Test 2: Neural Signaling (Neurons)

Front 1

Define: neuron

Back 1

an electrically excitable nerve cell that transmits information by electrical or chemical signaling

Front 2

Define: reception

Back 2

the process of detecting a stimulus

Front 3

Define: Transmission

Back 3

process of sending messages along a neuron, from one neuron to another or from a neuron to a muscle or cell gland
ex: receptor --> CNS through afferent sensory neuron

Front 4

Define : Integration

Back 4

sorting and interpreting incoming sensory information and determining the appropriate response

Front 5

Define: Response

Back 5

action taken by effectors; neural messages carried from CNS through efferent neurons to effectors

Front 6

What are effectors?

Back 6

other nerves, muscles, glands

Front 7

What are the neuron classifications?

Back 7

1. afferent neuron
2. interneuron
3. efferent neuron

Front 8

What does the afferent neuron do?

Back 8

sensory; sends information to CNS

Front 9

What does the interneuron do?

Back 9

receive information from afferent neurons; integrate input and output; found in CNS

Front 10

What does the efferent neuron do?

Back 10

sends messages from CNS to effectors; motor neurons are efferent neurons that go to the skeletal muscle

Front 11

Describe the features of a myelinated neuron?

Back 11

1. cell body (soma)
2. dendrites
3. axon hillock
4. axon (vary in length)
5. myelin sheath (insulator)
6. nuerolemma nodes (node of Ranvier)
7. collateral branches (branching axons)
8. axon terminal

Front 12

What are the two types of myelinated cells? and where are they found?

Back 12

1. Neurolemmaocytes (Schwann cells); PNS
2. Oligodendrocytes; CNS

Front 13

What are special about collateral branches?

Back 13

multiple will effect motor unit size, which is advantagous

Front 14

What are the structural types of neurons?

Back 14

1. multipolar
2. bipolar
3. unipolar

Front 15

Describe a multipolar neuron and what is its function?

Back 15

1. multiple dendrites connected directly to soma and has an extending neuron
2. sensory neuron

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Front 16

Describe a bipolar neuron and what is its function?

Back 16

1. soma between dendrite stalk and axon
2. integration neuron

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Front 17

Describe a unipolar neuron and what is its function?

Back 17

1. soma hangs off middle of axon
2. motor neuron

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Front 18

What is the difference between a nerve and ganglia?

Back 18

1. nerve - many groups of axons
2. ganglia - cell bodies of neurons grouped in masses

Front 19

What are some support cells (neuroglial cells)?

Back 19

1. Neurolemmocytes (Schwann cells)
2. Oligodendrocytes
3. Astrocytes
4. Ependymal cells
5. MIcroglial cells

Front 20

What doNeurolemmocytes (Schwann cells) do?

Back 20

mylination of axon (in PNS)

Front 21

What do oligodendrocytes do?

Back 21

1. mylination of axons in CNS

Front 22

What do astrocytes do?

Back 22

1. pH regulation
2. structural support
3. phagocytic
4. regulate extracellular ion and neurotransmitter concentrations
5. induce cells from blood-brain barrier during embryonic development

Front 23

What do ependymal cells do?

Back 23

1. line ventricles of central canal of spinal cord
2. formation and circulation of spinal fluid

Front 24

What do microglial cells do?

Back 24

1. phagocytic defensive
2. originate in red bone marrow

Front 25

What do radial cells do?

Back 25

1. guide neural connections to fetus brain
2. stem cell function

Front 26

What is the function of neural signals?

Back 26

that all information is piassed through electrical signals along axons

Front 27

What is the transmembrane potential?

Back 27

negative difference across membrane

Front 28

What is membrane permeability?

Back 28

isolation of ions and charges across a membrane: [K], [Na], [Cl]

Front 29

What is needed to establish a transmembrane potential?

Back 29

slight movement of ions will change potential

Front 30

What is needed to establish transmembrane equilibrium?

Back 30

movement occurs until [electrical gradient] = [chemical gradient] OR outward movement = inward movement

Front 31

What is ion movement?

Back 31

membrane is selectivity permeable (more to K than Na); 1 out of 100,000 K is needed to change potential by 100 mV

Front 32

Describe sodium-potassium pumps

Back 32

1. Na and K pumped against their concentration and electrical gradients
2. pumps require ATP
3. 3 Na pumped OUT, 2 K pumped IN
4. [Na] greater on outside of cell
5. [K] greater on inside of cell

Front 33

What are the components of an action potential?

Back 33

1. resting membrane potential
2. threshold potential
3. depolarization
4. repolarization
5. hyperpolarization

Front 34

What is occurring at resting membrane potential?

Back 34

it is being altered by membrane permeability

Front 35

What is occurring at threshold potential ?

Back 35

point that allows an action potential to fire

Front 36

What is occurring at depolarization?

Back 36

1. stimulus causes membrane potential to become LESS negative than resting potential
2. bring neuron closer to transmitting an impulse
3. Na gates open

Front 37

What is occurring at repolarization?

Back 37

1. membrane potential returns to resting level
2. K channels opening

Front 38

What is occurring at hyperpolarization?

Back 38

1. membrane potential MORE negative than resting potential
2. decreases ability of the neuron to generate a neural impulse

Front 39

What is special about neurons concerning action potentials?

Back 39

all cells can generate a graded potential, but only neurons can generate action potential

Front 40

What is the "all or none" law?

Back 40

1. action potential either occurs or doest
2. action potential must reach threshold to fire
3. no variation of strength in a single impulse (meaning, no matter how strong the impulse, it still generates the same action potential )
4. if signals are close, can add subthreshold values to get to threshold

Front 41

Where does Na spike occur?

Back 41

depolarization

Front 42

Describe sodium voltage-gated channels

Back 42

1. have two gates (activation and inactivation)
2. fast
3. conformational, so not ATP needed
4.inactivation gates open at resting

Front 43

What is the difference between activation and inactivation gates?

Back 43

1. activation gates open more quickly
2. activation gate closed at resting state

Front 44

Describe potassium voltage-gated channels

Back 44

1. only one gate (activation)
2. slower than Na gates
3. open during repolarization

Front 45

What is the feedback cycle in an action potential?

Back 45

1. positive feedback: opening of Na channels during depolarization
2. negative feedback: opening of K channels during repolarization

Front 46

Where does Na spike occur?

Back 46

depolarization

Front 47

Describe sodium voltage-gated channels

Back 47

1. have two gates (activation and inactivation)
2. fast
3. conformational, so not ATP needed
4.inactivation gates open at resting

Front 48

What is the difference between activation and inactivation gates?

Back 48

1. activation gates open more quickly
2. activation gate closed at resting state

Front 49

Describe potassium voltage-gated channels

Back 49

1. only one gate (activation)
2. slower than Na gates
3. open during repolarization

Front 50

How many Non-licensed personnel should a pharmacist supervise at the time?

Back 50

No ratio (unlimited # of clerks)

Front 51

Describe the types of propagation of an action potential

Back 51

1. contiguous
2. saltatory

Front 52

Describe saltatory propagation

Back 52

1. myleniated axon
2. leaping motion
3. occur at Nodes of Ranvier
4. mylelin is an insulator, makes the movement much faster
5. when nodes are father apart, impulse is quicker and requires less energy

Front 53

Describe contiguous propagation

Back 53

1. unmyelinated
2. speed proportional to diameter
3. greater the diameter, faster it goes

Front 54

What are the refractory periods?

Back 54

1. absolute
2. relative

Front 55

Describe absolute refractory period

Back 55

1. Na channels are inactivated
2. axon can't transmit another action, no matter how strong it is

Front 56

What is relative refractory period?

Back 56

1. Na channels have been reset
2. axon can transmit impulses, but the threshold is higher

Front 57

What factors affect the transmission speed of an action potential?

Back 57

1. temperature
2. axon diameter
3. myelination

Front 58

What factors do not affect the transmission speed of an action potential?

Back 58

stimulus strength

Front 59

Describe electrical synapses

Back 59

1. spread via jap junctions allowing for faster movement
2. can flow in either direction (disadvantage)
3. no time delay
4. heart, fast escape mechanisms
5. can't continue across cleft

Front 60

Describe chemical synapses

Back 60

1. diffuse across cleft
2. delay
3. receptor protein on effector binds neurotransmitter and initiates response
4. unidirectional (advantage)
5. slower

Front 61

What are some neurotransmitters?

Back 61

1. ACh
2. Biogenic amines (NOR, seratonin, dopamine)
3. amino acids (glutamate)
4. neuropeptide (endorphines)
5. nitric oxide (gaseous)

Front 62

Describe synaptic transmission

Back 62

1. calcium voltage gates open and flow into synaptic terminals
2. calcium induces synaptic vesicles to fuse with presynaptic membrane and release neurotransmitters
3. postsynaptic neuron (effector)
4. neurotransmitter receptors --> ligand- gated channels
5. ligand-gated channels are many receptors; once neurotransmitter binds, channels open
6. inhibit reuptake of neurotransmitters (for neuron to repolarize quickly)

Front 63

Events of neuromuscular junction

Back 63

1. ACh is stored in synaptic vesciles
2. When impulse reaches terminal Ca diffuse into terminal and make vesicles fuse with membrane to release ACh by exocytosis
3. ACh bind with ACh receptors on sarcolemma
4. depolarization of sarcolemma

Front 64

What are the different kinds of membrane channels?

Back 64

1. ion
2. voltage-gated
3. ligand-gated

Front 65

What are ion channels?

Back 65

passive diffusion

Front 66

What are voltage-gated channels?

Back 66

ATP required

Front 67

What are ligand-gated?

Back 67

neurotransmitter activated

Front 68

What is ESP?

Back 68

1. bring neuron closer to firing
2. additive
3. excitatory postsynaptic potential

Front 69

What is IPSP?

Back 69

1. move neuron away from firing level
2. additive
3. inhibitory postsynaptic potential

Front 70

What are the types of summations?

Back 70

1. Temporal
2. Spatial

Front 71

What is temporal summation

Back 71

1. may bring neuron to threshold
2. occurs when repeated stimuli cause news EPSPs to develop before ESPS decay

Front 72

What is spatial summation?

Back 72

1. stimulated at several places at once
2. occurs when several closely placed terminals release neurotransmitters simulate

Front 73

What is EPSP-IPSP cancellation

Back 73

they can have cancelling effects on each other

Front 74

What kind of neural circuits are there?

Back 74

1. convergent
2. divergent
3. reverberating

Front 75

What is a convergent circuit?

Back 75

1. several converging to one
2. a lot of info to one neuron
3. ex: spine - receives converging info from sensory neurons

Front 76

What is divergent circuits?

Back 76

1. neuron in brain can synapse hundreds of inter-neurons in spine
2. one feeding out on several sending information to several body parts

Front 77

What is reverberating?

Back 77

1. positive feedback
2. feedback loop
3. feedback on initial stimulus
4. ex: breathing, memory