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