Nervous System

  1. What are the functions of the nervous system?
    • 1.) Transmitting impulses: electrical with chemical neurotransmitters
    • 2.) Conduction: type of communication to cells of the body, carrying info to regulate body functions
  2. what are the cells of the nervous system?
    • neurons- they carry impulses, specialized in conduction and responsiveness
    • glia
  3. glia
    supportive cells of the nervous system
  4. Types of info transmitted by neurons
    • sensory input
    • motor output
    • integration
  5. sensory input
    • awareness of changes in the external and internal environment- makes us aware of stimuli
    • sensory info is afferent- goes to the brain
  6. motor output
    • regulates the effectors of the body (structures with all 3 types of muscle and all glands that receive nervous info)
    • motor info is efferent- travels from the brain
  7. Integration
    • not sensory or motor
    • happens in 2 ways
  8. What are the 2 ways that integration happens?
    • 1. processes sensory info and determines a motor response
    • 2. controls a mental function- thinking, analyzing, planning
  9. Organs of the nervous system
    brain, spinal cord, and nerves attached to the both of them
  10. Central nervous system (CNS)
    • the brain and attached spinal cord
    • occupies a central location
  11. Peripheral Nervous System (PNS)
    • all the nerves of the body
    • cranial nerves: attached to the brain
    • spinal nerves: attached to the spinal cord
  12. What is in a nerve
    • sensory and/or motor neurons
    • no integrative neurons
  13. What are the divisions of the PNS
    • Somatic nervous system
    • autonomic nervous system
  14. somatic nervous system
    nerves to the skeletal muscles and the skin
  15. autonomic nervous system
    nerves to the viscera (with smooth and cardiac muscle and glandular tissue) has 2 parts
  16. 2 parts of the autonomic nervous system
    • sympathetic nervous system: nerves important in stress situations (fight or flight)
    • parasympathetic nervous system: nerves important in homeostasis- not stress
  17. Nervous system cells- types of neuroglia, glia cells
    • astrocytes
    • microglia
    • ependymal cells
    • oligodendricytes
    • satellite cells
    • schwan cells
  18. Glia cells
    smaller than neurons, some are starlike, but are not dendrites and axon neurons because they dont transmit impulses
  19. Where is most cancer of the nervous system?
    • of the glia
    • called a glioma
  20. astrocytes
    • starlike in shape
    • most abundant
    • found in the CNS
    • found between blood vessels and neurons 
    • part of the blood-brain barrier
    • help regulate what reaches the neurons from the blood (nutrients rely on these cells)
    • has a general physical support function- connection between parts of the nervous system
    • regulates the environment of the neuron
  21. microglia
    • small cells in the CNS
    • usually has a similar function to astrocytes, but in an infection/injury they take on a defense role
    • can enlarge and carry our phagocytosis of microbes and other material
    • immune system function to protect neurons
  22. ependymal cells
    • in the CNS they line the spaces that contain cerebral spinal fluid (ventricles) 
    • filter the cerebral spinal fluid and inluence the environment around the neurons
  23. oligodendricytes
    • have a few processes 
    • produce the myelin sheath in the CNS; wrap around the axons
    • provides insulation
  24. satellite cells
    • found tin the PNS around cell bodies of neurons
    • generally located in bumps called ganglia
    • protects and supports the neurons
  25. schwan cells
    • also called neurolemmacytes
    • make the myelin sheath in the PNS
    • functions like the oligodendricytes, but also have a role in repair of damaged nerve fibers (axons)
  26. General Structure of a neuron (what does it contain?)
    • cell body
    • dendrites
    • nissa bodies
    • nerve fibers
    • axon
    • myelin sheath (on some)
    • axon terminals
  27. cell body
    • also called perikaryon or soma
    • contains nucleus and nucleolus
  28. dendrites
    • often receive info 
    • cell body sometimes can receive
    • all cells have one or more dendrites and the free end of the dendrite is the receptor which can be stimulated by either a sensory or synapse
  29. Nissa Bodies
    • in cell body, type of rough ER
    • contain neurofibrils
  30. neurofibrils
    network of filaments and tubules, important for maintaining the structure of the neuron
  31. nerve fibers
    • includes the dendrites and the axon
    • only one axon but it can branch (called a collateral)
  32. myelin sheath
    • many neurons have axons covered in this (called myelinated neurons)
    • insulates the axon and speeds up impulses
  33. myelin
    • a fatty material
    • protects and insulates
    • the tissue looks white- white matter
  34. white matter
    • areas where the axon is clustered with myelin
    • from meylinated axons
  35. grey matter
    • cell bodies grouped and unmyelinated (have fibers)
    • areas of grey matter include centers, nuclei (in CNS) 
    • in PNS its in the ganglia
  36. How does the myelin sheath speed up impulses?
    using segments, nodes of ranvier and having impulses jump
  37. segments
    glial cells wrapping the myelin sheath
  38. nodes of ranvier
    spaces between glia
  39. how do impulses jump?
    • they jump from node of ranvier to node of ranvier
    • unmeylinated must depolarize each space while myelin sheath allows jumping
  40. neurilemma
    • exposed part of the schwan cell membrane, only in the PNS
    • important in repair to damaged axon
  41. tracts
    • areas of white matter in the CNS
    • All the neurons in a tract complete a similar function
    • in the PNS white matter is in nerves
  42. 2 ways to categorize types of neurons
    • 1.) by number of processes (axons and dendrites)
    • 2.) by function
  43. types of neurons (by # of processes)
    • multipolar neuron
    • bipolar neuron
    • unipolar neuron
  44. multipolar neuron
    • 3 or more processes- 1 axon & 2 or more dendrites
    • most common type of neuron based on shape
    • motor neurons and many interneurons have this shape
  45. bipolar neurons
    • 2 processes, one axon and one dendrite
    • rare, only seen in the sensory neurons of the eye and ear
  46. unipolar neurons
    • one pole
    • 2 process that branches (pseudo unipolar-bc its technically one but has 2 functions)
    • most sensory neurons are of this type
  47. Types of neurons by function
    • sensory
    • motor
    • interneuron
  48. sensory neuron
    • also called afferent neurons
    • brings information towards the CNS and up to the brain
  49. motor neuron
    • an efferent neuron
    • brings info from the CNS down from the brain
    • ex: controlling a muscle- brain sends info down the spinal cord towards the motor neurons
  50. interneuron
    • also called association neuron
    • neither sensory or motor
    • either communicates between sensory and motor neurons or has a mental function
    • only in the CNS not nerves
  51. Nervous impulse
    • electrical
    • created by the movement of ions in and out of cells
  52. resting neuron
    • no impulse yet
    • intracellular and extracellular fluids both contain (+) and (-) ions, however even though the total number is about the same the distribution is different
  53. ion distribution in the resting neuron
    • major cation (+) outside the cell: Na+
    • major cation (+) inside the cell: K+
    • major anion (-) outside the cell: Cl-
    • major anion (-) inside the cell: protein
    • overall negative charge inside the cell and positive charge outside
  54. Active Transport
    completed by Na+/K+ pumps that keeps the ions concentrated in and out of the cell
  55. what can measure the charges in the cell
    • a mircoelectrode
    • outside- +30 millivolts
    • inside- -70 millivolts
  56. what happens when the opposite charges are in and out of the cell?
    the membrane is polarized
  57. membrane potential
    potential differences in charges in and out of the cell
  58. resting potential
    cell is not conducting
  59. resting membrane potential
    differences in Na+ and K+ concentrations and different permeabilities
  60. electrochemical gradients (differences)
    • vital for impulse
    • we cant get impulse if the charge in and out of the cell is equal
  61. membrane ion channels
    • proteins in the membrane form these channels
    • 2 types: leakage channel and chemically gated channels
  62. leakage channel
    • nongated channels
    • always open
  63. chemically gated channels
    • ligangated
    • only open if the neuron is stimulated for example by a neurotransmitter
    • wont open to let ions flow without a stimulus
  64. how do charges stay the same before stimulation
    pumps are critical for keeping Na+ out and K+ in
  65. What happens to channels with stimulation?
    • permeability of the membrane changes
    • when the gated channels open, ions diffuse down the electrochemical gradient (from area of higher concentration to area of lower concentration)
    • Na+ tends to diffuse in while K+ diffuses out
    • ions also move towards the opposite charge ex: positive Na will be attracted to - charge of proteins mostly in the cell
  66. What happens when the membrane becomes permeable to sodium
    • Na+ diffuses in by the chemical gradient 
    • it also is attracted to the negative charge in the celll
    • some leakage when no stimulation but mostly pumps keep Na out and K in
  67. draw unstimulated cell
    • ++++++++++++
    • ________________
    • -----------------------
    • ________________
  68. draw stimulated cell where impulse begins to generate
    • -----++++++++++++
    • ____________________
    • +++-----------------------
    • ____________________
  69. what happens after the impulse is generated?
    • the charges begin to reverse at the point of stimulation
    • then the impulse must spread down the axon to the termials and you have to restore the resting potential charges so you can get another impulse later
  70. action potential
    resting potential was the charges in the resting neuron and the action potential is the charges during the impulse (reversed)
  71. Depolarizing
    • taking away the original polarity
    • reversing the charges
    • decreasing the membrane potential by stimulation of the axon
    • happens when you get an impulse
  72. Threshold
    the minimum stimulus required to cause an impulse (action potential) in a neuron
  73. all or none principle
    • either the stimulus is strong enough to cuase an impulse or there will be no impulse at all
    • even if you increase the stimulus greater than the threshold, the impulse will always be the same strength
    • no such thing as a stronger impulse
  74. How does the body show response to increased stimulus
    • not by impulse strength but by impulse frequency
    • rate increases
  75. General principle of the nervous impulse
    ion movement causes electrical current in the neuron and propagates down the whole length of the axon
  76. steps of the nervous impulse
    • depolarize the membrane: reverse the charges in and out of the cell to take away original polarity
    • at point of stimulation membrane becomes permeable to Na and it enters into the axon hillock
    • gated channels open and na will diffuse from high to low concentration (into the cell)
    • so much na enters that inside becomes + and leaves outside -
    • reversed charges act as a stimulus to the next part of the membrane and that next part becomes permable to na and it starts again-cascade effect
    • you create a wave of negative charges outside the axon and it flows to the end of the axon
    • repolarization
  77. what kind of feedback is the stimulus of a neuron
    • positive
    • stimulus makes more and more impulses down the neuron
  78. Repolarization
    • restoring the resting potential original charges
    • starts at the point of stimulation and happens simultaneously while depolarization is still happening further down the cell
  79. steps of repolarization
    • Na channels become inactivated and pumps reset so no more can flow in
    • k+ channels open and it diffuses out down the concentration gradient (b/c more k inside) and also towards the outer (-) charge
    • sometimes k channles remain open after the sodium pumps have been reset and functioning (na being pumped out) meaning k can diffuse more than the minimum required to restore resting potential
    • the K+ pump begins working again and the membrane is now not permeable to k or na
  80. continuous conduction
    each part of the axon has charge reversed all the way down meaning each part is depolarized bit by bit
  81. Saltitory conduction
    • happens if there is a meylin sheath around the axon
    • saltitory- "leap"
    • the impulse jumps from node to node
    • up to 30x faster
    • the myelin sheath also prevents any extraneous ion movement by leakage
  82. in what kind of axons are impulses faster
    • myelinated
    • axons with a wider diameter (causes less resistance)
  83. refractory period
    • the time after the impulse starts when the neuron will not respond to any stimulus because you have yet restored the resting potential 
    • milliseconds long
    • 2 types
  84. 2 refractory periods
    • absolute refractory period: the impulse has just started flowing and restoration hasnt begun --> absolutely no response to stimulus
    • relative refractory period: if you have begun to restore a very strong stimulus could create another impulse
  85. synapse
    • the junction where a neuron sends info to another cell
    • this other cell can be another neuron (for thinking/feeling) or it could be a muscle or gland cell
    • includes 2 cells
  86. 2 cells at the synapse
    • presynaptic neuron: the cell that releases the neurotransmitter
    • post-synaptic cell: the cell that responds to the neurotransmitter
  87. Are synapses in our bodies electrical or chemical
    • usually chemical using neurotransmitters
    • there are rare instances in adults where youll have an electrical synapse where the 2 cells are electrically coupled and you dont use a neurotransmitter- this involves synchronizing activity of cells; seen more in an embryo and it is later replaced by the use of a neurotransmitter
  88. How is the neurotransmitter released
    released from the synaptic bouton (axon terminal) by exocytosis
  89. what happens after the neurotransmitter is released?
    • the NT diffuses across the synaptic cleft and binds to a receptor on the post synaptic cell membrane
    • then the effects of the neurotransmitter are terminated (ended)- multiple ways to do this
  90. what are the ways that a neurotransmitter is terminated?
    • 1.) degradation of the NT in the synapse by an enzyme that can be in the synaptic cleft or on the post synaptic cell membrane
    • 2.) Reuptake- the neurotransmitter is taken back up into the presynaptic neuron and is stored or broken down by an enzyme
    • 3.) Diffusion away from the synapse (ex- it could go into a nearby blood vessel or taken up by an astrocyte)
  91. Neurotransmitters function
    can either be excitatory or inhibitory
  92. excitatory
    • they will stimulate the post synaptic cell 
    • will try to get an impulse in the next neuron but may not be strong enough
  93. inhibitory
    • will try to prevent the next cell from an impulse (neuron) or being stimulated (another cell)
    • they do hyperpolarization: increasing the (+) charges outside the cell
  94. summation with neurotransmitters
    • the post synaptic cell sums up the influence of all the neurotransmitters at the synapse to determine response- do you reach a threshold or not for a response 
    • 2 types: temporal summation and spacial summation
  95. temporal summation
    • time
    • if a neuron has many impulses in a row so that the neurotransmitter accumulates in the synapse before it is removed, there is an additive effect of that neurotransmitter
  96. spacial summation
    • you have 2 or more presynaptic neurons releasing neurotransmitters at the same time to the same post synaptic cell causing an additive effect
    • it will be the same neurotransmitter
  97. How many chemicals have been identified as neurotransmitters or punitive (possible) neurotransmitters
    • more than 50
    • some release only one type of NT while others release more than one
    • found in different parts of the CNS and from different nerves in different pathways
  98. What are several nervous disorders caused by?
    • not having the usual amount of a neurotransmitter
    • ex: parkinsons, not enough dopamine
  99. what can you do if there is not enough of a neurotransmitter?
    • you can treat it by increasing the synthesis of a neurotransmitter or its release by giving a precursor (ex- for dopamine you can give l-dopa)
    • you can give a drug to mimic the neurotransmitter at the receptor
    • you can give a drug to prevent the removal of a neurotransmitter at the synapse at a certain time- preventing reuptake or enzyme breakdown (this method used in depression- Seratonin reuptake inhibitors)
  100. what can you do if there is too much of a neurotransmitter
    you want to decrease synthesis, block the neurotransmitter from the receptor or remove it from the synapse (physically or by breakdown via enzymes)
  101. Neuromodulator
    • a chemical that does not directly cause an action potential at the synapse but in some way it does affect a neurotransmitter at the synapse
    • ex: may stimulate release, degradation or reuptake
    • may influence the receptor functioning
    • may be a paracrine substance
    • influences the cell in some way but doesnt function as a direct neurotransmitter
  102. paracrine substance
    • a regulator that acts locally
    • made by one type of cell and released and affects a nearby cell
  103. name any 2 neurotransmitters
    • GABA- gamma-amino butyric acid
    • glutamate
    • glycine
    • endorphins enkephalins
    • substance P
    • somatostatin
    • cholecystokinin
    • nitric oxide
    • acetylcholine
    • norepinepherine
    • dopamine
    • serotonin
    • histamine
  104. CNS
    the brain and spinal cord
  105. development of the CNS
    • early on in prenatal life
    • neurons appear early in develoment- you get new ones prenatally and then a few months after birth
    • you generally dont get new neurons later in life, but yours will grow
    • ability for neuron mitosis only lasts 3-4 years
  106. Parts of the brain
    • forebrain
    • midbrain
    • hindbrain
  107. parts of the forebrain
    • cerebellum
    • diencephalon
  108. parts of hind brain
    • medulla 
    • pons
    • cerebellum
  109. what structures make up the brain stem
    midbrain, pons, medulla
  110. Cerebrum
    • the largest most superior part of the brain
    • has 2 cerebral hemispheres (halves)
  111. What does each cerebral hemisphrere contain?
    5 lobes: frontal, parietal, occipital, temporal and insula (internal)
  112. concolutions
    folds in the cerebrum that increase the surface area
  113. Corpus Collosum
    • area of white matter that connects the 2 halves of the cerebrum, a type of commisure (connection)
    • there are also association tracts- info going from one part of a hemisphere to another
  114. Tracts
    • made of white matter which is made up of nerve fibers
    • goes between both cerbral hemispheres to communicate between them
  115. projection tract
    • where you communicate info from lowere parts of the nervous system ascending up towards the cerebrum
    • --->function is sensory
    • you also have projection tracts from the cerebrum descending down to the lower parts of the nervous system
    • --->function is motor
  116. Cerebral cortex
    • the outside area on the surface of the brain
    • grey matter
    • has 6 layers of cell bodies
  117. islands of grey matter in the cerebral cortex
    • include basoganglia (nuclei or centers that are deep) and those include the caudate nucleus and putamen
    • this part of the brain is affected in Parkionsons disease (stops movement)
    • usual function is to prevent unnecessary movement and regulating starting and stopping in movement
  118. What neurotransmitters regulates the starting and stopping movement functions in the cerebral cortex?
  119. What side of the cerebrum controls the right side of the body
    • left because the pathways  going up and down from the cerebrum cross over 
    • ex: stroke on left side of the brain causes right side of body to disfunction
  120. What does the left side of the cerebrum function in?
    • speech
    • written language
    • numerical reasoning
    • logic
    • skilled movements
  121. What does the right side of the cerebrum specialize in?
    • musical auditory and artistic awareness
    • spacial pattern
    • perception
    • insight
    • imagination
  122. Cerebral cortex function
    • sensory, motor, visceral and mental
    • general sensations
    • special sensations 
    • fine control of movement
    • mental functions
  123. general sensations (cerebral function)
    • ie from skin
    • primarily regulated by the parietal lobe
    • visceral organs regulated by the insula
  124. special sensations
    • vision from the visual cortex of the occipital lobe
    • hearing- autidory cortex of temporal lobe
    • taste- gustatory cortex of the parietal but also from the frontal and inusla
    • smell- olfactory cortex of the temporal lobe
    • equiliburim or balance- vestibular cortex of the insula and parietal lobes
  125. fine control of movement (cerebral function)
    • the primary motor area is in the frontal lobe (most important)
    • this controls groups of muscles 
    • pinpoints exact places where muscle moves
  126. Mental functions
    • info travels back and forth by association tracts connecting multiple parts of the brain
    • in memory: there are different parts of the cerebral cortex involved
    • limbic system
    • higher mental functions (ie- planning)- frontal lobe
    • personality- prefrontal cortex
    • speech- frontal parietal, temporal
    • consciousness- cerebral cortex
    • influences viscera via autonomic NS
  127. Limbic system
    • part of the cerebrum near the corpus collossum (hippocampus)
    • also includes the diencephalon (thalmus and hypothalmus)
    • important in memory, emotions and motivation
    • associates pleasant and unpleasant memories
  128. Reticular Activating System
    • controls consciousness- awareness of yourself and others in the environment
    • multiple impulses, especially sensory and integrated, alert the cerebrum
  129. reticular formation
    the parts of the medulla, pons and midbrain that get info from cranial and spinal nerves+cord that send impulses to the diencephalon then to the cerebrum
  130. Diencephalon
    • Thalmus
    • Hypothalmus 
    • Pineal Gland
  131. Thalmus
    • important for sensations
    • a relay center for most sensory pathways
    • contains a synapse and when the info gets there there is a crude understanding of the sensation (once it reaches the cerebrum theres a fine understanding)
    • part of the reticular activating system- consciousness
    • part of the limbing system- associating emotions with memory
    • has some complex cranial reflexes
  132. What does the thalmus connect
    cerebrum and lower parts of the brain
  133. Hypothalmus
    • makes hormones and influences other hormones
    • has pituitary gland attached to it
    • a bridge between the 2 communication systems (nervous and endocrine)
  134. hypothalmus functions
    • important in reproduction, growth and water balance
    • influences viscera via autonomic NS
    • part of limbic and reticular activating systems
    • important in daily rythems (circadian rythems- around a day), being awake/asleep, eating/not eating, things that change in a day
    • influences eating behavior (has feeding and satiety[feeling full] centers)
    • contains the thirst center, temperature center (Acts as a thermostat for the body- causes shivering, sweat, etc)
  135. Pineal Gland
    attached to the diencephalon, makes melatonin
  136. melatonin
    • important in sleep and daily rythems
    • a biological clock
  137. Midbrain
    • Contains nuclei for certain auditory and visual reflexes
    • a reflex center for cranial nerves (ocularmotor and trochlear)
    • involved in reflexes involving motor coordination and posture
  138. Pons
    • important in the reticular formation, respiration (has respiratory centers for the rythem of breathing)
    • contains nuclei for cranial nerves involved in chewing, taste, eye movement and equilibrium
  139. what cranial nerves have synapses in the pons
    • trigeminal
    • abducens
    • facial
    • vestibulocochlear
  140. medulla oblangata
    • attaches to the spinal cord
    • lowest part of the brainstem
    • involved in reticular formation- consciousness
  141. for what cranial nerves does the medulla have nuclei and synapses
    • vestibulocochlear
    • glossopharangeal
    • vagus
    • accessory
    • hypoglossal
  142. the medulla contains vital centers for
    • respiratory system- regulates the rate and depth of breathing
    • circulatory system- regulates the heart and blood vessels (its most important in this system)
  143. other functions of the medulla
    • invovled in vommiting, coughing, sneezing and swallowing
    • info coming up from the spinal cord has to go through the medulla- it is a place of projection tracts going up to the brain from the spinal cord and going down
  144. what pathways go through the medulla?
    • sensory and motor
    • when info comes up or down most pathways experience decussion (crossing over to the other side of the body)- happens either in the medulla or spinal cord
  145. Cerebellum
    • very important in muscle coordination- vital for skilled movements (as opposed to crude reflexes)
    • acts with the cerebrum in motor pathways
    • important in controlling groups of muscles
    • important in memory of movements- ex remembering how to walk
    • equilibrium (balance)- receives impulses from the ears
    • important in posture- receives info about (ex upsidown) position from ears and from muscles, tendons and joints (ex youre aware if youre holding your arm up)- regulates movements needed to retain posture
    • kinesthesia
    • equilibrium from eyes- you can see wheere you are
  146. kinesthesia
    a sense of position and movement of the body (you know if youre upside down spinning etc)
  147. What are the spinal cord and brain protected by
    membranes called the meningies, adipose tissue and bone
  148. how is spinal cord shaped
    like an oval cylinder and attaches to the medulla
  149. spinal nerves
    • paired and attached to the spinal cord
    • they come out from different levels of the cord- cervcal, thoracic, lumbar, sacral, and coccygeal
  150. are spinal nerves sensory or motor
    • all are mixed (both sensory and motor)
    • spinal nerves contain the dendrites of sensory neurons and axons of motor neurons
  151. rami
    branches of the spinal nerve
  152. central canal
    • in cross section of the spinal cord
    • holds cerebral spinal fluid
  153. neurons in the spinal nerve
    can be just sensory to motor or go from sensory to interneuron then to motor
  154. dorsal root
    • has dorsal root ganglion w/ cell bodies
    • sensory only
  155. ventral root
    motor only
  156. reflex
    a very quick response to a stimulus and the pathway of neurons in a reflex is called a reflex arc
  157. simplest reflex arc
    • where you have one synapse 
    • sensory neuron to motor neuron
    • the fewer number of synapses the faster the reflex
  158. reflex with 3 neurons
    sensory neuron to interneuron to motor neuron
  159. types of reflexes
    • spinal reflex
    • cranial reflex
    • ipsilateral reflex
    • contralateral reflex
  160. spinal reflex
    • this involves spinal nerve and spinal cord but not the brain
    • ex: knee and kick reflex
  161. cranial reflex
    • involves cranial nerves and the brain
    • ex: pupil constricts when shining light in eye
  162. ipsilateral reflex
    • the stimulus and response are on the same side of the body
    • ex: if you hit your right knee you kick your right knee
  163. contralateral reflex
    • also have a stimulus and response is on the opposite sides of the body
    • interneuron: branch of axon that crosses over to the other side-synapse with motor neurons is on the other side
    • ex: shining a light in one pupil, both will dialate
  164. Functions of the spinal cord
    • reflexes 
    • sensory function
    • motor function
  165. sensory function of spinal cord
    • contains ascending pathways to the brain
    • there are seperate pathways for the different senses (pain touch, etc)
  166. motor functions of the spinal cord
    • contains decending pathways from the brain
    • seperate pathways for different movements in distinct areas
  167. tract in the spinal cord (motor function)
    • nerve fibers in the CNS go to other places in the CNS
    • if a tract has a 2 part name the first part is where the tract starts and the second is where it ends
    • ex: spinothalmic tract- spinal cord to thalmus- ascending so sensory
  168. pathways in the spinal cord (motor functioning)
    • how the neurons bring info from one place to another, also called circuts
    • they do this by divergence or convergence
  169. divergence
    • if you have one neuron sending info to a number of neurons in different parts of the Nervous system
    • ex: you touch a tack and it hurts- info from the sensation of pain and limbic system info to make it a bad memory
  170. convergence
    • if one neuron receives info from a number of neurons
    • ex: multiple parts of the brain send info down the spinal cord by convergence
  171. sensory pathway path in spinal cord
    • ex touch
    • starts with the receptor of the sensory neuron (tactile receptors in skin). that neuron is in the spinal nerve and it will have a synapse with another neuron in the spinal cord, info is then sent to thalmus and before it gets there there will be crossover in either the spinal cord or medulla then goes from the talmus to the cerebral cortex (parietal lobe)
  172. motor pathway path in the spinal cord
    start from cerebral cortex (ex- frontal lobe). cerebral cortex sends and impulse down to the medula oblongata. the cerebellum also sends an impulse here. then medulla to the spinal cord to spinal nerve to the effector (usually muscle), again, crossover occurs in the medulla  or spinal cord
  173. 12 cranial nerves
    • olfactory
    • optic
    • oculomotor
    • trochlear
    • trigeminal
    • abducens
    • facial
    • vestibulocochlear
    • glossopharangeal
    • vagus
    • accessory
    • hypoglossal
  174. olfactory
    • smell
    • only sensory
  175. optic
    • vision
    • sensory only
  176. oculomotor
    • eye movement
    • more regulates the pupil size
    • adjusts the amount of light
    • regulates the lens of the eye, adjusts lens for near and far vision
    • motor only
  177. trochlear
    • also moves eye
    • motor only
  178. trigeminal nerve
    • controls sensation so of the head and chewing
    • sensory and motor
  179. abducens
    • moves eye
    • motor
  180. vestibulocochlear
    • to ears
    • just sensory
    • controls hearing and equilibrium (balance)
  181. glossopharangeal
    • involved in taste, swallowing, secretion of saliva
    • regulates the blood pressure and breathing
    • sensory and motor
  182. vagus
    • sensations of the throat
    • regulates the blood pressure and breathing
    • swallowing, coughing, speaking 
    • regulates the heart and the other viscera
  183. broccas area
    area of the cerebrum associated with speaking language
  184. wernickes area
    area of the cerebrum associated with understanding language
  185. accessory nerve
    • important in swalliowing 
    • head and shoulder movement
    • motor
  186. hypoglossal
    • swallowing and speech
    • motor
  187. autonomic nervous system summary
    • nerves to internal organs
    • sensory, motor and reflex pathways
  188. cranial nerves involved in the autonomic nervous system
    • culomotor
    • facial
    • glossopharangeal
    • vagus
  189. organs controlled by the autonomic ns have what kind of muscle
    • smooth or cardiac
    • or they are glandular cells
  190. how many nerves do most organs in the autonomic ns have
    • 2- dual innervation
    • have sympathetic and parasympathetic nerves- they have opposite functions
    • but some organs only have sympathetic nerves
  191. how are somatic nervous system and autonomic nervous system different in amount of motor neurons
    • somatic: one motor neuron connected to accessory, releases acetyl choline to skeletal muscle
    • autonomic: 2 motor neurons, motor neuron 1 always releases acetylcholine while #2 releases norepinepherine (sympathetic) or acetylcholine too (parasympathetic)
  192. where is the synapse between the 2 autonomic motor neurons located
    autonomic ganglion
  193. preganglionic motor neuron
    • motor neuron number 1
    • releases acetyl choline
  194. postganglionic motor neuron
    • motor neuron #2
    • releases acetylcholine or norepinepherine
  195. sympathetic nervous system
    • called the thoracolumbar division
    • spinal nerves that are comming out from lumbar and thoracic regions of the spinal cord
  196. does the sympathetic nervous system have spinal or cranial nerves
    spinal only
  197. autonomic ganglia- sympathetic nervous system
    • sympathetic ganglia are near the spinal cord in a chain
    • sympathetic chain ganglia impulses can go up and down the chain in addition to directly to the organ (so something going down one neuron can affect another because they are connected)
    • preganglionic neurons are short-cholonergic neuron- release acetylcholine
    • postganglionic neurons are long- release norepinepherine, called adrenergic neurons if they release norepinepherine
  198. adrenal medulla
    • medulla, inner portion of adrenal gland
    • in sympathetic ns
    • makes hormones- epinepherine+ norepinepherine (also a NT)
    • develops alongside the sympathetic ganglia
    • a motor neuron releases acetylcholine causing adrenal medulla to release epinepherine/norep into the blood
  199. epinepherine in the sympathetic nervous system
    • fight or flight hormone
    • released into the blood
  200. What is the parasympathetic ns also called
    craniosacral division
  201. cranial nerves of the parasympatheic nervous system
    • oculomotor
    • facial
    • vagus
    • glossopharangeal
    • also involves spinal nerves from the saccral region
  202. ganglionic nerves of the parasympathetic ns
    • pregangionic motor neuron is long
    • parasympathetic ganglion is near the organ or effector
    • postganglionic motor neuron is short
  203. organs that only get one nerve
    • the one nerve is always sympathetic
    • adrenal medula: regulates secretion of hormones epinepherine and norepinepherine
    • sweat glands:when stressed, these increase sweat production and release 
    • most blood vessels only get a sympathetic nerve: causes the constriction (narrowing) of the smooth muscle on an artery
    • spleen: influences blood flow
    • arrector pilli: hair movement
    • kidneys: decrease urination in the sympathetic NS
  204. Functioning of the parasympathetic ns
    • if there are 2 nerves its not just on or off situation, there is a balance between the 2
    • --- sympathetic will dominate in stress situations
    • --- parasympathetic will dominate in non stress situations for homeostasis
  205. example of opposite functions of the sympathetic and parasympathetic ns
    • in stress- heart pumps faster is stimulated and digestion is inhibited or slowed down
    • balance regulated by the hypothalmus
  206. Stressful situation
    • the sympathetic ns gets the most out of the body (ie you can run faster, do more)
    • this is very fast
    • adrenal medulla helps to prolong the stress response and the sympathetic ns is stimulated while the parasympathetic is inhibited
  207. hormones
    • in stress- epinepherine and nor epinepherine
    • in homeostasis- hormoens such as hydrocortizone help return to homeostasis
  208. Types of stress
    • physical
    • emotional
    • medical
  209. Heart in stress
    • beats faster
    • is stronger
    • pumps blood to the skeletal muscles to bring o2 and nutrients to get the most out of the muscle
  210. respiratory system in stress
    sympathetic ns and norepinepherine dialate the passageways to get as much o2 in the body as possible
  211. eyes in stress
    symp ns cuases dialation of pupils to get the maximum amount of light into the eyes
  212. adrenal medulla during stress
    makes epinepherine to prolong effects of symp ns
  213. organs not as critical in stress
    • digestive organs
    • kidneys
    • these are inhibited
    • you return to homeostasis after stress and parasympathetic does reverse effects
  214. reverse functions of parasympathetic NS to restore homeostasis
    • decreses rate and force of heart contraction
    • decreases diameter of respiratory passageways
    • decreses pupil size
    • stimulates digestion, urine formation
    • sends impulses to inhibit during stress but symp still sending many impulses so you only see the inhibitory effect of the parasympathetic ns after the stress is over
  215. brain control of the autonomic ns
    • certain regions are key to controlling viscera (ex medulla controlling heart and blood vessels)
    • hypothalmus integrates the parasym and symp to determine the balance and gets info from the cerebrum
    • hypothalmus also stimulates the brainstem
    • cerebrum- cerebral cortex and limbic system
    • brainstem-bottom line for survival
  216. cerebral cortex and limbic system influence in the autonomic ns
    • mental functions and emotions can influence the autonomic nerves and therefore the viscera
    • a mental function (thinking aobut some stress) is a function of cerebral cortex while a direct emotion is limbic system
    • both influence viscera
  217. a
Card Set
Nervous System
Quiz of 10/27/14