Biopsychology Flashcards
What is the nervous system and what does it consist of?
The nervous system is a specialised network of cells in the human body and is our primary internal communication system;
It consists of the central nervous system and the peripheral nervous system.
What are the two main functions of the nervous system?
To collect, process and respond to information in the environment;
To coordinate the working of different organs and cells in the body.
What is the Central Nervous System (CNS) made up of?
The brain and spinal chord
Describe the structure and role of the brain.
The brain is the centre of all conscious awareness;
The cerebral cortex is the outer layer of the brain and is what distinguishes human mental functions from those of animals;
The brain is divided into two hemispheres - the left and the right;
Each hemisphere has 4 lobes - frontal, parietal, occipital and temporal.
Describe the structure and role of the spinal chord.
The spinal chord is an extension of the brain;
It is responsible for reflex actions;
It passes messages to and from the brain and connects nerves to the Peripheral Nervous System (PNS)
What is the role of the PNS?
Transmit messages via millions of neurons to and from the central nervous system.
What is the PNS subdivided into?
The autonomic nervous system and the somatic nervous system.
Describe the role of the autonomic nervous system.
Governs vital functions in the body such as breathing, heart rate, digestion - involuntary effect.
What is the autonomic nervous system subdivided into?
The sympathetic nervous system - it activates internal organs and increases bodily activities
The parasympathetic nervous system - it relaxes internal organs and decreases bodily activities.
Describe the role of the somatic nervous system.
Transmits information from receptor cells in the sense organs to the CNS;
It receives information from the central nervous system that directs muscles to act - voluntary effect.
State the role of a sensory neuron.
Carry nerve impulses from sensory receptors (PNS) to the spinal chord and brain (CNS)
State the role of a relay neuron.
Allow sensory and motor neurons to communicate with each other.
State the role of a motor neuron.
Carry nerve impulses from the spinal chord and brain (CNS) to effectors which are muscles and glands (PNS).
Describe the three neurons in terms of axon and dendrite length.
Sensory - Short axon and long dendrites
Relay - Short axon and short dendrites
Motor - Long axon and short dendrites
What is the function of the cell body.
The factory of the neuron;
Contains the nucleus and produces the proteins that a neuron requires to function.
What is the function of a nucleus.
Contains the genetic material within the neuron.
Describe the structure and role of dendrites.
Branch-like features protruding from cell body;
They carry nerve impulses from neighboring neurons towards the cell body.
Describe the structure and role of axons.
Covered in myelin sheath;
Carries the electrical impulse from the cell body down the length of the neuron.
Describe the structure and role of myelin sheath.
Fatty layer which surrounds and protects the axon;
Helps to speed up electrical transmission of the impulse.
Describe the structure and role of the nodes of Ranvier.
Gaps between the myelin sheath;
Their purpose is to speed up the transmission of the impulse, by forcing it to jump across the gaps along the axon
Explain the role of the terminal buttons.
Located at the end of the axon;
Communicate with the next neuron that is on the other side of the synaptic cleft.
Explain the process of synaptic transmission.
An electrical impulse travels down a pre-synaptic neuron along its axon and to the terminal buttons;
The electrical impulse stimulates synaptic vesicles which contain neurotransmitters;
Neurotransmitters are released from synaptic vesicles and travel across the gap - electrical impulse changes to a chemical impulse;
Receptors on the post-synaptic neuron are complementary in shape to specific neurotransmitter;
The connection between the neurotransmitter and receptor either produces an excitatory or inhibitory effect;
If the neurotransmitter is excitatory it is more likely that the electrical impulse will travel along the post-synaptic neuron;
If the neurotransmitter does not fit receptor there will be no electrical impulse.
Describe the two effects neurotransmitters can have.
Increase of the likelihood of a neuron firing - excitation
Decrease the likelihood of a neuron firing - inhibition
Give an example of an excitatory neurotransmitter and its function.
Adrenaline - causes excitation of the post-synaptic neuron by increasing its positive charge and making it more likely to fire.
Give an example of an inhibitory neurotransmitter and its function.
Serotonin - causes inhibition in the post-synaptic neuron as neuron becomes negatively charged and less likely to fire.
Whether or not a post synaptic neuron fires is decided by what?
Summation
What is meant by summation?
The excitatory and inhibitory influences are summed up;
If the net effect on the post-synaptic neuron is inhibitory it is less likely to fire;
If the net effect is excitatory it is more likely to.
Describe the two impacts drugs can have on synaptic transmission.
Increase the amount of neurotransmitter by blocking reuptake channels
OR
Decrease the amount of neurotransmitter by blocking the receptors.
Information can only travel in one direction at a synapse.
Explain why neurons can only transmit information in one direction at a synapse.
[3 marks]
- Receptor binding sites are only found on the post synaptic neuron.
- Neurotransmitters can only diffuse across synapse down a concentration gradient from a high concentration in the pre-synaptic neuron to a low concentration in the post-synaptic neuron.
- The synaptic vesicles containing neurotransmitters are only released from the pre-synaptic neuron.
What is the role of the endocrine system?
Instructs glands to release hormones directly into the blood stream.
Where are hormones carried towards?
Target organs.
What is a gland?
An organ in the body that produces hormones.
Give two examples of glands and the hormones released from each gland.
Describe their impacts.
- Ovaries - release oestrogen;
Controls the regulation of the female reproductive system, including the menstrual cycle and pregnancy. - Adrenal gland - releases adrenaline;
Responsible for the fight or flight response - stimulates the heart rate, contracts blood vessels etc.
What is the main endocrine gland and where is it located?
Pituitary gland, located in the brain.
Why is the pituitary gland often called the ‘master gland’?
Because it controls the release of hormones from all of the other endocrine glands in the body.
Describe the fight or flight response.
- The hypothalamus recognises that there is a threat in the environment.
- The ANS activates the sympathetic nervous system.
- The sympathetic nervous system tells the pituitary gland to release ACTH.
- This sends a message to the adrenal gland.
- The adrenal gland responds by releasing adrenaline.
- The adrenaline travels via the bloodstream and targets organs in the body which have adrenaline receptors.
- Causes many physical changes e.g. stimulating the heart rate.
- Once the threat has passed, the parasympathetic nervous system brings the body back to normal, resting functions.
Give 6 responses to the body when adrenaline is present - sympathetic state.
- Increased heart rate
- Increased breathing rate
- Dilates pupils
- Inhibits digestion
- Inhibits saliva production
- Contracts rectum
Give 6 responses to the body when adrenaline is not present - parasympathetic state.
- Decreased heart rate
- Decreased breathing rate
- Constricts pupils
- Stimulates digestion
- Stimulates saliva production
- Relaxes rectum
Evaluate the fight or flight response. [10 marks]
- TEND AND BEFRIEND - females adopt a ‘tend and befriend response. Taylor et al.
- BETA BIAS - research was typically conducted on males - androcentric. This is an example of beta bias. Cannot be applied to all individuals.
- MALADAPTIVE RESPONSE - Stressors of modern day life can repeatedly activate the fight or flight response. Leads to increase in blood pressure which can damage blood vessels and cause heart disease.
- BIOLOGICALLY REDUCTIONIST - attempts to explain behaviour based on the role of adrenaline and the effect of the nervous system. Does not take into account other elements such as cognitive processes. It may be too limited.
What are the four scanning techniques to study the brain?
- fMRIs
- EEGs
- ERPs
- Post Mortem
Describe fMRIs. (4 POINTS)
- fMRIs work by detecting blood oxygenation and blood flow that indicate increased neural activity.
- People are asked to do a task and it is observed where the brain activity is.
- When a brain area is more active it consumes more oxygen and to meet this increased demand, blood flow is directed to that area.
- Produces 3D images showing which areas of the brain are involved in particular processes which is important for establishing localisation of function.
Evaluate fMRIs. (8 marks)
- fMRI is NON-INVASIVE - unlike other scanning techniques it does not rely on radiation so it is safe.
- Produces images with HIGH SPATIAL RESOLUTION - so can provide a clear picture.
- EXPENSIVE - limits the appropriateness.
- POOR TEMPORAL RESOLUTION - 5 second lag - not truly represent moment-to-moment brain acitivity.
Describe EEGs. (3 POINTS)
- EEGs record changes in electrical activity using electrodes attached to the scalp.
- The scan recordings represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity.
- It is often used as a diagnostic tool as unusual arrhythmic patterns may indicate neurological abnormalities e.g. epilepsy.
Evaluate EEGs (8 marks)
- VALUABLE IN DIAGNOSING CONDITIONS - identified epilepsy and used to understand the stages of sleep.
- HIGH TEMPORAL RESOLUTION - more able to represent moment-to-moment brain activity.
- GENERALISED SIGNAL - difficult to know the exact source of neural activity.
- DO NOT provide a complete picture of brain activity - cannot reveal electrical activity in deeper brain sites.
Describe ERPs. (3 POINTS)
- It records changes in electrical activity using electrodes attached to the scalp but uses a SPECIFIC STIMULUS to see where activity is.
- Using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out, leaving only those responses that are related to a specific stimulus or task.
- Research has revealed many different forms of ERP and how these are linked to cognitive processes.