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Journal. What gets on your nerves? (10 sentences). The Nervous System Ch. 6. The Nervous System. Central nervous system Made up of brain and spinal cord Peripheral Nervous system Branching parts from the spinal cord to all other parts of the body
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Journal • What gets on your nerves? (10 sentences)
The Nervous System • Central nervous system • Made up of brain and spinal cord • Peripheral Nervous system • Branching parts from the spinal cord to all other parts of the body • Nerves get smaller the further away from the spinal cord you are
Neurons • Long, thin cells of the nerve tissue • Messages travel along “neuron highway” • “All or none” principle • A neuron “fires” at full strength or not at all
Parts of the Neuron Dendrite: protrude from cell body, receive messages (impulses) from other neurons and send them to other parts of the body Axon: carries messages (impulses) toward axon terminals Axon terminals: release neurotransmitters to excite dendrites of next neuron Myelin sheath: fatty substance that protects and insulates the axon, speeds up impulses -lack of myelin sheath leads to erratic, uncoordinated movements (multiple sclerosis)
Types of Neurons • Afferent • “Sensory neurons” • Relay messages from sense organs to brain • Efferent • “Motor neurons” • Messages from brain to muscles • Interneurons • Process signals to other neurons
Firing Across the Synapse • Synapse: gap between nerve cells • Chemicals known as neurotransmitters are released from one dendrite and excite the receptors of the next neuron • Release (or non-release) of different neurotransmitters leads to different emotions • Happiness/learning (dopamine), inhibit pain (endorphin), depression (seratonin)
Voluntary vs. Involuntary Activity • Somatic Nervous System • Controls VOLUNTARY activities • Lifting your arms/legs • Autonomic Nervous System • Controls INVOLUNTARY activities • Breathing, heartbeat, digestion • Sympathetic nervous system • Prepares body for emergencies • Increases oxygen supply, speeds heart rate • Parasympathetic nervous system • Tries to conserve energy, recovery • Reduces heart rate, bring body to “resting” state
Outside Activity • Set yourself up as the nervous system • You must pass the signal (ball) from the brain, down the spinal cord and back to the brain • You must describe the parts of the nervous system as the message is being passed to and from the muscles • What was the final action? • What happens if there is a break in the nervous system?
Journal • Are you ever in your “right mind?” • If you do not know what this means, answering the following question: • Should sports that are known for concussions and head injuries be televised? What are the implications of (boxing, American football, hockey, UFC, football/soccer)? • 10 sentences for either one
The Brain (pt. 1) Parts & Functions 6.2 (p. 160-165)
Hindbrain • Responsible for basic processes • Located at rear base of skull • Parts of the hindbrain: • Cerebellum • Controls posture, balance, VOLUNTARY movement • Medulla • Controls breathing, heart rate, reflexes • http://www.youtube.com/watch?v=UfC4u5GCy3I • Pons • Connects brain and spinal cord; chemicals for sleep
The Midbrain • Located just above the pons (hindbrain) • Arouses brain • Integrates sensory info • Reticular activating system (RAS) • Part of sleep/wake cycle • Alerts brain to incoming signals
The forebrain • Responsible for higher thinking processes • Parts of the forebrain • Cerebral cortex (outer layer of forebrain) • Learn and store complex info; conscious thinking • Cerebrum (inner layer of forebrain): emotions • Limbic system: • Hypothalamus: controls hunger, thirst, sexual behavior, temperature • Thalamus: receives sensory info (except smell), send to cortex • Amygdala: controls rage and fear • Hippocampus: forms memories
Cortexes • Somatosensory cortex • Located at back of frontal lobe • RECEIVES info from touch sensors • Number of touch sensors in a body part determines amount of brain tissue associated • Ex: hands have more brain area than bicep • Motor cortex • SENDS info to control body movement • More sophisticated the movement, more brain area
Left vs. Right Hemispheres • Cerebrum comprised of 2 sides (hemispheres) • Each hemisphere controls opposite half of body • Left hemisphere controls right side of body, vice versa • Connected by corpus callosum (lots of fibers) • Carries messages between both hemispheres • **Left/Right test: http://www.wherecreativitygoestoschool.com/vancouver/left_right/rb_test.htm
Split-brain Functioning • Separate the corpus callosum • Hemispheres can no longer “talk” to each other • Done to prevent severity and frequency of seizure patients • Research shows each hemisphere is specialized • Patients retain their intelligence, emotions, and personality
Journal • How would your behavior be different if you were to have serious head trauma? (10 sent) • Things to consider as you write: • How did your brain get hurt? • What parts of the brain were affected? • Can you recover?
The brain (pt. 2) 6.2 (p. 165-168) Problems and solutions to brain damage
How to study the brain • Electroencephalograph (EEG) • Use electrodes to study electrical activity in the brain (looks at neurons firing) • http://www.bbc.co.uk/news/science-environment-22764978 • Stimulate brain • Use electric shock to affect different parts of the brain (can reduce pain, control behavior) • Lobotomy/lesions • Remove or destroy certain parts of the brain • Formerly done to prisoners, behavior issues • Real life accidents • Look at what parts of the brain were affected and see how person’s behavior changed after accident • http://www.youtube.com/watch?v=MtA8wRPHlV4
Medical Devices • CT (computerized axial tomography) Scan: • Looks at how density of the brain to determine injuries or deterioration • PET (positron emission tomography) Scan: • Uses injected solution to see how much of the solution the brain absorbs • Shows activity of different areas of the brain • MRI (magnetic resonance imaging) • Looks at brain activity AND structure • Good for identifying tumors
Quiz/Test Hints • Be able to explain where each part (lobes, 3 main parts, hemispheres) • What does each part do? • Besides the neuron, what are other parts of the nervous system? • What are their functions? • What are ways to DETECT abnormalities in the brain? • What are ways to STUDY the brain?