” • Depression, A + B = boo hoo • Prozac blocks the neural path (engram) • new memories are formed • Conjoint therapy: • drugs & therapy A B Engram (Memory) C

24. Types of Neurotransmitters • Chemical messengers released by terminal buttons through the synapse.

25. Neurotransmitters Key-Lock Relationship Dendritic receptor sites can only receive 1 specific shape

26. Neurotransmitters: 3 Shapes Key-Lock Relationship Y Y Y Only 1 shape accepted

27. Sodium Potassium Pump • The cell nucleus (soma) contains more • neg. ions • (Potassium, K) • The pump regulates the nucleus and pumps sodium out • (Na, pos ions)

28. Polarization more negative ions inside the neuron than positive ions outside Resting Potential is the neuron’s usual charge which is approximately -70 millivolts.

29. How Does a Neuron Fire? It is an electrochemical process • Electrical inside the neuron • Chemical outside the neuron • (the neurotransmitter in the synapse). • The firing is called Action Potential.

30. How Does a Neuron Fire? Synapse, cerebral spinal fluid Neurotransmitters Travel Here “Picked Up” Here (If the Lock-Key Shape Matches) Dendritic receptor sites Dendrite Soma (Cell) Membrane Nucleus Axon Hillock (Trapdoor) Axon

31. How Does a Neuron Fire? Synapse, cerebral spinal fluid Na+ Dendritic receptor sites Dendrite Soma (Cell) Membrane Nucleus Axon Hillock (Trapdoor) Axon K- Sodium Potassium Pumps (Gateways through membrane) Sodium: Na+ (pos iond) Potassium: K-(neg ions) (Tech. Neutral) Like a magnet, Na is attracted to the Neurotransmitter

32. How Does a Neuron Fire? Synapse, cerebral spinal fluid Na+ Dendritic receptor sites Dendrite Soma (Cell) Membrane Nucleus Axon Hillock (Trapdoor) Axon K- Sodium Potassium Pumps (Gateways through membrane) Sodium: Na+ (pos ions) Potassium: K-(neg ions) (Tech. Neutral)

33. How Does a Neuron Fire? Synapse, cerebral spinal fluid Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+ Na+Na+Na+ Dendritic receptor sites Dendrite Soma (Cell) Membrane Nucleus Axon Hillock (Trapdoor) Axon -70 Resting Potential (Ex: TIVO, Toilet) 70/30 70 Potassium Inside (Neg)30 Sodium Outside (Pos Ion) K-K- K- K- K- K- K- When you gain +10 more Na+ Reach Absolute Threshold -70 + 10 = -60 (Ex: Doorway, Toilet) Sodium Potassium Pumps (Gateways through membrane) Sodium: Na+ (pos) Potassium: K-(neg) (Tech. Neutral)

34. Depolarization • The cell stops pumping sodium out and positive ions rush in until the potential reaches +50 millivolts. • When the cell’s potential has changed from negative to positive it has been depolarized.

35. How Does a Neuron Fire? Synapse, cerebral spinal fluid Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Dendritic receptor sites Dendrite Soma (Cell) Membrane Nucleus Axon Hillock (Trapdoor) Axon K-K- K- K- K- K- K- When NA+ reaches +50 Depolarization The Neuron Fires Activates the Pump Sucks Sodium into Nucleus Pushes Potassium Out Rub together, electrical discharge, hits cell nucleus, DNA,Travels down axon Sodium Potassium Pump (Gateways through membrane) Sodium: Na+ (pos) Potassium: K-(neg) (Tech. Neutral)

36. It’s Electric! Boogie..oogie… oogie

37. Electrical Potential - is the state of the electrical charge which can be measured • Action Potential - once the resting potential has changed +10 millivolts, the membrane changes drastically to create action potential

38. Each neuron fires with the same intensity—regardless of the strength of the stimulus (doesn’t affect the speed of action potential) Neurotransmitters…or drugs…

39. Why Did the Neuron Cross the Synapse? Charge travels down axon Causes release (Gateways open) Neurotransmitters drop Travel in Synapse to next Key-Lock Neuron Neurotransmitter Vesicle Button

40. Reuptake… New Neurotransmitters Secreted from other neurons Travel in Synapse and re-fill open Key-Lock positions Called Reuptake process Neurotransmitter Vesicle Button

41. Timing Is Everything • From -70 to 50 to -60 (-70) • 1 nanosecond (.001 second, Myelinated) • Absolute Refractory Period: time it takes to get back to resting potential, ready to fire again • Ex: time to reload a bullet • car at stop sign • refill a toilet • reload a sneeze

42. The All-or-None Response • The idea that either the neuron fires or it does not- no part way firing. • Like a gun • Being a “little bit pregnant”

43. Indirect System Synapse, cerebral spinal fluid Chemical Reaction Like 2 trains passing They do not directly connect Pick up and drop off passengers (neurotransmitters) on different train lines No Cross-over! Electrical Reaction Chemical Reaction Synapse, cerebral spinal fluid

44. How Neurons Communicate

45. Review: Steps of Action Potential • Dendrites receive neurotransmitter from another neuron across the synapse. • Reached its threshold- then fires based on the all-or-none response. • Opens up a portal in axon, and lets in positive ions (Sodium) which mix with negative ions (Potassium) that is already inside the axon (thus Neurons at rest have a slightly negative charge). • The mixing of + and – ions causes an electrical charge that opens up the next portal (letting in more K) while closing the original portal. • Process continues down axon to the axon terminal. • Terminal buttons turns electrical charge into chemical (neurotransmitter) and shoots message to next neuron across the synapse.

46. I’m Exhausted Just Thinking About It • This process is repeated 100x or 1000x a second • Metacafe Video

47. Make Your Own Neuron (Soma) Nucleus Axon hillock (trapdoor) One-way door Protects DNA from electrical charge (surge protector) Direction of Action Potential

48. Neurotransmitters

49. Neurotransmitters • A chemical which produces a change in a neuron’s potential. • These chemicals are stored in terminal buttons’ synaptic vesicles • these are sent from the presynaptic terminal button to the postsynaptic dendrite. • NTs are either: Excitors (gas) or Inhibitors (brakes).

50. Neurotransmitters • Dendrites contain receptor sites for neurotransmitters. • Only certain molecules fit these receptors, the way a key fits a lock.