Normal Function of the Nervous System

Question 1

Part 1 Overview of the Nervous System as a Control System

Question 2

Nervous System and Endocrine System

• Are the major _____ systems to maintain _____

Answer 2

• control, homeostasis

Question 3

2 Major Branches of the Nervous System

1. ___ (brain and spinal cord)
2. ___
   
   • Afferent division = ______ arm - carries info from ___ towards ___
     
     • Sensory stimuli (____-sensory stimuli) = we are ___ of (sight, touch, heat, pain)
     • Visceral stimuli = reflects status of ____ function ie. BP, blood volume, blood osmolarity - part of our ______ nervous system arm
   • Efferent division = carries commands from ___ towards _____

Answer 3

1. CNS
2. PNS
   
   • sensory, body towards CNS
     
     • somato, aware
     • visceral, autonomic
   • CNS towards body

Question 4

Nervous System Chart

Answer 4

Question 5

Efferent Commands

1. ______ nervous system -> ____ neurons -> _____ muscle - V______ CONSCIOUS COMMAND MOVEMENTS
2. ______ nervous sysyem = we are ___ aware of -> controls ____ function that includes s____ muscle, c____, gl____
   
   1. ​_______ nervous system = fight or flight response (stress responses)
   2. _______ system = rest and digest function (dominant most of the time)

Answer 5

1. Somatic -> motor, skeletal, VOLUNTARY
2. Autonomic, not, organ, smooth, cardiac, glands
   
   1. ​Sympathetic
   2. Parasympathetic

Question 6

Ramon y Cajal

• Spanish Neuroscientist in late 1800’s
• Pioneered a type of cellular ____ called ____ staining
  
  • ​Special bc it was specific to ______ cells -> in great ____, sp_____
• From these he created detailed _____ of neuronal cells -> before this we did not understand the nervous system was made up of ____ CELLS by demonstrating the structure of those cells

Answer 6

• Spanish neuroscientist
• staining, Golgi
  
  • neuronal, detail, sporadically
• drawings, DISTINCT

Question 7

Nervous Tissue

• Along with muscle cells, neurons are known as “______ cells”
  
  • means they are capable of firing ____ _____ (explosive movement of charged ions across plasma membrane creating _____ impulses -> units of _____ flow) -> how neuronal cells send sensory or command messages from body to brain or brain to body

Answer 7

• excitable
  
  • ​action potentials, electrical, info

Question 8

Structure of a Typical Neuron

• Bulbous central ____ ____ where nucleus resides
• _____ ______Where stimulation or information comes into a neuronal cell through its dendrites
  
  • So if enough info comes in -> cell will ____ an action potential (electrical impulse) - that starts at the ____ ____ -> down the long _____ -> out through the ____ _____ (______ terminal which other ______ of a neuronal cell)

Answer 8

• cell body
• Dendritic tree
  
  • ​fire, axon hillock -> axon -> axon terminal (presynaptic, dendrites)

Question 9

Myelination in the PNS

• Myelination = ______ of axon
  
  • Purpose of myelination (2)
• Schwann Cells =
• Nodes of Ranvier =

Answer 9

• insulation (kind of like wires at home that use plastic covering to insulate flow of electricity)
  
  • ​Speeds up rate of electrical impulse traveling down axon
  • Preservation of signal to not lose the signal
• PNS Myelination in form of Schwann Cells (purple circles are the nuclei)
• Bits of exposed axon in between schwann cells where electrical impulses jump from one node to the next to speed up action potential of an axon)

Question 10

Myelination in CNS

• What is the group of cells that provide myelination in the CNS?
  
  • Type of cell is called _____ cells
  • Sends out ______ projections that wrap around axons that surround the cell
  • In pic you can also see ____ of exposed axon between areas of myelination

Answer 10

• Oligodendrocytes
  
  • ​glial cells
  • footlike
  • nodes

Question 11

3 Basic Types of Neurons

(3)

Answer 11

• Efferent Neurons
• Afferent Neurons
• Interneurons

Question 12

Efferent Neurons

• Cell bodies live in the ___
  
  • _____ neurons where action potential/electrical impulse starts in the ____ and moves towards the ____ and eventually toward ___ cell
  • Axons in the ____, Axon terminals in the _____

Answer 12

• CNS
  
  • Command, CNS, PNS, target
  • PNS, periphery

Question 13

Afferent Neurons

• = _____ ____ neurons
  
  • Provides somato sensation -> have a particular appearance - has a s_____ receptor in the organ that its providing sensation (ie pressure receptor)
  • Cell body of this sensory neuron resides in the? -> then signal enters the spinal cord

Answer 13

• somato-sensory
  
  • specialized
  • in the PNS but CLOSE TO BOUNDARY oF CNS

Question 14

Interneurons

• = neuronal cells that ____ afferent neurons to efferent neurons
  
  • ______ afferent sensory signal and creates efferent _____
  • Located entirely in the ____

Answer 14

• = connect
  
  • processes, command
  • CNS

Question 15

Part 2 Ionic Basis of Resting Membrane Potential and the Action Potential

Question 16

Membrane Potential (mV)

Membrane Potential =

• The difference in charge is created by composition of ____ vs ____
• Action potential = mode through which a neuron transports _____ signal, predictable change in membrane potential due to open and closing of voltage gated ion _____ of cell membrane​

Answer 16

voltage difference across the membrane

• ICF vs ECF
• electrical, channels

Question 17

Membrane Potential Notes

• What gives the cell an overwhelmingly negative charge compared to the outside?
• What is the resting membrane potential for most cells?
  
  • ​Therefore ______ membrane potential has a high negative charge inside cell (whenever we talk about potential of cell: talking about inside compared to outside)

Answer 17

• Abundance of amino acids and proteins
• -70mv
  
  • ​resting

Question 18

Ionic Basis for Membrane Potential

• Ions are influenced by both a _____ and _____ gradient across the membrane
• The natural “drive” for all ions is to reach a state of ______: no net _____ force = no net ______
• For ions this state of “equilibrium” occurs when the plasma membrane is at a particular voltage called the ______ _____ = the voltage where an ion’s _____ gradient ______ out it’s ____ gradient
• An ion’s equilibrium potential is dependent on the _____ of that ion and its ______ gradient (difference across the membrane)

Answer 18

• chemical, electrical
• equilibrium, driving, movement
• equilibrium potential, electrical, balance, chemical
• valence (electrons that occupy the outermost shell), concentration

Question 19

Ionic Basis for Membrane Potential

• In electrical gradients = ______ attract
  
  • K+
    
    • What direction is its concentration gradient pointing in?
    • What direction is its electrical gradient pointing in?
  • Na+
    
    • What direction is its concentration gradient pointing in?
    • What direction is its electrical gradient pointing in?
• Therefore, Na+ has a huge motivation to get ____ the cell and at rest, what keeps it in is the membrane (bc is not lipid, cannot passively diffuse)
• Conclusion: Na+ has a huge driving force to get into cell but low _______

Answer 19

• opposites
  
  • K+
    
    • out
    • in
  • Na+
    
    • in
    • in
  • inside
  • low permeability

Question 20

Resting Membrane Potential

• Equilibrium potential of Na+ =
• Equilibrium potential of K+ =
• Resting Membrane Potential =
• Membrane Potential depends on (3)

Answer 20

• +60
• -90
• -70
• which ions, what their equilibrium potential is, and permeability

Question 21

Ionic Basis for Membrane Potential

• If a cell is perfectly permeable to an ion (and there’s only one ion present) then membrane potential will equal the?
• In reality, there are severeal ions present in human cells so a particular’s cell’s membrane potential will depend on (3)
  
  • The ion that has the greatest permeability to the membrane gets to drive its agenda the _____-> so if cell is more permeable to K then its resting membrane potential is closer to _____
  • So bc the cell at rest is more permeable to ______, its resting membrane potential is closer to potassium’s _____

Answer 21

• equilibrium potential of that ion
• ions present, equilibrium potentials, permeability
  
  • most, -90
  • K, equilibrium

Question 22

Depolarization

• Upward deflection = _______ in potential
• Downward deflection = _______ in potential
  
  • Less negative =
  • More negative =

Answer 22

• Decrease
• Increase
  
  • ​Depolarization
  • Hyperpolarization

Question 23

Overview of Action Potential

• Parts of an action potential (electrical impulse)
  
  • ​Starts around ___, something is making it less negative (na influx/fast depolarization) - hits a threshold where something big happens at around ___ -> cell gets rush of movement __wards and gets positive very quickly -> then tide shifts and drops down rapidly (fast hyperpolarization) -> hits an _______ then back to _____
• An __ or ____ event

Answer 23

• Action potential
  
  • -70, -50, upwards, undershoot, normal
• All or nothing

Question 24

Overview of Action Potential Notes

• Equilibrium potentials of Na+ and K+ are _____ values and parts of the action potential get _____ to both at different points
• Action potentials is always in this order
  
  • Rising phase towards ____
  • Falling phase towards ____
• Action potentials only happen in _____ cells (2)

Answer 24

• fixed, closer*
• Action potentials
  
  • Na+ (Na+ in)
  • K+ (K+ out)
• exctiable (nervous and muscle tissue)

Question 25

Resting Potential ## Footnote * The reason why muscle and nervous tissue can fire action potentials bc they possess a unique set of ____ gated ion channels * ​What opens those gates is some particular voltage or _____ of membrane potential * At resting potential = \_\_\_ * ​At rest, both Na and K voltage gated channels are \_\_\_\_\_ * Depolarization = when membrane potential becomes more _____ (\_\_\_ in) * Hyperpolarization = when membrane potential becomes more ____ ( __ out)

Answer 25

* voltage * value * -70 * closed * positive (Na+ in) * negative (K out)

Question 26

Threshold ## Footnote * If you hit threshold you're going to get an _____ (no such thing as small or large) * What happens to the gates when you hit threshold? * Only a few _______ for that inactivation gate to ___ after it opens

Answer 26

* action * Sodium gates start to open * milliseconds, close

Question 27

Depolarization ## Footnote * What happens to the gates? * Once you get above 0, what happens to the gates? * Relative Refractory Period = * If cell is overstimulated, getting too many action potentials but not enough of them experience hyperpolarization -\> you get \_\_\_\_\_

Answer 27

* Sodium channels fully open and sodium bursts into the cell dt huge driving force and brings + charge with it * potassium gates start..to open, the more positive you get the more potassium gates open -\> cells start to repolarize * ideal amount of time cell needs to fire another action potential * ​tetany

Question 28

Repolarization ## Footnote What is happening to the gates?

Answer 28

Closing of Na channels and Opening of K+ channels

Question 29

Hyperpolarization ## Footnote What is happening to the gates? What causes this stage? This stage prepares the cell for another?

Answer 29

K+ channels starting to close When more potassium leaves the cell than necessary to get back to baseline (undershoot purple line) Action potential

Question 30

Absolute Vs Relative Refractory Period ## Footnote Absolute Refractory Period = Relative Refractory Period =

Answer 30

* most but N_ot all Na +channels have reset_ to be able to stimulate another action potential (however if you do that enough times, your going to run out of those rest Na channels) * Can confirm that _All Na+ chanels have reset_ and is the ideal amount of time that cell needs to fire another action potential

Question 31

**Part 3 Neuronal Communication**

Question 32

Neuronal Communication ## Footnote * Via Synapses - **\_\_\_\_\_\_** or **\_\_\_\_\_\_** * **​Chemical Synapse -** via either + or - \_\_\_\_\_\_\_\_\_ * ______ **Junction** as a classic study of the chemical synapse * **Neurotransmitters (3)** * **Neuroactive \_\_\_\_\_\_** * **Electrical Synapses** - ____ Junctions - direct electrical spread

Answer 32

* **Electrical, Chemical** * **​**neurotransmitters * **Neuromuscular** * **Amino Acids, Monoamines, Caetcholamines** * **Peptides** * Gap

Question 33

Neuronal Communication Notes ## Footnote * Synapses = * Which synapse is more common?\* * In chemical synapses, we have the release of a neurotransmitter by the _____ cell -\> that neurotransimtter stimuates the ______ cell which causes stimulation or \_\_\_\_\_\_

Answer 33

* connection between two neuronal cells * _CHEMICAL\*_ * presynaptic, postsynaptic, inhibition

Question 34

Chemical and Electrical Synapse Notes ## Footnote * Which neurotransmitter does this describe? 1. Derived from a single amino acid that's then been modified chemically 2. Acts as energy, helps build proteins, can act as a neurotransmitter 3. Subgroup of monoamine (derived from tyrosine) 4. Are not neurotransmitters but are peptides that are ___ released with neurotransmitters that ____ response in the post-synaptic cell * Electrical synapses are known as? and they allow for ____ spread of the action potential from the pre synaptic to post synaptic cell

Answer 34

* Neurotransmitters * Monamines * Amino Acids * Catecholamines * Neuroactive peptides = co-released, modify response * Gap junctions, direct

Question 35

The NMJ as the Classic Chemical Synapse ## Footnote 1. Neurotransmitter molecules and synthesized and packaged in \_\_\_\_\_\_ 2. An action potential arrives at the presynaptic \_\_\_\_\_ 3. Voltage gated ____ channels open and Ca2+ enters 4. A rise in Ca2+ triggers _____ of synaptic vesicles with the presynaptic \_\_\_\_\_\_ 5. Transmitter molecules ______ across the synaptic ___ and bind to specific _____ on the _____ cell 6. Bound receptors _____ the postsynaptic cell 7. A neurotransmitter _____ down, is taken up by the presynaptic terminal or other cells, or diffuses ____ from the synapse

Answer 35

1. vesicles 2. terminal 3. Ca2+ 4. fusion, membrane 5. diffuse, cleft, receptors, postsynaptic 6. breaks, away

Question 36

NMJ Notes ## Footnote * Vesicles of neurotransmitter are produced and packaged in the? Shuttled down through ____ and ___ within the axon terminal * Steps of chemical synaptic transmission 1. **Action potential penetrates the ____ \_\_\_\_\_\_** -\> triggers the rapid **\_\_\_\_\_ by __ entering the cell** that stimulates a **third voltage gated ion channel (\_\_\_ ion channels)** 2. Calcium ions enter the cell and stimulate **\_\_\_\_\_\_\_ of vesicles of neurotransmitters** (where vesicles fuse with membrane) -\> releasing neurotransmitters into the synaptic \_\_\_\_ * The nature of chemical synapses = the _____ signal turns into a ___ signal then back to a ___ signal

Answer 36

* cell body, microtubules, stored * Steps 1. ​​**axon terminal, depolarization, Na+, Ca** 2. **exocytosis,** cleft * electrical -\> chemical -\> electrical

Question 37

Electron Micrograph of Two Cells ## Footnote What are the arrows pointing to? What are the little circles?

Answer 37

Active zones where you have release of neurotransmitter into synaptic cleft Vesicles of neurotransmitter

Question 38

Amino Acids ## Footnote (3) * Which one is the ubiquitous * **inhibitory** neurotransmitter in the brain? * **excitatory** neurotrasmitter in the brain?

Answer 38

**Glutamic Acid** **y-Aminobutric acid (GABA)** **Glycine** * GABA and Glycine * Glutamic acid -*nearly every excitatory synapse releases glutamate - is the general workhorse for stimulation in the brain*

Question 39

Monoamines ## Footnote (3)

Answer 39

**Acetylcholine** **Serotonin** (from tryptophan) **Histamine**

Question 40

Catecholamines ## Footnote (3) Group of neurotransmitters derived from?

Answer 40

**Dopamine** **Norepinephrine** **Epi** Tyrosine

Question 41

Neuroactive Peptides ## Footnote * = * Very di\_\_\_\_ * Often \_\_-relaased with other neurotransmitters (often in brain) * They **\_\_\_\_\_** the response to the neurotransmitter * ex) can increase or decrease production of receptors in postsynaptic cleft -\> if increases the next time that neurotransmitter is released, there is an enhanced/greater sensitivity for that neurotransmitter

Answer 41

* = shorter chains of amino acids * diverse * co-released * **modulate**

Question 42

Electrical Synapse ## Footnote Connected by ___ \_\_\_\_\_ - where\_\_\_ moves through and causes action potential of next cell

Answer 42

Question 43

Patterns of Synaptic Connections ## Footnote (2) And why are they different in function?

Answer 43

* Spatially Focused: ratio of 1 cell to next is low * usually task oriented circuits * Widely Divergents: high ratio of one to many cells * more regulatory