A Level Psychology - Paper 2 - Biopsychology Revision Document
Includes; The Nervous System (CNS & PNS), Endocrine System, Responses to Stress, Neurons & Synaptic Transmissions, Ways of studying the brain, Localisation and function of the brain, Plasticity and Functional recovery of the brain, Hem...
A Level Psychology – Paper 2 - Biopsychology
The Nervous System –
The nervous system is a specialised network of cells in the human body and is our primary
internal communication network.it has 2 main functions; to collect, process and respond to
information in the environment and to co-ordinate the working of different organs and cells
in the body.
Central Nervous System –
This is made up of the brain and spinal cord. The brain is the centre of all conscious
awareness.
The CNS has 2 main functions; to control behaviour and to regulate the body’s natural
processes. For this to happen the brain must be able to receive information from the
sensory receptors and be able to send messages to the muscles and glands in the body.
Brain - The brains outer cortex is highly developed in humans and is what distinguished our
higher mental functions from animals. It is involved in psychological processes and its main
job is to make sure that life is maintained. It is split up into 3 main areas; Cerebrum – largest
part that is responsible for controlling emotions, personality, vision and thinking.
Cerebellum – controls balance, co-ordination of muscles. The brain stem – responsible for
regulating automatic functions such as breathing, heart rate and swallowing. Neurones pass
through the brain stem allowing messages to be sent between the brain and spinal cord.
Spinal cord – This is where the messages pass through between the brain and peripheral
nervous system. The main function is to relay information between the brain and the rest of
the body. This allows the brain to monitor systems such as digestion and respiration. This
also allows us to perform reflexes without direct involvement from the brain.
Peripheral Nervous System –
This transmits messages through millions of neurones to and from the CNS.
The PNS extends beyond the CNS and transmits messages from the whole body from the
brain and vice versa.
All the nerves outside of the CNS make up the PNS.
There are 2 main divisions of the PNS; somatic nervous system and autonomic nervous
system.
Somatic Nervous System –
This controls muscle movement and receives messages for sensory receptors. Its job is so
transmit and receive messages from the senses. It also directs muscles to react and move.
It is made up of 12 pairs of cranial nerves (emerging from the underside of the brain) and 31
pairs of spinal nerves (emerging from the spinal cord).
These nerves are both sensory and motor neurones. Sensory neurones relay messages to
the CNS and motor neurones relay information from the CNS to other areas of the body. It is
also involved in reflexes.
Autonomic Nervous System –
This looks after the body’s important functions like breathing, heart rate and digestion.
Original Author – P E McLeod
, It helps transmit and receive messages from the organs.
It is split into 2 parts; Sympathetic Nervous System and Parasympathetic Nervous System.
Sympathetic Nervous System –
This is involved in responses such as fight or flight. This does this by increasing heart rate and
blood pressure. This also dilates blood vessels in the muscles.
Neurones from the SNS travel to every organ and gland within the body, preparing the body
for action when under threat.
Parasympathetic Nervous System –
The parasympathetic nervous system relaxes the body once the emergency has passed. It
slows the heart rate and lowers blood pressure. Digestion will occur again.
Endocrine System –
The function of the endocrine system is to work alongside the nervous system to regulate
vital body functions, it is made up of a network of glands which secrete hormones. These
hormones will then communicate messages to the target organs and cause a physiological
change within the body. The hormones travel through the bloodstream.
Glands – these are responsible for producing and secreting hormones that regulate the
activity of cells or organs in the body. Each gland in the body produces a different hormone
which regulates different organs in the body.
Hormones – Behaviour is thought to be influenced by hormones and each hormones is
thought to affect the body in a different way. Normal functioning occurs when these
hormones are at their normal levels. Too much or too little can impact behaviour as they
cause the body systems to dysfunction.
Pituitary (some of the hormones released are important for regulating the endocrine
system). This is controlled by the hypothalamus. There is 2 parts of it; anterior (front) and
posterior (back). The front of the gland released a stress hormone called ACTH that
stimulates the glands to produce cortisol. It also produces some hormones that only females
have that stimulate the ovaries to produce oestrogen. The back of the gland produces
oxytocin which stimulates the uterus in childbirth to start contractions.
Adrenal (important in the fight or flight as it released adrenaline). This gland sits just above
the kidneys. Each gland has 2 parts the cortex (outer) and medulla (inner). The Cortex
produces cortisol, which is a stress hormone. It has a variety of different functions such as
cardiovascular and anti-inflammatory functions. The medulla released adrenaline and
noradrenaline – hormones that prepare the body for fight or flight.
Testes (these facilitate the release of Testosterone). This causes development of male
characteristics and growth. This is controlled by the hypothalamus and the pituitary gland.
Ovaries (these facilitate the release of oestrogen). These are responsible for the production
of eggs and the hormones oestrogen and progesterone.
Original Author – P E McLeod
, Response to stress –
When someone is in stress the amygdala in the brain is stimulated. This associates our
senses with the emotions of the fight or flight response. The amygdala then sends a distress
signal to the hypothalamus, which functions like a command centre. Communicating with
the rest of the body through the PNS.
When adrenaline is released in the blood stream prompts a number of changes within the
body.
Behaviour Why?
Production of Sweat To facilitate temperature regulation
Muscle Tension To increase reaction time and speed
Pupil Dilation To improve vision
Reduced functioning of the digestion and To save energy for important functions
immune system
Faster rate of breathing To increase Oxygen intake
Increased Heart Rate To speed up the blood flow and improve the
spread of adrenaline through the body
Neurones and Synaptic transmissions –
Sensory Neurones – These carry messages from the PNS to the CNS. Receptors in the PNS
pick up an impulse and transmit it along the sensory neuron, which then transmits an
impulse to the CNS. These have long dendrites and short axons. They are found in various
locations in the body. When these impulses reach the brain, they are translated into
sensations so that the organism can respond appropriately. Not all of the impulses are sent
all of the way to the brain, some only go to the spinal cord so that it can get a fast reflex.
Relay Neurones – These receive impulses from sensory neurones and carry these messages
to either other relay neurones or motor neurones to communicate with each other. These
neurones are only in the brain and spinal cord. They have short dendrites and short axons.
Motor Neurones – These carry the impulses away from the CNS to the organs and muscles
in the body (effectors). The cell body is located in the spinal cord and the axon is outside of
the spinal cord. Their axons are nerve fibres that carry signals from the spinal cord. They
have short dendrites and a long axon.
Sensory Neurones Relay Neurones Motor Neurones
Function – To carry impulse Function – Receives impulses Function – These connect the
Original Author – P E McLeod
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