Ch. 12 Flashcards
(109 cards)
1
Q
Types of neuroglia aka glial cells (found in CNS):
Bank: Microglia, Ependymal cells, Oligodendrocytes, Schwann Cells, Astrocytes, Satellite Cells
Description:
- Star-shaped cells with many processes
- Metabolize NT’s, maintain [K+] balance for CNS neurons
- Help form the blood-brain barrier (BBB)
- Serve as link between neurons & blood vessels
Nutshell: Maintains environemnt for neurons, which involves balancing POTASSIUM
A
Astrocytes
2
Q
_______ = two or more graded potentials added together creates a greater change in membrane potential
A
Summation
3
Q
Types of Neurotransmitters associated with CNS & PNS:
Acetylcholine is the most ______ of the neurotransmitters. It exists in both the somatic and autonomic nervous systems. It’s also excitatory (i.e. moves muscles) and inhibitory (i.e. slows heart rate)
A
versatile
4
Q
Graded potential is
- Generated on _______ (axons/membrane of dendrites and cell body)
- Remains localized; _____ (short/long)-distance communication only
A
membrane of dendrites and cell body
short
5
Q
Quiz: Which items fit “Graded Potential” vs “Action Potential”
A
6
Q
____________ - small deviation from RMP caused by a certain stimulus
_______________ GP – inner membrane more negatively charged than normal RMP
_______________ GP – inner membrane less negatively charged than normal RMP
A
Graded Potential
Hyperpolarized
Depolarized
NOTE: Occurs due to the opening/closing of mechanically or chemically gated channels (not voltage gated)
When ions move thru these gated channels, the membrane either depolarizes OR hyperpolarizes (relative to RMP); depends on ion charge & flow direction
7
Q
Faulty neurotransmitters are treated in 2 ways:
1) With drugs that _____ a NT
2) Drugs that ______ a transmission
A
mimic
block
8
Q
Types of Neurotransmitters associated with CNS & PNS:
_____ Acids
• Excitatory CNS: Glutamate & Aspartate
• Inhibitory CNS: GABA (brain) & Glycine (spinal cord)
A
Amino
9
Q
Types of Ion Channels: Chemically-Gated, Voltage-Gated, Mechanically-Gated, Leak Channels
- Not gated
- Randomly Open/Close
- Membrane more permeable to K+ than Na+
- More K+ leak channels and are leakier than sodium
- Found in nearly all areas & types of neurons
A
Leak Channels
10
Q
Nervous system serves 3 basic functions that relate to maintenance of an internal balance called ___________
What are those 3?
A
homeostasis
- Sensing changes, both inside & outside the body (sensory function)
- Interpreting these changes (integrative function)
- Reacting to these changes by causing muscle contractions or glandular secretions (motor function)
11
Q
Neurotransmitters are _____ (slowly/quickly) removed from the synaptic cleft by:
- ______ out of (away from) the synaptic cleft
- Enzymatic degradation (e.g. acetylcholinesterase)
- Uptake into cells – ______ transported back into neurons (reuptake) or into neuroglia (uptake)
A
quickly
- Diffusion
- actively
12
Q
Branch of medical science that deals with nervous system is ___
A
neurology
13
Q
Types of Ion Channels: Chemically-Gated, Voltage-Gated, Mechanically-Gated, Leak Channels
- Gate opens in response to neurotransmitters, hormones, and some ions
- • Found in dendrites of some sensory (pain) neurons, interneurons, & motor neurons
A
Chemically-Gated
14
Q
What are nerve cells called?
A
Neurons
15
Q
Other factors that can modify of membrane potential:
- Increased excitability - reduce the threshold; easier to depolarize membrane
- Alkalosis (pH > 7.45) - lightheadedness, tingling, numbness spasms, etc.
- Caffeine & nicotine
- Decreased excitability – increases threshold; more difficult to depolarize
- Acidosis (pH < 7.35) - weakness, lethargy, coma
- Hypnotics, tranquilizers, anesthetics
A
just look at this a few times
16
Q
The PNS is divided into 3 “subdivisions”:
The _____ nervous system (SNS) is voluntary. It’s basically your muscles.
- Sensory (afferent) neurons conduct impulses from cutaneous & special sensory receptors to the CNS
- Motor (efferent) neurons send impulses from CNS to __________
A
Somatic
skeletal muscles
17
Q
Saltatory Conduction:
• Myelin sheath = electrical insulator; blocks membrane depolarization
• Nodes of Ranvier = contains many voltagegated channels (e.g. Na+)
• Membrane depolarizes/repolarizes very _______ (slowly/quickly) at nodes
• Stops at myelin sheath
• Nerve impulse “leaps” from node to node; travels very FAST
• Also uses ______ (less/more) ATP, since only small portions of the membrane gets depolarized
A
Quickly
less
18
Q
The word _____ means = the capability to change based on experience.
Repeat to yourself: Learning new things means making new connections! Expending the dendrites to connect to other neurons (and using your neurons!). i.e, repitition is the best way to learn).
A
Plasticity
Repeat to yourself: Learning new things means making new connections! Expending the dendrites to connect to other neurons (and using your neurons!). i.e, repitition is the best way to learn).
19
Q
In the CNS, there is no connective tissue between nerve fiber bundles; therefore, bundle of nerve fibers (axons) are called a _____ instead of a nerve.
A
tract
20
Q
Two basic types of synapses:
- Electrical synapse - found in smooth muscle, cardiac muscle, CNS (between neurons)
- _____ (one-way/two-way) communication between cells:
- • Ionic current spreads directly from cell to cell thru ____ junctions
- • Electrical synapses are ____(faster/slower) than chemical synapses
- • Quickly coordinates (synchronizes) activity of a group of
- neurons or muscle fibers (e.g. in heart, bladder, etc.)
A
two-way
gap junctions
faster
21
Q
Myelination ________(decreases/increases) from birth to maturity (e.g. better coordination with time)
A
increases
22
Q
Excitatory & Inhibitory Postsynaptic Potential:
Excitatory NT - __________ (hyperolarizes/depolarizes) the postsynaptic neuron membrane
- Inner membrane less negative; Cations IN or anions OUT
- Generates _______ (excitatory/inhibitory) postsynaptic potential (EPSP) – closer to threshold potential
- A single EPSP is not enough to start a nerve impulse. However, it is more excitable (closer to its threshold). The next EPSP may be enough to start a nerve impulse (summation).
A
depolarizes
excitatory
23
Q
A bundle of nerve fibers in the PNS is called a nerve.
A bunde in the CNS is called a tract because it doesn’t have __________ surrounding it
A
nerve
connective tissue
24
Q
Which cell produces the lipids and mylinates the axon?
A
Schwann cell
25
Node of __________ = Gaps in the myelin sheath; neurofibral nodes
Ranvier
26
Types of neurons based on transmission:
**Bank:** Presynaptic neuron, Postsynaptic neuron
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ - Sends the signal toward synapse
\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_- Receives the signal and carries message away from synapse
Prestsynaptic neuron
Postsynaptic neuron
27
2. Chemical synapse (“slower”) - e.g. neuromuscular junction
\_\_\_\_\_\_\_\_ (two-way/one-way) transfer of information (presynaptic to postsynaptic neuron or effector)
\_\_\_\_\_\_\_\_\_\_\_ neuron has end bulbs to release neurotransmitter
\_\_\_\_\_\_\_\_\_\_\_ neuron has receptor to recognize neurotransmitter
\_\_\_\_\_\_\_\_\_\_\_\_ - gap between pre-postsynaptic neurons
**Bank:** Postsynaptic, Presynaptic, Synaptic cleft
one-way
Presynaptic
Postsynaptic
Synaptic cleft
28
\_\_\_\_\_\_\_\_\_\_\_ (association neurons)
Connects sensory & motor neurons inside CNS
Most are multipolar
Interneurons
29
Review this "nuclei in the brain" image several times to get familiar with it
30
**_Regeneration of Nervous Tissue:_**
In CNS, injury ____ (can/can't) be repaired. Learning DOES frequently stimulate production of NEW neurons in the hippocampus of the brain; but no repair of injured neurons.
**Example:** A spinal cord injury makes you paralyzed for good!
can't
31
Durring the after-Hyperpolarizing Phase, the voltage-gated K+ channels close and RMP (resting memberate potential) returns to -70 mV with help of Na+/K+ pump.
^this pump is slowly letting _#_ sodium **out**, and _#_ potassium **in** until it polarizes down to -70 mV
3 sodium **out**, 2 potassium **in**
32
This is a ______ neuron.
It has _#_ axon and _many_ dendrites.
It comes in the form of both Motor Neurons & \_\_\_\_neurons. Located in PNS & CNS
Multipolar
1
Inter-neurons
33
What autoimmune disease where our body destroys our own mylin sheath in the CNS.
Caused nerve impulses to short-circut.
Multiple Sclerosis (MS)
34
**_Types of neuroglia aka glial cells (found in CNS):_**
**Bank:** Microglia, Ependymal cells, Oligodendrocytes, Schwann Cells, Astrocytes, Satellite Cells
_Description:_
* Looks like small astrocytes
* Form a network around axons in CNS,
* Produce the lipoprotein myelin for support
Oligodendrocytes
35
What is Myelination?
The process of forming a myelin sheath around a nerve to allow nerve impulses to move more quickly.
36
Parts of a neuron:
What is this?
Nerve fiber that conduct impulses away from cell body to another neuron OR to an effector (e.g. muscle or gland) Long, thin, cylindrical projection that may be short (mm CNS) or long (meter PNS); Has synaptic end bulbs located at terminal end; Can be myelinated.
Axon
37
\_\_\_\_\_\_\_\_ - functional junction between neurons OR between a neuron & an effector (muscle or gland)
Synapse
NOTE: This is when the signal finally gets down the axon
38
**_Types of neuroglia aka glial cells (found in CNS):_**
**Bank:** Microglia, Ependymal cells, Oligodendrocytes, Schwann Cells, Astrocytes, Satellite Cells
_Description:_
* Phagocytic; Clean-up & protective
Microglia
39
Two types of neuroglial cells that myelinate neuronal axons:
\_\_\_\_\_ is in the CNS.
* Forms myelin sheath on more than one axon;
* Non-regenerative
* Myelinated (\_\_\_\_\_ matter) vs. Unmyelinated (\_\_\_\_ matter)
Oligodendrocyte
white, grey
40
This is a ______ neuron.
It has _#_ axon and _#_ dendrites.
These are rare ________ (specialized / generalized) sensory neurons. (e.g. olfaction, seeing, & hearing)
Bipolar
1 axon, 1 (main) dendrite
specialized
41
The endoneurium covers the \_\_\_\_\_\_
axons
42
Excitatory & Inhibitory Postsynaptic Potential:
Inhibitory NT - ___________ (hyperolarizes/depolarizes) the postsynaptic neuron membrane
* Inner membrane more negative; Anions IN or cations OUT
* **Generates ______ (excitatory/inhibitory) postsynaptic potential (IPSP) – _further_ from threshold potential**
hyperolarizes
inhibitory
43
review this overview of how signals transfer through a synapse
44
The PNS is divided into 3 "subdivisions":
Autonomic nervous system (ANS) – _______ (voluntary/involuntary)
* _____ (afferent) neurons conduct impulses to CNS
* Motor (efferent) neurons send impulses from CNS to _____ muscle, ______ muscle, and glands
The ANS is made up of two opposing functional branches. The ___ which is Fight or Flight; and the _____ which is Rest & Digest
involuntary
Sensory
smooth, cardiac
Sympathetic & Parasympathetic
45
Mixed nerves contain both ______ & ______ fibers
So, a mixed nerve can take a nerve to the \_\_\_\_, and then bring it back out
sensory, motor
CNS
46
This is a ______ neuron.
It has an axon/dendrite fused process from cell body
These are ________ (specialized / generalized) sensory neurons in PNS. (e.g. touch, pressure, pain, temperature)
Unipolar
generalized
47
Does stimulus cause polarization or depolarization?
Depolarization
A larger stimulous = greater depolarization = larger excitation
48
Mylin is made of _____ + _____ (lipoprotein)
What is does:
* Electrically insulates the axon
* Increases conduction rate of nerve impulses
Lipid + protein
49
Conduction (Propagation) of AP’s (AP (nerve impulse) arises at trigger zone and travels down axon to axon terminal.)
**Which happens on a mylinated axon, and therefore faster?**
* continuous conduction
* saltatory conduction
• saltatory conduction
50
Note: Graded Potential can go through summation.
What is summation?
Summation, in physiology, the additive effect of several _________ impulses on a neuromuscular junction, the junction between a nerve cell and a muscle cell. Individually the stimuli cannot evoke a response, but collectively they can generate a response.
electrical
Note: makes sense because graded potentials are smaller.
51
Actioin Potential - a sequence of rapidly occurring events that depolarize the membrane followed by repolarization
```
Action Potential (unlike graded potential)
• Generated on the membrane of ____ where voltage-gated channels are located
• Good for short & long-distance communication
```
axons
52
Types of synapses based on transmission:
\_\_\_\_\_\_\_\_\_\_\_ - Synapse between axon & dendrite
\_\_\_\_\_\_\_\_\_\_\_ - Synapse between axon & cell body
\_\_\_\_\_\_\_\_\_\_\_ - Synapse between two axons
**Bank:** axoaxonic, axodendritic, axosomatic
axodendritic
axosomatic
axoaxonic
53
\_\_\_\_\_\_\_\_\_ (afferent) neurons
Conduct impulses _from_ receptors _into_ the CNS via
\_\_\_\_\_\_\_ or ______ nerves
Most are unipolar.
Sensory
cranial or spinal
54
Types of Neurotransmitters associated with CNS & PNS:
\_\_\_\_\_\_ amines:
Big impact on sleep/wake patterns, feelings, moods, emotions
• NERPI (noradrenalin) & EPI (Adrenalin are also hormones)
These fuck with neurotransmitters like Norepinephrine, Epinephrine, Dopamine, and Serotonin
Imbalance linked to depression & bipolar disorder.
Biogenic amines
55
how many cranial nerves do we have?
12
56
Parts of a neuron:
Cell Body:
\_\_\_\_\_: contains cytoplasm, nucleus, & various organelles
Nissl bodies: “rg ER” produces _____ for growth/repair
Hillock: where soma connects to \_\_\_\_; where AP is generated
## Footnote
Soma
protiens
axon
57
Ion Channels
• Ions move across PM with its concentration gradient (H to L)
• Positive cations move toward negative anions and vice versa
• When ions move they generate ______ current that changes membrane potential
• Ions use channel proteins to move across PM
electrical
58
Each post-synaptic neuron receives input from _____ (many/one) presynaptic neurons.
many
59
Two body systems that help control and integrate all body activities:
Nervous & Endocrine
60
Two types of neuroglial cells that myelinate neuronal axons:
\_\_\_\_\_\_ is in the PNS.
* Forms myelin sheath up to 100 layers on an axon;
* Aids in repair (regenerates axon)
* Myelinated vs unmyelinated axon
* Neurolemma – outer nucleated cytoplasmic layer
Schwann cell
61
Neurotransmitters Definition:
A chemical substance that is released at the end of a nerve fiber by the arrival of a _____ \_\_\_\_\_\_ and, by diffusing across the synapse (chemical) or junction (electrical), causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.
nerve impulse
62
see image.
63
Resting Membrane Potential (RMP):
Membrane of a non-conducting (resting, non-stimulated) neuron normally is _________ charged on the outside and _________ charged on the inside.
RMP = -70 mV (milliVolts) ; Membrane is considered \_\_\_\_\_\_\_\_\_\_.
positively, negativity
polarized
**NOTE:** Being polarized means that the electrical charge on the outside of the membrane is positive while the electrical charge on the inside of the membrane is negative. The outside of the cell contains excess sodium ions (Na+); the inside of the cell contains excess potassium ions (K+).
64
The epineurium covers \_\_\_\_\_\_\_
the entire nerve
65
Factors that can modify the effects (synaptic transmission) of neurotransmitters:
1. Synthesis – stimulated or inhibited
* Parkinson’s – _______ (decreased/increased) synthesis of dopamine
2. Release – enhanced or blocked
* Amphetamines enhance release of dopamine & norepinephrine
* Botulism toxin blocks release of Ach at NMJ causing paralysis (the problem with ____ injections because you need the right strain of the boutulism toxin)
3. Receptor sites – activated or blocked
* Curare (is poison) blocks Ach receptors at NMJ causing muscle paralysis
4. Removal from cleft – stimulated or inhibited
* Cocaine inhibits dopamine ______ – euphoria due to excessive stimulation of brain
1. decreased
2. Botox
4. reuptake
66
Alzheimer’s is linked to what neurotranmitter?
ACh (Acetylcholine)
67
Which ion channel generates the action potential for the Axon?
Voltage-Gated
68
The CNS has an integrative function. It ______ sensory information & _______ a response
Interprets, generates
69
Some Presynaptic signals are excitatory (EPSPs)
Some Presynaptic signals are inhibitory (IPSPs)
But it's the sum of all messages tells the postsynaptic neuron what to do.
* If EPSPs \> IPSPs, the postsynaptic neuron will ________ (depolarize/hyperpolarize)
* If IPSPs \> EPSPs, the postsynaptic neuron will _________ depolarize/hyperpolarize)
depolarize
hyperpolarize
70
Propagation Speed related to:
1. Larger the diameter of nerve fiber, ______ (slower/faster) the impulse travels
2. Myelinated fibers conduct impulses _____ (slower/faster) than unmyelinated fibers
3. _____ (warm/cooled) nerve fibers conduct impulses faster than _____ (warm/cooled) fibers
Stimulus Intensity due to ______ (frequency/size) of AP generated at trigger zone.
## Footnote
1) faster
2) faster
3) warm
Frequency
71
**Types of Ion Channels:** Chemically-Gated, Voltage-Gated, Mechanically-Gated, Leak Channels
* Gate opens in response to vibration, touch, stretch, & pressure
* Found in auditory receptors (ear); touch & pressure receptors (skin)
Mechanically-Gated
72
Two or more graded potentials added together creates a greater change in depolarization & membrane potential is called?
Summination
i.e. - stimuluses can overlap. Like, one might not be finished when the next one starts
73
CONCEPTS:
Graded potential is:
* Generated on membrane of _____ and cell body (not typically axons)
* Remains localized; does NOT travel far; \_\_\_\_\_(short/long)-distance communication only
* Note: it doesn't travel down the axon because it's not big enough
dendrites
short
74
Epilepsy is when your ___ are abnormal
neuronal circuits
75
**_Types of neuroglia aka glial cells (found in CNS):_**
**Bank:** Microglia, Ependymal cells, Oligodendrocytes, Schwann Cells, Astrocytes, Satellite Cells
_Description:_
* **\*PRODUCE CEREBRAL SPINAL FLUID\***
* Simple cuboidal/columnar epithelial cells;
* May be ciliated
* Line brain ventricles & central canal of spinal cord;
* Produce CSF
Ependymal cells
76
The PNS is divided into 3 "subdivisions":
Enteric Nervous System = closely related to ANS; ______ (voluntary/involuntary)
Here, the smooth muscle & glands service the _________ via enteric plexuses
In lamens terms, it helps us _____ food.
Involuntary
gastrointestinal tract
digest
77
What type of neuron is the sensory neuron?
Unipolar
78
What are the 2 "subdivisions" or body parts contained in the CNS?
Brain & Spinal Cord
79
Parts of a neuron:
What is this?
Nerve fiber that receives input and conducts it toward cell body; Non-myelinated, short, highly branched processes
dendrite
80
Structural Organization of the Nervous System (2 parts):
Central Nervous System (CNS) is contains the ________ & \_\_\_\_\_\_\_\_\_\_
Peripheral Nervous System (PNS) contains the cranial & spinal \_\_\_\_\_\_, \_\_\_\_\_\_\_, & sensory receptors
brain, spinal cord
nerves, ganglia
81
Review Slides 40-45 for: Steps Generating an Action Potential
82
**Types of Ion Channels:** Chemically-Gated, Voltage-Gated, Mechanically-Gated, Leak Channels
* Gate opens in response to change in membrane potential
* Found in axon of all types of neurons
* Gives nerve & muscle cells excitability via action potential
Voltage gated channels
83
* _______ – Clusters of neuronal cell bodies in PNS
* _______ – Clusters of neuronal cell bodies in CNS
Ganglia
Nuclei
84
NEUROGLIA (AKA _____ cells)
* “Support” cells for the neuron
* Smaller & more numerous than neurons
* Capable of division
* Not electrically excitable
glial
85
Guillain-Barre Syndrome – Immune system response to bacterial infection causing macrophages to _______ axons (PNS) resulting in acute paralysis; Most patients have complete recovery.
Macrophage Definition: a large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.
de-myelinate
86
Durring the after-Hyperpolarizing Phase, the Potassium (K+) channels remain open actually a little too long, until the membrane potential becomes more negative than RMP (resting memberane potential).
It brings the cell's polarization down to ##. From there, the sodium/potassium pump kicks in.
-90 mV
87
how many spinal nerves do we have?
31
88
All-or None Principle:
Action Potential requires a threshold
stimulus of about -\_\_\_\_mV before
depolarization of the membrane occurs.
-55
NOTE: it's all or nothing - it eaither reaches threashold and fires, or it doen't.
89
**_Types of neuroglia aka glial cells (found in PNS):_**
**Bank:** Microglia, Ependymal cells, Oligodendrocytes, Schwann Cells, Astrocytes, Satellite Cells
_Description:_
* AKA Neurolemmocytes
* Flat cells wrapped around axons in PNS
* Produce part of the myelin sheath around one axon
Schwann Cells
90
\_\_\_\_\_\_\_ Refractory Period - time when another impulse cannot be generated (during depolarization and repolarization phase)
In general, frequency of nerve impulses range between _##_ and _####_ per second. So, this period doesn't last long.
Absolute
10, 1000
91
Which type of Neuronal Circuit is which?
**Bank:**
- Converging
- Reverberating
- Diverging
- "Parallel After Discharge"
- Diverging
- Converging
- Reverberating
- "Parallel After Discharge"
92
Parkinson’s & schizophrenia are linked to what neurotransmitter?
Dopamine
93
What houses the neurotransmitter, and releases the neurotransmissions?
Synaptic end bulbs
94
**_Types of neuroglia aka glial cells (found in PNS):_**
**Bank:** Microglia, Ependymal cells, Oligodendrocytes, Schwann Cells, Astrocytes, Satellite Cells
_Description:_
* Flat cells around the cell bodies of neurons
* Regulates exchange of materials in/out of neuronal
* cell body (in ganglia of PNS)
Satellite Cells
95
\_\_\_\_\_\_\_\_\_ (efferent) neurons
Conduct impulses _away_ from CNS to effectors
(muscles or glands) via cranial or spinal nerves;
Always \_\_\_\_polar.
Motor
multi-polar
96
Stimulus intensity (i.e. strength) affects the _______ of Action Potentials
frequency
97
The nervous system is ____ (fast/slow) to respond but it's effects are _____ (short-term/long-term)
The encocrine system is ____ (the same^ / opposite^)
The ____ system can overide the ____ system whenever nessisary.
fast, short-term
opposite
nervous, endocrine
98
\_\_\_\_\_\_\_ connect all regions of body to brain and spinal cord
They don't undergo _____ divisions, so in other words, they can't reproduce. We're born with them and they last like 100 years.
Neurons
mitotic
99
Just review this image a few times
100
The 3 types of nerves are motor, \_\_\_\_, and \_\_\_\_\_.
sensory, mixed
101
The Perineurium covers \_\_\_\_\_
A bundle of axons called a fascicle
102
Name that neuron!
103
Depression, Bipolar, and Seasonal Affective Disorder (SAD) are linked to the neurotransmitters - Serotonin, Norepi, and Dopamine.
Why do meds like Prozac, Paxil, and Zoloft help?
They inhibit serotonin reuptake. this prolongs activity of
serotonin at synapses in brain!
104
**_Regeneration of Nervous Tissue:_**
In ___ (CNS/PNS), myelinated axons & dendrites can be repaired, IF the cell body and the Schwann cell are not damaged (can surgically re-attach a severed nerve)
**Example:** You can reattach a severed pinky to your hand!
**Why:** Becasue Schwann cell can regenerate
PNS
105
Action Potentials go as high as _##_ in memberate potential millivolts
+30
106
The PNS has 2 components to how it functions: ______ & ______ functions. Of those 2, the:
* _____ component has _______ (incoming); Contains many different receptors which detect change (e.g. general & specific sense receptors)
* \_\_\_\_\_component = _______ (outgoing); It conducts impulses from CNS to muscles & glands!
Sensory & Motor functions
Sensory, Afferent
Motor, Efferent
107
Between the nerve fibers/bundles is \_\_\_\_\_\_\_\_
(e.g. endoneurium, perineurium, and epineurium)
connective tissue
108
**_Regeneration of Nervous Tissue:_**
At ~_#_ months of age, neuronal cell body loses mitotic apparatus; can’t divide
6
109
What is a bundle of nerve fibers (axons) in PNS?
Nerves
i.e. a bunch of axons wrapped up together
