BIOLOGICAL PSYCHOLOGY
Assumptions :
- Assumes our biology, especially psychology, affects our behaviour
- Many human behaviours have a physiological cause which may be genetically
or environmentally altered
- Psychologists should study the brain, nervous system, and other biological
systems (hormones, imbalanced chemicals)
Central nervous system Peripheral nervous system
Brain Motor Neuron
Spinal Cord Sensory Neuron
The CNS consists of the brain and spinal cord. It is the central processing and
control point for all human behaviour. The brain processes all the information from
the senses and is then responsible for controlling the behaviour that may result from this
information. The spinal cord connects the brain to the rest of your body and allows
messages to be passed from the body to the brain and also from the brain to other parts
of the body in order to get them to respond.
NEURONS
Neurons are cells within the nervous system which communicate with around 1000
other cells at a time in huge networks. Neuron has a cell body with a nucleus in the
middle. The neuron transmits nerve impulses which are electrical signals and then
send chemicals to the next neuron across a very small gap between them.
1. MOTOR – Carry messages from the CNS along the nerves in the PNS to the
effectors in the body (muscles or glands). They have short dendrites and long
axons.
2. RELAY – Connects sensory and motor neurons together and also connects other
relay neurons. They decide what to do and have short dendrites and axons. They
are only found in the CNS.
3. SENSORY – Carries messages from sensory receptors along nerves in the PNS
to the CNS. They have long dendrites and short axons
,STRUCTURE OF A NEURON
Name Description/Functions
Soma (Cell body) Includes a nucleus controlling the genetic
material of the cell, Branch-like dendrites
stick out from the cell body. These carry
impulses.
Axon Tube-like structure that carries the
impulses away from the cell body down
the length of the neuron.
Myelin sheath A fatty layer covering the axon, formed
from glial cells. Both protect the axon
and speed up electrical transmission
of the impulse. The nodes allow an
increase in speed by forcing the impulses
to jump.
Axon terminal button Not physically connected to the next
neuron in the chain but are involved in
the communication across the
synapse.
, ACTION POTENTIAL
Action potential is the electrical trigger that passes along the axon and stimulates
the neuron to activate and release neurotransmitters as a result of synaptic
transmission.
This is important because it holds great significance to the functioning of the brain since
they pass on information in the nervous system to the CNS and pass on
commands initiated in the CNS to the peripheral.
It plays a central role in cell to cell communication by providing for the passing of
signals along the neuron’s axon towards the synaptic buttons situated at the ends of an
axon ; these signals can then connect with other neurons, or motor cells or glands.
1. Neurotransmitter binds to the sodium gated channel (excitatory postsynaptic
potential)
2. Domino effect so other channels do the same and allow more sodium ions to
enter, the neuron becomes depolarised with a bundle of sodium and potassium
ions inside the neuron.
3. As it becomes too positive, the potassium ions leave through a potassium gated
channel.
4. The neuron becomes hyperpolarised.
5. Three sodium ions go out for two potassium ions.
Assumptions :
- Assumes our biology, especially psychology, affects our behaviour
- Many human behaviours have a physiological cause which may be genetically
or environmentally altered
- Psychologists should study the brain, nervous system, and other biological
systems (hormones, imbalanced chemicals)
Central nervous system Peripheral nervous system
Brain Motor Neuron
Spinal Cord Sensory Neuron
The CNS consists of the brain and spinal cord. It is the central processing and
control point for all human behaviour. The brain processes all the information from
the senses and is then responsible for controlling the behaviour that may result from this
information. The spinal cord connects the brain to the rest of your body and allows
messages to be passed from the body to the brain and also from the brain to other parts
of the body in order to get them to respond.
NEURONS
Neurons are cells within the nervous system which communicate with around 1000
other cells at a time in huge networks. Neuron has a cell body with a nucleus in the
middle. The neuron transmits nerve impulses which are electrical signals and then
send chemicals to the next neuron across a very small gap between them.
1. MOTOR – Carry messages from the CNS along the nerves in the PNS to the
effectors in the body (muscles or glands). They have short dendrites and long
axons.
2. RELAY – Connects sensory and motor neurons together and also connects other
relay neurons. They decide what to do and have short dendrites and axons. They
are only found in the CNS.
3. SENSORY – Carries messages from sensory receptors along nerves in the PNS
to the CNS. They have long dendrites and short axons
,STRUCTURE OF A NEURON
Name Description/Functions
Soma (Cell body) Includes a nucleus controlling the genetic
material of the cell, Branch-like dendrites
stick out from the cell body. These carry
impulses.
Axon Tube-like structure that carries the
impulses away from the cell body down
the length of the neuron.
Myelin sheath A fatty layer covering the axon, formed
from glial cells. Both protect the axon
and speed up electrical transmission
of the impulse. The nodes allow an
increase in speed by forcing the impulses
to jump.
Axon terminal button Not physically connected to the next
neuron in the chain but are involved in
the communication across the
synapse.
, ACTION POTENTIAL
Action potential is the electrical trigger that passes along the axon and stimulates
the neuron to activate and release neurotransmitters as a result of synaptic
transmission.
This is important because it holds great significance to the functioning of the brain since
they pass on information in the nervous system to the CNS and pass on
commands initiated in the CNS to the peripheral.
It plays a central role in cell to cell communication by providing for the passing of
signals along the neuron’s axon towards the synaptic buttons situated at the ends of an
axon ; these signals can then connect with other neurons, or motor cells or glands.
1. Neurotransmitter binds to the sodium gated channel (excitatory postsynaptic
potential)
2. Domino effect so other channels do the same and allow more sodium ions to
enter, the neuron becomes depolarised with a bundle of sodium and potassium
ions inside the neuron.
3. As it becomes too positive, the potassium ions leave through a potassium gated
channel.
4. The neuron becomes hyperpolarised.
5. Three sodium ions go out for two potassium ions.
