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Module 4 Incredible Nervous System. GENES & EVOLUTION Genetic information –brain and body developed according to complex chemical instructions that were.

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Presentation on theme: "Module 4 Incredible Nervous System. GENES & EVOLUTION Genetic information –brain and body developed according to complex chemical instructions that were."— Presentation transcript:

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

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

4 GENES & EVOLUTION (CONT.)

5 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.)

8 Chemical alphabet –each chromosome contains a long, coiled strand of DNA, which resembles a ladder that has been twisted over and 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

9 GENES & EVOLUTION (CONT.)

10 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

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 –It is a blue print of genes

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

13 EVOLUTION OF THE HUMAN BRAIN 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 –humans and chimpanzees share at least 98% of their DNA

14 EVOLUTION OF THE HUMAN BRAIN

15 Australopithecus (Lucy) –3-4 million years ago –brain weight 500 grams (size of a chimp) no tools, no language, no fire Homo erectus –1.5 million years ago –brain weight 1,000 grams Stone tools (possibly language) Homo sapiens –400,000 years ago –brain weight 1350 grams or 3 pounds

16 STUDYING THE LIVING BRAIN Brain scans –techniques that can look through the thick skull and picture the brain with astonishing clarity yet cause no damage to the extremely delicate brain cells –researchers are mapping a variety of cognitive functions: –attention, language, memory, motor skills

17 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

18 STUDYING THE LIVING BRAIN (CONT.)

19 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

20 STUDYING THE LIVING BRAIN (CONT.) Brain scans and Cognitive Neuroscience –Neuroimaging PET and fMRI scans are used to identify and map the living brain’s neural activity as a person performs complex behavioral and cognitive tasks, such as: –seeing –moving –thinking –speaking –empathizing –trusting –even reacting to TV violence

21 STUDYING THE LIVING BRAIN (CONT.)

22 Tools versus Animals –naming animals –naming tools

23 STUDYING THE LIVING BRAIN (CONT.)

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25 ORGANIZATION OF THE BRAIN Divisions of the Nervous System Major divisions of the nervous system –central nervous system - CNS –peripheral nervous system - PNS

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

27 ORGANIZATION OF THE BRAIN (CONT.)

28 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

29 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

30 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 (epinephrine) Parasympathetic division –returns the body to a calmer, relaxed state and is involved in digestion (norepinephrine) = Homeostasis

31 LIMBIC SYSTEM: OLD BRAIN (CONT.)

32 ORGANIZATION OF THE BRAIN (CONT.)

33 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

34 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

35 ORGANIZATION OF THE BRAIN (CONT.) Hindbrain –Has three distinct structures: Pons Medulla Cerebellum

36 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

37 CONTROL CENTERS: FOUR LOBES Wrinkled cortex –a thin layer of cells that essentially covers the entire surface of the forebrain

38 CONTROL CENTERS: FOUR LOBES (CONT.)

39 Four lobes –Frontal lobe –Parietal lobe –Occipital lobe –Temporal lobe

40 CONTROL CENTERS: FOUR LOBES (CONT.)

41 Frontal lobe –involved with personality, emotions, and motor behaviors, decision making Parietal lobe –involved with perception and sensory experiences Occipital lobe –involved with visual processing Temporal lobe –involved with hearing and speaking

42 CONTROL CENTERS: FOUR LOBES (CONT.) Frontal lobe: functions –Phineas Gage Frontal Lobotomy –A surgical procedure in which about one-third of the front part of the frontal lobe was cut away from the rest of the brain –18,000 were performed during the 1940s and 1950s

43 CONTROL CENTERS: FOUR LOBES (CONT.)

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45 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

46 CONTROL CENTERS: FOUR LOBES (CONT.)

47 Other functions of frontal lobe –much knowledge of other frontal lobe functions comes from individuals who had damage to that area –frontal lobes are involved in paying attention, organizing, planning, deciding, and carrying out various cognitive tasks and social-emotional behaviors –executive function

48 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

49 CONTROL CENTERS: FOUR LOBES (CONT.)

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51 Other functions of parietal lobe –involved in several cognitive functions, including recognizing objects, remembering items, and perceiving and analyzing objects in space

52 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

53 CONTROL CENTERS: FOUR LOBES (CONT.)

54 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

55 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 damage: Broca’s aphasia –person cannot speak in fluent sentences but can understand written and spoken words

56 CONTROL CENTERS: FOUR LOBES (CONT.) –Wernicke’s area located in the left temporal lobe necessary for speaking in coherent sentences and for understanding speech Damage: Wernicke’s aphasia –difficulty in understanding spoken or written words and a difficulty in putting words into meaningful sentences

57 CONTROL CENTERS: FOUR LOBES (CONT.)

58 Occipital lobe: functions –vision –primary visual cortex –located at the very back of the occipital lobe –receives electrical signals from receptors in the eyes and transforms these signals into meaningless basic visual sensations, such as lights, lines, shadows, colors, and textures

59 CONTROL CENTERS: FOUR LOBES (CONT.)

60 Occipital lobe: functions –visual association area –transforms basic sensations, such as lights, lines, colors, and textures, into complete, meaningful visual perceptions, such as persons, objects, or animals

61 LIMBIC SYSTEM: OLD BRAIN group of about half a dozen interconnected structures that make up the core of the forebrain involved with regulating many motivational behaviors such as obtaining food, drink, and sex organizing emotional behaviors such as fear, anger, and aggression; storing memories Structures and functions –Hypothalamus –Amygdala –Thalamus –Hippocampus

62 LIMBIC SYSTEM: OLD BRAIN (CONT.)

63 Hypothalamus –regulates many motivational behaviors, including eating, drinking, and sexual responses; emotional behaviors such as arousing the body when fighting or fleeing, and secretion of hormones, such as occurs at puberty Amygdala –located in the tip of the temporal lobe –receives input from all the senses –evaluates the emotional significance of stimuli and facial expressions, especially those involving fear, distress, or threat

64 LIMBIC SYSTEM: OLD BRAIN (CONT.) Thalamus –gathers and processes information from the senses –involved in receiving sensory information, doing some initial processing, and then relaying the sensory information to areas of the cortex Hippocampus –curved structure inside the temporal lobe –Involved in saving many kinds of fleeting memories by putting them into permanent storage in various parts of the brain


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