Neurophysiology Flashcards
(119 cards)
1
Q
What is the structures and function of the Central nervous system (CNS) ?
A
- Brain and spinal cord
2. Integrative and control centers
2
Q
What is the structures and function of the Peripheral nervous system (PNS) ?
A
- Cranial nerves and spinal nerves
2. Communication lines between the CNS and the rest of the body
3
Q
What is the structures and function of the Sensory (Afferent) division of the PNS ?
A
- Somatic and visceral sensory nerve fibers
2. Conducts impulses from receptors to the CNS
4
Q
What is the structures and function of the Motor (Efferent) division of the PNS ?
A
- motor nerve fibers
2. Conducts impulses from the CNS to effectors (muscles and glands)
5
Q
What is the structures and function of the Somatic nervous system ?
A
- Somatic motor ( voluntary)
2. Conducts impulses from the CNS to skeletal muscles
6
Q
What is the structures and function of the Autonomic nervous system (ANS)?
A
- Viseral Motor ( Involuntary)
2. Conducts impulses from the CNS to cardiac muscles, smooth muscles, and glands
7
Q
What is the function of the Sympathetic division of Autonomic nervous system (ANS)?
A
Mobilizes body systems during activity ( fight of flight)
8
Q
What is the function of the Parasympathetic division of Autonomic nervous system (ANS)?
A
- Conserves energy
2. Promotes “housekeeping” functions during rest
9
Q
The CNS is composed of ___ and ___ matter.
A
White and gray
10
Q
The gray matter consist of ?
A
neuron bodies and dendrites
11
Q
The white matter consists of ?
A
axon tracts
12
Q
The adult brains weighs ____ kg, contains _______ neurons, and receives ___ % of blood flow.
A
1.5
100 Billion
20%
13
Q
Describe the polarity of neurons in the sensory afferent nervous system.
A
Pseudounipolar
14
Q
Describe the polarity of neurons in the sensory afferent nervous system
A
Multipolar
15
Q
The immediate subdivion of the nervous system is ?
A
CNS and PNS
16
Q
What is the functional unit of the nervous system?
A
neurons
17
Q
What is the function of dendrites?
A
Receive impulses and conduct them to the neuron cell body.
18
Q
What is the function of axon?
A
Conduct impulses away from the cell body to neuron ending
19
Q
Nerve fiber vs peripheral nerve. General structure.
A
Nerve fiber: One axon and its surrounding cells and Connective tissue
Peripheral Nerve: a bundle of nerve fibers ( axons) with binding connective tissue and blood supply ( vasa nervorum)
20
Q
CNS vs PNS. Groups of cell bodies are called ?
A
CNS: nuclei
PNS ganglia
21
Q
What is a Schwann cell and where is it located.
A
A PNS glial cell that myelinates PNS axons.
22
Q
What is the uninsulated gap between adjacent Schwann cells?
A
Node of Ranvier
23
Q
What are the Glial cells in the CNS?
A
Oligodendrocytes
Microglia
Astrocytes
Ependymal cells
24
Q
Each oligodendrocyte _____ ______ CNS axons
A
Myelinates several
25
What is the neural stem cell?
Ependymal
26
What cell is involved with NS maintenance?
Astrocytic glial cells
27
What is the most common glial cell?
Astrocytes
28
The 8 functions of astrocytes?
1. Buffering K+ levels
2. Recycling neurotransmitters
3. Regulating adult neurogenesis
4. Releasing transmitters that regulate neuronal activity
5. Allows only certain compounds to enter brain
6. formed capillary specializations in brain
7. Gaps between adjacent cells are closed by tight junctions
8. Role in angiogenesis
29
Describe sensory nervous system pathway from stimulus to spinal cord.
1. Sensory receptors receive stimulus
2. Information travels via Pseudounipolar sensory neuron towards CNS.
3. Information travels through spinal sensory ganglion, into posterior sensory root, and finally reaches Dorsal horn of the spinal cord.
30
Describe sensory nervous system pathway from spinal cord to stimulus.
1. Impulse starts at Ventral root.
2. passes anterior motor root
3. travels via somatic multipolar motor neuron to effector organ
31
Dorsal root vs Ventral root.
| Type of fibers?
Dorsal has sensory
| Ventral has motor
32
What is the function of Association/Interneurons?
integrate NS activity located entirely inside spinal cord
33
In the brain, the term ______ is used for small, locally projecting neurons in contrast to larger _______ neurons with long-distance connections.
interneuron
projection
34
The horns of the spinal cord are made of ____ matter.
Gray
35
How many spinal nerve pairs are there?
31
36
What is the three continuous sheets of connective tissue that covers the spinal cord and brain? ( General term )
Meninges
37
What are the three meninges from out to in?
Dura mater
Arachnoid
Pia matter
38
Which meninge contains the blood vessel?
Arachnoid
39
The region between the arachnoid and pia mater is filled with ?
Cerebrospinal fluid
40
Each spinal nerve has two nerve roots (except the first (motor only). What are they called?
* anterior or ventral root (motor)
| * posterior or dorsal (sensory)
41
Each spinal nerve has a Rami That split into ?
Ventral (ant) Ramus and Dorsal (pos) Ramus
42
The ventral ramus supplies where?
body wall and limbs
43
The Dorsal ramus supplies where?
synovial joints of vertebrae, deep back muscles and skin
44
How many synapses occur outside the CNS through somatic and sensory pathways ?
None
45
How many neurons is involved with a automatic system impulse?
2
46
Where is the synapse located for the autonomic system ?
Outside the CNS in an autonomic ganglion
47
What are the effector organs of the autonomic nervous system?
Conduction system of cardiac muscle
glands
Smooth muscle
48
Describe the presynaptic neuron in relation to the autonomic nervous system.
Its cell body is in gray matter of the CNS and it can only terminate upon a postsynaptic neuron
49
Describe the postsynaptic neuron in relation to the autonomic nervous system
Cell body is in the autonomic ganglion and terminates on effector
50
What are the ANS smooth muscle end organs?
Blood vessels
hollow organs and ducts
arrector pili muscles
intrinsic eye muscles.
51
What are the ANS gland end organs?
sweat glands
lacrimal glands
salivary
52
Ascending sensory tracts _____ ( cross) so that brain hemispheres receive info from opposite side of body.
Decussate
53
Descending motor spinal tracts are called ? What is the 2 major groups?
Pyramidal
Anterior and Lateral
54
Pyramidal vs Extrapyramidal spinal tracts. Describe their synapse frequency
- Pyramidal descend form cerebral cortex to spinal cord w/o synapsing
- Extrapyramidal descends with many synapses
55
Pyramidal tract is AKA?
Corticospinal tract
56
Extrapyramidal tract are AKA?
reticulospinal stract
57
Pyramidal tracts function in control of ?
fine movements
58
Extrapyramidal tracts influence?
movement indirectly
59
At rest, all cell membrane have a ______ internal charge and _____ distribution of ions
Negative
Unequal
60
At rest, all cell membrane have a negative internal charge and unequal distribution of ions which results from?
Large anions being trapped inside cell
61
Na+ / K+ pump and limited permability keep what ?
Na high outside ocell
62
K is very _____ and is high inside the cell due to attraction of ______ charges inside.
permeable
negative
63
Give the inside cell conc. , outside cell conc. , and relative permeability of K+. Conc in mM.
inside : 100
outside: 5
Relative perm: 1
64
Give the inside cell conc. , outside cell conc. , and relative permeability of Na+. Conc in mM.
inside: 10
Outside: 100
Relative perm: 0.01
65
Give the inside cell conc. , outside cell conc. , and relative permeability of Cl-. Conc in mM.
inside: 10
Outside: 105
relative perm: 0.2
66
Give the inside cell conc. , outside cell conc. , and relative permeability of Large anions. Conc in mM.
inside 100
outside 0
relative perm 0
67
Give the inside cell conc. , outside cell conc. , and relative permeability of Ca2+. Conc in mM.
inside 10 ^ -4
Outside 1
Relative perm: 0.01
68
What occurs when the membrane potential becomes more positive?
Depolarization
69
What occurs when the membrane potential becomes more negative than the resting membrane potential?
Hyperpolarization
70
What occurs when the membrane potential returns to the resting membrane potential?
Repolarization
71
Excitable cells can discharge their resting membrane potential quickly via ?
Rapid changes in permeability to ions.
72
MP changes occur by ion flow through what?
membrance channels.
73
When are K+ leakage channels open?
always
74
What opens Voltage-gated channels?
Depolarization
75
What is the average resting membrane potential in mV?
-70 ish
76
Voltage gated K+ channels are _____ in resting cells.
closed
77
Na channels are ____-____; closed in ____ ___
Voltage gated
resting cells
78
Explain the action potential process.
1. depolarization stimulus
2. voltage regulated Na+ gates open
3. Na diffisues into cells
4. more depolarization until 30+ mv
5. Voltage gated K+ gates open
6. K+ diffuses out of cell
7 . Less depolarization until repolarization
79
How does an increase stimulus intensity affect action potential?
Size of AP remains constant but more APs are fired
80
What are Chemical and electrical synapses?
It is a functional connection between a neuron ( presynaptic) and another cell (postsynaptic)
81
Synaptic transmission at chemical synapse is via ?
neurotransmitters
82
Electrical vs Chemical synapses. Which is more prevelant?
Chemical
83
Synaptic cleft separates _____ ____ of presynaptic from postsynaptic cell.
terminal bouton
84
Neurotransmitters are carried in ?
synaptic vesicles
85
The amount of neurotransmitter released is based upon?
the frequency of the action potentials
86
Explain the process of synaptic transmission.
1. APs travel down axon the depolarize bouton
2. Open VG Ca channels in bouton
3. Ca is driven in by electrochemical gradient
4. Ca enters axon terminal via VG channels
87
Explains the process of neurotransmitter release after the CA enters the axon terminal.
1. The Ca binds to sensor protein in cytoplasm
| 2. Ca-protein complex stimulates fusion and exocytosis of neurotransmitter from vesicles into synapses.
88
Explain what happens after a neurotransmitter is released into the cleft.
1. Neurotransmitter diffuses across cleft
2. Binds to receptor proteins on postsynaptic membrane which opens chemically-regulated ion channels
3. Depolarizing channels cause EPSPs (excitatory postsynaptic potentials) 4. Hyperpolarizing channels cause IPSPs (inhibitory postsynaptic potentials)
5. These affect VG channels in postsynaptic cell
89
Explain what happens after excitatory and Inhibitory postsynaptic potentials have occurred.
1. The potentials summate.
| 2. If the membrane potential in postsynaptic cell reaches threshold at axon hillock, a new AP is generated.
90
Describe the Axon hillock,
axon hillock has many VG channels and is site where APs are normally initiated
91
Permeability of voltage and ligand gated channels are regulated by ?
membrane potential or neurotransmitter binding.
92
What is Glutamate?
major excitatory NT, ~50% of all synapses interneurons and output (projection) neurons
93
What is Gaba?
(γ-aminobutiric acid): major inhibitory NT in the brain, ~33% of all synapses mostly interneurons, but some projection neurons (FYI: Purkinje cells, medium spiny cells of basal nuclei, etc.)
94
What are the four basic functional and anatomical classifications of CNS neurotransmitters ?
1. Excitatory and inhibitory amino acids.
2. Widely projecting neurotransmitter systems
3. Neuropeptides
4. Atypical nuerotransmitters
95
What are the five widely projecting neurotransmitter systems?
1. Monoamines
2. Catecholamines
3. Serotonin
4. Histamine
5. Acetylcholine
96
Name the three catecholamines.
Dopamine
Norepinephrine
epinephrine
97
Explain the process of a cholinergic synapse.
1. Acetylcholine (ACh) is made by choline and aceytly CoA ( from mitochondria)
2. The Ach is released via a synaptic vesicle and reacts to a cholinergic receptor on the postsynaptic cell
3. The ACh is broken down by the enzyme acetylcholinesterase in the cleft. This breakdown releases choline back into the cell to make more ACh
98
The nicotinic receptor is a ionotropic channel. What does that mean?
It is a ligand gated ion channel
99
How many subunit does a nicotinic receptor have ? Which subunit does ACh bind to?
5 and ACh binds to the extracellular domains of a subunits
100
A nicotinic receptor opens a ______ _______ ion channel.
central transmembrane
101
The nicotinic receptor changes in ______ potential or ______ conc. within cell.
membrane
ionic
102
Nicotinic receptor Nm (muscle type) vs Nn (ganglion type).
| Location.
Nm: skeletal muscle end plates
Nn: In autonomic ganglia of all type ( ganglion type) -- sympathetic, parasympathetic, and adrenal medulla
103
Nicotinic receptor Nm (muscle type) vs Nn (ganglion type). Function.
Nm: stimulate skeletal muscle ( contraction )
Nn: depolarization and postganglionic impulse -- stimulate all autonomic ganglia
104
Nicotinic receptor Nm (muscle type) vs Nn (ganglion type). Mech of Act.
Nm: Postsynaptic and excitatory ( increase Na and K permeability)
Nn: Excitatory -- Na, K , and Ca channel opening
105
Where is M1 muscarinic receptors located ?
Straitum
Cortex
Hippocampus
106
Where is M2 muscarinic receptors located ?
```
Forebrain
thalamus
heart
pupil
spinal cord
exocrine
```
107
Where is M4 muscarinic receptors located ?
Striatum
cortex
hippocampus
spinal cord
108
What is the function and other name of M1 muscarinic receptor subtype?
Aka nueral
| Function: affects arousal attention, REM, emotional response and affective disorder
109
What is the function and other name of M2 muscarinic receptor subtype?
Aka Cardiac muscarinic receptors
| Function: Cardiac inhibition
110
What is the function and other name of M3 muscarinic receptor subtype?
Aka Glandular muscarinic receptors
| Function: Lacrimal, salivary, and mostly stimulatory effect.
111
Where is M3 muscarinic receptors located ?
Exocrine glands and smooth muscle
112
Where is M5 muscarinic receptors located ?
Substantia Nigra (CNS)
113
What is the function of M4 muscarinic receptor subtype?
Direct regulatory action of K and Ca Ion channels
114
What is the function of M5 muscarinic receptor subtype?
May regulate dopamine release at terminal within the striatum.
115
Explain how muscarinic receptors work. (basic)
Inhibitory or stimulatory G protein inhibit or prevent cAMP formation which would produce effect
116
Explain the process of a somatic response from the CNS to effector organs.
Motorneuron release ACh which reacts with nicotinic receptor in skeletal muscle
117
Explain the process of a sympathetic response from the CNS to effector organs.
1. Signal is sent through preganglionic neuron that cause release of ACH which reacts with nicotinic receptors on postganlionic neuron.
2. A. Postgnaglionic neuron release norepinephrine thar reacts with A and B receptors in smooth muscle and glands
2. B. Postganglionic neuron releases ACH which reacts with muscarinic receptors in sweet glands
118
Explain the process of a parasympathetic response from the CNS to effector organs.
1. Signal is sent through preganglionic neuron to release ACh which reacts with nicotinic receptors in postganglionic neuron.
2. Postganglionic neuron releases ACh which reacts with muscarinic receptor in smooth muscle and glands
119
Explain the process of a adrenal medulla response from the CNS to effector organs.
1. Signal is sent through preganglionic neuron to release ACh which reacts with nicotinic receptors which release epinephrine and norepinephrine into the circulation.
