Module 4

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Module 4

• Incredible Nervous System

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GENES EVOLUTION

• Genetic information
• 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

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GENES EVOLUTION (CONTD)

• Fertilization
• Human life has its beginnings when the fathers
  sperm, which contains 23 chromosomes, penetrates
  the mothers egg, which contains 23 chromosomes

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GENES EVOLUTION (CONTD)
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GENES EVOLUTION (CONTD)

• 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

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GENES EVOLUTION (CONTD)

• Chromosomes
• A short, rod-like, microscopic structure that
  contains a tightly coiled strand of the chemical
  DNA, which is an abbreviation for
  deoxyribonucleic acid

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GENES EVOLUTION (CONTD)
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GENES EVOLUTION (CONTD)

• 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

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GENES EVOLUTION (CONTD)
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GENES EVOLUTION (CONTD)

• 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

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GENES EVOLUTION (CONTD)

• 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

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GENES EVOLUTION (CONTD)

• 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

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GENES EVOLUTION (CONTD)

• 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 donors genes to look
  for specific diseases or disorders

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EVOLUTION OF THE HUMAN BRAIN

• 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

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EVOLUTION OF THE HUMAN BRAIN (CONTD)
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EVOLUTION OF THE HUMAN BRAIN (CONTD)

• 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) wont be
  selected and will be eliminated in a species

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EVOLUTION OF THE HUMAN BRAIN (CONTD)

• 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

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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

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STUDYING THE LIVING BRAIN (CONTD)

• 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

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STUDYING THE LIVING BRAIN (CONTD)
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STUDYING THE LIVING BRAIN (CONTD)

• 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

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STUDYING THE LIVING BRAIN (CONTD)

• Neuroimaging
• PET and fMRI scans are used to identify and map
  the living brains neural activity as a person
  performs complex behavioral and cognitive tasks,
  such as
• seeing
• moving
• thinking
• speaking
• empathizing
• trusting
• even reacting to TV violence

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STUDYING THE LIVING BRAIN (CONTD)
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The Nervous System
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ORGANIZATION OF THE BRAIN

• Divisions of the nervous system
• Major divisions of the nervous system
• Central nervous system (CNS)
• Peripheral nervous system (PNS)

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ORGANIZATION OF THE BRAIN (CONTD)

• 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

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Central Nervous System

• The Brain and spinal cord
• CNS

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ORGANIZATION OF THE BRAIN (CONTD)
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ORGANIZATION OF THE BRAIN (CONTD)

• 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

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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.

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ORGANIZATION OF THE BRAIN (CONTD)
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ORGANIZATION OF THE BRAIN (CONTD)

• 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

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Somatic Nervous System

• Controls voluntary muscle movement.
• Uses motor (efferent) neurons.

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ORGANIZATION OF THE BRAIN (CONTD)

• 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

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Autonomic Nervous System

• Controls the automatic functions of the body.
• Divided into two categoriesthe sympathetic and
  the parasympathetic

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ORGANIZATION OF THE BRAIN (CONTD)

• Major parts of the brain
• Forebrain
• Midbrain
• Hindbrain
• pons
• medulla
• cerebellum

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ORGANIZATION OF THE BRAIN (CONTD)
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ORGANIZATION OF THE BRAIN (CONTD)

• 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

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ORGANIZATION OF THE BRAIN (CONTD)

• 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 its ready to process
  information from the senses

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ORGANIZATION OF THE BRAIN (CONTD)

• Hindbrain
• Has three distinct structures
• pons
• medulla
• cerebellum

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ORGANIZATION OF THE BRAIN (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES

• Wrinkled cortex
• A thin layer of cells that essentially covers the
  entire surface of the forebrain

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• Four lobes
• Frontal lobe
• Parietal lobe
• Occipital lobe
• Temporal lobe

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)

• Anencephaly
• Condition of being born with little or no brain
• If some brain or nervous tissue is present, its
  totally exposed and often damaged because the top
  of the skull is missing
• Survival is limited to days

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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Ways to study the Brain!!!

• Accidents Phineas Gage.

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• Frontal lobe functions
• Motor cortex
• Narrow strip of cortex thats 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

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)

• Parietal lobe function
• Location of somatosensory cortex
• Narrow strip of cortex thats located on the
  front edge of the parietal lobe and extends down
  its side

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• Other functions of parietal lobe
• Sensory integration
• Spatial orientation
• Language abilities
• Visual and auditory attention
• Memory
• Numerical processing (counting)

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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)

• Temporal lobe functions
• Brocas area
• located in left frontal lobe
• necessary for combining sounds into words and
  arranging words into meaningful sentences
• damage Brocas aphasia
• person cant speak in fluent sentences but can
  understand written and spoken words

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CONTROL CENTERS FOUR LOBES (CONTD)

• Wernickes area
• located in the left temporal lobe
• necessary for speaking in coherent sentences and
  for understanding speech
• damage Wernickes aphasia
• Difficulty understanding spoken or written words
  and difficulty putting words into meaningful
  sentences

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)
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CONTROL CENTERS FOUR LOBES (CONTD)

• 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

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CONTROL CENTERS FOUR LOBES (CONTD)
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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

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LIMBIC SYSTEM OLD BRAIN (CONTD)
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LIMBIC SYSTEM OLD BRAIN (CONTD)

• 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

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LIMBIC SYSTEM OLD BRAIN (CONTD)

• 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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LIMBIC SYSTEM OLD BRAIN (CONTD)

• Autonomic nervous system
• Sympathetic
• Parasympathetic

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LIMBIC SYSTEM OLD BRAIN (CONTD)
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LIMBIC SYSTEM OLD BRAIN (CONTD)

• 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

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LIMBIC SYSTEM OLD BRAIN (CONTD)

• 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

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LIMBIC SYSTEM OLD BRAIN (CONTD)

• Autonomic nervous system
• Homeostasis
• sympathetic and parasympathetic systems work
  together to keep the bodys level of arousal in
  balance for optimum functioning

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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

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ENDOCRINE SYSTEM (CONTD)
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ENDOCRINE SYSTEM (CONTD)

• 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

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ENDOCRINE SYSTEM (CONTD)
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ENDOCRINE SYSTEM (CONTD)

• Pancreas
• Regulates the level of sugar in the bloodstream
  by secreting insulin
• Thyroid
• Located in the neck
• Regulates metabolism through secretion of
  hormones

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ENDOCRINE SYSTEM (CONTD)

• 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)

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ENDOCRINE SYSTEM (CONTD)

• 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