The Nervous system Flashcards
(96 cards)
1
Q
What are the functions of the nervous system?
A
- Monitor for changes inside and outside the body; Sensory input
- Process and interperet sensory info and decide what to do; Integration of information
- Creates response by activating muscles or glands; Motor output
2
Q
Sensory imput
A
- Information gathered from the senses
- example; you smell smoke
3
Q
Integration
A
- CNS decides what to do and sends out a response
- example; Brain takes in sensory info (small smoke) processes it, brain decides to tell your muscles to get you up so you can look for the the source of the smell
4
Q
Motor output
A
- Signal travels through efferent pathway to effector organ
- example; muscles contract in response to message from the brain
5
Q
example of an effector
A
- Sweat glands
- Muscles
- Mucous cells
6
Q
Sensory input —> _______
A
- Afferent
7
Q
Motor output —-> ________
A
- Efferent
8
Q
PNS
A
- Peripheral nervous system
- spinal and cranial nerves
- Nerves comming out of CNS; communicate between CNS and the rest of the body
9
Q
CNS
A
- Central Nervous system
- Brain and spinal cord
- Responsible for integration
- Multipolar cells
10
Q
What are the major cells of the nervous system? what do they release?
A
- Neurons
- Chemicals called neurotransmitters
11
Q
Name the divisions of the PNS
A
- PNS
- Sensory division (afferent)
- Motor division (efferent)
- Somatic nervous system
- Autonomic nervous system:
Sympathetic division
Parasympathetic division
12
Q
What does the sensory division of the PNS do?
A
- Sends info/ Conducts impulses to CNS
13
Q
What does the motor division of the PNS do?
A
- Sends info/ conducts impulses from CNS to effectors (muscles/glands)
14
Q
What does the somatic nervous system of the motor division of the PNS do?
A
- controls voluntary movement
- conducts impulses from CNS to skeletal muscles
15
Q
What does the Autonomic nervous system of the motor division of the PNS do?
A
- Responsible for involuntary (visceral action)
- Conducts impulses from the CNS to cardiac muscles, smooth muscles and glands
16
Q
What does the sympathetic nervous system do?
A
- Fight or flight
- Mobilizes body systems during activity
17
Q
What does the parasympathetic nervous system do?
A
- Conserves energy
- Promotes house-keeping functions during rest (breathing, digestion, etc)
- Rest and digest
18
Q
2 types of cells in nervous tissue
A
- Neurons; nerve cells
- Neuroglia; support cells
19
Q
Neurons are highly _______ for special _______.
A
- Modified
- Functions
20
Q
When a message is comming down an axon; ______ are flowing.
A
- ions
21
Q
Definition of synapses
A
- Point of close contact between 2 neurons or a neuron and effector cell
22
Q
Definition of synaptic cleft
A
- Fluid filled space at a synapse
23
Q
Definition Pre-synaptic cell
A
- neuron conducting impulse towards a cell body
24
Q
Definition of Post-synaptic cell
A
- Neuron conducting impulses away from a cell body
25
What is an action potential?
* An **electrical impulse** generated and conducted by an axon upon **stimulation**
26
Action potential underline the basic functioning of the \_\_\_\_\_\_\_\_\_\_
* Nervous system
27
What is happening as an impulse travels through a neuron?
* Ions are moving in and out of the axon
28
How do action potentials work?
* Resting membrane potential is possible because concentration gradient is maintained by Na+/K+ pump
* At rest the membrane is **slightly permeable to Na+**
* **ACTION POTENTIALS HAPPEN WHEN A CHANGE IN RESTING MEMBRANE POTENTIAL RESULTS FROM A STIMULUS**
* **MEMBRANE SUDDENLY BECOMES MORE PERMEABLE TO Na+**
29
A change in membrane potential can result from....
* Alteration of ion concentrations on ether side of the membrane
* Anything that changes ion permeability of the membrane
30
A cell can change its ion permeability by opening and closing \_\_\_\_\_\_\_.
* Membrane channels
31
Within a membrane you have 4 major Ion (protein) channels
1. Na+
2. K+
3. Cl-
4. Ca2+
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during an AP Na+ moves ______ the axon.
* Into the axon
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During an AP K+ moves _____ of the axon.
* Out of the axon
34
During an AP Cl- moves ______ the axon.
* into the axon
35
During an AP Ca2+ moves _____ the axon.
* into the axon.
36
What insulates ions (keeps ions inside the axon)
* Myelin sheath
37
What is the trigger zone of an neuron?
* Axon Hillock
38
What is grey matter composed of?
* Cell bodies
39
what is white matter composed of?
* Mylenated axons
40
What is an action potential?
* An electrical impulse that travels down an axon
41
Why is potassium leaving the axon when it is repolarizing?
* To make the axon more negative.
42
How many states does a voltage gated K+ channel have and what are they?
* 2
* Opened
* Closed
43
How many states does a Na+ voltage-gated channel have? what are they?
* 3
* Opened
* Closed
* Inactivated
44
Sodium channels must close before another Action Potential can happen, true or false?
* True\*
* If a strong enough stimulus happens inactive channels can be overriden
45
Resting state; Stage one
* K+ and Na+ voltage gated channels are both **Closed**
* More Na+ outside
* More K+ inside
* Na+/K+ ATPase keeps concentrations of ions inside and outside
* membrane is polarized
46
Depolarization; stage 2
* Na+ channel opens, lets Na+ ions floodinto axon
* K+ channel closed
* Flood of Na+ ions causes the inside of the cell to become more positive (depolarization)
* Action potential starts at -55mV threshold in neuron and peaks at +30mV
47
Repolarization
* Na+ voltage gated channel becomes innactive blocking more Na+ from entering the axon
* K+ voltage gated channels open releasing K+ into the ECFcausing the cellto become more negative (repolarize)
* Membrane potentialstarts moving back toward -70 mV (but not there yet)
48
Hyperpolarization
* Na+ voltage gated channels become closed
* K+ voltage gated-channels stay open letting more K+ ions out
* This makes the inside of the cell overly polarized below -70 mV
49
return to resting state
* Na+ voltage gated channel is closed
* K+ voltage gated channel is closed
* K+, Na+ leak channels return the ionic concentrations back to normal
* Na+/K+ ATPase maintains the differences
50
Long axons are called \_\_\_\_\_\_\_\_\_.
* Nerve fibers
51
The conducting region of the neuron is the \_\_\_\_\_\_\_\_\_\_\_.
* Axon
52
The secretory region of the neuron is the \_\_\_\_\_\_\_\_\_\_\_\_\_\_.
* Terminal boutons; axon terminals
53
Fatty insulation that wraps around the axon is called the myelin sheath, what are its functions?
* Electrically insulates (keeps ions in the axon)
* Increases transmission speed
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Nodes of Ranvier
* Uninsulated gaps on axon
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A cell at rest is \_\_\_\_\_\_\_\_\_\_.
* Slightly permeable to Na+
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The permeabilities of Na+ and K+ across the membrane are \_\_\_\_\_\_\_\_\_\_\_\_.
* Different
58
Absolute refractory period
* time period needed for Na+ channels to "re-set" themselves before the nerve can resopnd to another stimulus
59
Threshold
* Critical level of depolarization needed to generate an AP ( -55 to -50 mV)
60
APs are all-or-nothing events what does this mean?
* The AP happens completely or not at all; if threshold is not met an AP will not happen
61
What pump restores the ionic gradient after the AP is over?
* Na+/K+ pump
62
Do APs depend on stimulus strength?
* No
63
How does the CNS determine how strong a stimulus is?
* Strong stimuli generate APs more frequently over a given period of time than weak stimuli
64
conduction velocity varies across neurons; what would be the standard range?
100 m/ sec or more
65
The rate of an impulse propagation depends on....
* Axon diameter
* Degree of mylination
66
Multiple Sclerosis
* A condition where myelin is being slowly destroyed in the CNS; slows the signals sent by neurons
67
What does MS effect?
* Vision
* Muscle control
* Speech
* Urinary Incontinence
* it is an Autoimmune disease
68
Can AP signals be interupted? What chemicals would interupt these signals if so?
* yes
* Local Anesthetics
* Neurotoxins
* TTX
69
Local Anesthetics
* drugs used to block Na+ gated channels, stops siganls (APs) from being sent ------\> No pain
70
Neurotoxins
* Toxin that effects neurons functioning
71
TTX
a toxin found in puffer fish that blocks Na+ channels neurotransmitters
72
What is the most common type of synapse?
* Chemical synapse
73
Chemical synapse
* Allow for release and reception of chemical neurotransmitters
74
What happens at a chemical synapse?
* An electrical signal gets turned into a chemical signal
75
How many Neurotransmitters have been identified?
* Over 50
76
What kind of effects do NTs have?
* Excititory and inhibitory effects
77
All neurons that stimulate skeletal muscles release \_\_\_\_\_\_\_\_.
* Acetylcholine (ACh)
78
Nicotinic receptors
* Are found at NMJ on SM
79
Muscarinic receptors
* Found on viseral effectors
80
Norepinephrine
* (NE) both a hormone and a NT caausng vasocontriction, increased heart rate, increased BP
* A feel good NT
81
Dopamine
* A feel good NT
* enhanced by L-dopa and amphetamines
* Reuptake blocked by cocaine
* decreased in parkinsons
* increased in schizophrenia
82
Seratonin
* Inhibitory
* Plays a role in sleep, appetite, nausea, migraine and regulating mood
83
What are the type of neural circuits?
1. Diverging circuit/ Amplifying circuit
2. Converging circuit/concentrating circuit
3. Reverberating circuit/ Oscillating circuit
4. Parallel after-discharge circuit
84
Synaptic delay
85
Graded Potential
* AP that ravels short distances
* a change in potential in the cell body
86
Re-uptake
* axon terminal takes NTs back
87
Selective Serotonin Re-uptake Inhibitors
* (SSRI) a class of drugs used as antidepresents
88
What happens to extra seratoinin or NTs?
1. Enzyme degrades it
2. Re-uptake
3. Diffuses away
89
Diverging/ Amplifying circuit
* One imputs many out puts
* ex. A single neuron in the brain can activate 100 or more motor neurons in the spinal cord and thousands of SM fibers
90
Converging/ Concentrating circuit
* Many outputs, one imput
* ex. different sensory stimuli can all elict the same memory
91
Reverberating/Oscillating circuit
* Controlls rythmic activity
* ex. Involved in breathing, sleep wake cycle, and repetitive motor activities such as walking
92
Parallel after- discharge circuit
* Impulses reach output cell at different times, causing a burst of impulses called after discharge
* ex. May be involved in exacting mental processes such as mathematical calculations
93
The brain has a reward center....
* its involved in feeling pleasure and reward
* reward system consists of dopamine- releasing neurons in specific areas of the brain
* ex. Romantically in love; your brain releases large amounts of norepinephrine and releases dopamine
* oxytocin is also released but its a hormone
94
drug abuse hijacks the \_\_\_\_\_\_\_\_\_.
* Reward center
95
crystal meth artificially stimulates the brain to stop synthesising its own NTs, true or false?
* True, this promotes a vicious cycle of addiction
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