BTEC Level 3 90 Credit Diploma in Applied Science
Samuel James
Unit 12 – Physiology of Human Reg & Reproduction
The Nervous system
The nervous system is a bodily system which transmits electrical signals through a network of
specialised cells known as neurones around the body from the brain and spinal cord. The nervous
system is comprised of two parts; the central nervous system (CNS) and the peripheral nervous
system (PNS).
The nervous system is composed of specialised cells called neurones (shown below in the image),
with 100 billion contained in the brain alone. A neurone is composed of a dendrite, which has the
role of receiving electrical signals from other neurones and then passing them onto the other
component of a neurone, the cell body. The cell body contains the nucleus, endoplasmic reticulum,
mitochondria and Golgi apparatus. The cell body produces all the proteins needed for all the
components of the neurone and
provides all the energy needed. The
other component of a neurone is
the axon which is covered in a fatty
substance called the myelin sheath
which has the role of insulation.
The axon is the component of the
neurone which carries the electrical
signal, which allows it to be passed
on via chemical diffusion to other
neurones dendrite branches via the
synapse. The synapse is the area
between the axon of a neuron and
dendrite of another neurone.
(Zimmermann, 2018)
The central nervous system is composed of the brain and spinal cord and has the function of
transmitting, receiving and interpreting chemical signals from the body. The information received
and interpreted by the CNS is then sent to the PNS. As mentioned previously, the CNS is composed
of the brain which has the role of processing sensory information received from the other
component of the CNS, which is the spinal cord. The peripheral nervous system is similar to the
central nervous system, however it’s distinct in the location within the body compared to the CNS.
The PNS is located in all areas of the body which does not contain the CNS and has the role of
connecting the central nervous system to the skin, limbs and organs. The PNS allows both the brain
and spinal cord to transmit and also receive signals to and from the outermost part of the body.
(Zimmermann, 2018)
Unlike the CNS, which is directly involved with the brain and spinal cord, the PNS includes motor
neurones and sensory neurones. Sensory neurones are also a type of cell within the nervous system
and has the role of carrying sensory neural impulses which have been received from either receptors
or sensory organs. Motor neurones are a cell within the nervous system which have the role of
muscle contraction or relaxation. The motor neurone system can be further divided into two
categories – The somatic and autonomic nervous system. The somatic nervous system has the role
of transporting both motor and sensory information to the central nervous system. The somatic
nervous system is involved in all voluntary muscle movements and also the processing of sensory
Samuel James
Unit 12 – Physiology of Human Reg & Reproduction
The Nervous system
The nervous system is a bodily system which transmits electrical signals through a network of
specialised cells known as neurones around the body from the brain and spinal cord. The nervous
system is comprised of two parts; the central nervous system (CNS) and the peripheral nervous
system (PNS).
The nervous system is composed of specialised cells called neurones (shown below in the image),
with 100 billion contained in the brain alone. A neurone is composed of a dendrite, which has the
role of receiving electrical signals from other neurones and then passing them onto the other
component of a neurone, the cell body. The cell body contains the nucleus, endoplasmic reticulum,
mitochondria and Golgi apparatus. The cell body produces all the proteins needed for all the
components of the neurone and
provides all the energy needed. The
other component of a neurone is
the axon which is covered in a fatty
substance called the myelin sheath
which has the role of insulation.
The axon is the component of the
neurone which carries the electrical
signal, which allows it to be passed
on via chemical diffusion to other
neurones dendrite branches via the
synapse. The synapse is the area
between the axon of a neuron and
dendrite of another neurone.
(Zimmermann, 2018)
The central nervous system is composed of the brain and spinal cord and has the function of
transmitting, receiving and interpreting chemical signals from the body. The information received
and interpreted by the CNS is then sent to the PNS. As mentioned previously, the CNS is composed
of the brain which has the role of processing sensory information received from the other
component of the CNS, which is the spinal cord. The peripheral nervous system is similar to the
central nervous system, however it’s distinct in the location within the body compared to the CNS.
The PNS is located in all areas of the body which does not contain the CNS and has the role of
connecting the central nervous system to the skin, limbs and organs. The PNS allows both the brain
and spinal cord to transmit and also receive signals to and from the outermost part of the body.
(Zimmermann, 2018)
Unlike the CNS, which is directly involved with the brain and spinal cord, the PNS includes motor
neurones and sensory neurones. Sensory neurones are also a type of cell within the nervous system
and has the role of carrying sensory neural impulses which have been received from either receptors
or sensory organs. Motor neurones are a cell within the nervous system which have the role of
muscle contraction or relaxation. The motor neurone system can be further divided into two
categories – The somatic and autonomic nervous system. The somatic nervous system has the role
of transporting both motor and sensory information to the central nervous system. The somatic
nervous system is involved in all voluntary muscle movements and also the processing of sensory
