Chapter 2; Neurobiology Flashcards
How many neurons in the human brain?
85-100 billion
Neurobiology is the study of the ____ ____ and how the ____ works. Basic operating principals of the ____ ____, right down to ____ and ____ properties.
nervous system
brain
nervous system
electrical, chemical
The vertebrae neuron is ____ and measures approximately ____ ( _ x _ ^_ m) in diameter and up to more than a ____ in length.
microscopic
10 to 20 microns
1 x 10^-6, meter
Neurons are ____ packed.
densely
Glia: equal ____ to the neuron, and non-____ ____ cells.
volume
non-neuronal supporting
What is evolutionarily conserved in regard to the neuron?
unchanged; the neuron is basically the same across all vertebrate animals
Neurons are the ____ and ____ units of the nervous system.
structural
functional
A nerve is ____ and consists of a bundle of dozens to hundreds of ____ packed together in a ____ ____ ____.
macroscopic
neurons
connective tissue sheath
The neuron is a ____ cell used for ____ information between the ____ and your ____ from one region to another.
specialized
transmitting
brain
body
How is the neuron information transmitted (what form)?
electrochemical signals
Neuron sends information in what 2 ways?
Conduction of electrical impulses
Release of chemicals
What is the conduction of electrical impulses?
Action Potential
What is the release of chemicals?
Neurotransmitters
What are recognized and received by another neuron?
Neurotransmitters
How does the typical neuron send neurotransmitters? And what is it?
Across the synapse
Microscopic gap between cells
What does the postsynaptic neuron do with the chemical signal (neurotransmitter)? What does this trigger? And that activates a release of what?
Converts to an electric signal
An action potential
It’s own neurotransmitters
What are the 4 main components of a neuron?
Dendrites
Soma
Axon
Terminal Buttons
The dendrites receive and recognize ____ released from other cells and ____ the ____ signal into an ____ ____ signal.
neurotransmitters
convert
chemical
intracellular electrical
What signal travels down the dendrites? To what?
Electrical
Soma
What contains all of the machinery for manufacturing neurotransmitters?
Soma
What transmits the electrical signal from the dendrites?
Soma
What are the two main functions of an axon?
Transport neurotransmitters from soma to terminal boutons
Generate and conduct action potential down to the terminal buttons
Terminal buttons are responsible for ____ ____ for eventual release in response to arrival of an ____ ____ .
storing neurotransmitters
action potential
3 ways neurons are classified
shape
function
location
____ neurons compromise majority of nervous system.
multipolar
____ neurons have ____ processes which functions with a ____ end and a ____ end. Where are these found?
Bipolar Two Sending Receiving The retina of the eye
What process is the sending end called?
axonal process
What process is the receiving end called?
dendritic process
____ have a ____ process attached to the soma. Where is this found?
Unipolar
Single
Sensory System
What are the four components of neuron covered in?
Cell membrane
The cell membrane is a ____-____ membrane that ____ the entire ____.
double-layered
envelops
neuron
What is the cell membrane composed of?
Phospholipid Bilayer
The phospholipid bilayer consists of ____ phosphate molecules (“head”) sandwiching ____ fatty acids (____) in between (“____”).
polar
non-polar
lipid
tail
Phosphate heads are ____ or attracted to ____ which is also polar.
hydrophilic
Attracted to water
Polar
Describe phosphate head and tails in relation to water?
Head interacts with water in extracellular space in cytoplasm of cell.
Tail avoids water and is protected by phosphate head.
The ____ ____ is a specialized ____ (small “organ” of the cell) that regulates movement of ____ in and out of the ____ which allows ____ between the ____ space of a cell’s ____ and controlling the ____ changes of the neuron.
cell membrane organelle molecules neuron communication extracellular interior electrical
____ permeability:
____ , ____ , and/or ____ molecules do not go through the ____ by ____ (or ____ ).
semi large polar charged membrane diffusion osmosis
What is a lipid?
fatty acids and insoluble in water
Difference between polar and nonpolar?
Polar: electrons unequally shared by two atoms
Non-polar: electrons equally shared by two atoms
What kind of molecules readily diffuse through the membrane?
Small or lipid-derived molecules
What gives the cell membrane the ability to regulate cellular communication?
Membrane-Embedded Protein (MEP)
What three ways do the cell get the molecules through the membrane?
Transporter, Channel, and Receptors
How does the Transporter work (MEP)?
It functions like a pump. It spans the thickness of the membrane and uses energy (ATP) to actively transport nondiffusible molecules into and out of the cell.
What is ATP and what is it the source of?
Adenosine triphosphate; the cell’s source of energy
How does a Channel work (MEP)?
They are specific for particular ions and can be opened and closed depending on conditions. This is selective permeability.
Which MEP does not transmit molecules across the membrane?
Receptors
How does a Receptor work (MEP)?
Like a lock on a door. A molecule, like a neurotransmitter, connects or binds to a receptor that is specific for that molecule.
With a Receptor (MEP), after the molecule is binded, what happens?
The receptor changes, sends a piece of that information into the cell, letting the cell know the message from the extracellular space has been “received.”
What are amino acids?
Building blocks of proteins
What are most neurotransmitters derived from?
amino acids
Where are neurotransmitters made?
In the vicinity of the nucleus of the cell
Where is the nucleus of the cell?
Found in the soma
What structure of the cell contains chromosomes?
The nucleus
What are chromosomes?
Densely packed strands of DNA
Many neurotransmitters consist of a single ____ ____ that has been modified slightly.
amino acid
Neurotransmitter serotonin is just a modification of the dietary amino acid ____
tryptophan
In making of a neurotransmitter, what is split apart and what is it transcribed into?
the double helix of the DNA
mRNA (messenger ribonucleic acid)
mRNA is a ____ ____ of ____ with ____ pairs that correspond to the ____ ____ molecule.
single strand
nucleotides
base
parent DNA
In making of the neurotransmitter, after the DNA is transcribed into mRNA, what is translated to assemble chains of what?
The mRNA is translated to assemble changes of amino acids
What determines which amino acids are to be taken from the cytoplasm and assembled into proteins?
The unique sequence of nucleotides
The ____ is another intracellular ____ that runs down the ____ reading three ____ sequences at a time that correspond to a specific ____ acid.
Ribosome organelle mRNA nucleotide amino
A ____ is a particular sequence of ____ that codes for the production of a specific ____ or ____ .
gene
nucleotides
protein
trait
Proteins are ____, like muscle or keratin, or ____, like enzymes.
Structural
Regulatory
____ proteins regulate ____ reactions, controlling a wide variety of processes such as ____ synthesis, ____ (ie. breakdown), and thousands of other ____ functions.
Regulatory chemical neurotransmitter degradation metabolic
Starting with the soma, walk me through the steps to a neurotransmitter?
Soma to cell body to nucleus To chromosomes (densely packed DNA) and DNA splits and transcribed to mRNA that is translated into Amino Acids
Where are the newly synthesized neurotransmitters processed?
The Golgi Apparatus
What is the Golgi Apparatus?
Encloses the neurotransmitters inside a synaptic vesicle
What is a synaptic vesicle?
A bag of membranes that contains the neurotransmitters
Neurotransmitters have to be ____ (ie. stored and protected) inside of ____ in order to protect them from ____ ____.
sequestered
vesicles
degradative enzymes
What are degradative enzymes, and what can this lead to?
break down and permanently alter chemical structure, which can lead them to be inoperative
Where are the neurotransmitters sent to after being stored into the vesicles?
They are sent to the terminal buttons.
Where are neurotransmitters stored?
Terminal buttons
When the Golgi is complete, organelles known as ____ function as a conveyer belt for ____ vesicles down the length of the ____ through a process called ____ ____ .
microtubules
transporting
axon
axoplasmic transport
The vesicles that store the ____ keep them stored until they release the ____ into the ____ .
neurotransmitters
neurotransmitters
synapse
The arrival of what causes the release of a packet of neurotransmitters?
Action potential
What two things travel down the axon towards the terminal? Which is faster?
Synaptic vesicles Action Potentials (faster)
Action Potentials represent movement of ____ charge and travel down the ____ in time measured in ____ .
electrical
axon
milliseconds
Axoplasmic transport takes ____ to ____ to occur and involves ____ movement of ____ .
hours
days
physical
molecules
Half of the volume of the brain consists of ____ - ____ cells known as ____ which are also known as ____ cells.
non-neuronal
glia
supporting
What are the four kinds of Glial Cells?
astrocytes (star-cell)
Microglia
Eligodendrocytes
Schwann
Which type of glial cells provides nutritional and physical support for neurons?
Astrocytes
Which type of glial cell are small, branches cells that wrap their tentacles around capillaries?
Astrocytes
When a neuron dies, which glial cell secretes extracellular material that replaces the lost neuron with scar tissue (sclerosis)?
Astrocytes
What glial cell helps the immune system rid the brain of foreign material and cellular debris by holding on to and presenting these substances to the macrophages of the immune system that engulf (phagocytose) the material in order to remove it?
Microglia
What glial cell has processes that wrap around axons and create the myelin sheath?
Oligodendrocytes
What is an insulative covering?
The myelin Sheath
Myelin is a ____ substance that insulates ____.
fatty
axons
What is the CNS?
Central nervous system
What is the PNS?
Peripheral nervous system
The PNS contains only ____ cells (a glial cell) which are the analogs of the CNS’s ____ .
Oligodendrocytes
What enables action potentials to be conducted down the axon very efficiently and rapidly?
The myelin sheath
Which type of vertebrate completely lacks myelin?
Invertebrates
What is a physical parameter that “resists” the flow of electrical signals?
Resistance
Resistance can ____ down signals and make them ____ across distance.
slow
dissipate
Vertebrates have ____ resistance? (low/high)
high
Do vertebrate neurons conduct action potentials at a faster rate compared with invertebrates or slower? Why?
Higher
Special properties of the myelin sheath
Technical term for cutting axons is what?
Denervation
In CNS, do denervated axons attach to their target?
No, they do not reattach.
The spinal cord and brain consist of a very ____ and complex array of ____ .
dense
neurons
Differences in post-denervation recovery are conferred by major differences in the ____ in CNS vs PNS
glia
What is the fundamental different between the two myelin sheath-prodcuing cells? Examples of oligodendrocyte and Schwann
how they wrap around the axon.
Oligoendrocyte has several branches that warps around handful of axons so when the neuron is denervated, the branches wither back and if there is an attempt to grow back there is no guide.
Schwann wraps its whole body around a single axon and remains in place after denervation, when it grows back there is a path of tunnels still in tack.
Which has better neuronal recovery: CNS or PNS?
PNS
What triggers a neurotransmitter’s release from the synaptic vesicles waiting in the terminal boutons?
An action potential
Neurons are ____ batteries (in contrast to nerves that are ____ )
microscopic
macroscopic
The neuron stores ____ energy
potential
What is potential energy?
Energy that is stored-up, to allow for its later release
Potential energy in a neuron comes in the form of what?
membrane potential
Membrane Potential is defined as a difference in ____ on the ____ ( ____ ) of a cell vs. the ____ of the cell ( ____ ____).
voltage inside cytoplasm outside extracellular fluid
What is it called when the membrane potential is at rest or not doing anything in particular, not firing an action potential?
Quiescent
The membrane potential registers at ____ ____ (mV0.
-70 millivolts
The reading of -70mV represents the ____ ____ .
Resting potential
The membrane potential is the difference in ____ whereas the resting potential represents the ____ .
voltage
-70mV
What is the goal between the soma to the terminal?
To fire an action potential
It is the deviation from 0mV that represents and gives rise to the potential ____ .
energy
The action potential comes in the form of a release of the stored ____ ____ or a resting cell and a tremendous positive deviation in ____ ____ away from the negative ____ ____ .
potential energy
membrane potential
resting potential
The action potential will represent a swing from ____ mV all the way up to about ____ mV.
-70
+40
Every living cell contains ____ and is bathed in ____ fluid.
cytoplasm
extracellular fluid
Cytoplasm and extracellular fluid contain a large number of ____ .
molecules
Particular important to membrane potential are the charged elemental particles knows as ____ .
ions
