Neurons and the Nervous System

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Section 1: Neurons

• Learning Goals:– Students should be able to answer the following:

1. What are neurons, and how do they transmit information?

2. How do nerve cells communicate with other nerve cells?

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Neurons

*Multiple Sclerosis degrades the Myelin Sheath

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Cell Body is also called the “Soma”

The Synapse• Between Sending and Receiving Neurons AKA- “Cleft”

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Order of a Neuron(1) Dendrite (2) Soma (3) Axon (4) Axon Terminal (5) Synapse

Neural Communication• Resting Potential

– Negative Ions inside the axon• Action Potential

– Positive Ions move inside the axon• Refractory Period

– Neuron can’t fire (resetting effect)• Sodium-Potassium Pump

– How the Neuron Fires• Absolute Threshold

– How much stimulation the neuron needs to fire• All-or-None Response

– A neuron fires or it doesn’t fire (like a gun)

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Neural Communication

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Section 1: Neurons

• Reflection of Learning Goals:– Students should be able to answer the following:

1. What are neurons, and how do they transmit information?

2. How do nerve cells communicate with other nerve cells?

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Good Understanding

Little Understanding

Fair Understanding

Section 1: Test Your Knowledge1. Which part of the neuron helps to insulate the

action potential so that it moves faster?A. DendriteB. SomaC. AxonD. Myelin Sheath

2. Which two chemicals are involved in a neuron’s action potential?

A. Sodium and PotassiumB. Carbon and SodiumC. Potassium and CarbonD. Iron and Potassium

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Section 2: Neurotransmitters & Drugs

• Learning Goals:– Students should be able to answer the following:

1. How do neurotransmitters influence behavior, and how do drugs and other chemicals affect neurotransmission.

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Neurotransmitters

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Neurotransmitter Function Other Facts

Acetylcholine (ACh) Muscle action, Memory Too little = Alzheimer's

Dopamine Learning, pleasure emotion Too much = hallucinations (Schizophrenia)Too little = Parkinson's

Serotonin Mood Control, Aggression Too Little = Depression

Epinephrine/Norepinephrine

Alertness and Arousal Also a hormoneSometimes called adrenalineAlso Depression

GABA“Get a Brake adjustment”

Inhibits/stops us from getting too aroused

Too Little = OCD thoughts, Seizures and Anxiety

Endorphins Natural Painkillers Example: Runner’s High

Drugs and Neurotransmission• Agonists

– Excite, Mimics neurotransmitters

– Example: Heroin Mimics Endorphins

• Antagonists– Inhibit– Example: Botox Blocks ACh

• Lock and Key Model– How a neurotransmitter

binds with a receptor site

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Section 2: Neurotransmitters & Drugs• Reflection of Learning Goals:– Students should be able to answer the following:

1. How do neurotransmitters influence behavior, and how do drugs and other chemicals affect neurotransmission.

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Good Understanding

Little Understanding

Fair Understanding

Section 2: Test Your Knowledge1. You are conducting scientific

research on biology and behavior. For each of the following decide what type of neurotransmitter(s) you might look at

A. Parkinson’s DiseaseB. Generalized Anxiety DisorderC. Major Depressive EpisodeD. An agonist that causes people to feel

little pain

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Section 3: Nervous System vs. Endocrine System

• Learning Goals:– Students should be able to answer the following:

1. What are the functions of the nervous system’s main divisions?

2. How does the endocrine system transmit messages?

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The Nervous System

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Autonomic Nervous SystemSympathetic Nervous System: Division of the ANS that arouses the body, mobilizing its energy in stressful situations. (Fight or Flight)

Parasympathetic Nervous System: Division of the ANS that calms the body, conserving its energy.(Rest and Digest)

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Types of Neurons• Sensory Neurons (afferent)

– Carry information to the Central Nervous System– Detect Pressure, Heat or Light

• Interneurons– Connect Motor and Sensory Neurons in Central Nervous

System (Most Numerous Type of Neuron)– Carries information from spinal cord to brain

• Motor Neurons (efferent)– Carry information to the Muscles and Glands– Important part of the peripheral nervous system

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Reflexes

• Automatic response that requires no “brain messages” (Reflex Arc)

• Decision made at interneuron in the spinal cord

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The Endocrine System

• The Endocrine System is the body’s “slow” chemical communication system. Communication is carried out by hormones synthesized by a set of glands.

• Includes all glands

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The Endocrine System• Pituitary is the master

gland– Influences growth hormones

• Pituitary is controlled by the hypothalamus

• Slow System has lasting effects– Example: Adrenal Glands release

epinephrine and norepinephrine which increase blood pressure and heart rate, such as when you are caught in a lie

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Section 3: Nervous System vs. Endocrine System

• Reflection of Learning Goals:– Students should be able to answer the following:

1. What are the functions of the nervous system’s main divisions?

2. How does the endocrine system transmit messages?

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Good Understanding

Little Understanding

Fair Understanding

Section 3: Test Your Knowledge1. Which part of the nervous system is

responsible for fight or flight?A. SomaticB. SympatheticC. ParasympatheticD. Occipital

2. Endocrine is to _____, as nervous system is to_____.

A. Water, LandB. Brain, BodyC. Agonist, AntagonistD. Hormones, Neurotransmitters

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Section 4: Observing the Brain

• Learning Goals:– Students should be able to answer the following:

1. How do neuroscientists study the brain’s connections to behavior and the mind?

Mr. Burnes 23