Unit 4: Neurobiology Lesson 2: Neurons DAILY COMMENTARY (use link!): Warm up computers, please keep candy for candy neuron put away for now Clearly describe each step involved in passing a note from one side of the room to the other. BE SPECIFIC. Make sure you have: Submitted interview paper Essential Question How do neurons send and receive messages between the brain and body? Lesson Plan Daily commentary Module / neuron labeling Brief lecture Simulation of neuron firing Candy Neuron

TODAY’s PLAN & Assignments DUE Unit Plan Lesson 1: Today Lesson 2: Today, Tomorrow Lesson 3: Thursday Lesson 4: Friday Also Friday: Article Discussion Lesson 5: Monday 11/7 Quiz after lesson 5 Lesson 6: Wed 11/9 Lesson 7: Nov 10 & 14 Lesson 8: Nov 15 Unit Test: Thurs, Nov 17 HOMEWORK Assigned: For FRIDAY: Biology of homosexuality article Take notes / annotate answer challenge questions Prepare discussion question WILL WE GO OUTSIDE? For TOMORROW: Candy Neurons: Form Teams; GO SHOPPING Readings / Online Modules See Lesson Map Myers 54-60 Griggs 33-38 MODULE # 9

Do Daily Commentary; then: Until 11am-Finish PsychSim 5 Module Follow the link posted yesterday & resume work on the “neural messaging” module. As you work through it: Complete handout by labeling the neuron On the back, answer these questions: What role do dendrites and axons play in neural transmission? Identify & describe the three main types of neurons Explain “action potential” & and “depolarization” What role do sodium/potassium pumps play in repolarizing a neuron (ie., restoring its “resting potential”) Do your best to describe the synapse / synaptic gap

Neural Communication The body’s information system is built from billions of interconnected cells called neurons.

We are a biopsychosocial system. Neural Communication We are a biopsychosocial system. Cellular Level (Interconnected Neurons) Ethnic Level (Culture) Community Level (Society) Organ Level (Brain) Group Level (Family) OBJECTIVE 2| Explain how viewing each person as a biopsychosocial system helps us understand human behavior, and discuss why researchers study other animals in search of clues to human neural processes. System Level (Information Processing) Individual Level (Human Being)

Neural Communication Neurobiologists and other investigators understand that humans and animals operate similarly when processing information. Note the similarities in the above brain regions, which are all engaged in information processing.

A nerve cell, or a neuron, consists of many different parts. OBJECTIVE 3| Describe parts of a neuron and explain how its impulses are generated.

Parts of a Neuron Cell Body: Life support center of the neuron. Dendrites: Branching extensions at the cell body. Receive messages from other neurons. Axon: Long single extension of a neuron, covered with myelin [MY-uh-lin] sheath to insulate and speed up messages through neurons. Terminal Branches of axon: Branched endings of an axon that transmit messages to other neurons.

Afferent v. Efferent Neurons Afferent – sensory neurons Efferent – motor neurons (think “effort / efferent)

Synapse Synapse [SIN-aps] a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. This tiny gap is called the synaptic gap or cleft. OBJECTIVE 4| Describe how nerve cells communicate. Synapse was coined by Lord Sherrington (1857-1952) who inferred it through behavioral experiments. Cajal (1852-1934) described the synapse based on his anatomical studies of the brain.

Action Potential A neural impulse. A brief electrical charge that travels down an axon and is generated by the movement of positively charged atoms in and out of channels in the axon’s membrane.

Simulated Neural Firing

In your teams of 3 Create your Candy Neuron Permitted Materials: Paper/tape/glue/yarn/etc. candy

Depolarization & Hyperpolarization Depolarization: Depolarization occurs when positive ions enter the neuron, making it more prone to firing an action potential. Hyperpolarization occurs when negative ions enter the neuron, making it less prone to firing an action potential.

Threshold Threshold: Each neuron receives currents from many neurons. When the depolarizing current (positive ions) minus the hyperpolarizing current (negative ions) exceed minimum intensity (threshold) the neuron fires an action potential.

Action Potential Properties All-or-None Response: When the depolarizing current exceeds the threshold, a neuron will fire. If the depolarizing current fails to exceed the threshold, a neuron will not fire. Intensity of an action potential remains the same throughout the length of the axon.

Synapse Synapse [SIN-aps] a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. This tiny gap is called the synaptic gap or cleft. OBJECTIVE 4| Describe how nerve cells communicate. Synapse was coined by Lord Sherrington (1857-1952) who inferred it through behavioral experiments. Cajal (1852-1934) described the synapse based on his anatomical studies of the brain.

Refractory Period & Pumps Refractory Period: After a neuron fires an action potential it pauses for a short period to recharge itself to fire again. Sodium-Potassium Pumps: Sodium-potassium pumps pump positive ions out from the inside of the neuron, making them ready for another action potential.

Neurotransmitters Neurotransmitters (chemicals) released from the sending neuron travel across the synapse and bind to receptor sites on the receiving neuron, thereby influencing it to generate an action potential.

How Neurotransmitters Influence Us? Serotonin pathways are involved with mood regulation. OBJECTIVE 5| Describe how neurotransmitters affect behavior and outline the effects of acetylcholine and endorphins. From Mapping the Mind, Rita Carter, © 1989 University of California Press

Neurotransmitters – check your work

Lock & Key Mechanism Neurotransmitters bind to the receptors of the receiving neuron in a key-lock mechanism. OBJECTIVE 6| Explain how drugs and other chemicals affect neurotransmission, and describe the contrasting effects of agonists and antagonists.

Agonists

Antagonists

TODAY’s PLAN & Assignments DUE Lesson Plan Daily commentary Brief lecture Simulation of neuron firing Label parts of a neuron Candy Neuron HOMEWORK Assigned: ON DESK Reading Journal 4.2 For tonight: RJ 4.3 Griggs 33-42 Myers 55-58