In this work we have already done part of it please add on the word count to make it to
3000+10 %- words. These are the last questions of the criteria questions for regulation and
control that you did on 30TH January 2016 all I need you to do is add more of the wordcount
to make it to 3000.we already have 779 words I only need 2221 words.
3.
Understand the roles of the endocrine and nervous systems in humans.
3.1 Explain the roles of three key hormones and discuss the importance of hormones
in control and co-ordination.
3.3
Describe the structure of a motor neurone and a sensory neurone and explain
their role in a reflex arc.
3.3 Explain the mechanism of transmission of an impulse along a neurone.
3.4 Measure reaction times and evaluate the results.
3.5 Compare the modes of action of nerves and hormones.
Note: just use the questions above and add on the words to make it to 3000
words from the last assignment done that is below here. Remember its Harvard
referencing.
Roles of endocrine and nervous system in humans
As studied in different places, there is a combination of different systems that
coordinates in order to maintain what the regular or perfect requirements of body are.
Therefore, in this section, role of three key hormones and their importance in control
and coordination, structure of motor and sensory neuron and their role in a reflex,
mechanism of transmission of an impulse along a neuron, reaction times and results
as well as mode of action of nerves and hormones will be discussed.
Role of three key hormones and importance in control and coordination
The three key hormones are:

Insulin, helps in the regulation of blood glucose level

ADH, helps in the regulation of water content in blood

Adrenaline, helps to prepare a human being for fight/ flight state
Structure of motor neuron and sensory neuron and role in a reflex
There are three types of neurons; motor neuron, inter- neuron, and sensory
neuron. Motor neuron is responsible for the transport of signal from brain to effector
or target organ and the sensory neuron is responsible for transporting signal from
effector to the brain. Both the neurons coordinate in order to bring about an action
(PMG, 2014). Following two figures help to show how both types of neurons, sensory
and motor, are different from each other:
Figure: Structure of motor neuron and sensory neuron
Reflex actions are basically involuntary since the human body is an
unconscious state. In a reflex action or reflect arc, stimulus is detected by the sensory
neuron and the signal is transmitted immediately to the interneuron or relay neuron
that transmits the signal to brain and from brain to the motor neuron. The motor neuron
then sends signal to effector organ and the required action is produced. Following
figure shows how a reflex arc is carried out effectively through motor and sensory
neuron:
Figure: Reflex Arc (BBC, 2014)
Mechanism of transmission of an impulse along a neuron
The mechanism of transmission of an impulse or signal upon sensing of a
stimulus can be understood through the following figure:
Figure: Transmission of impulse through node of Ranvier
The figure shows the stimulus is sensed by sensory neuron through dendrites
that transmits the signal to axon and then the signal/ impulse is transmitted to the relay
or interneuron through a synapse. A synapse is a small gap between the two neurons
where neurotransmitters are released and helps in the completion of action. Once the
interneuron receives signal, it then transmits it to the motor neuron and brain. The
signal or decision made by brain is relayed to motor neuron which forwards the
required response to effector muscle (target organ or effector). The muscles fibers are
pulled back in order to protect hand from any possible injury. However, in the whole
procedure an important role is played by action potential generated in the axon or
node of Ranvier from where the impulse is transmitted, as shown on the last page.
Following is a figure showing synapse and signal transmission:
Figure: Signal Transmission and a synapse
Reaction times and results
Reaction time to any incident is crucial for the safety of a human being. Same
reaction time also plays a great role when it comes to everyday life routines. For
instance, taking an example of a ball that will hit the face; in order to save oneself from
the hit, the person has to act fast. In simpler words, the neurons have to be fast enough
so that he could save himself (Gandhi, et al., 2013). The following chart may help to
understand reaction time to various types of stimulus such as visual stimulus, audio
stimulus and touch stimulus:
Figure: Reaction time
The above chart shows that when a ruler was used to strike on a hand, the
reaction time taken from the distance of ruler to the hitting of ruler was this. The results
show that as the distance increases, the reaction time also increases.
Modes of action for nerves and hormones
Mode of action of nerves is initiated by electrochemical signals that generate
fast responses however, the response if short lived. Moreover, the nerves response is
voluntary that is imitated by signals from brain and ends when the required response
is acquired. Same case is seen in case of hormones, the effect subsides when the
required response has been acquired. On the other hand, mode of action for nerves
is specific, that is, they affect specific body parts; whereas, hormones could produce
an overall effect on the body. Also, hormones are usually initiated through a chemical
signal that is a response to a stimulus, which has already triggered brain (WestOne,
2014).