Nervous Tissue Flashcards
Muscular and nervous tissues are called ____ tissues because they are especially sensitive to stimulation and react with charges in membrane voltage.
excitable
What are the electrochemical signals which travel in waves to form nerve impulses called?
action potetials
When a nerve impulse reaches the end of a nerve fiber, the fiber releases ____ that diffuse across the gap and stimulate the next cell.
neurotransmitters
What components does the peripheral nervous system (PNS) consisit of?
nerves and ganglia
What are cells that carry out commands called?
effectors
What are the effectors of the somatic system?
skeletal muscle cells
What are the effectors of the automatic system?
cardiac muscle, smooth muscle, and gland cells
What are the two kinds of cells that compose nervous tissue?
- neurons (nerve cells)
- neuroglia (glial cells)
What are the three main parts of the neuron?
- soma
- axon
- dendrites
What are the four types of neuroglia in the central nervous system?
- oligodenrocytes
- ependymal cells
- microglia
- astrocytes
Why does there need to be a blood/brain barrier? How does the brain recieve oxygen and nutrients?
To prevent toxins in the bloodstream from reaching the brain. The cerebrospinal fluid is what provides the brain with oxygen and nutrients.
What are the two types of neuroglia in the periphreal nervous system?
- Schwann cells
- satellite cells
The brain is ____% of the body’s weight, but gets ____% of its blood flow.
2%; 15%
What is the purpose of the Blood-Brain Barrier (BBB).
To protect neurons from harmful blood-borne agents.
How does the process of myelination differ between the CNS and PNS?
In the CNS…
* myelination occurs in a centripetal fashion (towards the center)
In the PNS…
* myelination occurs in a centrifugal fashion (towards the outside)
What are the naked sections on the myelin sheath called in between the myelin/Schwann cell component? What happens here?
Nodes of Ranvier; the electrical signal is boosted
When a membrane potential is at rest, which ion is most prevelant within the cell?
this includes the sodium/potassium pump
potassim (K+)
At the peak of an action potential, the Na channels are ____ and the K+ channels are ____.
closed; opened
What are the two main divisions of the nervous system?
- central nervous system
- peripheral nervous system
What components of the body are included in the central nervous system?
- brain
- spinal cord
What are the first two divisions of the peripheral nervous system?
- sensory division
- autonomic (visceral motor) divison
Sensory division
* ____ division
* ____ division
- visceral sensory division
- somatic sensory division
Motor division
* ____ division
* ____ division
- visceral motor division
- somatic division
What are the two components of the visceral motor division?
- sympathetic division
- parasympathetic division
Name part (1) of the brain
frontal lobe
Label part (2) of the brain
parietal lobe
Label part (3) of the brain
occipital lobe
Label part (4) of the brain
cerebellum
Label part (5) of the brain
temporal lobe
Label part (6) of the brain
spinal cord
What are the main components of a neuron?
1) soma (cell body)
2) dendrites
3) axon (nerve fiber)
4) Schwann cells (neurilemmocyte)
Which part of the neuron includes…
* tiny branches, spines
* spreak out in the tissue
* ends of electric impulses
dendrites
Which compoment of the cell is composed mainly of myelin?
the myelin sheath
Which part of the neuron includes…
* neurofibrils
* chromstophilic substance
* no centrioles or mitosis
* melanin and lipofuscin
soma (cell body, neurosoma, perikaryon)
Which part of the neuron includes…
* axon hillock
* exolemma
* collateral branches
* terminal
axon (nerve fiber)
Which part of the neuron includes…
* spines
* branching
* extensions from the soma
dendrites
Which part of the neuron includes…
* neurilemma
* myelin sheath
* initial segment
* trigger zone
Schwann cells (neurilemmocyte) (type of glial cell)
What is located at the core of the brain?
basal ganglia
Which neuron shape includes cerebral neurons?
multipolar
Which neuron shape includes olfactory neurons and retinal neurons?
bipolar
Which neuron shape includes somatosensory neurons?
unipolar
Which neuron shape includes adrenal neurons, and some brain and retinal neurons?
anaxonic
Electric impulses flow from the ____ of the presynaptic terminal to the ____ of the postsynaptic terminal.
axon; soma
Which kind of neuroglia…
* extends arms out to several nearby nerve fibers
* wrap around them to form a spiral myelin sheath
oligodendrocytes
CNS
Which kind of neuroglia…
* Lines central cavaties of brain and spinal cord
* Secretes and circulates cerebrospinal fluid
ependymal cells
CNS
Which kind of neuroglia…
* is small macrophages of CNS
* probes nervous tissue with spindly arms, detects foreign matter, phagocytize microbes, dead nervouse tissue, and debris
* the “housekeepers” of the CNS
microglia
CNS
Which kind of neuroglia…
* cover brain surface
* cover nonsynaptic areas of neurons
* supportive frameworl for nervous tissue
* secrete nerve growth fractor (NGF)
* regulate chemical composition of tissue fluid in CNS
* Form scar tissue if CNS is damaged
* Stimulate formation of blood-brain barrier (BBB)
astrocytes
CNS
Which kind of neuroglia…
* Surround the cell bodies of
neurons in the PNS ganglia
(arrows).
* Provide electrical insulation
and chemical regulation
satellite cells
PNS
Which kind of neuroglia…
- Coil around axons in
the PNS. - Form a neurilemma
(single or outermost
coil) around all axons,
and… - Form multilayered
myelin sheath around
most.
Schwann cells
PNS
What does this picture depict?
Centripetal
myelination by an
oligodendrocyte
What does this picture depict?
Centrifugal myelination
by a Schwann cell
Label part (1) of this picture
axon
Label part (2) of this picture
myelin
Label part (3) of this picture
neurilemma
Label part (4) of this picture
unmyelinated nerve fiber
What component lies in the grooves in the surface of Schwann cells?
unmyelinated nerve fibers
Label part (1) of the nerve cross section (SEM)
myelinated nerve fibers
Label part (2) of the nerve cross section (SEM)
unmyelinated nerve fibers
Label part (3) of the nerve cross section (SEM)
endoneurium
Label part (4) of the nerve cross section (SEM)
fascicles
Label part (5) of the nerve cross section (SEM)
perineurium
Label part (6) of the nerve cross section (SEM)
blood vessels within the fascicles
Which nerves cross sections are visible under a light microscope?
- sensory nerves
- motor nerves
- mixed nerves
What is a collection of neuronal bodies found in the coluntary and autonomc branches of the peripheral nervous system (PNS)?
ganglion
The nerve signal arrives at the synapse from the ____ neuron. After reaching this neuron, the signal arrives at the ____ neuron.
presynaptic; postsynaptic
What is the most common point of termination at a synapse where the axon of one neuron ends at a dendrite of the postsynaptic cell?
axodendritic synapse
What is the second most common most common point of termination at a synapse where it ends at the soma of the next cell?
axosomatic synapse
What is the least common point of termination at a synapse where the axon of one neuron ends near the termination of the second neuron’s axon?
axoaxonic synapse
Each nerve fiber is surrounded by a thin connective tissue sleeve called a(n) ____.
endoneurium
Nerve fibers are bundled into groups called ____.
fascicles
Fascicle groups are surrounded by a thicker connective tissue layer called the ____.
perineurium
Several fascicles constitute the nerve which is surround by ____.
epineurium
What bundles are formed where nerves travel with small arteries and veins, wrapped in a common connective tissue sheath?
neurovascular bundles
What is a knot-like mass of meurosomas in the PMS? It is covered with epineurium continuous with that of the nerve.
ganglion
What structure includes the dorsal root ganglia adjacent to the spinal cord, containing the somas of unipolar somatosensory neurons?
sensory ganglia
Which structures are motor components of the autonomic nervous system, and do have synapses?
autonomic ganglia
Which ganglia are where the sympathetic and parasympathetic preganglionic neurons synapse with the postganglionic ones?
autonomic ganglia
