1. MOD 3 PART 2 AP PSYCHOLOGY

2. NEURAL COMMUNICATION How does one neuron communicate with another?  Original belief was that axons and dendrites were fused  Cajal noticed gaps between nerve cells  Sherrington noticed interruptions in the neural pathways  Synapse (Synaptic gap, synaptic cleft)  Space between sending axon and receiving dendrite  “Protoplasmic kisses”  Neurotransmitters (chemical messengers)  Released by axon  Attach to receptor sites in the dendrite  Lock and key  Unlocks channels to send ions into the axon, thus sending signal to the next  Excess neurotransmitters are reabsorbed into the sending neuron (reuptake) 2

3. SYNAPSE 3

4. ACHETYLCHOLINE AND ENDORPHINS Acetylcholine  Key role in learning and memory  Messenger between every motor neuron and muscle  causes muscle contraction  Poisons that affect Ach  Curare can block reception of Ach and in effect paralyze an animal  Botulin stops release of Ach from sending neuron  Black widow spider venom causes synaptic flood of Ach Endorphins  Discovery of opiates attaching to receptors in areas linked to mood and pain (Snyder 1973)  Endorphins are the key to the opiate lock (endogenous morphine)  Adrenaline  Runners’ high 4

5. 5

6. HOW DRUGS AND OTHER CHEMICALS AFFECT NEUROTRANSMITTERS Drugs often mock neurotransmitters  Neurons are flooded  Body shuts down production  Detox problems  Lingering side effects  Addiction  Agonists excite the neuron  Antagonists inhibit the neuron Some scientists attempt to create drugs that mimic neurotransmitters that are out of balance  Blood-brain barrier keeps most unwanted chemicals out  L-dopa as a treatment for Parkinsons 6

7. 7

8. THE NERVOUS SYSTEM The Nervous Sytem: The body’s primary information system  Central nervous system: the brain and spinal chord  The peripheral nervous system: links central nervous system with sense receptors, muscles, and glands  Nerves: the motor axons that carry the information  Optic nerve: million axons bundled together into a single cable carrying information from each eye (Mason and Kandel (1991)  Three types of neurons  Sensory neurons: sends information from the body’s tissues and sensory organs to the brain  Interneurons: allow internal communication for the central nervous system  Motor neurons: sends information from the central nervous system to the body’s tissues 8

9. THE PERIPHERAL NERVOUS SYSTEM Somatic Nervous System: Controls the movement of skeletal muscles Autonomic Nervous System: controls the glands and the muscles of internal organs Sympathetic Nervous System: arouses people for defensive action  Accelerate heartrate  Slow digestion  Raise blood sugar  Dilate arteries  Cool with perspiration Parasympathetic Nervous System: opposite of sympathetic nervous system  Slows heartrate  Speeds digestion  Lowers blood sugar  Dilate arteries 9

10. THE CENTRAL NERVOUS SYSTEM Spinal cord and Brian  Information superhighway  Reflexes: automatic responses  Simple pathway is one motor and one sensory neuron  Knee-jerk  pain (often felt AFTER the reflex)  Effects of severing spinal cord  No feeling below the point of injury  Reflexes still occur without the brain registering the pressure sensor  Sexual response  Genitals are still reflexive (Goldstein 2000)  No reaction to sexual imagery (Kennedy and Over 1990, Sipski et al 1999) Neural Networks  Brian receives information, interprets it, and decides responses  300 trillion cortical-synaptic connections (Rachmachadran and Blakesly 1998)  Neural networks: clustered work groups 10

11. THE ENDOCRINE SYSTEM Endocrine System: the body’s second communication system Hormones originate in one tissue and use the bloodstream to affect other tissues  Glands secrete hormones (another form of chemical messenger)  Much slower than the nervous system  Adrenal glands (top of kidneys  Produce epinephrine and norepinephrine to control arousal  Provide surge of energy when needed  Pituitary Gland  Controlled by the hypothalamus  Releases hormones that influence growth  Influences release of other hormones from other glands  “master gland”  Triggers release of sex hormones Feedback loop: Brain -> pituitary -> other glands -> hormones -> brain Distinction often fuzzy, as sometimes neurotransmitters can act like hormones (Agnati et al 1992, Pert 1986 11

12. EXIT TICKET AND HOMEWORK Exit Ticket  What are neurons and how do they transmit information?  How does a neuron communicate with other cells to influence behavior?  What are the elementary components of our nervous system?  What are the functional divisions of our nervous system?  How does the endocrine system deliver its messages? Homework:  Complete diagram packet  Read Pages 68-75  Be prepared for Quiz 12