Unit 9: Human Regulation and Reproduction
Regulation of the cardiovascular and respiratory systems
Introduction
The human body is made up of different systems such as the nervous system. The main function of
the nervous system is that it generates, transmits, and interprets impulses from and to the different
body systems. The nervous system is divided into two main different organisations that include the
central nervous system (CNS) and the peripheral nervous system (PNS). The flowchart below shows
the different divisions of the nervous system:
As shown in the above diagram, the two components of the CNS are the brain and the spinal cord.
The function of the brain is to receive and process sensory information as well as initiate responses
but also to store memories, generate thoughts and emotions. Alternatively, the function of the
spinal cord is to conduct signals from and to the brain as well as controlling any type of reflex
activities. However, the PNS is different from the CNS. This is because, it is separated into two
groups that are named as the somatic nervous system (SNS) and the autonomic nervous system
(ANS). The SNS is also known as the voluntary nervous system and its function is to control the
conscious tasks such as writing whereas the function of the ANS, also known as the involuntary
nervous system, is to control the unconscious tasks such as digestion.
The ANS is further divided into two categories that are very distinct from one another and they
consist of the parasympathetic nervous system and the sympathetic nervous system. The
parasympathetic nervous system consists of maintaining the functions of the body in an individual’s
everyday life. For example, a few actions that the parasympathetic nervous system carries out on
the body is that slows down the heartbeat, it also stimulates the flow of the saliva and constricts
pupils. Alternatively, the sympathetic nervous system prepares the reaction in an individual’s body in
emergency situations. For example, a few of the actions that the sympathetic nervous system carries
out on an individual’s body include the dilation of pupils, the acceleration of the heartbeat, and
inhabitation of the flow of saliva.
The nervous system is also made up of neurons that are cells that transmit electrical impulses in the
form of action potentials between the brain and the body tissues and organs. Sensory and motor
neurons are found in the PNS. Another type of neuron is a relay neuron, which is mostly found in the
CNS. They all have different functions as the sensory neurons, which are also known as afferent
neurons, carry impulses from the receptors to the CNS, whereas relay neurones, which are also
known as interneurons, connect the sensory neurones to the motor neurones in the CNS allowing
the motor neurons, which are also known as the efferent neurones, to carry the impulses from the
CNS to an effector to allow movement to take place. The structure of the different neurons is shown
below:
