1. Incredible Nervous System
Module 4
Incredible Nervous System

2. GENES & EVOLUTION Genetic information Fertilization Zygote Chromosomes
Brain/body develop according to complex chemical instructions written in a human cell no larger than a grain of sand
Fertilization
Zygote
Chromosomes
Chemical alphabet
Genes and proteins
Polymorphic genes
Dominant and recessive genes
Genome

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

4. GENES & EVOLUTION (CONT’D)

5. GENES & EVOLUTION (CONT’D)
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’D)
Chromosomes
A short, rod-like, microscopic structure that contains a tightly coiled strand of the chemical DNA, which is an abbreviation for deoxyribonucleic acid

7. GENES & EVOLUTION (CONT’D)

8. GENES & EVOLUTION (CONT’D)
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’D)

10. GENES & EVOLUTION (CONT’D)
Genes and proteins
Gene
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’D)
Polymorphic genes
Gene that has more than one version (e.g. eye color)
Combination of genes sibling receives from parents, resulting in two siblings having different eye colors
Dominant and recessive genes
Dominant gene: polymorphic gene that determines the development of a specific trait even if paired with a recessive gene
Recessive gene: polymorphic gene that determines the development of a specific trait only when inherited from both parents

12. GENES & EVOLUTION (CONT’D)
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

13. GENES & EVOLUTION (CONT’D)
Genetic factors
Researchers are discovering how genetic factors interact with the environment in the development of mental retardation, emotional and personality traits, mental disorders, and various cognitive abilities
Fragile X syndrome
An inherited developmental disability due to a defect in the X chromosome
Genetic testing
Involves taking a blood, hair, skin, or other sample and then examining donor’s genes to look for specific diseases or disorders

14. EVOLUTION OF THE HUMAN BRAIN
1859, Charles Darwin published The Origin of Species
Theory of evolution
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

15. EVOLUTION OF THE HUMAN BRAIN (CONT’D)

16. EVOLUTION OF THE HUMAN BRAIN (CONT’D)
Genetic mutations
Accidental errors in genetic instructions that lead to a change
Natural selection
Genes for traits that help an organism survive and reproduce (adaptive genes) will be selected and will continue in a species
Genes for traits that prevent survival and reproduction (maladaptive genes) won’t be selected and will be eliminated in a species

17. EVOLUTION OF THE HUMAN BRAIN (CONT’D)
Adaptations
Common features of a species that provide it with improved function
Evolutionary approach
Voluntary ideas, such as adaptation and natural selection, explain human behaviors and mental processes

18. 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
sites of emotional feelings and appetite
MRI and fMRI

19. STUDYING THE LIVING BRAIN (CONT’D)
MRI and fMRI
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

20. STUDYING THE LIVING BRAIN (CONT’D)

21. STUDYING THE LIVING BRAIN (CONT’D)
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

22. STUDYING THE LIVING BRAIN (CONT’D)
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

23. STUDYING THE LIVING BRAIN (CONT’D)

24. The Nervous System

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’D)
Central nervous system (CNS)
Made up of the brain and spinal cord
Bottom of brain is where spinal cord emerges
Made up of neurons, bundles of axons, and dendrites that carry information back and forth between the brain and the body

27. Central Nervous System
The Brain and spinal cord
CNS

28. ORGANIZATION OF THE BRAIN (CONT’D)

29. ORGANIZATION OF THE BRAIN (CONT’D)
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

30. Peripheral Nervous System
All nerves that are not encased in bone.
Everything but the brain and spinal cord.
Is divided into two categories….somatic and autonomic.

31. ORGANIZATION OF THE BRAIN (CONT’D)

32. ORGANIZATION OF THE BRAIN (CONT’D)
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

33. Somatic Nervous System
Controls voluntary muscle movement.
Uses motor (efferent) neurons.

34. ORGANIZATION OF THE BRAIN (CONT’D)
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

35. Autonomic Nervous System
Controls the automatic functions of the body.
Divided into two categories…the sympathetic and the parasympathetic

36. ORGANIZATION OF THE BRAIN (CONT’D)
Major parts of the brain
Forebrain
Midbrain
Hindbrain
pons
medulla
cerebellum

37. ORGANIZATION OF THE BRAIN (CONT’D)

38. ORGANIZATION OF THE BRAIN (CONT’D)
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

39. ORGANIZATION OF THE BRAIN (CONT’D)
Midbrain
Has a reward or pleasure center, which is 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’s ready to process information from the senses

40. ORGANIZATION OF THE BRAIN (CONT’D)
Hindbrain
Has three distinct structures
pons
medulla
cerebellum

41. ORGANIZATION OF THE BRAIN (CONT’D)
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

42. CONTROL CENTERS: FOUR LOBES
Wrinkled cortex
A thin layer of cells that essentially covers the entire surface of the forebrain

43. CONTROL CENTERS: FOUR LOBES (CONT’D)

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

45. CONTROL CENTERS: FOUR LOBES (CONT’D)

46. CONTROL CENTERS: FOUR LOBES (CONT’D)
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

47. CONTROL CENTERS: FOUR LOBES (CONT’D)
Anencephaly
Condition of being born with little or no brain
If some brain or nervous tissue is present, it’s totally exposed and often damaged because the top of the skull is missing
Survival is limited to days

48. CONTROL CENTERS: FOUR LOBES (CONT’D)

49. CONTROL CENTERS: FOUR LOBES (CONT’D)
Frontal lobe: functions
Located in front part of brain
Includes huge area of cortex
Many functions
voluntary motor movements, interpreting and performing emotional behaviors, behaving normally in social situations, maintaining a healthy personality, paying attention to things in the environment, making decisions, executing plans
executive functions

50. CONTROL CENTERS: FOUR LOBES (CONT’D)
Phineas Gage
Frontal lobotomy
A surgical procedure in which about one-third of the front part of the frontal lobe is cut away from the rest of the brain

51. Ways to study the Brain!!!
Accidents: Phineas Gage.

52. CONTROL CENTERS: FOUR LOBES (CONT’D)

53. CONTROL CENTERS: FOUR LOBES (CONT’D)
Frontal lobe: functions
Motor cortex
Narrow strip of cortex that’s 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

54. CONTROL CENTERS: FOUR LOBES (CONT’D)

55. CONTROL CENTERS: FOUR LOBES (CONT’D)
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

56. CONTROL CENTERS: FOUR LOBES (CONT’D)
Parietal lobe: function
Location of somatosensory cortex
Narrow strip of cortex that’s located on the front edge of the parietal lobe and extends down its side

57. CONTROL CENTERS: FOUR LOBES (CONT’D)

58. CONTROL CENTERS: FOUR LOBES (CONT’D)

59. CONTROL CENTERS: FOUR LOBES (CONT’D)
Other functions of parietal lobe
Sensory integration
Spatial orientation
Language abilities
Visual and auditory attention
Memory
Numerical processing (counting)

60. CONTROL CENTERS: FOUR LOBES (CONT’D)
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

61. CONTROL CENTERS: FOUR LOBES (CONT’D)

62. CONTROL CENTERS: FOUR LOBES (CONT’D)
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

63. CONTROL CENTERS: FOUR LOBES (CONT’D)
Temporal lobe: functions
Broca’s area
located in left frontal lobe
necessary for combining sounds into words and arranging words into meaningful sentences
damage: Broca’s aphasia
person can’t speak in fluent sentences but can understand written and spoken words

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

65. CONTROL CENTERS: FOUR LOBES (CONT’D)

66. CONTROL CENTERS: FOUR LOBES (CONT’D)
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

67. CONTROL CENTERS: FOUR LOBES (CONT’D)

68. CONTROL CENTERS: FOUR LOBES (CONT’D)
Occipital lobe: functions
Visual association area
Transforms basic sensations, such as lights, lines, colors, and textures, into complete, meaningful visual perceptions, such as people, objects, or animals

69. CONTROL CENTERS: FOUR LOBES (CONT’D)
Visual agnosia
Individual fails to recognize some object, person, or color
Has ability to see and even describe pieces or parts of some visual stimulus

70. CONTROL CENTERS: FOUR LOBES (CONT’D)

71. CONTROL CENTERS: FOUR LOBES (CONT’D)
Neglect syndrome
Refers to the failure of a patient to see objects or parts of the body on the side opposite the brain damage
May dress only on one side of body
May deny that opposite body parts are theirs

72. CONTROL CENTERS: FOUR LOBES (CONT’D)

73. 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

74. LIMBIC SYSTEM: OLD BRAIN (CONT’D)

75. LIMBIC SYSTEM: OLD BRAIN (CONT’D)
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

76. LIMBIC SYSTEM: OLD BRAIN (CONT’D)
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

77. LIMBIC SYSTEM: OLD BRAIN (CONT’D)
Autonomic nervous system
Sympathetic
Parasympathetic

78. LIMBIC SYSTEM: OLD BRAIN (CONT’D)

79. LIMBIC SYSTEM: OLD BRAIN (CONT’D)
Autonomic nervous system
Sympathetic
triggered by threatening or challenging physical or psychological stimuli
Fight or flight
state of increased physiological arousal caused by activation of the sympathetic division
helps body cope and survive threatening situations
Physiological responses
increased heart rate, increased blood pressure, and dilated pupils

80. LIMBIC SYSTEM: OLD BRAIN (CONT’D)
Autonomic nervous system
Parasympathetic
decreases physiological arousal
returns body to a calmer, more relaxed state
stimulates digestion during eating
Physiological responses
decreases heart rate
lowers blood pressure
stimulates digestion
body returns to more relaxed state

81. LIMBIC SYSTEM: OLD BRAIN (CONT’D)
Autonomic nervous system
Homeostasis
sympathetic and parasympathetic systems work together to keep the body’s level of arousal in balance for optimum functioning

82. ENDOCRINE SYSTEM Endocrine system
Made up of numerous glands located throughout the body
Glands secrete various chemicals called hormones
pituitary
pancreas
thyroid
adrenal glands
gonads

83. ENDOCRINE SYSTEM (CONT’D)

84. ENDOCRINE SYSTEM (CONT’D)
Pituitary gland
Hangs below the hypothalamus
Divided into anterior and posterior
Posterior (rear portion)
Regulates water and salt balance
Anterior (front portion)
Regulates growth through secretion of growth hormone
Produces hormones that control the adrenal cortex, pancreas, thyroid, and pancreas

85. ENDOCRINE SYSTEM (CONT’D)

86. ENDOCRINE SYSTEM (CONT’D)
Pancreas
Regulates the level of sugar in the bloodstream by secreting insulin
Thyroid
Located in the neck
Regulates metabolism through secretion of hormones

87. ENDOCRINE SYSTEM (CONT’D)
Adrenal glands
Adrenal cortex (outside part)
Secretes hormones that regulate sugar and salt balance
Adrenal medulla (inside part)
Secretes two hormones that arouse the body to deal with stress and emergencies
Epinephrine (adrenaline)
Norepinephrine (noradrenaline)

88. ENDOCRINE SYSTEM (CONT’D)
Gonads
Females
ovaries produce hormones that regulate sexual development, ovulation, and growth of sex organs
Males
testes produce hormones that regulate sexual development, production of sperm, and growth of sex organs