A: Understand the interrelationship and nervous control of the cardiovascular and
respiratory systems
The nervous system organisation
The brain and the spinal cord, along with a network of neurons make up the nervous system.
The role of the nervous system is sending, processing, and receiving information from all
parts of the body. The brain and the spinal cord are the two main organs in the central
nervous system. The motor nervous system cells has the role of carrying information to
organs, glands and muscles from the central nervous system, whereas the peripheral nervous
system has the role of sending information as it has sensory cells. It sends the information
from the central nervous system.
The autonomic and the somatic nervous system make up the nervous system. As many of the
actions are under conscious control; the somatic nervous system is referred to as the
voluntary nervous system. It includes sensory neurones which essentially transmit impulses
to the central nervous system. It does this from the receptors all over the body, and in turn the
motor neutrons transmit impulses to the muscles. On the other hand, the autonomic nervous
system is referred to as the involuntary nervous system. This is because it enables the
functioning of internal organs without the need for conscious control.
Involuntary responses are controlled by the autonomic nervous system. However, there is the
possibility for it to gain voluntary control over these responses. Examples of activities
controlled by the autonomic nervous system include; the opening of the anal sphincter and
the emptying of the bladder. Conditioning is the process in which the autonomic nervous
system can be brought under voluntary control.
The autonomic system has two distinct parts:
- In order for the body to maintain its functions daily, the parasympathetic nervous
system aids with this.
- In order for the body to react in an emergency situation, the sympathetic nervous
system aids with this.
The action of the parasympathetic and sympathetic nervous systems on the body are as
follows:
Whilst the sympathetic dilates the eye pupils, the parasympathetic constricts the pupil. The
sympathetic inhibits the flow of saliva, whilst the parasympathetic stimulates the flow of
saliva. The sympathetic action on the lungs dilates bronchi, and the parasympathetic
constricts the bronchi. The sympathetic action on the heart is to accelerate the heartbeat,
whilst the parasympathetic slows the heartbeat. The sympathetic action on the liver is to
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