Biopsychology
The nervous system
* The central nervous system consist of the brain and the spinal cord
* The brain is split into two hemispheres; right and left
* The spinal cord is responsible for moving your hand away from a hot plate, it
sends messages to and receives messages from the peripheral nervous system
* The peripheral nervous system consists of the autonomic nervous system which is
responsible for bodily functions such as heart rate, digestion, stress response
(fight or flight)
* The somatic nervous system is responsible for muscle movement and dealing with
information from the sensory receptors
Endocrine system
* This is slower than the nervous system but can be more powerful
* Hormones are produced through various gland, and these are released into the
bloodstream
* For example, the ovaries produce oestrogen and these are released into the
bloodstream
* Most hormones are produced by the pituitary glands, located in the brain. It
is often called the master gland as it controls all the other glands in the body
Fight or flight
* Your body is in one of two states, sympathetic and parasympathetic
* The parasympathetic state is when you are at rest. You can sleep and digest
food in this state (rest and digest)
* The sympathetic is when you notice a stressor and your body goes into fight or
flight
* Imagine you see a tiger walk past. Your senses send a signal to the brain that
something is wrong. The pituitary gland is activated and a chemical called ACTH is
released into the bloodstream. This instructs the adrenal glands to release
cortisol into the bloodstream. Adrenaline is also released as a signal is sent down
the spinal cord to the adrenal glands to release this.
Neurons
* neurons are cells that are specialised in carrying electrical charge and
transmitting that impulse. They are the basic build block of the nervous system
* The cell body (soma) contains a nucleus. It is in this nucleus that most of
the metabolic work of the cell is carried out
* At one end of the cell are dendrites which receive from other neurons and
conduct nerve impulses to the soma
* At the other end is the axon which conducts away from the soma and towards
other neurons
* Each neuron will send to around 1000 other neurons but they can only carry a
message in one direction
Sensory neurons
* They respond to stimulation from the sensory receptors and then send a signal
to the brain or spinal cord. This is an afferent neuron
* There are sensory neurons for all modalities, sound sight smell taste and
touch
* They are located in the peripheral nervous system
, * The sensory neurons receive information from the sensory receptor through the
dendrites, this is passed to the cell body to the axon and then the axon terminals
* The dendrites are long and the axons are short in comparison
Motor neurons
* these neurons are also found in the PNS and transmit signal from the brain and
spinal cord to the muscles or glands
* They are efferent neurons as they carry signals away from the central nervous
system/brain and spinal cord
* Information enters through the dendrites, passed to the cell, through to the
axon unit it reaches the axon terminal
* The axon terminals are known as motor end plates if the connect to a muscle
* The dendrites are short and the axon is long
Relay neurons
* These neurons form connections between other neurons. All neurons in the CNS
are relay neurons. They are also known as interneurons as they are neither sensory
nor motor
* They receive signals from sensory neurons or other relay neurons and pass
these onto motor neurons or other relay neurons
* There are over 100 million relay neurons in the body, more than sensory and
motor combined. This is because they have such a complex purpose integrating
sensory and motor information
* Information enters relay neurons through the dendrites, proceeds to the cell
body and to the axon and axon terminals. They typically have short dendrites and
short axons
Synaptic transmission
* Synapses are the gaps between neurons. They cannot touch as they are
electronically charged
* Neurons fire and release
* An action potential is part of the process when a neuron fires
* Part of the neural membrane open to allow positively charged ions into the
cell and negatively charged ions out
* This allows information to pass between the neurons and for commands to pass
in the nervous system
* Once the action potential is sufficient the vesicles release the NT from them
into the axon and then go out into the synaptic cleft or gap
* Once in the cleft or gap the aim is that the charge is suitably strong enough
for the NT to cross the cleft and bind with the receptor on the dendrite of
postsynaptic
* This means that the signal from the NT can be passed on and transmitted
through the neuron
* An action potential passes down presynaptic towards the axon terminal
* This excites the vesicle that contain the NT in question
* If the action potential is inadequate and neuron misfires then the NT may
become stuck in the cleft and cannot bind with the receptor
* It may take another electrical charge to ensure this can happen
* In some cases the NT may be reabsorbed by the axon terminal so it doesn't
cross the cleft at all
* One of the roles of SSRI drugs is to ensure that this does not occur and the
serotonin remains in the cleft
* Neurotransmitters can be inhibitory or excitatory
* Inhibitory reduces the chances of a neuron firing an action potential.
Examples would be serotonin and GABA
* Some NT are excitatory
The nervous system
* The central nervous system consist of the brain and the spinal cord
* The brain is split into two hemispheres; right and left
* The spinal cord is responsible for moving your hand away from a hot plate, it
sends messages to and receives messages from the peripheral nervous system
* The peripheral nervous system consists of the autonomic nervous system which is
responsible for bodily functions such as heart rate, digestion, stress response
(fight or flight)
* The somatic nervous system is responsible for muscle movement and dealing with
information from the sensory receptors
Endocrine system
* This is slower than the nervous system but can be more powerful
* Hormones are produced through various gland, and these are released into the
bloodstream
* For example, the ovaries produce oestrogen and these are released into the
bloodstream
* Most hormones are produced by the pituitary glands, located in the brain. It
is often called the master gland as it controls all the other glands in the body
Fight or flight
* Your body is in one of two states, sympathetic and parasympathetic
* The parasympathetic state is when you are at rest. You can sleep and digest
food in this state (rest and digest)
* The sympathetic is when you notice a stressor and your body goes into fight or
flight
* Imagine you see a tiger walk past. Your senses send a signal to the brain that
something is wrong. The pituitary gland is activated and a chemical called ACTH is
released into the bloodstream. This instructs the adrenal glands to release
cortisol into the bloodstream. Adrenaline is also released as a signal is sent down
the spinal cord to the adrenal glands to release this.
Neurons
* neurons are cells that are specialised in carrying electrical charge and
transmitting that impulse. They are the basic build block of the nervous system
* The cell body (soma) contains a nucleus. It is in this nucleus that most of
the metabolic work of the cell is carried out
* At one end of the cell are dendrites which receive from other neurons and
conduct nerve impulses to the soma
* At the other end is the axon which conducts away from the soma and towards
other neurons
* Each neuron will send to around 1000 other neurons but they can only carry a
message in one direction
Sensory neurons
* They respond to stimulation from the sensory receptors and then send a signal
to the brain or spinal cord. This is an afferent neuron
* There are sensory neurons for all modalities, sound sight smell taste and
touch
* They are located in the peripheral nervous system
, * The sensory neurons receive information from the sensory receptor through the
dendrites, this is passed to the cell body to the axon and then the axon terminals
* The dendrites are long and the axons are short in comparison
Motor neurons
* these neurons are also found in the PNS and transmit signal from the brain and
spinal cord to the muscles or glands
* They are efferent neurons as they carry signals away from the central nervous
system/brain and spinal cord
* Information enters through the dendrites, passed to the cell, through to the
axon unit it reaches the axon terminal
* The axon terminals are known as motor end plates if the connect to a muscle
* The dendrites are short and the axon is long
Relay neurons
* These neurons form connections between other neurons. All neurons in the CNS
are relay neurons. They are also known as interneurons as they are neither sensory
nor motor
* They receive signals from sensory neurons or other relay neurons and pass
these onto motor neurons or other relay neurons
* There are over 100 million relay neurons in the body, more than sensory and
motor combined. This is because they have such a complex purpose integrating
sensory and motor information
* Information enters relay neurons through the dendrites, proceeds to the cell
body and to the axon and axon terminals. They typically have short dendrites and
short axons
Synaptic transmission
* Synapses are the gaps between neurons. They cannot touch as they are
electronically charged
* Neurons fire and release
* An action potential is part of the process when a neuron fires
* Part of the neural membrane open to allow positively charged ions into the
cell and negatively charged ions out
* This allows information to pass between the neurons and for commands to pass
in the nervous system
* Once the action potential is sufficient the vesicles release the NT from them
into the axon and then go out into the synaptic cleft or gap
* Once in the cleft or gap the aim is that the charge is suitably strong enough
for the NT to cross the cleft and bind with the receptor on the dendrite of
postsynaptic
* This means that the signal from the NT can be passed on and transmitted
through the neuron
* An action potential passes down presynaptic towards the axon terminal
* This excites the vesicle that contain the NT in question
* If the action potential is inadequate and neuron misfires then the NT may
become stuck in the cleft and cannot bind with the receptor
* It may take another electrical charge to ensure this can happen
* In some cases the NT may be reabsorbed by the axon terminal so it doesn't
cross the cleft at all
* One of the roles of SSRI drugs is to ensure that this does not occur and the
serotonin remains in the cleft
* Neurotransmitters can be inhibitory or excitatory
* Inhibitory reduces the chances of a neuron firing an action potential.
Examples would be serotonin and GABA
* Some NT are excitatory
