1. BIOL2411 Human Anatomy And Physiology
Answers:
Introduction
Nervous system is the main regulatory, controlling and communicating system of human
body. It conducts all the mental activities like memory and learning (Cantile and Youssef).
The report aims at discussing general structure if neurons in the nervous system, functions
of CNS, reflex arc and contribution of brain in learning and memory.
Discussion
General Structure Of Neurons
The cells present in the nervous system are known as neurons. They send and receive
signals to the brain. The axons are special projections in neurons which are responsible for
sending chemical and electronic signals to other cells. These motions could also be received
by root like extensions called dendrites (Allen and Lyons). The main parts of neurons
consist of the following:
Axons: It is a long tail like structure and joins the body of neurons with structure called
axon hillock. Myelin is a fatty substance which defends numerous axons. Myelin assists
axons in transferring electrical indications (Cantile and Youssef).
Dendrites: These are fibrous root like structure that comes out from the head of neurons.
They are receptors of the electric signals.
Synapses: On the dendrites and cell bodies of other neurons, neuron-to-neuron associates
are formed. Information is transmitted from the first neuron, to the target neuron through
these links, which are known as synapses.
The flow of information starts from dendrite to the soma and then to the axon. Axon them
transmits information in the form of signals to terminal buttons and then finally it transmits
it to synapse.
The chemical messengers of the human body are usually mentioned as neurotransmitters.
2. They are the chemicals which the nervous system utilizes to direct and receive information
amongst neurons as well as among neurons and muscles (Butt, Bradley and Sills).
Neurotransmitter transfer information between synapses in the form of chemicals. The
discharge of neurotransmitter from the presynaptic cell is activated whenever a nerve
impulse passes down an axon and hits the axon terminal. Neurotransmitter molecules
penetrate the synapse and connect to postsynaptic cell membrane sensors, generating an
excitatory synaptic signal (Cantile and Youssef).
Figure: Structure of neuron
Source: (Vergnolle and Cirillo)
How CNS Coordinate With PNS
CNS is central nervous system which comprises of spinal cord and nerves in the brain. PNS
is peripheral nervous system involves peripheral nerves. The peripheral nervous system
(PNS) is among the body's two main nervous system mechanisms. The PNS manages action
and reactions with the central nervous system (CNS) through transmitting signs through
one part of the human body to another. CNS consists of brain, spinal cord and brain stem.
PNS includes sensory neurons like ganglia as well as connector neurons which interconnect
the CNS and other neurons. If PNS does not function properly or does not exist in human
body, CNS will not be able to receive any sensory information (Waxenbaum, Reddy and
Varacallo). This will make CNS impossible to react to external changes in
environment. Sensory receptors perceive variations in the interior and exterior
environments in the sensory nerves of the PNS. Afferent sensory nerves transmit this
information to the CNS. Indications are conveyed back to the PNS over efferent peripheral
nerves after data dispensation in the CNS. 32
Figure: CNS and PNS
Source: (Encyclopedia and system, 2022)
Importance Of Reflex Arc And How It Accomplishes Its Functions
Reflex arc is sensory and neural mechanism which regulates a reflex. This is vital in
generating involuntary reaction which is vital to prevent injury in a person. Interneurons
communicate with motor neurons that regulate muscle activity, while sensory neurons
could also interact directly with motor neurons (He et al.,). Reflex arcs safeguard human
muscles from overextension during stretching reflexes, and they also protect the body from
injury throughout withdrawal response to stimuli.
How does the Structure of the Brain Influence Memory and Learning?
3. The part of the brain which is involved in learning and memory are cerebellum, amygdala,
prefrontal cortex and hippocampus. Declarative, periodic, and recognition memory are all
related with the hippocampus. The cerebellum is linked with the processing of procedural
memories like learning in what way to play the piano. In order to remember semantic tasks,
the prefrontal cortex appears to be involved. Hippocampus is involved in spatial and
recognition memory (Edelmart). Another function of the hippocampus is to transfer
information to cortical regions which provide interpretation to memories and link them to
other memories. This also assists with memory formation, which is the process of moving
novel information from short-term memory to long-term memory.
Amygdala is involves in memory storage and implicit memories are created with the help of
cerebellum and prefrontal cortex. This includes motor learning, procedural memory as well
as classical conditioning (Edelmart). 33
Figure: Parts of the brain
Source: (Carter)
References
Allen, Nicola J., and David A. Lyons. "Glia as architects of central nervous system formation
and function." Science 362.6411 (2018): 181-185.
Butt, Mark T., Alys Bradley, and Robert Sills. "Nervous system." Toxicologic Pathology. CRC
Press, 2018. 1093-1132.
Cantile, Carlo, and Sameh Youssef. "Nervous system." Jubb, Kennedy & Palmer's Pathology
of Domestic Animals: Volume 1 (2016): 250.
Carter, Rita. The brain book: An illustrated guide to its structure, functions, and disorders.
Dorling Kindersley Ltd, 2019.
Edelmart, Gerald M. "Building a picture of the brain." The brain. Routledge, 2017. 37-70.
Encyclopedia, M., & system, C. (2022). Central nervous system and peripheral nervous
system: MedlinePlus Medical Encyclopedia Image. Medlineplus.gov. Retrieved 17 April
2022, from
https://medlineplus.gov/ency/imagepages/8679.htm.
He, Ke, et al. "An artificial somatic reflex arc." Advanced Materials 32.4 (2020): 1905399.
Vergnolle, Nathalie, and Carla Cirillo. "Neurons and glia in the enteric nervous system and
4. epithelial barrier function." Physiology 33.4 (2018): 269-280.
Waxenbaum, Joshua A., Vamsi Reddy, and Matthew Varacallo. "Anatomy, autonomic
nervous system." (2019). 1093-1132.
