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    Chapter 2 biological perspective notes Chapter 2 biological perspective notes Presentation Transcript

    • Chapter 2 Biological Perspective
      • Overview of the Nervous System
        • Nervous System: A network of cells that carries information to and from all parts of the body.
        • Neurons and Nerves
          • Neuroscience: Deals with the structure and function of neurons, nerves, and nervous tissue, especially focusing on their relationship to behavior and learning
    • Structure of the Neuron
      • Each cell in the body has a special function
      • Most cells have three things in common
        • A nucleus, a cell body, and a cell membrane
        • Neuron: The basic cell that makes up the nervous system and that receives and sends messages within that system
        • Dendrites: Branchlike structures that receive messages from other neurons
    • Neurons and Nerves
      • Dendrites are attached to the cell body (Soma): Maintains the life of the cell
      • Axon: Tubelike structure that carries the neural message to other cells
      • People use every cell in the brain for something
        • Neurons make up 10% of the brain
        • The rest are glial cells that provide support for the neurons and allow them to grow and thrive
    • Nerves and Neurons
      • Different types of glial cells that provide different functions for the neurons
      • Neurons send messages through electrical means. If they touch in the wrong area they will short out. Glial cells provide protection from this.
      • Neurons are found throughout the entire body
      • Glial Cells
        • Type one-Oligodendrocytes-Produce myelin for brain and spinal cord
        • Type two-Schwann Cells-Produce myelin for the rest of the body
        • Myelin covers the axons so they are protected from touching each other
        • The bundled axons are called nerves
    • Neurons and Nerves
      • Myelin-Not only protects the nerves, but allows the messages to travel faster
      • Node: Small space that separates the axons
        • The message “jumps” the node and moves faster because of the myelin sheath
        • Multiple Sclerosis is a disease that damages the myelin sheath so the cells do not function or function well
    • Neurons and Nerves
      • Axons of neurons in the body are coated with a thin membrane called the neurilemma or Schwann’s membrane
      • This is a tunnel that allows damaged nerves to repair themselves
        • This allows severed toes/fingers to repair themselves when reattached
      • The brain and spinal cord do not have this membrane and therefore cannot repair itself
    • Neurons and Nerves
      • A neuron that is not firing is electrically charged
      • The outside of the cell has positively charged ions and the inside has negatively charged ions
      • The cell membrane is semipermeable
        • Substances can easily get into and out of the cell
        • Negatively charged ions cannot get out easily so the cell stays negatively charged when at rest
        • When at rest the positively charged ions cannot get in
        • These opposite charges attract each other and cluster around the membrane
    • N eurons and Nerves
      • Cell is like a baseball stadium (Sodium Ions)
        • When the cell is at rest (closed) the positive neurons (fans) cannot get in. When the cell is stimulated by dendrites the cell membrane opens up the (gates) one by one and allows the fans in. The electrical charge moves down the axon causing the positive ions to rush inside reversing the charges on the inside and outside of the cells
        • Resting Potential- When the neuron is not firing (resting)
        • Action Potential- When the neuron fires causing a reversal of the electrical charge
    • Nerves and Neurons
      • When the charge reaches the end of the axon the charge is transmitted to another cell.
      • To return the cell to a resting state
        • The gates close when the action potential has passed
        • The positive ions (fans) get kicked out
        • Positive potassium ions also leave the cell making it negative faster
        • The inside is negative and the outside positive so another message can be fired and start the process allover again
        • Doors in a hallway (one opens, next opens, first closes)
    • Nerves and Neurons
      • Some signals cause a neuron to fire, others tell it not to fire
      • All or none- neuron either fires completely or does not fire at all
        • Palm of hand example
    • Nerves and Neurons: The Synapse
      • Axon Terminals- Branches at the end of the axon
      • Synoptic Knob- Rounded areas on the end of the axon terminals
      • Synoptic Vesicles-Saclike structure found inside the synaptic knob containing chemicals
      • Neurotransmitters- Chemical found in the synaptic vesicles that , when released, has an effect on the next cell
        • Inside a neuron and will transmit a message
    • Nerves and Neurons: The Synapse
      • Next to the synoptic knob is another dendrite.
      • Synapse/Synaptic Gap- fluid-filled space between the synoptic knob and dendrites or surface of the next cell
        • The vesicles at the end of axons contain the molecules of neurotransmitters
        • Receptor Sites- Locks on the surface of dendrites
        • Only allow particular neurotransmitters or molecules in ( Like a lock and key)
    • Nerves and Neurons: The Synapse
      • When the action potential reaches the synaptic vesicles they release neurotransmitters into the synaptic gap
      • The molecules float across the synapse into the receptor sites which activates the next cell, the process continues
      • Cells can be turned on and off
      • Excitatory Synapse- neurotransmitter causes the receiving cell to fire
      • Inhibitory Synapse- neurotransmitter causes the receiving cell to stop firing
    • Nerves and Neurons
      • How drugs affect us
        • Agonists- mimic or enhance the effects of a neurotransmitter on the receptor sites increasing/decreasing activity
        • Antagonists- block or reduce a cell’s response to the action of other chemicals or neurtransmitters
    • Nerves and Neurons
      • Neurotransmitters
        • Glutamate- Excitatory neurotransmitter that plays a role in learning and development
        • GABA (y-aminobatyric acid)- Inhibitory neurotransmitter that calms, alcohol enhances GABA
        • Serotonin- Can have excitatory or inhibitory effect associated with sleep, mood and appetite
          • Low serotonin=depression
    • Nerves and Neurotransmitters-
      • Dopamine- Either excitatory or inhibitory depending on where in the brain it is released
        • Too much=Schizophrenia
        • Too little=Parkinson’s Disease
        • Neural Regulators/Neural Peptides- Control the release of neurotransmitters
        • Endorphins- When a person is in pain the brain releases endorphins to bind with receptors and block the pain
        • Athletes do not feel pain until after game is over because of the high levels of endorphins during the game
    • Nerves and Neurons
      • Endorphins and Heroine
        • Heroine is addictive because this drug causes the body to stop producing endorphins. When the person is off heroine there are not any endorphins to block the pain and everything hurts so they go back onto the heroine. This pain is withdrawl.
    • Reuptake and Enzymes
      • Neurotransmitters must leave receptor sites so the next stimulation may occur
      • Reuptake-neurotransmitters are taken back into the synaptic vesicles
        • Cocaine blocks the reuptake
        • Acetylcholine is not taken back into vesicles because it is necessary for muscle function which happens continuously
        • An enzyme is released to clear the synapse of acetylcholine
    • Reuptake and Enzymes
      • Serotonin- regulates and adjusts mood
        • Some people’s serotonin is not released or produced causing depression
        • Treated with SSRI’s (Selective Serotonin Reuptake Inhibitors) Blocks the reuptake of serotonin so more is in the synapse to bond with receptor sites and decrease depression
    • Quiz 1
    • Central Nervous System
      • Central nervous system (CNS)- Consists of the brain and spinal cord
        • Composed of neurons and glial cells that control life-sustaining functions, thought, emotion and behavior
        • The Brain
        • Core of the nervous system
        • Makes sense of the information received from the senses
        • makes decisions, sends commands to muscles and the rest of the body
    • Central Nervous System
      • The Spinal Cord
        • A long bundle of neurons that carries messages between the body and the brain and is responsible for very fast, lifesaving reflexes
        • Is divided into two areas
          • The outer is made of axons and nerves
            • Carries messages from the body up to the brain and from the brain to the body
            • It is a message pipeline
          • The inner is made of cell bodies of neurons
    • Central Nervous System
      • The Reflex ARC in the Spinal Cord
        • Inside section made of glial cells
        • A primitive “brain”
        • Responsible for very fast life-saving reflexes
        • Three types of neurons
          • Afferent (Sensory) Neurons- Carry messages from the senses to the spinal cord
          • Efferent (Motor) Neurons- Carry messages from the spinal cord to the muscles and glands
          • Interneurons- Connect afferent neurons to efferent neurons
            • Make up the inside of the brain and spinal cord
    • The Central Nervous System
      • Example
        • Touch a hot stove
          • Afferent neuron will send the pain message up to the spinal column where it enters into the central area of the spinal cord. The interneuron in that central area will then receive the message and send out a response along an efferent neuron, causing your finger to pull back. If the pain message had to go to the brain more damage would be done.
          • Reflex Arc- the connection of the afferent neurons to the interneurons to the efferent neurons resulting in a reflex action
    • The Central Nervous System
      • A fferent neurons a ccess the spinal cord
      • E fferent neurons e xit the spinal cord
      • When pain message reaches the brain other reflexes are activated
        • Yelling “Ouch!”
        • Some damage to the central nervous system can be repaired
        • Neuroplasticity- The ability to constantly change both the structure and function of many cells in the brain response to experience and trauma
    • The Central Nervous System
      • Nerve implants can be made for the spinal cord making the area functional
      • Neurons in the brain can adapt to perform new functions to replace damaged ones
      • Dendrites grow and new synapses are formed as new information is learned
    • Stem Cells
      • Can create other cells such as blood, nerve and brain cells
      • Stem cells are retrieved from embryos from fertilization clinics and terminated pregnancies
      • Stem cells are found in many organs and bone marrow
        • Nonembryonic stem cells want to become cells from the areas they were retrieved
    • The Peripheral Nervous System (PNS)
      • Made up of all of the nerves and neurons that are not in the brain and spinal cord
      • Allows the spinal cord and brain to communicate with the rest of the body
      • Two major Systems
        • Somatic Nervous System
          • Consists of nerves that carry information from the senses to the CNS and from the CNS to the voluntary muscles of the body
    • Peripheral Nervous System
      • Somatic Nervous System
        • Somatic Pathway- Nerves coming from the sensory organs to the CNS consisting of afferent neurons
        • Motor Pathway- Nerves coming from the CNS to the voluntary (Skeletal) muscles, consisting of efferent neurons
          • These are the muscles that allow people to move their bodies
          • These are called voluntary muscles, but can be moved involuntarily as a reflex
          • Involuntary muscles (Heart, stomach and intestines, ect)
          • Controlled by clumps of neurons located on or near the spinal column
    • Autonomic Nervous System
      • The functions of this system are basically automatic
      • Controls the organs, glands, and involuntary muscles
      • Divided into two systems
        • The sympathetic Division
          • Located in the middle of the spinal column
          • Sympathy with emotions
          • Fight or flight response
          • Gets the body ready for stress
            • Pupils dilate to see in the dark, heart pumps faster to draw blood away from nonessential organs, ect
    • The Sympathetic Division
      • Adrenal glands told to release stress-related hormones
      • These only impact certain organs just like neurotransmitters fit only particular receptor sites for particular jobs
      • Not all organs are stimulated by the stress hormones
        • Digestion and excretion systems are shut down because they are not needed in times of stress
        • When the stress ends the parasympathetic division takes over
        • If stress goes on for too long the person may collapse
    • The Parasympathetic Division
      • The eat, drink and rest system
      • Located on top and bottom of spinal column
      • Para means beyond or next to
      • Job is to restore the body to it’s normal function after a stressful event
      • Responsible for most of the body’s regular functioning
    • Quiz
    • Inside the Brain
      • Clinical Studies
        • Animal studies
          • Electrically stimulate areas of the brain and see the results
          • Deep Lesioning- A thin wire is inserted into the brain and an electrical current is sent to destroy the neurons that are at the tip of the wire.
          • Shallow Lesioning- Lesioning done at the surface
          • Electrical stimulation of the brain (ESB)- weak electric current sent to cause stimulation and a reaction
    • Inside the Brain
      • Human studies
        • Cannot damage the brain on purpose for study so they study those that are already damaged
          • However, no two damaged brains are at the same extent
    • EEG
      • Electrocephalograph- Electrodes are placed on the skin of the skull
      • The wires are connected to a computer
      • Can indicate stages of sleep, seizures and tumors as well as activity during reading, writing and speaking
      • BETA waves- indicate waking activity-fast irregular waves
      • ALPHA waves- indicate relaxation-slow regular waves
      • THETA waves- Indicate drowsiness and sleep
      • DELTA waves- Indicate a deep stage of sleep-slow large waves
    • EEG
      • Independent Component Analysis (ICA)- Detailed interpretation of the signals coming from the different areas of the brain
      • Event-related potential (ERP)- The results of multiple readings and average the results
    • CT Scans
      • CT (Computed Tomography) means mapping slices
      • X-rays used to look at the inside of the brain
      • Shows stroke damage, tumors, injuries and abnormal brain structure
      • Shows the structure of the brain
    • MRI Scans
      • MRI (Magnetic Resonance Imaging) shows much more detail inside the brain
      • Magnetic field is used to show a 3 dimensional pix of the brain and even displays “slices” of it
      • Shows the structure of the brain
    • PET Scans
      • PET (Positron emission tomography)-Shows the brain working
      • Injected with a radioactive glucose (Sugar)
      • The cells that take up the glucose are active
      • Colors show levels of activity
      • Can have a person perform tasks to see which parts of the brain are active
    • Functional MRI (fMRI)
      • Tracks the levels of oxygen and where they go to see what areas are active
      • Give more detail, are clearer than PET scans
    • Structure of the Brain
      • The Hindbrain
        • Medulla means marrow or inner substance
        • Located at the top of the spinal column
        • Part of the brain that controls heartbeat, breathing and swallowing
          • This is where Christopher Reeves was hurt when he fell off a horse. He became paralyzed and could not breath on his own
          • This is where the nerves for the left side of the body cross to the right side of the brain and vice versa
    • Structure of the Brain
      • Pons means bridge
        • Connects the lower parts of the brain with the upper parts
        • Above the medulla
        • This is where the motor nerves carry messages to the body
        • Helps to coordinate the left side with the right side in movements
        • Influences sleep, dreaming and arousal
    • Reticular Formation (RF)
      • Where the neurons run through the middle of the pons and medulla
        • Area allows a person to pay attention to pertinent information
          • Allows a person to ignore white noise
        • Helps keep people alert and aroused
        • Reticular Activating System (RAS)-stimulates the upper part of the brain keeping the person awake and alert
          • Come to full attention when a car pulls in front of you
          • Mother hears only the crying baby and can ignore other noises
          • May be involved in ADHD
    • Reticular Formation
      • If the RF is stimulated in rats they immediately awaken
      • If it is damaged they go into a permanent coma
    • Cerebellum
      • Means little brain
      • Part of the lower brain that controls involuntary, rapid, fine motor movement
      • Learned reflexes, skills and habits are stored here so they become automatic
      • Allows people to not have to think about posture, muscle tone and balance
        • May use skills like skating, dancing play music
      • If this is damaged the person becomes uncoordinated
    • Cerebellum
      • Spinocerebellar Degeneration
        • Disease in which the symptoms are tremors, unsteady walk, slurred speech, dizziness and muscle weakness
        • Eventually looses all coordination
        • Similar to a intoxicated person
    • Structures under the Cortex
      • Cortex-The outer wrinkled covering of the brain
      • Limbic System
        • Includes the thalamus, hypothalamus, hippocampus and amygdala
        • Involved in emotions, motivation and learning
    • Limbic System
      • Thalamus (inner chamber)
        • Relays sensory information from the lower part of the brain to the proper areas of the cortex and processes some sensory information before sending it to its proper area
        • Damage to this area may lead to partial or total loss to any or all of these senses
        • Olfactory bulbs-two projections under the front of the brain that receive information from the receptors in the nose
          • This is the only sense that is not affected by damage to the thalamus
    • Limbic System
      • Hypothalamus (below the inner chamber)
        • Responsible for motivational behavior such as sleep, hunger, thirst and sex
        • Regulates temperature
        • Controls the pituitary gland
          • Pituitary Gland “Master Gland”- Controls the functions of all other endocrine glands
    • Limbic System
      • Hippocampus- located within each temporal lobe and is responsible for the formation of long-term memory and the storage of memory of the location of objects
        • Acetylcholine is a neurotransmitter that is involved in memory function
    • Limbic System
      • Amygdala (Almond)- Responsible for fear responses and memory of fear
      • Information from the senses goes through here before going to the upper part of the brain so the response can be quick
      • Damage to this area leads to a lack of fear
    • Limbic System
      • The Cortex
        • Outermost part of the brain
        • Made of tightly packed neurons
        • This is so wrinkly to allow for more area to exist within the skull
        • Corticalization- The cortex starts out smooth, but gains wrinkles as it becomes more complex and increases in size
        • This is the actual measure of intelligence
    • Quiz 3
    • Cortex and the Lobes
      • Cortex is divided into two sections called Cerebral Hemispheres which are connected by the Corpus Callosum
      • Corpus Callosum allows the two hemispheres to communicate
        • Each hemisphere can be divided into four sections
    • Cortex and the lobes
      • Occipital Lobes (Rear of the head)- Processes visual information in the primary visual cortex
      • Any stimulation to the area at the back of the head processes vision, so when you get hit back there you “see stars”
    • Cortex and the Lobes
      • Parietal Lobes (Wall)- Located at top of each hemisphere that contains the centers for touch, taste and temperature sensations
      • Somatosensory Cortex- Area of neurons running down the front of the parietal lobes responsible for processing information from the skin and internal body receptors for touch, temperature, body position and possibly taste
      • The cells at the top receive info from the bottom of the body and vice versa
    • Cortex and the Lobes
      • Temporal Lobes (of or near the temples)- Located just behind the temples, contain the Primary auditory cortex and Auditory association area
        • When hit in the side of the head, may hear a ringing sound
        • This area also deals with language and taste
    • Cortex and the Lobes
      • Frontal Lobes- Located at the front of the brain, this is where higher functioning of the brain is performed such as planning, personality, memory storage, complex decision making and language also helps with emotions
      • Damage to this area may cause a person to become “stuck” on one step of a task or repeat the wrong answer over and over
    • Cortex and the Lobes
      • Frontal Lobes
        • Motor Cortex- area in back of frontal lobe that sends motor commands to the muscles of the somatic nervous system
    • Association areas of the Cortex
      • Association areas- areas within each lobe of the cortex responsible for making connections between the sensory information coming into the brain and stored memories, images, and knowledge
        • This area makes sense of the sensory information that is received
      • Broca’s Area- Allows a person to speak smoothly and fluently
        • Broca’s Aphasia-Damage to this area makes it hard for the person to speak in a smooth, orderly fashion
        • May mispronounce words, they cannot control their pronunciation of the words (not a stutter)
        • “ I lov…..eat…….much
    • Association areas of the Cortex
      • Wernicke’s Area- Area of brain associated with understanding the meanings of words
      • Wernicke’s Aphasia- Damage to the Wernicke’s area that causes a person to not understand or produce meaningful language
        • “ Oh that’s so Saturday hard.”
        • “ Get me some milk out of the air conditioner!”
    • Spatial Neglect
      • Spatial neglect- Damage in the association areas of the right side of brain which prevents the person from recognizing objects on the left side of vision or body
        • Left side will be recognized if specifically called attention to it
        • Make-up and mirror examples pgs. 76-77
    • The Cerebral Hemispheres
      • Cerebrum- Upper part of brain consisting of two hemispheres with structures connecting them
      • Split-Brain research
        • Each side of the brain has it’s own specializations
        • Corpus Callosum was cut disconnecting the two halves of the brain
          • Showed objects to one side of person and if on right could identify the object, if on left could not verbally identify the object or be certain they saw anything
          • If left hand was used they could verbally state, but not see
    • Cerebral Hemispheres
      • Left side
        • Language, speech, handwriting, calculations, sense of time, rhythm and any thought analysis
        • Can break information down into small parts for interpretation
        • Right
          • Perception, visualization, spatial perception, recognition of patterns, faces, emotions, melodies and expression of emotions
          • Also comprehends simple language
          • Can process information all at once
    • Cerebral Hemispheres
      • Most right-handed people also have their left hemisphere in control of their other fine motor skills, such as speech, a few right-handers actually have their language functions in the right hemisphere
    • The Endocrine Glands
      • Some glands do not secrete chemicals that affect behavior; sweat and salivary
      • Endocrine glands- do not have ducts and secrete chemicals into bloodstream
        • These chemicals are hormones
        • The hormones are carried in the bloodstream to the organ they are meant to impact
        • The molecules of the hormones fit into the receptor sites of the organs and influence behavior
    • The Pituitary Gland
      • Pituitary gland- secretes human growth hormone (HGH) and influences all of the other hormone secreting glands
        • AKA the Master Gland
        • HGH impacts a child’s size as he/she grows
        • Is an important part of communication between the organs, hypothalamus and other glands
    • The Endocrine Glands
      • Pineal gland- Secretes melatonin which regulates the sleep-wake cycle
      • Thyroid gland- Secretes thyroxin which regulates metabolism
      • Pancreas- Controls the level of sugar in the blood by secreting insulin and glucagons
        • Too little insulin=diabetes, Too much insulin=hypoglycemia-hunger all of the time
    • The Endocrine Glands
      • The Gonads- sex glands including ovaries and testes
        • Secrete hormones that regulate sexual behavior and reproduction
        • Does not control all sexual behavior
          • The brain is the master controller of sexual behavior like psychological factors such as attractiveness
    • The Adrenal Glands
      • Both are located on top of the kidneys
      • Each one is divided into two sections
        • Adrenal medulla-releases ephinephrine and norepinephrine which are released in times of stress and aids in sympathy
    • The Adrenal Glands
        • Adrenal cortex- produces corticoids what regulate salt intake, initiate and control stress reactions, and provide sex hormones in addition to the gonads
          • Cortisol-released during times of stress
            • Influences the release of glucose into the bloodstream to give energy to the brain and fatty acids to the muscles for energy
    • Mirror Neurons
      • Neurons that fire when doing an action also fire when seeing that action preformed
        • Wince when see someone get hurt
        • Smile when see someone else smile
        • A stroke patient may be able to relearn a behavior if he/she sees it done by someone else
    • Mirror Neurons and Autism
      • Mirror neurons are a part of communication and socialization
      • People with autism
        • The mirror neurons to not fire when seeing others doing a behavior
        • Malfunctioning mirror neurons may be the cause of autism
        • In a bad mood/depressed=watch a comedy?