Chapter 2.1 - Neurons and Neuronal Signaling Flashcards
What are the two main types of cells in the nervous system?
Neurons and glial cells
Who deduced that neurons take in information and make a decision about it?
Santiago Ramon y Cajal
What class of cell varies in their form, location, and interconnectivity within the nervous system?
Neurons
How many neurons are in the human brain?
89 Billion
Which neuroscientist designed the first remote controlled neural implants?
Jose Delgado
Who understood that the nervous system uses electrochemical signaling for communication?
Jose Delgado
Inside the brain, neurons and their long-distance projections (axons) form:
Intricate wiring patterns
There are roughly as many ______ cells in the brain as there are neurons?
Glial
The central nervous system has three main types of glial cells:
Astrocytes, microglial and oligodendrocytes
What type of glial cells surround neurons and are in close contact with the brains vasculature?
Astrocytes
What permits astrocytes to transport ions across the vascular wall?
Contact with blood vessels at specialisations called end feet
What type of barrier do astrocytes create between the tissues of the nervous system and the blood?
Blood-brain barrier (BBB)
Many drugs and certain neuroactive agents, including dopamine and norepinephrine cannot cross the:
Blood-brain barrier (BBB)
The BBB plays a vital role in protecting the:
Central nervous system
Neuronal activity is moderated by _______activity?
Astrocyte
What type of neuron directly or indirectly regulates the reuptake of neurotransmitters?
Astrocytes
What type of cell forms myelin in the peripheral nervous system?
Schwann cell
What is squeezed out of the glial cell in the process of myelin formation?
Cytoplasm
______ is a good electrical insulator and speeds up, increases the distance of information travelling across a neuron
Myelin
What type of glial cells devour and remove damaged cells?
Microglial
What types of cells can proliferate in adults (unlike other cells in the central nervous system)?
Microglial
What is another word for a cell body in a neuron
Soma
Neuron cell structures (ie nucleus, mitochondria) are suspended in what fluid?
Cytoplasm
Cytoplasm is made up of what?
Ions, predominantly potassium, sodium, chloride, calcium as well as other molecules such as proteins
Two predominant cellular components unique to neurons are?
Dendrites and the axon
Most dendrites have _______, which are little knobs attached by small necks to the surface of the dendrites
Spines
The axon structure of the neuron represents the _____ side of the neuron
Output
Transmission of electrical or chemical signals occurs at what part of the neuron?
The synapse
What is an axon collateral?
Where an axon branches to transmit signals to more than one cell
Evenly spaced gaps in the myelin sheath are called?
Nodes of Ranvier
Explain neuronal signaling?
The process of neurons receiving, evaluating, and transmitting information
What are signaling molecules?
Neurotransmitters
Chemical synapses occur when information transfers across synapses, typically mediated chemically by?
Neurotransmitters
At an electrical synapse, signals between neurons travel via transsynaptic: ________
Electrical currents
At resting potential, the inside of the cell is more ________ charged than the outside of the cell
Negatively
Voltages within the cell depend on the concentration of potassium, sodium, and chloride, as well as on _________
Charged protein molecules both within and outside of the cell
About how many millivolts (mv) is resting potential within a neuron?
-70mv
What makes up the bulk of the neuronal membrane?
A bilayer of fatty lipid molecules that separate the cytoplasm from the extracellular milieu
The neuronal membrane is made up of fatty lipid bilayer, as well as transmembrane ________
Proteins
What does Neuroglia mean?
Nerve glue
Glial cells contribute to neural signaling via the production of ________
Myelin sheath
Which glial cell removes damaged cells as part of the nervous systems immune response?
Microglial
What cells are the basic building blocks of the nervous system?
Neurons
What part of the neuron produces energy and chemical substances?
The soma (cell body)
What part of the neuron receives information from other neurons?
The dendrites
What part of the neuron transmits information to other neurons?
The axon
The asymmetrical distribution of ions across a membrane results in resting __________
Membrane potentials
When does neuron signaling (involving action potentials) occur?
When the sum of multiple EPSP’s cause the membrane potential to pass a threshold
Action potentials jump from the _________ to the nodes of Ranvier
Axon hillock
Astrocytes form the _______, oligodendrocytes create ______ and ______cells in the Peripheral Nervous System, microglia remove ______
Blood brain barrier, myelin, Schwann, damaged cells
What transmembrane proteins serve as conduits for ions to move across the neuronal membrane?
Ion Channels and Ion Pumps
Ion channels found in neurons form transmembrane passageways and selectively permit one type of _______ to pass through the membrane
Ion
Neuronal ion channels are selective for what ions?
Sodium, potassium, calcium, or chloride ions (Na+, K+, Ca(2)+, and Cl-, respectively
The neuronal membrane is more permeable to Potassium or Sodium?
Potassium (K+)
Why is neuronal membrane permeability to Potassium (K+) larger than other ions?
Because there are many more Potassium (K+) selective channels than any other type of ion channel
Neurons are excitable, which means that their ________
Membrane permeability can change
In response to nearby transmembrane voltage, or chemical/physical stimuli, gated ion channels _________
Open and close
Ion channels that always allow their associated ion to pass through are known as ________ ion channels
Nongated
Under normal conditions, Na+ and Cl- concentrations are greater inside or outside the cell?
Outside
Under normal conditions, K+ concentrations are greater inside or outside the cell?
Inside
Inside and outside voltages of neurons are different because the membrane is more permeable to _______ than to _______.
K+ than to Na+
The force of the K+ concentration gradient pushes K+ out of the cell, leaving the inside of the neuron slightly more ______ than the outside
Negative
The difference in voltage between the inside and outside of the neuron creates an Electrical _________
Gradient
The resting membrane potential can be calculated if the ___________ of ions is known
Concentration
________ cause ionic currents to flow through the volume of the neurons cell body
EPSP’s
Passive current conduction is called __________
Electrotonic conduction or decremental conduction
The maximum distance a passive current can flow in a neuron
is ______
1 millimeter
What structure is small enough for a neuron-to-neuron communication via decremental conduction?
The retina
The lipid membrane maintains the separation of intracellular and extracellular ions and _________ charge, that ultimately permits neuronal communication
Electrical
Ion ______ are proteins with a pore in the center that allow certain ions to flow down their electrochemical and concentration gradients
Channels
Ion ______ are proteins that use energy to actively transport ions across the membrane against their concentration gradients, from regions of low concentration to higher concentration
Pumps
Ion pumps use _____ as an energy source to transport ions across the membrane
Adenosine Tri-phosphate
Who is the “Father of Neuroscience”
Santiago Ramon y Cajal (pathologist)
What types of cell senses changes in the environment, transmits information to other neurons and commands the body’s response?
Neuron
What type of cell insulates, supports and nourishes neighboring neurons?
Glia
Resting Membrane Potential in neurons is maintained by
Ion Channels
