Unit 3 Flashcards
- Identify this general part of a neuron. It is the receiving area of a neuron.
dendrite
- This arrow is pointing to that entire middle section of the cell that
contains a majority of the organelles. What is it generally called?
Cell body or soma
- This arrow is pointing to the center structure inside the cell where DNA is housed. What is it?
Nucleus
- This arrow is pointing towards several bundles of white material that are wrapped around a thin gray structure. These bundles function as insulation. What are they collectively called?
Myelin
- This line is pointing towards a specialized area of the neuron that
generates actions potentials when appropriately stimulated. What is it called?
Axon Hillock
- This arrow is pointing to the long, thin, gray cellular extension inside
the white bundles. This part of a neuron conducts or transmits action
potentials from the cell body to where neurotransmitters or neuromodulators are released. What is it?
Axon
- This arrow is pointing towards the bulbous end of a neuron where it interfaces with another cell by releasing neurotransmitters or neuromodulators. What is that part generally called?
Axon terminal
- This arrow is pointing towards the gap between the top neuron and
the bottom neuron in that zoomed-in view. What is that gap called?
Synaptic cleft
- This arrow is pointing towards the receiving area of the next neuron. What is that part called?
Dendrite
This division of the nervous system consists of the brain and spinal cord only.
CNS - Central Nervous System
This branch of the nervous system contains only sensory (afferent) neurons and motor (efferent) neurons.
PNS - Peripheral Nervous System
This branch of the nervous system is a network of neurons that lines the walls of the digestive tract. We will talk about it more towards the end of the course.
Enteric Nervous System
As you learned in your prerequisite Anatomy class, nerves are bundles of many separate axons. Nerves that carry afferent signals only from the periphery to the central nervous system are called __________.
Sensory Nerves
Nerves that carry only efferent signals from the central nervous
system out to skeletal muscles are called _________.
motor nerves
Nerves that carry both sensory and motor signals are called ________.
mixed nerves
This general type of cell is the functional unit of the nervous system.
neuron
For this specific type of neuron, all its components (dendrites, cell body, axon, axon terminals) are contained completely within the central nervous system. These cells are used to spread information from one place in the central nervous system to another.
interneuron
This general kind of cell in the nervous system gets its name from the Latin word for “glue.” These cells are crucial for providing support for neurons and also forming insulation around their axons.
Glial cells
These specific cells form the myelin sheath in the central nervous system. As a part of their name implies, they can typically myelinate “a few” separate neurons with their arm-like extensions.
Oligodendrocytes
Oligo = a few
These specific cells form the myelin sheath in the peripheral nervous system. They can only wrap themselves around one axon.
Schwann cell / neurolemmocyte
The spaces on the axon that are tiny gaps in the myelin sheath are called __________.
Nodes of ranvier / neurofibril nodes
These glial cells have a highly branched, star-like appearance and have many jobs, including take up and release of chemicals, providing neurons with substrates for ATP production, and help to maintain homeostasis in the CNS extracellular fluid. These cells are also important for forming the blood-brain-barrier.
astrocytes
These specialized glial cells are the part of the immune system that resides in the CNS. They remove damaged cells and destroy foreign invaders.
Microglia
These specific cells create a semi permeable layer that separates the fluid compartments of the CNS (ventricles) from the actual brain tissue.
ependymal cells
A/an _____ is a rapid change in membrane potential is an “all-or-none” phenomenon and transmits an electrical signal down the axon. This phenomenon is also known as a “spike”.
action potential
This is a general term for changes in membrane potential in the dendrites or cell body that vary in strength and can be either positive or negative. They also travel very short distances and lose strength rapidly. However, multiple ones in close spatial proximity or close in time add together to travel further or last longer.
graded potential
Graded potential is a general term with two specific sub-types. A(n) _____ is the sub-type that describes a small depolarization.
EPSP - Excitatory post-synaptic potential
A sub-type of graded potential that is defined by a small hyperpolarization. (Hint: See pp. 260 - 261).
IPSP - Inhibitory post-synaptic potential
What is the typical resting membrane potential for a neuron in
millivolts?
-70 mV
If the sum of all graded potentials at the axon hillock surpasses a
particular membrane potential called the __________ , the neuron will
generate or “fire” an action potential.
threshold voltage
At what membrane potential (in millivolts) will an action potential be
generated in a typical neuron?
-55 mV
When a neuron generates an action potential, it will rapidly depolarize
due to the influx of a few of these specific ions.
Na+
During the depolarization phase of an action potential, channels for this specific ion will be slow to open and achieve maximum
permeability just after the membrane reaches its maximum potential.
K+
The repolarization of the membrane during an action potential is
mostly due to efflux of a few of these specific ions.
K+
The phase of the action potential when the cell’s membrane potential dips below its resting level.
hyperpolarization
When a neuron is in the process of generating an action potential (including the depolarization and repolarization phases), it cannot fire a second action potential, no matter how much additional stimulation it receives. This period is called the ______________.
absolute refractory period
As the neuron’s membrane potential is slowly returning to the resting level from a hyperpolarized state, it CAN fire a second action potential IF the next stimulus is larger than normal. This period is called the ______________.
relative refractory period
______ is the specific term for an action potential moving rapidly down a myelinated axon.
saltatory conduction
When an action potential reaches the axon terminal, voltage-gated
____ channels will open and this ion will influx.
Ca2+
Calcium moves into the cell, _______ will fuse with the plasma membrane and release whatever signal molecule (a
neurocrine) they contain.
synaptic vessicles
A signal molecule that is released by a neuron into the synaptic cleft
could be a neuromodulator or a ___________.
neurotransmitter
A signal molecule that is released by a neuron into the circulatory
system (blood) is called a __________.
neurhormone
. If a signal molecule is released into a synaptic cleft, it will bind with
receptors on post-synaptic membrane. Eventually the effect of that
signal molecule will be turned off by several mechanisms. In some
cases, neurotransmitters are degraded by ______ in the synaptic cleft.
enzymes
In other cases, neurotransmitters will be transported back into the
neuron that secreted them for recycling or into a nearby glial cell for
degradation. This process is called _______________.
reuptake
This general category of neurotransmitters includes norepinephrine,
dopamine, serotonin, and histamine.
amines
This general neurotransmitter category includes adenosine.
purine
This is the only gas shown in this table that acts as a neurotransmitter.
nitric oxide
This specific neurotransmitter has two types of receptors – nicotinic
and muscarinic.
aceytlcholine