NERVOUS TISSUE Flashcards
(148 cards)
1
Q
what maintains the resting membrane potential
A
The inactivity of gated channels in the plasma membrane helps maintain resting membrane potential.
2
Q
How is the charge distributed across the plasma membrane during resting membrane potential?
A
The outside of the membrane is positively charged, while the inside is negatively charged.
3
Q
What triggers depolarization?
A
A stimulus that opens gated channels, allowing sodium ions (Na⁺) to enter the cell.
4
Q
What happens to the charge inside the plasma membrane during depolarization?
A
The inside of the plasma membrane becomes more positive due to the influx of sodium ions.
5
Q
How does the influx of sodium ions lead to an action potential?
A
The influx creates a “domino effect,” causing depolarization to spread and generate an action potential.
6
Q
What is an action potential?
A
It is the electrical impulse generated when depolarization reaches a peak in membrane potential.
7
Q
How is the original charge of the membrane restored?
A
Potassium (K⁺) exits through potassium channels, restoring the negative charge inside.
8
Q
What role do potassium channels play in repolarization?
A
They allow the exit of K⁺ ions, helping to reset the membrane potential to its resting state.
9
Q
anatomically the nervous system is divided into
A
central nervous system
peripheral nervous system
10
Q
Functionally, the nervous system is divided into
A
somatic nervous system
autonomic nervous system
11
Q
the one that innervates the voluntary movement or the voluntary reaction of the body
A
somatic nervous system
12
Q
the one that regulates in involuntary movement or reaction of the body
A
Autonomic Nervous System
13
Q
functional unit of the nervous system
A
neurons
13
Q
Nerve tissue consists of two (2) principal types of cells
A
neurons
neuroglial cells
13
Q
other terms of neuroglial cells
A
supporting cells
glia
glial cells
14
Q
these are non-conducting cells located close to the neurons
A
glia
glial cells
neuroglial cells
supporting cells
15
Q
The supporting cells usually support the neurons in various ways such as:
A
Aiding in the conduction of the nerve impulse
Protects the neurons
Maintains the nutrients or metabolites that is needed by the neurons
16
Q
state the three general categories of neurons
A
sensory neurons
motor neurons
interneurons
16
Q
the one that collects information and generates an action potential coming from the outside environment (from the external environment) to the CNS
A
sensory neurons
16
Q
this is known as the afferent neurons
A
sensory neurons
17
Q
these are known as the effector/efferent neurons
A
motor neurons
18
Q
the one that RECEIVES information from the CNS to the effector organs
A
motor neurons
19
Q
this is also known as “soma” or “perikaryon”
A
cell body
19
Q
99% of the neurons in our body are
A
interneurons
20
These are the neurons involved in the delivery of information from sensory neurons to the CNS. From the CNS to the motor neuron
interneurons
21
The ones that delivers the information or impulses from the cell body to the other neurons
axon
21
a single process which extends from the cell body
axon
22
also extends from the axon which usually branches into numerous branches
dendrites
23
this usually receives the information from other neurons
dendrites
24
represent ribosomes & rough endoplasmic reticulum inside a cell body
nissl bodies
25
the enlargement of the cell body where the axon originates
axon hillock
26
this also the location where the axon impulse or action potential is/was generated
axon hillock
27
the connections between the axon of another cell to the dendrite of the receiving cell
synapse
28
the one that covers the axon
myelin sheath
29
generates or produces the myelin that covers the axon
schwann cells
30
the gaps found between two schwann cells
node of ranvier
31
other term for interneurons
integrative neurons
32
These are characterized by numerous branching dendrites & axon
interneurons or integrative
33
this cell usually contains numerous sub-branching of dendrites
purkinje cell
34
pyramidal cells are usually found in
neuropil
35
sensory neurons are either
pseudounipolar or bipolar neurons
36
only consist of a one (1) axon, however, the 1 axon branches out into two axons that is directed into two directions
Pseudounipolar
37
this type of neuron has a process which delivers the information, while there is a single process that accepts the information from another cell
bipolar
38
receptors that receive stimuli from other neurons or the external environment.
dendrites
39
this is when dendrites branches into finer numbers of branches.
dendritic trees
40
these are the locations where the axons usually bind to
dendritic spines
40
Dendritic spines are small protrusions of the dendritic plasma membrane containing:
Actin filaments
Postsynaptic density
40
these are small protrusions of the dendritic plasma membrane
dendritic spines
40
this contains numerous gated channel that has the capability to bind with the neurotransmitters that is usually found at the end of the axons
postsynaptic density
41
Basically, these are the places the axons form synapses with the dendrites
dendritic spines
42
effector processes that transmit stimuli to other neurons or effector cells
axons
43
Microtubules are composed of tubulin heterodimers with two (2) distinct ends, name them:
plus (+) end
minus (-) end
43
These certain characteristic are unique and critical to the functional polarity of neurons
organization of microtubule
43
the portion of the axon immediately after the axon hillock and is where the actin potentials are first generated
Axon initial segment
43
this end is directed away
plus (+) end
44
microtubules elongate via tubulin polymerization and extend to periphery
plus (+) end
45
the end of the microtubule is AWAY from the origin of th microtubule
plus (+) end
46
this end is anchored to a microtubule-organizing center
minus (-) end
47
the portion where the microtubule originated
minus (-) end
48
Microtubules in axons are uniformly oriented with their plus (+) ends directed
distally
49
Microtubules in dendrites display _ , both plus (+) & minus (-) are directed distally away from the cell
mixed polar orientation
50
State the four (4) steps in action potentials:
1. Resting membrane potential
2. Depolarization
3. Generating of action potentials
4. Repolarization & Afterpotentia
50
specialized junctions between neurons that facilitate the transmission of impulses from one neuron to another neuron or effector cells.
Synapses
51
The synapse contains
presynaptic neuron
synaptic cleft
postsynaptic neuron
52
neuron that delivers the information
Presynaptic neuron
53
space between presynaptic neuron & postsynaptic neuron
synaptic cleft
53
neuron that accepts or receives the information from the presynaptic neuron
Postsynaptic neuron
53
State the morphological classification of Synapses
axodendritic
axosomatic
axoaxonic
54
Majority of synapse are ___
axodendritic
55
the axon synapses to the dendrite
axodendritic
56
the axon synapses with a cell body
axosomatic
57
axon synapses with an axon
axoaxonic
58
state the classifications of synapses based on mechanism of conduction
chemical synapse
electrical synapse
59
this mechanism of conduct is common in mammals & usually this is consists of neurotransmitters
chemical synapse
60
the chemical messengers in the nervous system
Neurotransmitters
61
In humans, the one similar to electrical synapse is not seen in the nervous system but it is found as the
gap junctions in the connective tissues
61
this mechanism of conduction is no common in mammals & is usually found in invertebrates
electrical synapse
61
what does the electrical synapse contains which open or closes to permit the entry & exit of ions
gap junction
62
The WHOLE length of the axon contain neurotransmitter. True or False
False.
The WHOLE length of the axon DOES NOT contain neurotransmitter
63
Boutons en passants has the capability to synapse with a dendrite. true or false
True
64
element found at the end of the axon (the axon terminal).
Presynaptic element
65
space between the presynapse and the postsynapse
Synaptic cleft
66
element which contains the postsynaptic density
Postsynaptic element
66
the portion of the postsynaptic membrane that contains receptors for the neurotransmitters that was ejected or released by the presynaptic element
Postsynaptic density
66
this opens the transmitter gated sodium channels at the postsynapse
Excitatory synapse
67
The release of neurotransmitter can cause either
excitation or inhibition
68
Excitatory synapse neurotransmitters which results to the opening of the sodium gated channels
Acetylcholine
Glutamine
Serotonin
69
open chloride (Cl⁻) ion channels in the postsynaptic membrane
Inhibitory synapse
70
Since chloride ions are negatively charged, their influx makes the inside of the postsynaptic neuron more
more negative (hyperpolarization).
71
How does hyperpolarization affect neuronal excitability?
This hyperpolarization makes it more difficult for the neuron to reach the threshold needed to generate an action potential, effectively reducing neuronal excitability.
72
Two key inhibitory neurotransmitters responsible for hyperpolarization are:
γ-aminobutyric acid (GABA)
Glycine
73
Neurotransmitters act on either
ionotropic receptors or metabotropic receptors
74
this contain integral transmembrane ion channels, also known as transmitter-gated channels or ligand-gated channels
Ionotropic receptors
75
Neurotransmitter binding to an ionotropic receptor causes
Gated channels to open, allowing the influx of certain ions.
76
Which ion typically enters the cell when ionotropic receptors are activated?
Sodium ions (Na⁺) enter the cell.
77
How do metabotropic receptors interact with intracellular signaling?
They interact with G-proteins, which play a key role in intracellular signaling.
guanine nucleotide-binding proteins (G proteins)
78
Does neurotransmitter binding to a metabotropic receptor directly open ion channels?
No.
It triggers a signaling mechanism instead.
79
What happens when a neurotransmitter binds to a G-protein?
Activates enzymes that synthesize second messengers, which help transmit the signal inside the cell.
79
Chemical messengers that transfer information from the presynaptic element to the effector organ.
Second Messengers
80
What happens when an action potential reaches the terminal bouton?
triggers the influx of calcium (Ca²⁺) through voltage-gated calcium channels.
81
How do neurotransmitter receptor gated-channels work?
When a neurotransmitter binds, the gated channel undergoes a conformational change, leading to ion influx or efflux.
81
How does calcium influx affect synaptic vesicles?
causes the movement of synaptic vesicles toward the presynaptic membrane, leading to neurotransmitter release into the synaptic cleft.
82
What detects and binds neurotransmitters after they are released?
postsynaptic density
82
What determines whether the influx of ions is positive or negative?
The type of ion that enters or exits the channel, depending on the neurotransmitter and receptor involved.
82
state the functions of neuroglial cells
- Physical support (protection) for neurons
- Insulation for nerve cell bodies and processes; that
- Facilitates rapid transmission of nerve impulses
- Repair of neuronal injury
- Regulation of the internal fluid environment of CNS
- Clearance of neurotransmitters from synaptic clefts
- Metabolic exchange between the vascular system and the neurons of the nervous system
83
what are the two types of neuroglial cells
Peripheral Neuroglia
Central Neuroglia
84
Peripheral Neuroglia is usually composed of
Schwann cells
Satellite cells
85
these surround the processes of nerve cells and isolate them from adjacent cells & extracellular matrix
schwann cells
86
the one that produce myelin sheath that surrounds the peripheral nerve
Myelinating Schwann Cells
87
does not produce myelin sheath but nevertheless covers the axons
Nonmyelinating Remark Schwann Cells
88
Nonmyelinating Remark Schwann Cells is usually found where
the end of the schwann cell in the neuromuscular junctions
89
neuroglia found at the Neuromuscular junction (NMJ)
Teloglia
90
the one that facilitates the repair of the schwann cells that was destroyed during nerve damage or neuron injury
Repair Schwann Cells
91
small cuboidal cells that surrounds the neuronal cell bodies of the ganglia
Satellite cells
92
both schwann cell & satellite have the same function; differentiate them
satellite cells acts/covers on ganglia
schwann covers nerves
93
a collection of nerve fibers and cell bodies outside the CNS
Ganglia
94
94
State the four (4) types of CENTRAL neuroglia:
astrocytes
oligodendrocytes
microglia
ependymal cells
95
96
97
98
morphologically heterogeneous cells that provide physical & metabolic support for neurons of the CNS
astrocyte
99
small cells that are active in the formation and maintenance of myelin in the CNS.
Oligodendrocytes
100
These are the analogues of the schwann cells in the PNS
Oligodendrocytes
101
inconspicuous cells with small, dark, elongated nuclei that possess phagocytic properties.
Microglia
102
These are the phagocytes inside the CNS
microglia
103
columnar cells that line the ventricles of the brain and the central canal of the spinal cord.
Ependymal cells
104
important function of the astrocytes is to
maintain the blood-brain barrier
104
Usually the ends of the astrocytes:
perivascular feet & perineural feet
105
the end processes or end terminals of the astrocytes process that binds to the blood vessels
Perivascular feet
106
state the two kinds of astrocytes
Protoplasmic astrocytes
Fibrous astrocytes
106
Astrocytes also maintain or regulate the potassium ion concentrations in the nervous system. True or False
True
107
The processes are smaller or shorter and is more common in the gray matter of the CNS
Protoplasmic astrocytes
108
more common in the white matter of the CNS and has fewer processes but LONGER compared protoplasmic astrocytes
Fibrous astrocytes
109
has same function w/ schwann cells
Produce and maintain the myelin sheath in the CNS
Oligodendrocytes
110
Form the epithelial-like lining of the ventricles of the brain and spinal canal
ependymal cells
111
state the types of ependymal cells
Tanycytes
Choroid plexus
112
special ependymal cells which do not contain cilia
Tanycytes
113
portion or lining of the ventricles & the spinal cord
Choroid plexus
114
choroid plexus contains
Modified ependymal cells
Certain capillaries
115
its primary function is the production of CSF
Choroid plexus
116
Sensory functions include:
I (1)
II (2)
VIII (8)
V (5)
VII (7)
IX (9)
X (10)
117
Somatic motor — delivers information which includes
IV (4)
VI (6)
XI (11)
XII (12)
V (5)
III (3)
VII (7)
IX (9)
X (10)
118
Parasympathetic includes
III (3)
VII (7)
IX (9)
X (10)
119
this serves as a metabolically active diffusion barrier since this is where blood vessels & capillaries travel
Perineurium
120
dense irregular connective tissue that surrounds the nerve fascicle
Epineurium
121
a layer in nerve tissue which is composed of loose connective tissue
Endoneurium
122
a special connective tissue that covers a bundle of nerve fibers
Perineurium
