Physiological Psychology: Neuron Analogy Assignment

This assignment presents a detailed analogy between a neuron and a tree to explain the structure and function of nerve cells. The student explores the different components of a neuron, including the axon, dendrites, and soma, and compares them to the trunk, branches, and cell body of a tree. The assignment further explains how the axon conducts nerve impulses, the role of the myelin sheath, and the function of dendrites in receiving electrochemical stimulations. It also discusses the resting membrane potential, action potential, threshold potential, and the all-or-none law, relating these concepts to the processes in a plant. The assignment also draws parallels between the release of neurotransmitters and the release of plant hormones, thus concluding that the structure and function of a neuron are analogous to that of a tree.

Running head: PHYSIOLOGY
Neuron Analogy
Name of the Student
Name of the University
Author Note

1PHYSIOLOGY
Neurons are also referred to as nerve cells that are responsible for conduction of
electrical impulses. The neurons are the most basic structural and functional units of the
nervous system. They are extremely diverse in their shape and size. A nerve looks almost
similar to a tree and also has several tree like structures. This assignment shall analyze the
different parts and functioning of a neuron, with regards to a tree.
It can be suggested that upon enlarging a nerve cell thousands, the structure resembles
a tall tree. Furthermore, an analysis of the smaller regions of the nervous system at a
magnified scale bear a resemblance to a massive, eccentric forest. This basic majesty helps in
building the correlation between a neuron and a tree. All neurons are comprised of three
major components, namely, an axon, dendrites (Dendron), and a soma (cell body). The
dendrites represent the branches of a tree. Just like the tree branches are responsible for
providing a way for the leaves of the tree to act in the form of a net for absorbing sunlight,
the dendrites are the branched protoplasmic neuronal extensions. These are primarily
responsible for propagating electrochemical stimulations that are received from different
neuronal cells (adjacent trees), by establishing synapses (networks) (Shepherd 2015).
The axon of a neuron resembles the three trunk. The trunk acts as the principle
wooden axis and has been recognized as an essential feature. The branches of a tree grow
from the trunk. The fact that the primary function of the tree trunk is to provide support to the
tree and conduct water and nutrients can be related to the function of the axon to conduct
nerve impulses. Just like the tree trunk contains the xylem and phloem that help in the
translocation of food and water, the axons are guarded by a myelin sheath or medullary
sheath that provides a protective covering and enhances transmission of electrical impulses,
all along the axon (Bechler and Byrne 2015). The Nodes of Ranvier in a neuron resembles
the internodes and nodes between tree branches.

2PHYSIOLOGY
A tree contains a root system at the lower end that lies below the soil surface and have
two functions namely, anchoring the tree to the ground and collection of water, minerals, and
nutrients. Parallel to this analogy, a neuron has root like branches at the end of an axon that
terminates at specialized structures called axon terminals that help in the release of
neurotransmitters. Under cold conditions, trees enter a state of dormancy or hibernation
where the metabolism of the plant slows down. Similarly, the neurons have a resting
membrane potential of -70 mV that is related to differences in concentration of ions inside
and outside of the cells. The tree roots of axon terminals are the output of a neuronal structure
(Haydon and Nedergaard 2015). At times when a neuron wants to communicate with an
adjacent one, an electrical message is sent in the form of an action potential throughout the
axon (Duan et al. 2013).
Showing consistency with tropic responses in plants that occur in response to different
forms of environmental stimuli, a stimuli outside a neuron results in electrochemical changes
that travel all along the neuronal length and lead to movement of different ions. Threshold
potential refers tom the critical level to which the depolarization must occur for initiating
action potential. This is similar to the light-sensing threshold that brings about phototropism
in a plant. While IPSP refers to synaptic potentials that reduce the likelihood of postsynaptic
neurons to generate action potentials, EPSP is the postsynaptic potential that increases the
action potential likelihood. This can be compared to positive and negative tropism that
governs the growth or movement of the plant either towards the direction of external
stimulus, or away from it (Bastien, Douady and Moulia 2015). The process of communication
between the neurons also occurs according to the all-or-none-law where a neuron gives a
complete response if stimulus does not exceed the threshold, or else there will be no response
(Selverston 2013). The release of neurotransmitters is identical to the release of plant
hormones from the trees upon under specific conditions. Trees release a plethora of plant

3PHYSIOLOGY
hormones that are signal molecules, present in small concentrations inside the plants. The
different plant chemicals are auxins, cytokinins, jasmonates, and gibberellins, respectively.
These can be compared to different neurotransmitters such as, acetylcholine, glycine,
dopamine, histamine, epinephrine and norepinephrine.
To conclude, it can be suggested that the release of chemicals from neurons brings
about changes in the nervous system in response to stimuli, just like the effects of plant
hormones. Hence, the structure of a neuron is analogous to that of a tree and both of them
serve important functions in animals and plants, respectively.

4PHYSIOLOGY
References
Bastien, R., Douady, S. and Moulia, B., 2015. A unified model of shoot tropism in plants:
photo-, gravi-and propio-ception. PLoS computational biology, 11(2), p.e1004037.
Bechler, M.E. and Byrne, L., 2015. CNS myelin sheath lengths are an intrinsic property of
oligodendrocytes. Current Biology, 25(18), pp.2411-2416.
Duan, X., Fu, T.M., Liu, J. and Lieber, C.M., 2013. Nanoelectronics-biology frontier: From
nanoscopic probes for action potential recording in live cells to three-dimensional cyborg
tissues. Nano today, 8(4), pp.351-373.
Haydon, P.G. and Nedergaard, M., 2015. How do astrocytes participate in neural
plasticity?. Cold Spring Harbor perspectives in biology, 7(3), p.a020438.
Selverston, A., 2013. Model neural networks and behavior. Springer Science & Business
Media.
Shepherd, G.M., 2015. Foundations of the neuron doctrine. Oxford University Press.