1 Chapter 2 The Biological Perspective
2 The Nervous System - An extensive network of specialized cells that carries information to and from all parts of the body.
3 Neurons & Nerves: Building the Network Neuron basic unit (cell) of nervous system and receives and sends messages within that system microscopic; 100 billion; 200 types (size / shape)
4 3 Structures of the Neuron 1. Dendrite branches that receive information from other neurons & transmits information toward the cell body (tree like) 2. Soma Cell body that keeps neuron alive; determines if it will fire (transmit info) 3. Axon extending fiber that conducts impulses away from cell body & transmits them to other neurons or neural cells Glial Cells grey fatty cells that provide support for the neurons to grow on & around, deliver nutrients, produce myelin, clean up waste & dead neurons Myelin sheath fatty substance that coats axon to insulate, protect & speed up impulse Nerve bundles of axon coated in myelin that travel together through the body
6 Message W/in the Neuron: The Neural Impulse Resting potential when neuron is not firing (- charge inside + outside) Action Potential release of the neural impulse consisting of the reversal of the electrical charge within the axon (+ sodium (Na) enters the cell) All or nothing a neuron either fires completely or does not fire at all
7 Sending the Message to Other Cells: Synapse Synapse site of transmission of nerve impulses from one nerve cell to another Axon terminal branches at the end of axon Synaptic bulb (knob) rounded area on the end of the axon terminal Synaptic cleft (gap) space between bulb of one cell and the dendrite of another Receptor sites- holes is surface of dendrite; shaped to receive certain neurotransmitters Neurotransmitters chemicals in the synaptic vesicles; when released effect the next cell
8 Neurotransmission / Synapse 1- Neuron at rest (- inside + outside) 2 - Neural impulses move down axon; gate opens; +Na enters cell voltage changes from (-) to (+) 3- When impulse reach button tip; must get across synaptic cleft (gap); synaptic vesicle release neurotransmitter 4- When reaches the other side; briefly bond w/ receptor sites (lock & key) 5- Receiving membrane will change; excite increase firing (+ voltage) inhibit decrease firing (- voltage) 6- Neuron returns to resting state (- voltage) Action potential - a sequence of gates opening down the length of the cell (as 2 nd gate opens 1 st closes) -multiple +/- messages sent; take average
9 Synapse Excitatory Synapses synapse at which a neurotransmitter causes the receiving cell to fire. Inhibitory Synapses synapse at which neurotransmitter causes the receiving cell to stop firing. Agonists chemical substances that mimic or enhance the effects of a neurotransmitter on the receptor sites of the next cell, increase in or decreasing the activity of that cell Antagonists chemical substances that block or reduce a cells response to the action of other chemicals or neurotransmitters.
10 Neurotransmitters (NT) Serotonin Excitatory or inhibitory; involved in mood, sleep and appetite Dopamine Excitatory or inhibitory; control of movement and pleasure Acetylcholine Excitatory or inhibitory; muscle contraction, memory Norepinephrine Mainly excitatory; involved in arousal and mood GABA - (gamma-aminobutyric acid) major inhibitory NT; sleep & inhibits movement Glutamate major excitatory NT memory formation, nervous system development Endorphins inhibitory neural regulators; involved in pain relief natures opiate endorphin rush: falling in love / battle field
12 Cleaning up the Synapse 1) Reuptake - neurotransmitters are take back into the synaptic vesicles Cleans up the synapse Some drugs inhibit the reuptake like cocaine Depression if small amounts of serotonin released Medications SSRIs (selective serotonin reuptake inhibitors) Leaves more serotonin in synapse to elevate mood 2) Enzymes breakdown neurotransmitters not taken back into vessels Acetylcholine muscle activity can t wait for reuptake; enzyme breaks it down
13 Quiz 1) Which part of the neuron receives messages from other cells? a) Axon c) Soma b) Dendrite d) Myelin 2) Which one of the following is NOT a function of the myelin? a) Insulates the axon b) Speeds up the neural message c) Protects the nerve fiber from damage d) Aids in reuptake 3) When the neuron s action potential is released, ions are rushing into the axon through openings on the membrane. a) Sodium c) Chloride b) Potassium d) Oxygen
14 Quiz 4) When the action potential reaches the end of the axon terminals, it causes the release of a) An electrical spark that sets of the next neuron b) Positively charged ions that excite the next cell c) Negatively charged ions that inhibit the next cell d) Neurotransmitters that excite or inhibit the next cell 5) Receiving neurons have special that fit the shape of certain molecules. a) Synaptic vesicles c) Receptor sites b) Gaps d) Branches 6) Which of the following is associated with sleep, mood and appetite? a) Acetylcholine c) Serotonin b) GABA d) Endorphin
15 Quick Quiz a) Which word in ( ) better fits each of the following definitions? 1. Basic building blocks f the nervous system (nerves, neurons) 2. Site of communication between neurons (synapse, myelin sheath) 3. Opiate-like substance in the brain (dopamine, endorphin) 4. Chemicals that make it possible for neurons to communicate (neurotransmitters, hormones)
16 The Nervous System 1) Central Nervous System (CNS) 2) Peripheral Nervous System (PNS)
17 The Nervous System 1. Central Nervous System (CNS) 1. Brain Interprets & stores information & sends orders to muscles glands, & organs 1. Spinal Cord long bundle of neurons that carry messages between the body & brain responsible for fast, life saving reflexes
18 2) Peripheral Nervous System (PNS) The Nervous System Transmits information to and from the central nervous system All nerves and neurons that are not contained in the brain and spinal cord but that run through the body itself 1. Somatic nervous system - carries sensory info from the senses to CNS & from the CNS to the voluntary muscles. a) Sensory pathways (Afferent) nerves from sensory organs to CNS b) Motor pathways (Efferent) nerves from CNS to the voluntary muscles 2. Autonomic nervous system- controls involuntary muscles, organs & glands 1) Sympathetic nervous system prepares body to react and expend energy in time of stress (fight or flight) 2) Parasympathetic nervous system maintain body functions in relaxed state; conserves energy; restore to normal functioning after arousal
19 The Peripheral Nervous System
20 Parasympathetic & Sympathetic
21 Stem cell research: Pro or Con Neurogenesis production of new neurons from immature stem cells Stem Cells immature cells that renew themselves; grow into any cell Need cells a few days old Abortion clinics Excess from fertility clinics
22 The Endocrine Glands Endocrine Glands organs produce hormones & release into blood stream Hormones produced by endocrine glands; effects functioning of other organs
23 The Endocrine Glands a) Pituitary Gland growth hormones & affects all other glands (Master Gland) Oxytocin enhances uterine contractions during birth; ejection of milk /nursing b) Pineal Gland Melatonin regulate daily biorhythms; promotes sleep c) Thyroid Gland regulates metabolism d) Pancreas - controls levels of sugar in the blood e) Gonads - Sex glands development & maintenance of reproductive organs - Ovaries and testes androgen testosterone male characteristics at puberty estrogen female characteristics at puberty progesterone lining of uterus in prep for fertilized egg f) Adrenal Glands Adrenal hormones - produced by adrenal glands; emotion and stress respond to heat; cold; pain; exercise; caffeine; nicotine Cortisol - ^blood sugar; boost energy; gain weight Epinephrine adrenaline; fight or flight; memory
24 Quiz 1. If you burn your finger, your immediate reaction will probably involve all BUT which of the following? a) The brain c) Afferent neurons b) Spinal cord d) Efferent neurons 2. If you are typing in the computer keyboard, the sensation of your fingers touching the keys is most likely communicated by. a) The autonomic neurons b) Motor pathway neurons c) Sensory pathway neurons d) Autonomic neurons 3. The neurons of the motor pathway control. a) Stress reactions c) Involuntary muscles b) Organs and glands d) Voluntary muscles
25 Quiz 4) What type of cell can become other types of cells in the body? a) Blood cells c) Neurons b) Stem cells d) Basal cells 5) Which of the following is NOT a function of the sympathetic division? a) Increasing digestive activity to supply fuel for the body b) Dilating the pupils of the eyes c) Increasing the heart rate d) Increasing the activity of the lungs 6) Which of the following would be active if you are sleeping? a) Sympathetic division c) Somatic Division b) Parasympathetic division d) motor division 7) Andrew never really grew to be very tall. The doctor told his parents that Andrew s gland did not secrete enough growth hormone. a) Pituitary c) Thyroid b) Adrenal d) Pancreas
26 The Structures of the Brain Location of function brain areas for particular functions Brain stem top of spinal cord ; pons & medulla Pons sleeping; waking & dreaming; left-right body coordination; arousal Medulla some automatic functions; breathing, swallowing & heart rate functions that are not consciously willed Cerebellum control & coordinate involuntary, rapid, fine motor movement Reticular activating system: Reticular formation General attention, alertness and arousal
27 Structures Under the Cortex Limbic System structures involved in learning, emotion, memory & motivation Thalamus relays sensory message to the cortex; processes some sensory info Traffic officer of the brain directs to higher area olfactory bulb (smell)
28 Structures Under the Cortex Hypothalamus Hypothalamus motivational behavior; sleep, hunger; thirst & sex
29 Structures Under the Cortex Amygdala arousal and regulation of emotions initial emotional response to sensory info ( danger or threat) fear and memory of fear Hippocampus sea horse in Latin formation of long term memory storage of memory for locations objects
30 The Cortex The Cerebrum higher forms of thinking largest grain structure upper part of brain; 2 hemispheres most sensory; motor and cognitive processes Cerebral hemispheres 2 halves of cerebrum (right & left) Corpus callosum thick bundle of neurons connecting 2 cerebral hemispheres Lateralization specialization of 2 hemispheres for particular operations Cortex collection of several thin layers of cells covering cerebrum higher mental functions & interpret sensory input 1/8 thick ¾ of all cells in human brain deep crevices and wrinkles (more neurons) rat-smooth Grey matter grey tissue of brain (White matter long myelin coved axons)
31 Lobes of the Cortex Occipital visual centers blindness / recognition Parietal somatosensory cortex touch, taste & temp Temporal auditory cortex hearing & meaningful speech Wernicke s aphasia use of meaningless words Frontal higher mental functioning make plans; think creatively; fluent speech Motor cortex Mirror neurons Left lobe - Broca s area speech Broca s aphasia inability to understand written or spoken language
32 Neuron and Brain Lobes
33 Prefrontal Cortex & Personality Phineas Gage
34 Prefrontal Cortex - personality Rats and mice only 3.5% Humans 29% Phineas Gage railroad worker inch thick 31/2 foot rod through head miracle lived; think; speak; remember Dr. Jekyll / Mr. Hyde change not Phineas mild mannered to mean & angry responsible to not work; hold jobs
36 Right and Left Brain Right Brain Controls left hand Non verbal Spatial visual ability Facial recognition Emotional thought Emotional recognition Process the whole Pattern recognition Musical / artistic Intuitive Left Brain Controls right hand Spoken language Written language Reading Logic Symbolic Sequential task Rational / analytic Analysis of detail Math
37 Split Brain
38 Split Brain: Shown composite of photo (a) asked to pick out the face seen from series of photos (b); Stated; seen face on right side of composite; Yet, pointed with their left hands to the face that had been on the left 2 hemisphere not communicate Verbal left side only saw right half Mute right side aware of left half is left dominant?
40 Quick Quiz 1) Keeping in mind what both sides of the brain are involved in most activities, which of the following is / are more closely associated with the left hemisphere? a) Enjoying a musical recording b) Wiggling the left big toe c) Giving a speech in class d) Balancing a checkbook e) Recognizing a long lost friend
41 His and Her Brains?
42 His and Her Brains Gender differences (intuition, abilities) are stereotypes More alike than different. Sex differences; result rather than cause of behavioral differences Nature or nurture Brain difference not explain behavior or performance Difference in brain activity but not ability to complete Listen to John Grisham; women left and right temporal; men only left.
44 Quiz 1. In which lobe of the cortex do you find the primary auditory area? a) Frontal c) Occipital b) Temporal d) Parietal 2. The higher mental function, such problem solving are found in. a) Frontal c) Temporal b) Parietal d) Corpus 3. A man wakes up and finds that people around him are using words that make no sense, and they don t understand him. This is like a) Wernicke s aphasia c) apraxia b) Broca s aphasia d) spatial neglect 4. If you were a split brain patient, which would be TRUE? a) Objects in your left visual field would be easily named b) Objects in you left visual field are invisible c) Objects in your right visual field would be easily named d) Objects in you right visual fields are invisible
46 Neurotransmission / Synapse 1- Neuron at rest (- inside + outside) 2 - Neural impulses move down axon; gate opens; +Na enters cell voltage changes from (-) to (+) 3- When impulse reach button tip; must get across synaptic cleft (gap); synaptic vesicle release neurotransmitter 4- When reaches the other side; briefly bond w/ receptor sites (lock & key) 5- Receiving membrane will change; excite increase firing (+ voltage) inhibit decrease firing (- voltage) 6- Neuron returns to resting state (- voltage) Action potential - a sequence of gates opening down the length of the cell (as 2 nd gate opens 1 st closes) -multiple +/- messages sent; take average
48 The Brain