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PYC1512 Assignment 1 Semester 1 2026 (Answer Guide) - DUE 26
March 2026
VERIFIED AND CERTIFIED ANSWERS. WRITTEN IN REQUIRED FORMAT AND WITHIN
GIVEN GUIDELINES. IT IS GOOD TO USE AS A GUIDE AND FOR REFERENCE, NEVER
PLAGARIZE. Thank you and success in your academics.
UNISA, 2026
Contents
Question 1 (4 marks) ....................................................................................................................... 2
Question 2 (2 marks) ....................................................................................................................... 2
Question 3 (4 marks) ....................................................................................................................... 2
Question 4 (6 marks) ....................................................................................................................... 3
Question 5 (5 marks) ....................................................................................................................... 4
Question 6 (4 marks) ....................................................................................................................... 4
Reference List ................................................................................................................................... 5
, 2|Page
Question 1 (4 marks)
The Central Nervous System (CNS) and the Peripheral Nervous System (PNS) are the
two primary divisions of the nervous system, distinguished by their structures and
functions. The CNS is composed of the brain and the spinal cord. Its primary function is
to act as the body's main control centre and processing unit, integrating information it
receives and coordinating activity across the entire organism (Kalat, 2017).
In contrast, the PNS consists of all the neural pathways—nerves and ganglia—that lie
outside the brain and spinal cord. Its function is to connect the CNS to the limbs,
organs, skin, and other parts of the body. The PNS serves as a communication relay,
carrying sensory information from the body to the CNS and transmitting motor
commands from the CNS out to the muscles and glands (Pinel & Barnes, 2021). In
essence, the CNS is the command centre, while the PNS is the vast communication
network that links the centre to the rest of the body.
Question 2 (2 marks)
The autonomic nervous system (ANS) is a division of the PNS responsible for regulating
involuntary bodily functions. Its main functions are to control internal organs and glands,
maintaining a stable internal environment (homeostasis) without conscious effort. It
governs processes such as heart rate, digestion, respiratory rate, salivation,
perspiration, and pupillary dilation (Weiten, 2017). The ANS achieves this through its
two main branches: the sympathetic nervous system, which mobilises the body's
resources during stress or threat (the 'fight-or-flight' response), and the parasympathetic
nervous system, which conserves energy and promotes restorative functions during
times of rest (the 'rest-and-digest' response).
Question 3 (4 marks)
Using the concept of epigenetics, we can explain how life experiences influence genetic
function without changing the underlying DNA sequence.
Epigenetic changes refer to modifications in gene expression that do not involve
alterations to the DNA sequence itself. Instead, these changes affect how cells "read"
genes. Think of the DNA as a vast library of instructions. Epigenetic changes act like
bookmarks or sticky notes on specific pages, determining which instructions are read
and followed and which remain silent. Common mechanisms include DNA methylation,
which typically silences a gene, and histone modification, which can make genes more
or less accessible for transcription (Moore, 2015).
How life experiences influence gene functioning: Life experiences, such as drug
addiction, childhood trauma, or living in a war zone, can trigger these epigenetic
changes. These environmental factors can send signals to the cell that lead to the
addition or removal of these chemical "bookmarks" on the DNA. For example, chronic
PYC1512 Assignment 1 Semester 1 2026 (Answer Guide) - DUE 26
March 2026
VERIFIED AND CERTIFIED ANSWERS. WRITTEN IN REQUIRED FORMAT AND WITHIN
GIVEN GUIDELINES. IT IS GOOD TO USE AS A GUIDE AND FOR REFERENCE, NEVER
PLAGARIZE. Thank you and success in your academics.
UNISA, 2026
Contents
Question 1 (4 marks) ....................................................................................................................... 2
Question 2 (2 marks) ....................................................................................................................... 2
Question 3 (4 marks) ....................................................................................................................... 2
Question 4 (6 marks) ....................................................................................................................... 3
Question 5 (5 marks) ....................................................................................................................... 4
Question 6 (4 marks) ....................................................................................................................... 4
Reference List ................................................................................................................................... 5
, 2|Page
Question 1 (4 marks)
The Central Nervous System (CNS) and the Peripheral Nervous System (PNS) are the
two primary divisions of the nervous system, distinguished by their structures and
functions. The CNS is composed of the brain and the spinal cord. Its primary function is
to act as the body's main control centre and processing unit, integrating information it
receives and coordinating activity across the entire organism (Kalat, 2017).
In contrast, the PNS consists of all the neural pathways—nerves and ganglia—that lie
outside the brain and spinal cord. Its function is to connect the CNS to the limbs,
organs, skin, and other parts of the body. The PNS serves as a communication relay,
carrying sensory information from the body to the CNS and transmitting motor
commands from the CNS out to the muscles and glands (Pinel & Barnes, 2021). In
essence, the CNS is the command centre, while the PNS is the vast communication
network that links the centre to the rest of the body.
Question 2 (2 marks)
The autonomic nervous system (ANS) is a division of the PNS responsible for regulating
involuntary bodily functions. Its main functions are to control internal organs and glands,
maintaining a stable internal environment (homeostasis) without conscious effort. It
governs processes such as heart rate, digestion, respiratory rate, salivation,
perspiration, and pupillary dilation (Weiten, 2017). The ANS achieves this through its
two main branches: the sympathetic nervous system, which mobilises the body's
resources during stress or threat (the 'fight-or-flight' response), and the parasympathetic
nervous system, which conserves energy and promotes restorative functions during
times of rest (the 'rest-and-digest' response).
Question 3 (4 marks)
Using the concept of epigenetics, we can explain how life experiences influence genetic
function without changing the underlying DNA sequence.
Epigenetic changes refer to modifications in gene expression that do not involve
alterations to the DNA sequence itself. Instead, these changes affect how cells "read"
genes. Think of the DNA as a vast library of instructions. Epigenetic changes act like
bookmarks or sticky notes on specific pages, determining which instructions are read
and followed and which remain silent. Common mechanisms include DNA methylation,
which typically silences a gene, and histone modification, which can make genes more
or less accessible for transcription (Moore, 2015).
How life experiences influence gene functioning: Life experiences, such as drug
addiction, childhood trauma, or living in a war zone, can trigger these epigenetic
changes. These environmental factors can send signals to the cell that lead to the
addition or removal of these chemical "bookmarks" on the DNA. For example, chronic
