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Module 4

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  1. Module 4 Incredible Nervous System

  2. GENES & EVOLUTION • Genetic information • brain and body developed according to complex chemical instructions that were written in a human cell no larger than a grain of sand • Fertilization • Zygote • Chromosomes • Chemical alphabet • Genes and proteins • Genome • Genetic factors

  3. GENES & EVOLUTION (CONT.) • Fertilization • human life has its beginnings when a father’s sperm, which contains 23 chromosomes, penetrates a mother’s egg, which contains 23 chromosomes


  5. GENES & EVOLUTION (CONT.) • Zygote • the largest human cell, about the size of a grain of sand • a zygote is a cell that results when an egg is fertilized • a zygote contains 46 chromosomes arranged in 23 pairs

  6. GENES & EVOLUTION (CONT.) • Chromosomes • a short, rodlike, microscopic structure that contains a tightly coiled strand of the chemical DNA, which is an abbreviation for deoxyribonucleic acid

  7. GENES & EVOLUTION (CONT.) • Chemical alphabet • each chromosome contains a long, coiled strand of DNA, which resembles a ladder that has been twisted over an over upon itself • each rung of the DNA ladder is made up of four chemicals • the order in which the four different chemicals combine to form rungs creates a microscopic alphabet

  8. p68 DNA

  9. GENES & EVOLUTION (CONT.) • Genes and proteins • Gene • a specific segment on the long strand of DNA that contains instructions for making proteins • Proteins • chemical building blocks from which all the parts of the brain and body are constructed

  10. p68 CHROMOSOME

  11. GENES & EVOLUTION (CONT.) • Genome • The Human Genome Project • began in 1995 and cost over $2.7 billion • reached its first goal in 2003 of mapping all the human genes • researchers found only about 30,000 human genes instead of the estimated 100,000

  12. GENES & EVOLUTION (CONT.) • Genetic factors • researchers are discovering how genetic factors interact with the environment to result in the development of mental retardation, emotional and personality traits, mental disorders, and various cognitive abilities • Fragile X syndrome • an inherited developmental disability, is due to a defect in the X chromosome

  13. GENES & EVOLUTION (CONT.) • Evolution of the human brain • 1859 Charles Darwin published the Origin of Species • Theory of Evolution • says that different species arose from a common ancestor and that those species that survived were best adapted to meet the demands of their environment

  14. p69 SKULL SIZE

  15. STUDYING THE LIVING BRAIN • Brain scans • techniques that can look through the thick skull and picture the brain with astonishingly clarity yet cause no damage to the extremely delicate brain cells • MRI and fMRI

  16. STUDYING THE LIVING BRAIN (CONT.) • MRI • magnetic resonance imagery • involves passing nonharmful radio frequencies through the brain • fMRI • functional magnetic resonance imaging • measures the activity of specific neurons that are functioning during cognitive tasks, such as thinking, listening

  17. p70 MRI

  18. STUDYING THE LIVING BRAIN (CONT.) • Brain scans and Cognitive Neuroscience • PET scan • positron emission tomography • involves injecting a slightly radioactive solution into the blood and then measuring the amount of radiation absorbed by brain cells called neurons

  19. p71 PET

  20. STUDYING THE LIVING BRAIN (CONT.) • Tools versus Animals • naming animals • naming tools



  23. ORGANIZATION OF THE BRAIN • Divisions of the Nervous System • Major divisions of the nervous system • central nervous system - CNS • peripheral nervous system - PNS

  24. ORGANIZATION OF THE BRAIN (CONT.) • Central nervous system - CNS • made up of the brain and spinal cord

  25. p72 CNS

  26. ORGANIZATION OF THE BRAIN (CONT.) • Peripheral nervous system - PNS • includes all the nerves that extend from the spinal cord and carry messages to and from various muscles, glands, and sense organs located throughout the body • Subdivisions of the PNS • somatic nervous system • autonomic nervous system - ANS • sympathetic division • parasympathetic division

  27. p72 PNS

  28. ORGANIZATION OF THE BRAIN (CONT.) • Somatic nervous system • network of nerves that connect either to sensory receptors or to muscles that you can move voluntarily, such as muscles in your limbs, back, neck, and chest • nerves contain two kinds of fibers • Afferent • sensory fibers; carry information to the brain • Efferent • motor fibers; carry information from brain or spinal cord to the muscles

  29. ORGANIZATION OF THE BRAIN (CONT.) • Autonomic nervous system - ANS • regulates heart rate, breathing, blood pressure, digestion, hormone secretion, and other functions • Sympathetic division • triggered by threatening or challenging physical or psychological stimuli, increases physiological arousal and prepares the body for action • Parasympathetic division • returns the body to a calmer, relaxed state and is involved in digestion

  30. ORGANIZATION OF THE BRAIN (CONT.) • Major Parts of the Brain • Forebrain • Midbrain • Hindbrain • pons • medulla • cerebellum


  32. ORGANIZATION OF THE BRAIN (CONT.) • Forebrain • largest part of the brain • has right and left sides called hemispheres • hemispheres are responsible for a number of functions, including learning and memory, speaking and language, emotional responses, experiencing sensations, initiating voluntary movements, planning, and making decisions

  33. ORGANIZATION OF THE BRAIN (CONT.) • Midbrain • has a reward or pleasure center, which stimulated by food, sex, money, music, looking at attractive faces, and some drugs (cocaine) • has areas for visual and auditory reflexes • contains the reticular formation, which arouses the forebrain so that it is ready to process information from the senses

  34. ORGANIZATION OF THE BRAIN (CONT.) • Hindbrain • Has three distinct structures: • Pons • Medulla • cerebellum

  35. ORGANIZATION OF THE BRAIN (CONT.) • Pons • functions as a bridge to interconnect messages between the spinal cord and brain • Medulla • located on top of the spinal cord • includes a group of cells that control vital reflexes, such as respiration, heart rate, and blood pressure • Cerebellum • located in the very back and underneath the brain • involved in coordinating motor movements but not in initiating voluntary movements

  36. CONTROL CENTERS: FOUR LOBES • Wrinkled cortex • a thin layer of cells that essentially covers the entire surface of the forebrain

  37. CONTROL CENTERS: FOUR LOBES (CONT.) • Four lobes • Frontal lobe • Parietal lobe • Occipital lobe • Temporal lobe

  38. p74 FOUR LOBES

  39. CONTROL CENTERS: FOUR LOBES (CONT.) • Frontal lobe • involved with personality, emotions, and motor behaviors • Parietal lobe • involved with perception and sensory experiences • Occipital lobe • involved with visual processing • Temporal lobe • involved with hearing and speaking

  40. CONTROL CENTERS: FOUR LOBES (CONT.) • Frontal lobe: functions • motor cortex • narrow strip of cortex that is located on the back edge of the frontal lobe and extends down its side • involved in the initiation of all voluntary movements • right side controls left • left side controls right • organization and function of motor cortex

  41. p76 MOTOR CORTEX

  42. CONTROL CENTERS: FOUR LOBES (CONT.) • Other functions of frontal lobe • much knowledge of other frontal lobe functions comes from individuals who had damage to that area • Phineas Gage

  43. CONTROL CENTERS: FOUR LOBES (CONT.) • Parietal lobe: function • location of somatosensory cortex • narrow strip of cortex that is located on the front edge of the parietal lobe and extends down its side


  45. CONTROL CENTERS: FOUR LOBES (CONT.) • Other functions of parietal lobe • involved in several cognitive functions, including recognizing objects, remembering items, and perceiving and analyzing objects in space

  46. CONTROL CENTERS: FOUR LOBES (CONT.) • Temporal lobe: functions • primary auditory cortex • located on top edge of each temporal lobe, receives electrical signals from receptors in the ears and transforms these signals into meaningful sound sensations, such as vowels and consonants


  48. CONTROL CENTERS: FOUR LOBES (CONT.) • Temporal lobe: functions • auditory association area • located directly below the primary auditory cortex • transforms basic sensory information, such as noises or sounds, into recognizable auditory information, such as words or music

  49. CONTROL CENTERS: FOUR LOBES (CONT.) • Temporal lobe: functions • Broca’s area - frontal lobe • located in left frontal lobe • necessary for combining sounds into words and arranging words into meaningful sentences • Wernicke’s area • located in the left temporal lobe • necessary for speaking in coherent sentences and for understanding speech