biology part 1 f24.pdf

Finishing Correlations & Experiments Beginning Brain and Behaviour Today:  Begin Brain & Behaviour  Quiz 1 (Couse Outline Quiz) and Quiz 2 (on Weeks 1-2) due before midnight Sun., Sept. 22 Part 1. Neurons and the Nervous System BRAIN AND BEHAVIOUR HOW DO WE RESPOND TO THE WORLD...

Finishing Correlations & Experiments Beginning Brain and Behaviour Today:  Begin Brain & Behaviour  Quiz 1 (Couse Outline Quiz) and Quiz 2 (on Weeks 1-2) due before midnight Sun., Sept. 22 Part 1. Neurons and the Nervous System BRAIN AND BEHAVIOUR HOW DO WE RESPOND TO THE WORLD AROUND US? Descartes’ Notion of Reflexes René Descartes ▪ French philosopher ▪ 1596-1650 ▪ “animal spirits” flow through the nerves  To and from the brain Descartes’ Notion of Reflexes René Descartes ▪ French philosopher ▪ 1596-1650 ▪ “animal spirits” flow through the nerves  To and from the brain Where it all begins: Neurons ▪ Specialized cells that conduct impulses through the nervous system ▪ The smallest functional unit of the brain ▪ No two neurons are exactly alike Three Types of Neurons Involved in Reflexes Sensory (afferent) neurons ▪ Brings in information from the perimeter of the body to the central nervous system Motor (efferent) neurons ▪ Communicate information from the nervous system to muscles and glands Interneurons ▪ Connect sensory and motor neurons, carrying messages between the two Copyright © 2012 McGraw-Hill Ryerson Sensory, motor, inter- neurons Glial cells – the support staff Specialized cells that hold neurons together  Remove waste, dead neurons  Make myelin coating  nourish ▪ Smaller than neurons ▪ Make up more than half the volume of the human brain  It is proposed that there are approximately one trillion neurons that are responsible for controlling our behaviour. Although there are a variety of functions that the neurons are responsible for the basic structure (anatomy) is the same. Anatomy of a neuron ▪ Cell body (soma):  Anatomy of a neuron ▪ Dendrites:  Anatomy of a neuron ▪ Axon: The Structure of a Typical Neuron Myelin sheath Axon terminals Copyright © 2014 Pearson Canada Inc. The Structure of a Typical Neuron Copyright © 2014 Pearson Canada Inc.  This is what the picture looks like in your textbook. Copyright © 2016 by Nelson Education Ltd. 2-17 The synapse ▪ The space between the neurons ▪ Where the messages sent from the axon of one neuron are released to be picked up by the dendrites of receiving neurons The synapse: Neurotransmitters Chemical released into synaptic cleft from axon terminal of sending neuron. Crosses synapse and binds to appropriate receptors on dendrites or cell body of receiving neuron. Influences cell to fire/not fire. Message: The firing of a neuron Neural impulse: the firing of a neuron Resting potential When a neuron is at rest (not firing), the inside of the neuron has a slight negative electrical charge compared to the outside Neural impulse: the firing of a neuron Action potential ▪ When a neuron is stimulated ▪ More positively charged particles flow into the cell  making the inside suddenly positive compared to the outside of the cell ▪ Triggers the firing of the neuron Neural impulse: the firing of a neuron The neuron “fires” ▪ The action potential travels down the axon ▪ Stimulates the release of neurotransmitters from the axon terminals ▪ All or nothing Neural impulse: the firing of a neuron ▪ Immediately after the neuron fires, some positive particles are actively pumped out of the cell ▪ The neuron returns to its resting potential and is ready to fire again if stimulated. Fig. 2.2 (Action Potential) a) Neuron at rest b) When stimulated c) Neuron fires d) Returns to resting potential Message: received and delivered Receptor sites: Locks for Neurotransmitter keys Receptors: sites on the dendrites or cell body that will only react with specific neurotransmitters Receptor sites: Locks for Neurotransmitter keys Receptors: sites on the dendrites or cell body that will only react with specific neurotransmitters NEUROTRANSMITTERS Different types, different messages Neurotransmitter Believed to Affect Acetylcholine ( ACh) Movement, learning, memory, REM sleep Dopamine ( DA) Learning, attention, movement, reinforcement Norepinephrine ( NE) Eating habits, sleep Epinephrine Metabolism of glucose, energy release during exercise Neurotransmitter Believed to Affect Serotonin Neurobiological functions such as mood, sleep, impulsivity, aggression, and appetite GABA Neural inhibition in the central nervous system Endorphins Relief from pain; feelings of pleasure and well- being Neural Networks ▪ Each neuron receives messages from many other neurons  Excitatory  Inhibitory ▪ Reflex arc Copyright © 2016 by Nelson Education Ltd. 2-33 Copyright © 2016 by Nelson Education Ltd. 2- 34 Copyright © 2016 by Nelson Education Ltd. 2-35 Neuroplasticity and Neurogenesis ▪ The capacity of our brains to change in response to experience ▪ Neural networks are constantly changing ▪ Self-directed neuroplasticity ▪ Neurilemma Copyright © 2016 by Nelson Education Ltd. 2- 36 Neural Networks ▪ Each neuron receives messages from many other neurons  Excitatory  Inhibitory ▪ Reflex arc Copyright © 2016 by Nelson Education Ltd. 2-37 Copyright © 2016 by Nelson Education Ltd. 2- 38 Copyright © 2016 by Nelson Education Ltd. 2- 39 Neuroplasticity and Neurogenesis ▪ The capacity of our brains to change in response to experience ▪ Neural networks are constantly changing ▪ Self-directed neuroplasticity ▪ Neurilemma Copyright © 2016 by Nelson Education Ltd. 2- 40