Chapter 12 - Nervous Tissue Flashcards
The functional unit of the nervous system is a
Neuron
The Nervous system that focus on the brain and spinal cord
Central Nervous System
The nervous system that focus on nerves , ganglia, and some sensory structures
Peripheral nervous system
Movements that you can control , voluntary or outside
Somatic nervous system
uncontrolled responses , involuntary or inside
Autonomic nervous system
fight/fright/flight
symphathetic
rest, relax, recover, and reproduce
Parasympathetic
The division that regulates digestion
Enteric
Contains the nucleus and many other organelles
Cell body
Receives the information or inputs generally from other neurons
Dendrites
carries signals to target cells , sometimes over great distances
axon or nerve fiber
where action potentials starts on the cell
Hillock or initial segment
the axon sometimes divide into ____
Axon collaterals
connects to target cells through synapses
Axon terminals
also called the synaptic bouton , is part of the synapse
Synaptic knob
Axons that extend for long distances are insulated by specialized cells called
Glial cells
Glial cells produce fats and lipoproteins called
Myelin
Carry information INTO the CNS
Afferent (Sensory) Neurons
Carry information OUT or from the CNS
Efferent ( Motor) Neurons
There are more ____ than afferent or efferent
Interneurons
carry sensory information that stimulates responses generated by efferents
Afferents
Are the neurons inside the CNS that carries signals to one neuron to another neuron
Interneurons
internal organs , sense taste ,pain
Interoceptors
skin, sense touch, temp, pressure, sight, smell, hearing
Exterceptors
muscles , tendons, ligaments, sense, position, and movement of muscles and joints
Proprioceptors
has their cell body in the dorsal root ganglion of the spinal cord
Sensory neurons
has their cell body in the spinal cord and the axon goes from the spinal cord to the NMJ
Somatic motor neurons
A group of neurons (Cell bodies) outside of the brain or spinal cord in PNS
Ganglion
The ANS axon going from the ganglion to the organ or gland it innervates is known as the
postganglionic fiber
Collection of cell bodies in the CNS
Nucleus
Bundle of axons
Tract
Connection between R& L sides
Commissure
Collection of cell bodies in the PNS
Ganglion
Bundle of axons in the PNS
Nerve
Neurons are named based on how many ____ they have extending from the soma
Processes
_____ and ____ are usually much larger than bipolar and anaxonic neurons
Unipolar and Multipolar
An Axonal transport thats from the soma to terminal
Anterograde
An axonal transport thats from the terminal to soma
Retrograde
Kinesin is what axonal transport ?
Anterograde
dynein is what axonal transport ?
Retrograde
____ largely carried out in the cell soma
Protein synthesis
“walk” down microtubules that run the length of axons like railroad tracks carrying materials
Molecular motors
Can be either fast or slow
Axonal transport
forms the blood-brain barrier
astrocyte
the graded potential that occurs on the post synaptic neuron can be either ___ or __
EPSP
Excitatory post synaptic potential. Depolarizing, help lead to action potential
EPSP
inhibitory post synaptic potential. Hyper polarizing, prevent action potential
IPSP
repeated post synaptic potentials coming from one receptor that add up.
temporal summation
post synaptic potentials coming from multiple receptors that add up.
spatial summation
When there are few connections that means that there are
few graded potentials. These graded potentials won’t be able to summate and cause an action
potential.
facilitation.
small peptides or amino acids or compounds formed from amino acids
neurotransmitters
made from an acetyl group and choline; it is different chemically from other
neurotransmitters
Acetylcholine
examples include nitric oxide and carbon monoxide (a gas that can kill in
general circulation but appears to be a neurotransmitter in certain parts of brain)
Small gas molecules
Amino acid derivatives:
Catecholamines and Monoamines
(a sub-group of amino acid derivatives) include dopamine,
norepinephrine and epinephrine (also a hormone)
Catecholamines
are another sub-group of amino acid derivatives. Histamine and serotonin
are monoamines
Monoamines
examples include gamma-aminobutyric acid (GABA) and glutamine
Amino Acids:
examples include a group of compounds called endogenous opiates. Some of the
endogenous opiates are beta-endorphin and enkephalins.
Peptides
Most common neuromodulator in CNS
associated with sleep, anxiety, hunger, mood
LSD acts as antagonist
Serotonin:
Most common inhibitory neurotransmitter in spinal cord
Strychnine acts as antagonist
Glycine:
Most common inhibitory neurotransmitter in brain
Valium acts as agonist
GABA:
Most common excitatory neurotransmitter in CNS
MSG acts as agonist
Glutamate:
Binds to either a nicotinic receptor (ligand gated ion channel) or muscarinic
receptor (G-protein coupled)
Acetylcholinesterase is the enzyme that degraded it in synapse
Usually found at neuromuscular junction and in ANS
Acetylcholine
Binds to either alpha adrenergic receptor or beta adrenergic receptor
alpha receptor usually causes smooth muscle contraction (constriction of
tubes/vessels)
beta receptor usually causes smooth muscle relaxation (dilation of
tubes/vessels)
Norepinephrine
Monoamine oxidase (MAO) is enzyme that degrades it
Found in ANS
Epinephrine uses same receptors
Norepinephrine:
– bind and activate neurotransmitter receptors
Agonists
bind and block neurotransmitter receptors
Antagonists
prevent normal reuptake of a neurotransmitter back into its presynaptic
knob, a normal mechanism to stop signaling at a synapse. Reuptake inhibitors cause
more neurotransmitter to be active and binding its receptors for a longer time once released.
This “strengthens” some synapses by increasing the size of the post-synaptic potentials.
Reuptake inhibitors
prevent normal enzyme breakdown of a neurotransmitter within the
synaptic cleft. This also means that neurotransmitter is binding to receptors for a longer
period of time. This also “strengthens” some synapses by increasing the size of the postsynaptic
potential.
Enzyme inhibitors
when one neuron sends signals to many different places.
Divergence
when lots of signals from different neurons are sent to one neuron
Convergence
memory you have from seconds to hours. It deals with small changes in synaptic
strength.
Working memory –
memory you have for weeks to lifetime. Long term potentiation is a mechanism for
long term memory. Through repeated use, the density of receptors is increased on the post synaptic
density, so memories are recalled easier.
Long term memory
glial cell in the CNS that forms the blood brain barrier and helps shuttle nutrients from blood
to neuron; “cares” for needs of neuron in other ways too “blood barrier”
Astrocytes
glial cell in the PNS that helps provide nutrients and important chemicals and signals to
neurons; similar to astrocytes.
Satellite cells –
– glial cell in the CNS that insulates the axon with a myelin sheath. One
oligodendrocyte wraps around one myelinated segment of several different axons
Oligodendrocytes
glial cell in PNS that insulates axon with myelin sheath. Schwann cells wrap around one
segment of one axon.
Schwann cells –
glial cells in the CNS that act as macrophages.
Microglia
line ventricles in the brain and spinal cord. They produce cerebrospinal fluid (CSF).
Ependymal cells
The diseases that result in loss of myelin
multiple scelerosis and guillian-barre syndrome
the portion of the axon still attached to the soma is called
the proximal end
the portion of the axon that contained the nerve terminals is called
the distal end
action potential moving down myelinated axon
saltatory onduction
fat, myelinated axons , fatestest
Type A
skinny, myelinated axons, slower than A
Type B
Skinny, unmyelinated axons, slowest
Type C
they alter response to a neurotransmitter , associated with long term events like learning and etc.
Neuromodulators
axo-axonic synapses can lead to DECREASE release of neurotransmitters called
pre synaptic inhibition
axo-axonic synapses can lad to INCREASE release of neurotransmitters called
pre- synaptic facilitation
ability to modify synaptic strength or to make and maintain new synapses
Synaptic plasticity
