Biopsychology Flashcards
What is a genotype?
The genes an organism has inherited (23 from each parent = 46 in total)
What is phenotype?
The traits that are actually expressed. Can be physical traits e.g. eye colour, can be non-physical e.g. temperament, depression etc
What determines whether or not a gene will be expressed?
- Interaction with other genes: dominant = will always be expressed as phenotype, recessive = only expressed as phenotype if inherited from both parents
- Interaction between genes and environment: for psychological disorders, gene-environment interactions can be explained by the diathesis stress model. Development of disorders is due to a combination of diathesis factors (genetic vulnerability) and stress factors (environmental triggers). One factor by itself cannot cause behaviour
What are twin studies?
- Twin studies investigate may pairs of twins and assess how often they share a particular characteristic
- The statistic used to measure the chance that two twins share a characteristic is known as the concordance rate
- Monozygotic (MZ) twins are identical and share 100% similarity of their genetic material whereas dizygotic (DZ) twins are non-identical and share about 50% similarity of genetic material
LINK TO HUMAN BEHAVIOUR:
- If concordance rate for MZ twins was significantly higher than DZ twins this would suggest that characteristics are mainly due to genetics. Thus genes lead to behaviour.
- If concordance rate was similar we can assume that characteristics is due to environment
GOLDEN RULE:
- As the proportion of shared genes increases when comparing DZ (50%) twins to MZ twins (100%) so does the likelihood of both twins demonstrating the same behaviour
What is the central nervous system?
AO1
- Composed of the brain and spinal cord
- Brain is divided in separate areas - each has a different function ranging from higher level functions (e.g. controlling thought and decision making) to controlling skills and balance
- Function of the spinal cord is to relay info between the brain and the rest of the body
What is the peripheral nervous system?
AO1
- Comprised of nerves outside of CNS
- Relays nerve impulses between the brain and the rest of the body
- Has 2 main functions: the autonomic nervous system and the somatic nervous system
What is the autonomic nervous system?
AO1
- The ANS connects with and controls internal organs and glands
- Controls INVOLUNTARY functions and only uses motor pathways
- Has 2 divisions:
- sympathetic branch = have an arousing effect on the body e.g. preparing body for ‘fight or flight’
- parasympathetic branch = calming effect on the body and helps the body return to homeostasis after a period of excitation
What is the somatic nervous sytem?
AO1
- Consists of nerves which recieve input from sense organs and send output to control VOLUNTARY muscle movement
- Comprised of sensory and motar neurons (NOT RELAY)
- Connects CNS and the senses
What is the structure and function of a sensory neuron?
AO1
STRUCTURE:
- Long dendrites
- Short axon
- Unipolar - only transmits info
FUNCTION:
- Type of afferent nerve cell that carries sensory impulses FROM sense organs e.g. skin TO the CNS
What is the structure and function of a relay neuron?
AO1
STRUCTURE:
- Short dendrites
- Short axon
- Multipolar - sends AND receives info from many sources
- Found in the CNS
FUNCTION:
- Connects with and acts between other neurons e.g. sensory and motor
- Involved in analysis of the sensation: deciding what something means and how to respond
What is the structure and function of a motor neuron?
STRUCTURE:
- Short dendrites
- Long axon
- Multipolar
FUNCTION:
- Type of efferent nerve cell that caries sensory impulses AWAY from CNS TO muscles and glands
What is the process of synaptic transmission?
- Synthesis: precursor chemicals are transported to the axon terminal in the PRE-synaptic neuron. They are used to produce neurotransmitters which are packaged into vesicles
- Release: in response to an electrical impulse, neurotransmitters are released into the synapse
- Receptor Activation: neurotransmitters diffuse across the synapse and bind to specific receptor sites in the POST-synaptic neurone
- Inactivation: neurotransmitters then unbind from receptor and either goes through reuptake into the PRE-synaptic neuron (via active transport) and is packaged back into vesicles, OR is broken down by enzymes in the synapse
What is the post-synaptic process within synaptic transmission?
- When an excitatory neurotransmitter binds to a receptor site on the post-synaptic neuron it produces an excitatory post-synaptic potential (EPSP)
- When an inhibitory neurotransmitter binds to a receptor site on a post-synaptic neuron it produces an inhibitory post-synaptic potential (IPSP)
- Following this, summation occurs. This is when the post-synaptic neuron aggregates the overall IPSP and EPSP to decide whether or not to fire
- If EPSP is greater than IPSP there is an overall positive charge. Therefore, the post-synaptic neuron is more likely to fire - this is called excitation or depolarisation
- If IPSP is greater than EPSP there is an overall negative charge. Therefore the post-synaptic neuron is less likely to fire - this is called inhibition or hyper-polaristion
Why can signals in the synapse only travel in one direction?
Surprise 3 Marker
- The synaptic vesicles containing neurotransmitters are only released from the pre-synaptic neuron
- Neurotransmitters in the synapse go from an area of high concentration to low concentration (via diffusion) so travel from pre to post-syanptic membrane
- The receptor for neurotransmitters to bind with are only present on the POST-synaptic neuron and it is the binding which passes on info
What is the difference between neurotransmitters and hormones?
- Neurotransmittters are produced within neurons whereas hormones are secreted by glands
- Neurotransmitters pass very quickly from one neuron across the synapse to another nearby neuron whereas hormones travel less quickly through the bloodstream to often quite distant target organs
What is the endocrine system?
Consists of glands which produce hormones that have many regulatory functions such as metabolism, development, tissue function, sexual function, reproduction, sleep and mood.
It provides a chemical system of communication through the bloodstream with each type of hormone targeting specific organs/tissues
e.g. ACTH triggers adrenal glands to secrete corticosteroids resulting in a stress response
What is a hormone and what do they do?
Chemical messengers produced by the glands of the endocrine system
1. Upon the brain’s signal hormones are secreted into the bloodstream by glands
2. The hormones travel through the blood streams to target cells
3. Hormones exert influence on target cells by stimulating receptors on the surface of or inside the cell
4. Presence of the hormone leads to a physiological reaction in the cell altering its activity
What is the pituitary gland?
- Helps regulate the function and secretion of other glands in the endocrine system
- Releases prolactin which helps with lactation
What is the adrenal gland?
- Secretes adrenaline and responds to the sympathetic division during a fight or flight response
What is the thyroid gland?
- Secretes thyroxine which regulates metabolism rate and growth
What is the sympathomedullary pathway?
- A stressor is perceived and assessed
- The hypothalamus activates the sympathetic branch of the autonomic nervous system
- Sympathetic nerves transmit the signal from the CNS to adrenal glands
- The adrenal medulla releases adrenaline and noradrenaline into the bloodstream
- Adrenaline constricts blood vessels in the skin to divert blood to the muscles
What are some impacts adrenaline has on the body?
INCREASES:
- heart rate to increase blood pumped around the body
- blood pressure to speed up blood flow
- lung function to increase oxygen intake
- blood glucose for energy from respiration
- pupil size so more light can enter the eye to improve vision
- blood flow to muscles to increase mobility
DECREASES:
- salivation as digestion isn’t prioritised
- digestion as blood is directed to muscles
What is the parasympathetic response to fight or flight?
- Once the threat of the stressor is gone, the autonomic nervous system switches from the activation of the sympathetic branch to the parasympathetic branch
- This reduces the release of adrenaline into the bloodstream causing a calming effect on the body known as ‘rest and digest’
- This decreases heart rate and brings the return of digestive processes
- Parasympathetic activation returns the body to a balanced state known as homeostasis
How can we criticise fight or flight?
(random surprise question unlikely to come up again)
- A weakness is that human behaviour in response to threatening situations is not limited to 2 responses
- Gray argued that the first response to danger is often to ‘freeze’. During this response humana are hyper-vigilant and assess the situation carefully to plan the best course of action
- This suggests that fight or flight is too restrictive in its explanation of behavioural responses to threats and cannot fully explain the range of biological and cognitive influences on behaviour
- Thus research into fight or flight is incomplete and our understanding reduces in validity
How can we support fight or flight?
(random surprise question unlikely to come up again)
- A strength is that the supporting evidence uses scientific methodology
- e.g. flight or flight research operationalises arousal through levels of hormones which is an objective measure and free from bias
- Also the research into fight or flight is often conducted in controlled conditions meaning that methods can easily be replicated
- This also allows researchers to test the reliability of the findings
- Thus validating the research into fight or flight and so our understanding
