Nervous System Flashcards
1
Q
What are the starting concentrations of cell ions?
A
More Na, Cl, Calcium out
More K+ inside the cell
2
Q
Which ion leaks more quickly?
A
Potassium leaks out more quickly
3
Q
Factors Responsible for Resting Membrane Potential?
A
- ) 80% due to K+ more permeable than Na+ for leak channels- greater exit of K+ than entrance of Na+
- )Electrogenic pump separation of Na+ & K+ ->counter leak channels
- )Intracellular anion concentration
4
Q
Nernst Equation
A
Em= 61 x log out/log in
5
Q
What equation takes into account differences in permeability of ions together?
A
Goldman equation
6
Q
What happens when electromagnetic potential equals 0?
A
Not capable of repolarization of the cell
7
Q
What is the resting membrane potential of a neuron?
A
-70 mV
8
Q
Where is threshold for Na+/K+ pumps?
A
-55 mV
9
Q
What happens with an increase in permeability to chloride?
A
Hyperpolarization (bc it is negative)
10
Q
What happens during the refractory period?
A
Prolonged outward diffusion of K+ (drives below resting membrane potential)
11
Q
What kind of potential is a post-synaptic potential?
A
Graded (EPSP, IPSP)
12
Q
Where must post-synaptic potentials get to to cause depolarization (first spot of threshold)?
A
Axon hillock
13
Q
Examples of graded potentials
A
Post-synaptic potential, receptors, end plate, pacemaker potential
14
Q
What do graded potentials not have?
A
Thresholds or refractory periods
15
Q
Does an action potential die out over the length of the membrane?
A
No
16
Q
Negative after potential
A
Potassium of K+ takes longer to reach maxiumum & drives membrane permeability below threshold
17
Q
Current Sync
A
Negativity on outside of cell from first action potential attracts positive charges from second cell to depolarize
18
Q
What happens to the action potentials when the amplitude of the stimulus received goes up?
A
Nothing, all or none response- no summation
19
Q
What happens to action potentials when the frequency of the stimulus recieved goes up?
A
More action potentials
20
Q
What effects increase graded potentials?
A
Temporal & spatial summation
21
Q
What happens to nerve cells when stimulus intensity increases?
A
Recruitment- more axons of a nerve become activated
22
Q
Saltatory conduction
A
Because of mylein sheaths from Schwann cells, action potentials are faster
Thicker diameter means less resistance to flwo
23
Q
What causes action potentials to not be able to travel backward?
A
refractory periods
24
Q
Absolute refractory period
A
Na+ & K+ channels are open and can’t open more
25
Extracellular recording of action potential
Shows negative potentials over electrodes- though opposite direction of curve
26
Compound action potential
Extracellular recording of all nerve cells in a grouping
27
Increasing stimulus strength of a compound action potential does what?
Recruit smaller diameter neurons in spatial summation
28
What happens when the electrodes are separated further in a extracellular potential?
Increase distance between humps
29
What happens when the nerve is crushed in the middle of two electrodes?
Monophasic hump
30
What is the effect of an anodal block?
(+) compound action potential decreases in size because of its blocking hyperpolarization of membrane
31
Afferent neuron
Conducts impulses from sensory receptors to CNS
32
Efferent neuron
Conducts impulses out of CNS to effector organs
33
Interneurons
Entirely in the CNS & associate with other nerves
34
Nerve
Bundle of axons outside the CNS
35
Glial Cells in PNS
Schwann cell/Neurilemma
Ganglionic gliocytes-support neuron bodies
Nodes of Ranvier
Unmyelinated axons
36
Glial cells in CNS
Oligiodendrocytes- form mylein sheaths
Microglia-phagocytose foreign & degenerate material
Astrocyte- regulates external environement of neurons
Takes up excess K+ outside neruon
Aid in formation of blood-brain barrier
Take up glucose from blood as lactic acid
Ependymal cells- epithelial cells lining ventricles of brain & central canal of spinal cord
37
Grey matter
CNS region with high concentration of cell bodies & dendrites
38
White matter
more myelinated axons
39
Neurons/cardiac muscle have what to connect stimuli
Gap junctions (made of 6 connexin molecules)
40
What is a Cell Adhesion Molecule (CAM)?
Keeps the presynaptic & post-synaptic membranes together
41
Where are voltage-gated channels
In axons )
42
Where are chemical-gated channels?
On post-synaptic membranes
43
Process of Neurotransmitter Secretion
1. ) Action potential causes voltage gated channels to let Ca2+ in
2. )Ca2+ through calmodulin activates protein kinase
3. )Protein kinase phosphorylates synapsin proteins
4. )Synapsin binds synaptic vesicles to cytoskeleton inside nerve terminal & be released
5. ) Neurotransmitter passes through & causes EPSP or IPSP
44
What causes EPSP
Calcium, sodium
45
What causes IPSP
chloride
46
What hormone do cholinergic receptors secrete?
Acetylcholine
47
When do cholinergic recpetors depolarize/hyperpolarize?
Excitatory in CNS
| Either in PNS
48
What are the two types of cholinergic receptors?
Nicotinic
| Muscarinic
49
Which receptor is a 5-subunit protein with 2 binding sites for ACh
Nicotinic
50
What happens when ACh binds to a nicotinic receptor?
Na+ goes down concentration gradient
Is attracted by negativity of outside
K+ rushes inside
Na+ wins & always causes hypo-polarization
51
Where are nicotinic receptors located?
All autonomic ganglia
All neuromuscluar junctions
Some CNS pathways
52
Which cholinergic receptor is a G-protein receptor?
Muscarinic
53
What happens when the B/gamma subunit binds to the K+ channel?
opens channel- hyperpolarization (slower heart rate)
54
What happens when the a subunit binds to the K+ channel?
Closes K+ channel, hypopolarize membrane
55
What stimulates muscarinic receptors?
Postganglionic parasympathetic neurons (smooth muscle, cardiac muscle, glands)
Excitatory(peristaltic movement) or inhibitory(slow heart rate)
56
What effect does di-isopropyl alcohol & NO have on cholinergic receptors
Interferes with acetylcholine esterase & prolong muscle contractions
57
What stops cholinergic reception?
Acetylcholine esterase
58
What is an agonist?
Bind & activate receptor proteins
59
Adrenergic Receptors
Secrete norepinephrine & epinephrine
| In both PNS & CNS
60
What are catecholeamines
Epinephrine, Norepinephrine, Dopamine
61
What is norepinephrine made from?
From monoamines: Tyrosine-->Dopamine-->norepinephrine
62
How is norepinephrine broken down?
by MAO in the neuron reuptaken
| Post-synaptic cell by COMT
63
Mechanism of Norepinephrine Action?
1. ) G protein turns on adenylate cyclase through use of a subunit B/gamma
2. )Adenylate cyclase turns ATP to cAMP
3. )cAMP turns on protein kinase which turns on many other proteins (glycogen phosphorylase)
64
Mechanism of norepinephrine action with a subunit binding?
1. ) G protein turns on phospholipase C by use of a subunit
2. ) Breaks PIP2 into DAG & IP3
3. ) IP3 increases permeability to Ca2+ into cell
4. )Another second messanger to calmodulin & activates protein kinase
65
What are the secretions of the medulla of the adrenal gland?
80% epinephrine
| 20% norepinephrine
66
What is serotonin a derivative of?
Tryptophan
67
What is the effect of serotonin?
Increased mood, behavior, appetite, cerebral circulatoin
68
LSD mimics what monamine neurotransmitter?
Serotonin
69
What blocks reputake of seorotonin?
Prozac
70
What does dopamine come from?
Tyrosine
71
What is the effect of dopamine?
Stimulates emotional rewards (alcohol, cocaine, morphine stimulate)
72
What amino acid neurotransmitters causes EPSPs?
Glutamate, aspartate
73
What amino acid neurotransmitters cause IPSPs?
Glycine, GABA
74
What effect does glycine have?
Increase permeability of chlorine -->hyperpolarization of K+
75
Glutamate Reception
1. )Glutamate binds to AMPA receptor-->increases Na+ permeability
2. )NMDA receptor has Mg inside-can't open until AMPA hypopolarizes membrane
3. )With NMDA receptor open, more permeable to Ca2+ & Na+
76
What effect does Ca2+ have on glutamate uptake?
Upregulates AMPA receptors to cause larger EPSP with more Na+ being inside
Activates calmodulin-dependent protein kinase II to aid in upregulation
77
What is the effect of NO on glutamate uptake?
Goes to pre--synaptic membrane to enhance more release of glutamate
78
What are pseudounipolar neurons used for in body?
Sensory neurons/afferent neurons - graded electro potentials
79
Where is the nerve cell body in pseudounipolar neurons?
Dorsal root ganglion
80
What are bipolar neurons used for in the body?
Sensory receptor or attached to a sensory receptor
81
What are multipolar neurons used for in the body?
All neurons in the CNS
82
Where is the nerve cell body of multipolar neurons?
Ventral horn of gray H of spinal cord
83
How many neurons make up the somatic nervous system?
1 neurons innervating skeletal muscle
84
Many neurons make up the autonomic nervous system?
2 neurons innervating heat, smooth muscle & glands
85
What kind of receptors are at neuromuscular junctions?
Cholinergic (ACh)
86
Ganglion
collection of nerve cell bodies in the PNS
87
What are the sympathetic neurons like?
```
Short chol (N)pre ggl
Long adren post ggl
```
88
What are parasympathetic neurons like?
Long
89
Where is the ganglion of the sympathetic nervous system?
Sympathetic chain ganglion
90
What kind of nervous outflow is the sympathetic system?
Thorico-lumbar
91
What kind of outflow is the parasympathetic nervous system?
Craniosacral
92
What are parasympathetic neurons like?
Long nicotinc, cholinergic pre ggl
Ganglion close to or inside effector organ
Short muscarinic chloinergic post ggl
93
Exceptions to dual innervation?
Blood vessels -sympathetic
Sweat glands-sympathetic
Salivary- parasympathetic- water, sympatetic-mucousy
94
Where is the cell body of afferent neurons?
Dorsal root ganglion
Meets with interneuron in dorsal horn
pseudounipolar neuron
95
Parts of the spinal cord
Central canal w/ ciliated cells & cerebrospinal fluid
Meninges-protect spinal cord
Pia mater- tight to nervous tissue
Dura mater- on inside of vertebral column
Arachnoid tissue- produces cerebrospinal fluid
96
What is different about autonomic v. somatic innervation?
Synapses en passant of autonomic
97
What is the difference in somatic & autonomic myelination?
Somatic- fast & highly myelinated
Autonomic- slower, lightly myelinated
Post ggl non-myelinated
98
What kind of reception is skeletal muscle innervation?
Cholinergic nicotinic
99
What kind of innervation is in the diaphragm
Phrenic nerve- somatic nerve to skeletal muscle- 1 voluntary, skeletal muscle
100
Atropine
parasympathomimetic antagoist
| Blocks Ach at muscarinic receptor so sympathetic predominates
101
Curari
Autonomic mimetic antagonis
| Blocks nicotinic receptors and all autonomic reception is blocked
102
A1 adrenergic receptors
Vasoconstriction, pupil dilation, sphincter contraction
| Stimulates phospholipase C & rise in cytoplasmic Ca2+
103
A2 adrenergic receptor
Presynaptic inhibitor - negatively feedsback norepi to a2 receptors on presynaptic membrane-->inhibits adenylate cyclase
104
B1 adrenergic receptor
Chronotropic & Inotropic effect
105
B2 adrenergic receptor
Dilation of lung bronchioles bc of smooth muscle relaxation
106
Alpha receptors respond mostly to?
Epinephrine
107
Which receptors respond more to isopreternol AND norepinephrine?
B2
108
What effect on pupils does sympathetic innervation have?
Dilation
109
What effect on pupils does parasympathetic innervation have?
Constriction
110
Lacrimal (tear) glands are innervated by?
Parasympathetic innervation?
111
Where is there in a sympathetic cholinergic receptor?
Muscarinic, sympathetic receptor in vascular smooth muscle within skeletal muscle
Causes smooth muscle contract & cause vasodilation
112
What is the effect of B2 adrenergic receptor in coronary arteries?
Coronary artery dilation
113
Do neurons remain mitotic?
No
114
Cerebrum
Higher mental functions
115
Central sulcus
Front- primary motor cortex, behind-primary sensory cortex
116
Parietal lobe
Somatastetic interpretation (touch, pressure, pain, heat), speech & words, texture, shape
117
Occipital lobe
Vision
118
Frontal lobe
Voluntary motor activity
119
Temporal lobe
Sound & visual interpretation
120
Brain stem
Pons & medulla
| Integration of all input, arousal, cardiovascular & respiratory
121
Cerebellum
Muscle tone, balance, posture, coordination & voluntary movement control
122
Hypothalamus
Only area without blood brain barrier- senses changes is osmotic pressure
123
Ventromedial hypothalamic nucelus
Sensation of fullness
124
Basal neucli
Substantial nigra, striatum, elucidum, subthalamus
| Important in dopamine reception
125
Transducer
Converts one form of energy into another
126
Propioreceptor
Recieves body position & movement
127
Tonic receptor
Never gains adaption to action potential (pain receptors)
128
Phasic receptor
After longer time periods of stimulation, receptor adaptatoin
129
Adaptation v. Habituation
Adaptation-PNS phenomenon (decrease receptor potentials)
| v. CNS phenomenon- alter synaptic effectiveness(less permeability to Ca2+)
130
Pacinian corpuscle
Deep pressure sensation
131
Meissner's corpuscle
dermal papilla- notices change in texture
132
Two point test
Only feel different sensation if field has two different afferent receptor fields
133
Lateral inhibition
CNS blocks lower stimulations laterally with blunt objects so only greater sensation gets through
134
Where must light go through on the eye?
Bend around cornea
| Bends through front & back of lens
135
Where does light focus in the eye?
Retina
136
What 4 things must occur for proper vision?
1.)Refraction of light rays to fovea centralis in retina
2.)Accomodation of lens
Relaxed-stretches out zonal ligaments (distant vision
Contracted- ligaments relaxed & lens focused close
3.)Constriction of pupil
Sympathetic dilation- radial muscle contract to dilate pupil
Parasympathetic constriction-circular muscles contract to constrict pupil
4.) Convergence of Eyes
137
Horizontal cells
Recieve input from rods & cones to pass information on to bipolar cells
138
Cones
Color reception
139
Rods
Visual acquity in dim light
140
3 auditory bones
Mallus, incus, stapes
141
Top & bottom chambers of cochlea
Scala vestibule, scala tympani
