Biopsychology uses biology to explain behaviour:

• Biopsychology is all about how biology influences behaviour. Biolopsycgologists study things like the nervous system, neurotransmitters and hormones- and that means you should too

The nervous system has two parts:

1. Your nervous system allows you to respond to environmental changes (stimuli). It also allows you to coordinate your actions

2. Receptors detect stimuli and effectors bring about a response to a stimulus. Effectors include muscle cells and cells found in glands, e.g the pancreas

3. Receptors communicate with effectors via the nervous or endocrine systems, or sometimes both

4. The nervous and endocrine systems coordinate the response

5. The nervous system has 2 parts, CNS and PNS

The nervous system:

• The central nervous system (CNS)- made up of the brain and the spinal cord

• The peripheral nervous system is made up of the neurons that connect the CNS to the e rest of the body. It also has 2 different systems:

  • The somatic nervous system controls conscious activities e.g running and playing video games

  • The automatic nervous system (ANS) controls unconscious activities e.g. digestion. It’s got two divisions that have opposite effects

    • The sympathetic nervous system gets the body ready for action ‘flight or fight’ system

    • The parasympathetic nervous system calms the body down. It’s called the ‘rest and digest’ system.

The cells of the Nervous System are called Neurons:

1. Neurons transmit information as electrical impulses around the body

2. The cell body has dendrites that receive information from other neurons

3. The info passes along the axon in the form of an electrical impulse that ends up at a synaptic knob. The myelin sheath insulates the axon to speed up nervous transmission

4. There’s a small gap before the next neuron called the synapse

5. Neurotransmitters are chemicals that are released from the synaptic knob. They pass across the synapse, to pass on the signal to the dendrites of the next neuron

Different types of neurons have different roles:

Different types of neurons are involved in the transfer of information to and from the CNS. The structure of these neurons differs:

• Sensory neurons: The nerve cells that transmit electrical impulses from receptors to the CNS

• Relay neurons: The nerve cells that transmit electrical impulses between sensory neurons and motor neurons

• Motor neurons: The nerve cells that transmit electrical impulses from the CNS to effectors.

The transmission of information to and from the CNS is:

Sensory neuron- Relay neuron- Motor neuron

1. Stimulus

2. Receptors

3. CNS

4. Effectors

5. Response

Reflexes help prevent injury:

Reflexes are fast, automatic responses to certain stimuli. They bypass your unconscious brain completely- instead, they go through the spinal cord or through an unconscious part of the brain. These rapid responses help us to avoid damage

A synapse is a junction between a neuron and the next cell:

1. A is the junction between a neuron and another neuron, or between a neuron and an effector cell, e.g a muscle or gland cell

2. The tiny gap between the cells at a synapse is called the synaptic cleft

3. The presynaptic neuron (the one before the synapse) has a swelling called synaptic knob. This contains synaptic vesicles filled with neurotransmitters

4. When an electrical impulse reaches the end of a neuron it causes neurotransmitters to be released into the synaptic cleft. They diffuse across to the postsynaptic membrane (The other after the synapse) and bind to specific receptors

5. When neurotransmitters bind to receptors they might trigger an electrical impulse (in a neuron), cause a muscle contraction (in a muscle cell), or cause a hormone to be secreted (from a gland cell)

6. Here’s what happens when an electrical impulse arrives at a synapse between 2 neurons:

   1. Electrical impulse reaches the end of the first neuron

   2. Neurotransmitters are released

   3. Receptors are stimulated

   4. This can lead to a new impulse being set off in the next neuron if enough receptors are stimulated

7. Because the receptors are only on the postsynaptic membranes, synapses make sure impulses are unidirectional- the impulse can only travel in one direction

8. Neurotransmitters are removed from the cleft so the response doesn’t keep happening, e.g they’re taken back into the presynaptic neuron or they’re broken down by enzymes (and the products are taken into the neuron)

Neurotransmitters are excitatory or inhibitory:

• Excitatory neurotransmitters increase the likelihood that an electrical impulse will be triggered in the postsynaptic neuron

• Inhibitory neurotransmitters decrease the likelihood that an electrical impulse will be triggered in the postsynaptic neuron

Some neurotransmitters come up a lot in psychology:

There are lots of different neurotransmitters, but some play a larger role in human behaviour:

• Acetylcholine: This excitatory neurotransmitter is involved in voluntary movement, memory, learning and sleep. Too much is linked to depression and too little may result in dementia

• Dopamine: Dopamine is a neurotransmitter that helps with movement, attention and learning. Too much is linked to schizophrenia, and too little could result in depression and Parkinson’s disease

• Noradrenaline: It is closely related to adrenaline. It is often associated with the ‘fight or flight’ response. Too much is linked to schizophrenia and too little may result in depression

• Serotonin: It is involved in emotion, mood, sleeping and eating. Too little is linked to depression

• GABA: It is an inhibitory neurotransmitter. Too little is linked to anxiety disorders.