1. Incredible Nervous System
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. 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.)

8. GENES & EVOLUTION (CONT.)
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 & 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

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
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. EVOLUTION OF THE HUMAN BRAIN
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. 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

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

23. STUDYING THE LIVING BRAIN (CONT.)

24. STUDYING THE LIVING BRAIN (CONT.)

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. 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

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. 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

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. CONTROL CENTERS: FOUR LOBES (CONT.)
Frontal lobe
Parietal lobe
Occipital lobe
Temporal lobe

40. CONTROL CENTERS: FOUR LOBES (CONT.)

41. CONTROL CENTERS: FOUR LOBES (CONT.)
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.)

44. CONTROL CENTERS: FOUR LOBES (CONT.)

45. 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

46. CONTROL CENTERS: FOUR LOBES (CONT.)

47. 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
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.)

50. CONTROL CENTERS: FOUR LOBES (CONT.)

51. 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

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. 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

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. CONTROL CENTERS: FOUR LOBES (CONT.)
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. CONTROL CENTERS: FOUR LOBES (CONT.)
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. LIMBIC SYSTEM: OLD BRAIN (CONT.)
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