Neurons Flashcards

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1
Q

Function of Nervous System

A

Taking in and interpreting sensory info, determining response and signalling appropriate effector to respond

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2
Q

What does a neuron do

A

Conducts impulses between pns and cns

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3
Q

What does a glial cell do

A

Non conducting
Nourish
Removes waste
Defends again infection

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4
Q

Dendrite

A

Branching nerve fiber
Received impulse from other neurons and relays it to soma

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5
Q

Soma

A

Has nucleus and site of metabolism

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6
Q

Axon

A

Nerve fiber projection that carry impluses away from soma

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7
Q

Myelin Sheath

A

Insulating coat around axon made of lipids (white fatty)

Speeds up impulse transmission

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8
Q

Nucleus of Schwann cell

A

Glial cell
Forms myelin
Protects and supports neuron

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9
Q

Nodes of ranvier

A

Spaces between Schwann cell along myelin sheath

Impulses jump node to node= High speed transmission

Saltatory conduction

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10
Q

Neurilemma

A

Membrane around myelin

In PNS ONLYYY

Allows regeneration of damaged axons by guiding broken ends together

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11
Q

Synaptic terminals

A

Specialized endings of branched axon

Release neurotransmitters (chemical) to relay signals between neurons l

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12
Q

Synapse

A

Area between neurons

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13
Q

Neuromuscular junction

A

Where neuron and muscle meet

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14
Q

Identify the 3 types of neurons and compare and contrast

A

Sensory- PNS, myelinated, detect environment changes, carry impulse to CNS, soma in center of neuron, long dendrites and axons

Interneurons- CNS, Not always myelinated, connect motor and sensory neurons, cell body at end, short dendrites w/ branches in axon

Motor- PNS, always myelinated, carry impulses from CNS to muscle, soma at DENDRITE end, short dendrite long axons

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15
Q

Reflex Arc

A

Involuntary

1 Sensory receptors detects stimuli
2 Sensory neuron tells CNS
3 Interneuron (Spinal Cord)
4 Motor neuron relays info to effector which responds

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16
Q

Migration of Neurons

A

Immature neurons must migrate to final position before forming circuits

Mature neurons are stationary but their axons and dendrites grow

17
Q

Development of Axons

A

Chemical stimulus causes axon to grow from immature neuron

18
Q

Nerve impulse and Cole and Curtis discovery

A

NI- Electrochemicla msgs due to ion movement

Cole and Curtis- Giant squid axon and found inside of axon was more negative then outside when unstimulated (resting potential- more Na outside and less K+ inside so outside more positive)

19
Q

Explain Action Potential and the voltage gated channels involved

A

Initial Concentration Gradient- More Na outside, more k+ inside

Resting potential- (-70mV) when unstimulated (membrane more permeable to K+ and leaky k+ channel allow more K+ to go out then Na to come in= + charge leaving makes inside negative)

Depolarization- Stimulus causes voltage gated Na channel to open. Bcz more Na outside then inside, Na rush into axon= Inside bcz + and keeps rising to 40mV

Repolarization- Na channels close once Na at equilibrium and K+ channel opens. More K+ inside then outside so K+ leave. Positive charge leaving= inside becomes negative

Hyperpolarization- K+ channel close slowly so K+ keep leaving so inside membrane potential becomes more negative then resting potential (-75)

Refractory Period- Na and K are at equilibrium now so to return to initial concentration gradient, sodium potassium pump uses ATP to pump 3Na out:2 K in

20
Q

Propagation of Action Potential

A

AP at one point on axon triggers AP on next axon (Domino effect)

Ion movement that causes depolarizion in one part of axon will cause it in the next

21
Q

Threshold in Action Potential

A

Minimum level of stimulus to cause response

22
Q

Presynaptic vs Postsynaptic Neuron and Synaptic Cleft (Synapse)

A

Pre- Where impulse comes from
Post- Received impulse

SC- Space between 2 neurons or neuromuscular junction

23
Q

Steps in Neurotransfer

A
  1. AP arrived at axon terminal
  2. Ca+ channels open and calcium enters (more Ca outside then inside)
  3. Increase in membrane potential causes proteins to release vesicles which release neurotransmitters via exocytosis
  4. NeuroTM diffuse across cleft and bind to ligand receptor on postsynaptic neuron
  5. Postsynaptic neuron changes permeability
  6. After NeuroTM transmits msg, it’s broken down by enzymes and reabsorbed into pre synaptic neuron (no longer in cleft)
24
Q

Types of NeuroTM

A

Excitatory- Allow Na into neuron (depolarization)
Inhibitory- Allow K out (hyper polarization)

25
Q

Integration

A

Summation of excitatory and inhibitory NeuroTM

When total integration>threshold=AP

26
Q

Development of Synapses in CNS and PNS

A

CNS- neuron synapses w another axon, dendrite or soma

PNS- Synapse w muscle or gland

Some form synapse with capillaries