Nerve Physiology Flashcards
1
Q
2 major regulatory systems in the body
A
Nervous system
Endocrine system
2
Q
Regulated relatively slow, long-lived responses
A
Endocrine system
3
Q
Regulated fast, short-term responses
A
Nervous system
4
Q
2 organs in the Central Nervous System
A
Brain
Spinal cord
5
Q
2 divisions of Peripheral Nervous System
A
Somatic Nervous System
Autonomic Nervous System
6
Q
What Somatic Nervous System controls
A
Skeletal muscle
7
Q
2 subdivisions of Autonomic Nervous System
A
Parasympathetic division
Sympathetic division
8
Q
What Autonomic Nervous System controls
A
Smooth muscle
Cardiac muscle
Glands
9
Q
4 effectors
A
Skeletal muscle
Smooth muscle
Cardiac muscle
Glands
10
Q
3 receptors
A
Special sensory receptors
=provide sensations of smell, taste, vision, balance, hearing
Somatic sensory receptors
=monitor skeletal muscles, joints, skin surface; provide position sense and touch, pressure, pain, or temperature sensations
Visceral sensory receptors
=monitor internal organs, including those of cardiovascular, respiratory, digestive, urinary, or reproductive systems
11
Q
Sensory receptor (eyes)
Sensory input
Integration (brain and spinal cord)
Motor output
Effector (muscle)
A
12
Q
____ signal in one neuron must be transformed into a ____ signal if it is to be passed on to another cell
A
Electrical
Chemical
13
Q
What types of cells are found in the nervous system?
A
Neurons: excitable cells
Neuroglia: supporting cells (glial cells)
14
Q
Most important cells for producing coordination
Communicate information using a combination of electrical and chemical signal
A
Neurons
15
Q
Membranes of most neurons are _____
A
Electrically excitable
16
Q
3 main parts of a neuron
A
Cell body
Dendrites
Axon
17
Q
8 neurotransmitters
A
Adrenaline
Noradrenaline
Dopamine
Serotonin
Gaba
Acetylcholine
Glutamate
Endorphins
18
Q
Fight or flight neurotransmitter
A
Adrenaline
Produced in stressful or exciting situations.
=increases heart rate and blood flow, leading to a physical boost and heightened awareness
19
Q
Concentration neurotransmitter
A
Noradrenaline
Affects attention and responding actions in the brain, and involved in fight or flight response.
=contracts blood vessels, increasing blood flow
20
Q
Pleasure neurotransmitter
A
Dopamine
Feeling of pleasure, and also addiction, movement, and motivation.
People repeat behaviors that lead to dopamine release.
21
Q
Mood neurotransmitter
A
Serotonin
Contributes to well-being and happiness, helps sleep cycle and digestive system regulation.
Affected by exercise and light exposure.
22
Q
Calming neurotransmitter
A
Gaba
Calms firing nerves in the CNS.
High levels improve focus; low levels cause anxiety.
Also contributes to motor control and vision
23
Q
Learning neurotransmitter
A
Acetylcholine
Involved in thought, learning, and memory.
Activates muscle action in the body.
Also associated with attention and awakening.
24
Q
Memory neurotransmitter
A
Glutamate
Most common brain neurotransmitter.
Involved in learning and memory, regulates development and creation of nerve contacts.
25
Euphoria neurotransmitter
Endorphins
Released during exercise, excitement and sex, producing well-being and euphoria, reducing pain.
Biologically active session shown.
26
Types of neurons
Anaxonic neuron
Bipolar neuron
Pseudounipolar neuron
Multipolar neuron
27
Neurons that have more than 2 processes, but alone cannot be distinguished from the dendrites
Anaxonic neuron
28
Neurons that have 2 processes separated by the cell body.
Bipolar neuron
29
Neurons that have a single elongate process with the cell body situated to 1 side.
Pseudounipolar neuron
30
Neurons that have more than 2 processes; there is a single axon and multiple dendrites
Multipolar neuron
31
3 types of multipolar cells
Motor neuron (spinal cord)
Pyramidal cell (hippocampus)
Purkinje cell (cerebellum)
32
Neural circuits I
a) Divergence
b) Convergence
33
Neural circuits II
c) Serial processing
d) Parallel processing
e) Reverberation
34
What do neurons do?
1. Sensory perception of stimuli
2. Integration
3. Motor output (muscles, glands)
35
Conduct signals from receptors to the CNS
Sensory (afferent) neurons
36
Neurons that conduct signals from the CNS to Effector such as muscles and glands
Motor (efferent) neurons
37
Interneurons (_______) are confined to the CNS
Association neurons
38
Why are neurons among the most thoroughly studied of all cell types?
1. Neurons transmit information electrically, which allow scientists to monitor the activity of individual neurons by using various instruments originally developed for the physical sciences.
2. Recordings of electrical activity in neurons have revealed that the properties of individual neurons from nearly all animals are similar.
3. Neurons process information in a highly sophisticated manner, but in doing so they rely on the surprisingly small number of physical and chemical processes, making it possible to formulate general principles about their function.
39
All of the neurons in an organism's body, along with supporting cells
Glial cells
40
9-10 times more common than neurons
How many in CNS
How many in PNS
Glial cells
4
2
41
Found in the parenchyma of brain and spinal cord
Neuroglial cells
42
Lining the internal cavities or ventricles
Ependymal cells
43
Surrounding neurons of the sensory and autonomic ganglia
Capsular or satellite cells
44
Forming sheaths for axons of peripheral nerves
Schwann cells
45
Ensheating the motor and sensory nerve terminals, and supporting the sensory epithelia
Several types of supporting cells
46
Glial cells include...
Neuroglial cells
Ependymal cells
Capsular or satellite cells
Schwann cells
Several types of supporting cells
47
Satellite cells and schwann cells are found in (PNS or CNS)?
PNS
48
Surround neuron cell bodies in ganglia; regulate O2 and CO2 nutrients, and neurotransmitter levels around neurons in ganglia
Satellite cells
49
Surround all axons in PNS; responsible for myelination of peripheral axons; participate in repair process after injury
Schwann cells
50
Ependymal cells, microglia, astrocytes, and oligodendrocytes are found in (PNS, CNS)
CNS
51
Myelinate CNS axons; provide structural framework
Oligodendrocytes
52
Maintain blood-brain barrier; provide structural support; regulate in, nutrient, and dissolved gas concentrations; absorb and recycle neurotransmitters; form scar tissue after injury
Astrocytes
53
Remove cell debris, wastes, and pathogens by phagocytosis
Microglia
54
Line ventricles (brain) and central canal (spinal cord) ; assist in producing, circulating, and monitoring of cerebrospinal fluid
Ependymal cells
55
Macrophages of the CNS
Microglia
56
Similar to Schwann cells; single cell can myelinate multiple nerve processes
Oligodendrocytes
57
Glial cells that provide nutritional and structural support to neurons. Maintain extracellular in balance and involved in repair and scaring after injury.
Astrocytes
58
Cuboidal cells with cilia and microvilli. Line ventricles of brain and central canal of spinal cord. Produce cerebrospinal fluid
Ependymal cells
59
What glial cells are in the CNS
Astrocytes = most abundant
Microglia = functions as cleanup
Ependymal cells = produce CSF
Oligodendrocytes = form myelin sheaths
60
Gray matter in PNS
Ganglia = Collection of neuron cell bodies in the PNS
61
White matter in the PNS
Nerves = Bundles of axons in the PNS
62
CNS gray matter organization
1. Neural cortex = gray matter in the surface of the brain
2. Centers = collection of neuron cell bodies in the CNS; each center has specific processing functions
3. Nuclei = collection of neuron cell bodies in the interior of the CNS
4. Higher centers = the most complex centers in the brain
63
White matter organization in the CNS
1. Tracts = bundles of CNS axons that share a common origin and destination.
2. Columns = several tracts that form an anatomically distinct mass
64
What glial cells are in the PNS
Satellite cells
Schwann cells (myelin sheaths)
65
Classification of glial cells
The neuroglial cells, found in the parenchyma of brain and spinal cord are broadly classified as:
Macroglia = of ectodermal (neural) origin, comprising astrocytes, oligodendrocytes, and glioblasts.
Microglia = of mesodermal origin
66
Microglia or Macroglia
Type of neuroglia which are specialized macrophages or immune cells in the CNS
Microglia
67
Microglia or Macroglia
Type of neuroglia which are neuronal supportive cells in the CNS and PNS
Macroglia
68
Microglia or Macroglia
Derived from embryonic mesoderm
Microglia
69
Microglia or Macroglia
Have a neuroectodermal embryonic origin
Macroglia
70
Microglia or Macroglia
Specialized macrophages
Microglia
71
Microglia or Macroglia
Oligodendrocytes, astrocytes, ependymal cells. Schwann cells and satellite cells.
Macroglia
72
Microglia or Macroglia
CNS
Microglia
73
Microglia or Macroglia
CNS and PNS
Macroglia
74
Microglia or Macroglia
Act as immune cells/macrophages and mediate immune responses in the CNS, clear cellular debris and dead neurons in the CNS
Microglia
75
Microglia or Macroglia
Synthesize myelin around the axons in the CNS and PNS, form blood-brain barrier, regulate brain metabolisms and homeostasis, secrete CSF, clear cellular debris in PNS, regrowth of neurons in the PNS and regulate the external chemical environment in the PNS
Macroglia
76
Star-shaped cells because of their numerous processes radiating all directions
Astrocytes
77
Astrocytes with thick and symmetrical processes are found in the Grey matter
Protoplasmic
78
Astrocytes with thin and asymmetrical processes are found in the white matter
Fibrous
79
These cells have fewer processes
Oligodendrocytes
80
According to their distribution, the oligodendrocytes may be:
1. Intrafascicular cells = found in the myelinate tracts
2. Perineuronal cells = seen on the surface of the somata of neurons
81
Myelination I
In the CNS, myelin is formed by the oligodendrocytes
1 oligodendrocyte can contribute to the myelin sheath of several axons
82
Myelination II
In the PNS, myelin is formed by the Schwann cells
Each Schwann cell associates with only 1 axon when forming a myelinated internode
83
Stem cells which can differentiate into macroglial cells
Are particularly numerous beneath the ependyma
Glioblast
84
Smallest of the glial cells which have a flattened cell body with a few short, fine processes.
Often related to capillaries, and are said to be phagocytic in nature.
Possibly derived from the circulating monocytes which migrate into the CNS during the late fetal and early postnatal life
Microglia
85
Functions of glial cells
1. Provide mechanical support to neurons.
2. Non-conducting nature: act as insulators between the neurons and prevent neuronal impulses from spreading in unwanted directions.
3. Remove the foreign material and cell debris by phagocytosis.
4. Repair the damaged areas of nervous tissue by proliferation (gliosis).
5. Can take up and store neurotransmitters released by the neighboring synapses.
6. Help in neuronal functions by maintaining a suitable metabolic and ionic environment for the neurons.
7. Oligodendrocytes myelinate tracts.
8. Ependymal cells are concerned with exchanges of materials between brain and CSF.
86
No difference in polarity, charge or concentration
Normal, unpolarized, equilibrium
87
Differences in charge (+ or -) across membrane
Membrane potential not 0 mV
Polarized
88
Membrane potential of the cell at rest
Resting membrane potential
89
Membrane potential becomes less negative than resting level
Depolarization
90
Membrane potential returning to resting level
Repolarization
91
Membrane potential more negative than resting potential
Hyperpolarization
92
Charges in membrane potential:
Upward deflection = decrease in potential
Downward deflection = increase in potential
93
Changes in membrane potential = caused by changes in ion movement across plasma membrane
Changes in ion movement = caused by changes in permeability the membrane
Changes in permeability = caused by a triggering event (stimulus)
94
2 types of channels
Leak channels (nongated channels)
- remain open
Gated channels
- opens and closes in response to some triggering events
95
Mechanically-gated channels open in response to ______
Pressure
96
2 basic electrical signals generated by the movement of ions accross the membrane
Graded potentials
Action potentials
97
Local changes in membrane potential that occur in varrying grades or degrees of magnitude or strength
Graded potentials
98
Amplitude directly related to level of stimulus but inversely related to distance
99
Unbalanced charges distribution across the plasma membrane are responsible for membrane potential
100
Decremental spread of graded potential
Adjacent portion of the initial active area
101
Term: gradually decreases form the initial site
Decremental
102
Types of graded potentials
1. Postsynaptic potentials
2. Receptor potentials
3. End-plate potentials
4. Pacemaker potentials
5. Slow-wave potentials
103
Summation of graded potentials
A. Subtreshold, no summation
B. Temporal summation
C. Spatial summation
D. Spatial summation of EPSP and IPSP
104
Which substances move in and out of the cell during depolarization and repolarization
Na+ goes in
K+ goes out
105
The interval of time during which a second action potential will not happen no matter how large the stimulus is
Absolute refractory period
106
a time in which the neuron can fire an action potential, but it needs a greater stimulus
Relative refractory period
107
Spread of AP across entire membrane in series of small steps
Continuous propagation
108
AP spreads from node-to-node, skipping internodal membrane
Salutatory propagation
109
Voltage-gated Na+ and K+ channels have how many gates
2 (at rest, 1 gate is open and when the membrane becomes depolarized enough the 2nd gate will open)
1 (this gate is much slower to respond to depolarization)
110
Explain how AP is a positive feedback
Triggering event >
1. Depolarization (decreased membrane potential).
2. Opening of some voltage-gated Na+ channels
3. Influx of Na+ which further decreases membrane potential
Back to 1
111
Synaptic transmission
1. Arrival of the AP to the synaptic knob
2. Entry of extracellular Ca2+ and exocytosis of ACh
3. Binding of ACh to the receptors and depolarization of postsynaptic membrane may bring initial segment to treshold
4. Removal of ACh by acetylcholinesterase (AChE) (propagation of AP)
112
In the transmitter opens a cation influx, resulting in depolarization, it is called
Excitatory Post Synaptic Potential
113
In the transmitter opens an anion influx, resulting in hyperpolarization, it is called
Inhibitory Post Synaptic Potential
114
Difference between temporal summation and spatial summation
A. Temporal summation = 1st stimulus + 2nd stimulus
B. Spatial summation = 2 simultaneous stimuli
115
Presynaptic inhibition vs. Presynaptic facilitation
Inhibition
Gaba released = inactivation of calcium channels
Facilitation
Serotonin released = activation of calcium channels
116
How botox works
Botox: Enters synapse and blocks release of acetylcholine. Muscle activity is dampened resulting in smooth skin
