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Chapter 6- Body and Behavior
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Chapter 6- Body and Behavior

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  1. Chapter 6- Body and Behavior

  2. The Nervous System • Controls emotions, thinking, movements, and behavior • Two Parts • Central Nervous System (CNS)- brain and spinal cord • Peripheral Nervous System (PNS)- smaller nerves that reach other parts of the body • All parts are protected by sheathing and vertebrae (injury could lead to paralysis)

  3. Neurons • Long, thin, cells of nerve tissue along which messages travel to and from the brain • Transmission occurs when neurons are stimulated past a minimum point and emit a signal • All-or-none principle- neurons fire at full length only

  4. Basic Neuron Parts • Cell Body- Contains the nucleus and produces energy • Dendrites- receive impulses or messages from other neurons and send to cell body

  5. Basic Neuron Parts • Axon- long fiber that carries impulses away from the cell body towards the dendrites of the next neuron • Myelin Sheath- protects the axon • Axon Terminals- opposite dendrite of another neuron

  6. Basic Neuron Parts

  7. The Neuron Connection • Synapse- the space between the axon terminals of one neuron and the dendrites of another neuron

  8. The Neuron Connection • A neuron transmits its impulses or message to another neuron across the synapse by releasing chemicals called neurotransmitters. • Can either: • Excite the next neuron • Stop it from transmitting (inhibit) • Only allow flow in one direction

  9. Neurotransmitters

  10. Neurotransmitters • Norepinephrine- involved with memory and learning • Endorphins- inhibit pain- “inside morphine” • Too much or too little is linked to certain diseases • Undersupply of acetylcholine(memory and movement)- Alzheimer's • Oversupply of dopamine (learning, emotional arousal)- Schizophrenia • Undersupply of dopamine- Parkinson’s disease • Undersupply of norepinephrine and serotonin- depression

  11. Neuron Activity Intensity of activity in each neuron depends on how many other neurons are acting on it Each individual neuron is either ON or OFF depending on whether most of the neurons acting on it are either exciting or inhibiting

  12. Neuron Activity Afferent neurons- relay messages from the sense organs to the brain Efferent neurons- relay messages from brain to glands and muscles Interneurons- carry impulses between neurons

  13. Voluntary and Involuntary Activities • Parts of the Peripheral Nervous Nervous System • Somatic Nervous System (SNS)- voluntary activities • Autonomic Nervous System (ANS)- involuntary activities • Sympathetic- prepares for emergencies or strenuous activity • Increases HR and BP, suspends digestion • Parasympathetic- conserves energy and enhances recovery from strenuous activity • Reduces HR and BP

  14. The Three Brains: Hindbrain • Includes the • Cerebellum- posture, balance, voluntary movements • Medulla- breathing, heart rate, reflexes • Pons- bridge between spinal cord and brain, also helps in sleep

  15. The Three Brains: Midbrain • Integrates sensory information and regulates it upward • Brain stem= medulla +pons +midbrain • Reticular Activating System- plays a role in the sleep cycle

  16. The Three Brains: Forebrain • Thalamus- integrates sensory input (except smell) • Hypothalamus- hunger, thirst, sexual behavior, changes in temp. • Cerebral cortex- learning and storing information, projecting information • Limbic System- core of forebrain- includes above and: • Amygdala- violent emotions • Hippocampus- forming new memories

  17. The Lobes of the Brain • The cerebrum is two hemispheres connected by a band of fibers called the corpus collosum • Divided into lobes • Occipital- visual • Parietal- senses from all over the body • Temporal- hearing, memory, speaking • Frontal- organization, planning

  18. Motor Area Sensory Area

  19. Left and Right Hemispheres • Properties of the two sides have been simplified • Complement and help each other • Each side is connected to one half of the body in a criss-cross pattern • Left side- speech, math, logic, understanding • Right side- visual, spatial ability (puzzles), creativity, music

  20. Split Brain Operations When people are prone to grand mal seizures, separating the brain hemispheres will make them more severe Side effects: seem normal … but, if a man whose brain has been split holds a ball in his right hand, he will be able to say it is a ball, but in his left hand, he will not be able to say what it is. Information cannot cross to the speech center in the left hemisphere

  21. Studying the Brain • Recording: • Inserting electrodes (wires) into the brain- record activity • EEG- can record activity of large portions of the brain • Rhythmic pattern that depends on whether a person is awake, drowsy, or asleep

  22. Studying the Brain • Stimulation- causing neurons to fire • Use during brain surgery to find the malfunctioning part • By applying an electric current to the temporal lobe, can trigger memory sequences • One woman believed that a radio was being played in the operating room ** Pain relief without drugs

  23. Studying the Brain • Lesions- cutting or destroying part of an animal’s brain • Difference in behaviors • Removing part of the temporal lobe of monkeys made them less fearful and violent- aggression • Far more complex than people thought at first

  24. Studying the Brain • Accidents- Phineas Gage • Railroad foreman who had a 13 pound, three foot long iron bar go through his skull (1848) • Survived, but suffered personality changes- was short tempered and said inappropriate things • In 1994, realized that damage had been done to the frontal cortex, which censors thoughts and ideas

  25. CT Scans: An x-ray of the brain. A CT scan is essentially a computerized assembly of several x-ray images taken from a series of different angles. With a CT, the resolution is much better than conventional x-rays, and the detail that can be seen is much greater. **Can pinpoint brain injuries and deterioration

  26. P E T S C A N S PET measures the emission of positrons from the brain after a small amount of radioactive isotopes, or tracers,  have been injected into the blood stream.  A common example is a glucose-relative with embedded fluor-18.   With this molecule, the activity of different regions of the brain can be measured.  The result is a three-dimentional map with the brain activity represented by colors.

  27. Tumor   MRI is a noninvasive imaging technique that does not use x-rays.   The process involves passing a strong magnetic field through the head.  The magnetic field used is 30,000 + times that of the earth's magnetic field.  It's effect on the body, however, is harmless and temporary.  The MRI scanner can detect radiation from certain molecules, which are present in different concentrations in different tissues. 

  28. The Endocrine System • A chemical communication system that uses hormones to send chemical messages through the bloodstream • Produced in the endocrine glands • Site specific • Released directly into the bloodstream • Affect growth, metabolic processes, determine gender, secreting during stress, influence mood and drives

  29. The Pituitary Gland • Center of control of the endocrine system that secretes a large number of hormones • Monitored by the hypothalamus

  30. The Thyroid Gland • Produces thyroxine- stimulates chemical reactions important for all tissues • Too little- lethargic • Too much- overactivity

  31. Sex Glands • Testes and ovaries • Produces testosterone, estrogen, and progesterone

  32. Hormones vs. Neurotransmitters • The same chemical (norepinephrine) can be used as both • Neurotransmitter- released right beside the cell it will excite or inhibit • Hormone- released into the blood and diffused without the body

  33. Heredity and Environment • Heredity- the genetic transmission of characteristics from parents to offspring • Genes- the basic units of heredity, can interact with environment to cause behavior • Nature vs. Nurture • Galton- success runs in families • Watson- “give me a dozen healthy infants and I’ll guarantee to take any one at random and train him to be any specialist I might select”

  34. Twin Studies • Identical Twins- develop from a single fertilized egg (monozygotic) and share the same genes • Fraternal Twins- come from two different eggs fertilized by two different sperm • Minnesota Twin Study- share many common behaviors despite different social, cultural, and economic backgrounds