Unit 3 Flashcards
What is the receiving area of a neuron
Dendrite
What is the entire middle section of the cell that contains a majority of the organelles
Cell body/soma
What is the center structure inside the cell where DNA is housed?
Nucleus
What is a myelin sheath
Formation of several bundles of white material that are wrapped around a thin gray structure. The bundles function as an insulation. It spreads up a action potential
What part of a neuron is a specialized area of a neuron that generates action potentials when appropriate stimulated
Axon
What is the enteric nervous system?
It act to autonomously or can be controlled by the CNS through the autonomic division of the PNS. Regulated digestive system.
Define sympathetic
The fight / flight mode
Define parasympathetic
Rest and digest
Define efferent neurons
Involuntary control
Where are the voltage gated channels on a neuron?
On the axon
Where are the receptor channels on a neuron?
On the dendrites
Define a axon hillock
It is a thin , long gray cellular extension inside white bundles. This part of a neuron conducts or transmits action potentials from the cell body to where a neurotransmitter or neuromuscular it’s are released
What is an axon collateral?
When a axon splits off into multiple terminals
Define a pseudounipolar neuron
It have a single proceeds called the axon during the development the dendrite fuse with an axon
Define a interneuron
Have bits and pieces that communicate between one part of the brain to another part. Internal CNS communication
Define a bipolar neuron
Have two relatively equal fibers extending off the central cell body
Define anaxonic neuron
Have interneurons with no apparent axon
Define a oligodendrocytes
A specific cells to form a myelin sheath in the CNS. They wrap a few separate neurons with their arm like extensions
Define microglia cells
Modified immune cells. They act as scavangers during brain development. To remove excess neurons
Define astrocytes. What do they do
•They take up k+, water and neurotransmitters
•The secrete neurotrophicfactors
•They help form blood brain barrier , therefore provide substrates for ATP
• A source of neural stem cells like ependymal cells
Define neurotrophic
Neurogrowth
What are ependymal cells?
They form a barrier between brain tissue and the ventricles.
What are the glial cells of the CNS
Ependymal cell
Astrocyte
Microglia
Oligodendrocytes
What are the PNS glial cells?
Satélite cell
Schwann cell (neurolemmocytes)
What do satélite cells?
Protect cluster of neuron cell bodies outside the CNS
What is a Schwann cell (neurolemmacyte)
Form myelin sheaths and secrete neurotrophic factors
What voltage do neurons test at
~-70 mV
What type of channels on dendrites and cell body control ion permeability and allow for changes in a neuron membrane potential
Gated channels allow the neuron to go from resting to active state
If sodium and calcium in flux what is the intracellular charge
Depolarized
If sodium and calcium efflux what change in intracellular charge
Hyperpolarized
If chloride channel influx what is the change of intracellular charge?
Hyperpolarized
If chloride efflux what is the intracellular charge
Depolarize the cell
If potassium efflux what is the intracellular charge
Hyperpolarized , depolarized
What is a axon terminal
The bulbous end of a neuron where it interfaces with another cell by realeasing neurotransmitter or mueromodulators
What is the gap between two neurons?
Synaptic cleft
Define Central Nervous System
Division of the nervous system that consist of the brain and spinal cord only
Define peripheral nervous system
Branch in the nervous system that contains only sensory (afferent) neurons and motor (efferent ) neurons
What type of nerves carry afferent signals only from the periphery to the central nervous system
Sensory nerves
What nerves only carry out efferent signals from the CNS out to skeletal muscles
Motor nerves
Nerves that carry both sensory and motor signals are called what?
Mixed nerves
What is the general type of cell that function as a unit in the nervous system
Neuron
What is a grade potential
The vary in strength and effect of a stimulus
What is a excitatory post synaptic potentials (EPSP’s)
Increase the likelihood that the neuron will generate its own AP. Small depolarization of the dendrites and soma body
Sodium and calcium influx
What type of neuron contain all its components such as dendrites, soma, axon , axon terminal completely within the CNS to communicate from one side of the CNS to the other
Interneurons
Define glial cells
General kind of cell in the nervous system the support neurons and form insulation around their axons
What are nodes of ravier
Tiny gaps in the myelin sheath
What is an action potential?
A all or nothing phenomenon that transmits an electrical signal down the axon. A rapid change in membrane potential
What is a inhibitory post synaptic
hyper-polarization / repolarization of the dendrites or the soma
Potassium efflux or chloride influx
What is threshold voltage
The sum of all graded potentials at the axon hillock surpasses a particular membrane potential. The neuron will fire a AP
What is the milivolts an action potential be generated by a typical neuron
-55 mg
Define absolute refract period
When a neuron generates its own action potential how ever it cannot send a second Action Potential no matter how much additional stimulation it receives
When a neuron depolarizes causing an action potential this is due to the influx of what ions
Na+ , ca2+
During depolarization of an action potential, which ion channels will be slow to open and achieve maximum permeability just after the membrane reaches maximum potential
K+
Since potassium is slow to open and close what phase do the contribute (depolarization, hyper-polarization, repolarization ) when the cells membrane potential dips below its resting level
Hyperpolarization
Define relative refracting period
When a neuron membrane potential slowly returns to a resting level from a Hyperpolarized state, it CAN fire a second action potential IF the stimulus is larger than normal
What is saltatory conduction
The description of an Action Potential moving rapidly down a myelinated axon
What is the general category of neurotransmitter that includes noreepinephrine, dopamine, serotonin and histamine
Amines
This general neurotransmitter category includes adenosine
Purines
This is the only gas that is shown as a neurotransmitter
Nitric oxide
What is the specific neurotransmitter / signal molecule that has two types of receptors nicotinic and muscarinic
Acetylcholine
Many antipsychotic drugs are antagonists for this neurotransmitter. Drugs of abuse are also typically agonist of this neurotransmitter
Dopamine
Molecules such as glutamate, GABA, glycine belong to this general family of neurotransmitter
Amino Acids
Curare and alpha bungartoxin will block the action of these acetylcholine receptors so avoid be shot by poison darts
Nicotinic
Atropine will
Block the action of acetylcholine receptors. This is why atropine is used to elevate heart rate during anestesia 
Muscarinic
What is GABA
GABA : gamma aminobuytric acid. Alcohol, barbiturates and benzodiazepines potentials the effects of this neurotransmitters
What neurons control the smooth muscle, cardiac muscle many glands and some adipose tissue?
Autonomic neurons
What is the name for the efferent peripheral nervous system neurons always control skeletal muscles
Somatic motor neuron
What autonomic neurons is dominant in stressful or active situations and is often linked to the “fight or flight” response
Sympathetic branch
What branch in the autonomic nervous system is more active if you are resting quietly after a meal or during the quiet activities of day to day living. Aka “rest & digest”
Parasympathetic branch
All autonomic neural circuits consist of two neurons connected in series between the CNS and the effector. The first neuron has its cell body within the CNS
Pregangolinc neuron
What neurotransmitter is secreted by pre- gangolic neurons in both parasympathetic and sympathetic nervous system
Acetylcholine
The next neuron in circuit has its cell body out side the CNS and projects to an effector organ or target tissue
Post ganglionic neuron
What neurotransmitter is secreted by post ganglionic neurons of the sympathetic nervous system onto effector cells
Noreepinephrine
What neurotransmitter is secreted by post gangolinic neurons in the parasympathetic nervous system on effector cells
Acetylcholine
What is the adrenal medulla
It contains chromaffin cells and are modified post-gangolinic sympathetic neurons that secrete their neuron prime into the blood stream
What neurohormone is secreted by the adrenal medulla / chromaffin cells
Epinephrine
Pregangolinic Neurons of both the sympathetic and parasympathetic nervous system release, acetylene onto what type of receptors on the postganglionic neurons
NN nicotinic receptors
Somatic motor neurons always release acetylcholine onto what type of receptors? They are located on the motor and plates of skeletal muscle cells.
NM nicotinic receptors
What kind of receptors are NM & NN nicotinic receptors
Cholinergic channels, always excitatory
Postgangolinic parasympathetic neurons release acetylcholine onto their target cells. However what type of receptors accept acetylcholine
Muscarinic receptors