Biopsychology Flashcards
How is the nervous system split
- central nervous system (CNS)
- peripheral nervous system (PNS) => further split
What does the CNS consist of
- brain
- spinal cord
What does the CNS do
- control behaviour and regulation of body’s physiological processes
What are the different brain regions involved in the CNS
- cerebrum
- cerebellum
- diencephalon
- brain stem
What’s the role of the cerebrum in the CNS
- largest part of the brain
- four lobes => split down the middle into two halves => left and right hemisphere
What’s the role of the cerebellum in the CNS
- responsible for motor skills, balance, and coordinating the muscles to allow for precise movements
What’s the role of the diencephalon in the CNS
- thalamus => regulates consciousness, sleep and alertness
- hypothalamus => regulations body temperature, stress response and hunger and thirst
What’s the role of the brain stem in the CNS
- regulates breathing and heart rate
What’s the role of the spinal cord in the CNS
- relay information between brain and rest of body
- allows brain to monitor and regulate bodily processes
- connected to different parts of body by pairs of spinal nerves => connected to specific muscles and glands
- if spinal cord damaged, body areas connected to nerves below damage will be cut off and stop functioning
What does the PNS consist of
- whole nervous system
- transmits messages via neurons to and from CNS
How is the PNS split
- somatic nervous system
- autonomic nervous system => further split
What does the somatic nervous system do
- controls voluntary movements => under conscious control
- connects senses with CNS
- has sensory pathways and motor pathways
- controls skeletal muscles
- controlled by motor cortex
What does the autonomic nervous system do
- involuntary movements => not under conscious control
- only has motor pathways
- controls smooth muscles and internal organs and glands of body
- controlled by brain stem
How is the autonomic nervous system split
- sympathetic nervous system
- parasympathetic nervous system
What does the sympathetic nervous system do
- activated when a person is stressed
- heart rate and breathing increase
- digestion stops
- salivation reduces
- pupils dilate
- flow of blood diverted from surface of skin
What does the parasympathetic nervous system do
- activated when body is relaxing => conserving energy
- hear rate and breathing reduce
- digestion starts
- salivation increases
What are neurons
- specialised nerve cells
- move electrical impulses to and from CNS
What are the different parts of a neuron
- cell body => control centre of the neuron
- nucleus => contains genetic material
- dendrites => receives electrical impulses (action potential) from other neurons or sensory receptors
- axon => long fibre carrying electrical impulse from cell body to axon terminal
- myelin sheath => insulating layer protecting axon and speeding transmission of impulse
- schwann cells => make up myelin sheath
- nodes of ranvier => gaps in myelin sheath, speed up impulse along axon
Label the typical neuron diagram
What are the different types of neurons
- sensory neuron
- motor neuron
- relay neuron
Explain the role of a sensory neuron
- found in sensory receptors
- carry electrical impulses from sensory receptors to CNS via PNS
- convert information from sensory receptors to electrical impulses
- when impulses reach brain, they convert into sensations => so body can react appropriately
- some impulses terminate at spinal cord => reflexes
Explain the role of a motor neuron
- located in CNS but project axons outside of CNS
- send electrical impulses via long axons to glands and muscles
- glands and muscles called effectors
- when motor neurons stimulated, they release NTs that bind to receptors on muscles to trigger response => movement
Explain the role of a relay neuron
- found in CNS
- connect sensory neurons to motor neurons so they can communicate
- during reflex arc, relay neurons in spinal cord are involved in analysis of sensation => decide how to respond without waiting for brain
Label the relay neuron diagram
Label the motor neuron diagram
Label the sensory neuron diagram
Label the diagram
What is synaptic transmission
- electrical impulses being sent to release NTs
How does synaptic transmission work
- neurons transmit electrical impulses (action potentials) between presynaptic neuron and postsynaptic neuron
- when action potential reaches presynaptic terminal, it triggers release of NTs from sacs on the presynaptic membrane (vesicles) => process called exocytosis
- released NTs diffuse across synaptic cleft where it binds to specialised postsynaptic receptor sites
How can synaptic transmission stop
- synaptic transmission takes only a fraction of a second
- effects can be terminated by re-uptake
- NTs are taken back by vesicles on presynaptic neuron
- stored for later release
- the quicker the NT is taken back, the shorter the effects
Explain neurotransmitters in relation to synaptic transmission
- can be excitatory or inhibitory => most can be both but GABA is purely inhib
- excit NTs cause electrical charge in membrane of postsynaptic neuron => results in excit postsynaptic potential (EPSP) => post synaptic neuron more likely to fire impulse
- inhib NTs cause inhib postsynaptic potential (IPSP) => postsynaptic neuron less likely to fire impulse
How does a neuron decide if it fires an impulse or not
- neuron can receive both EPSPs and IPSPs at same time
- likelihood of neuron firing an impulse is determined by adding excit and inhib synaptic input
- net result of calculation (summation) determines whether or not the neuron will fire an impulse
- if net effect is inhib, neuron will not fire
- if net effect is excit, neuron will fire
What direction does the synapse travel in
- information can only travel in one direction at a synapse
- vesicles containing NTs are only present on presynaptic membrane
- receptors for NTs are only present on postsynaptic membrane
- it is the binding of NTs to the receptors which enables information to be transmitted
- diffusion means they can only go from high to low concentration
How can synaptic transmission be used for medication
- psychoactive drugs affect transmission of NTs
- pain meds mimic effects of inhib NTs
- stimulation of postsynaptic receptors by inhib NT lead to inhibition of postsynaptic membrane
- inhib NT binding to postsynaptic receptors makes postsynaptic neuron less likely to fire
- due to summation, if inhib NTs are higher than excit they can inhibit action potential from occuring
- therefore pain meds would decrease overall activity and reducing brain activity may lead to less pain
Label the diagram
What is the endocrine system
- provides a chemical system of communication in body via blood stream
- works alongside nervous system to control vital functions in the body
- acts more slowly than nervous system but has very widespread effects
- uses endocrine glands
What is the function of endocrine glands
- produce and secrete hormones into bloodstream which are required to regulate bodily functions
- each gland produces different hormones which regulate activity of organs/tissues in the body
- although hormones come into contact with most cells, they only affect certain cells => target cells
- target cells respond to particular hormone as they have receptors for it
- when enough receptor sites stimulated by hormone, there is a physiological reaction
What is the pituitary gland
- located in brain
- produces hormones whose function is to influence release of other hormones from other glands
- controlled by hypothalamus
- split into two divisions
How is the hypothalamus involved in the endocrine system
- receives information about basic functions of body
- sends signal to pituitary gland in form of releasing hormone
- causes pituitary gland to send stimulating hormone into bloodstream to tell target gland to release its hormone
- as levels of this hormone rise in bloodstream, the hypothalamus shuts down production of releasing hormone and pituitary gland shuts down secretion of stimulating hormone
How is the pituitary gland split
- anterior pituitary gland => releases hormone ACTH which regulates levels of hormone cortisol
- posterior pituitary gland => responsible for releasing hormone oxytocin which is crucial for infant/mother bonding
What is the adrenal gland
- two adrenal glands situated on top of kidney
- each gland is made up of two parts
What are the two parts of the adrenal glands
- adrenal cortex
- adrenal medulla
What is the adrenal cortex
- outer section of adrenal gland
- produces cortisol => produced in high amounts when someone is experiencing chronic stress
- cortisol also responsible for cardiovascular system, e.g. will increase blood pressure and cause blood vessels to constrict
What is the adrenal medulla
- inner section of adrenal gland
- produces adrenaline => hormone needed for fight or flight response that is activated when someone is acutely stressed
- increases heart rate, dilates pupils and stops digestion
What are the main organs in the endocrine system
- pituitary gland
- hypothalamus
- pineal gland
- thyroid and parathyroid gland
- thymus
- pancrease
- ovary
- adrenal glands
- placenta
- testicle
Label the diagram
What is the sympathomedullary pathway
- used in fight or flight response
- involves sympathetic nervous system, adrenaline and parasympathetic nervous system
How is the fight or flight response started
- when person is faced with threat, amygdala is activated
- amygdala associates sensory signals with emotions associated to fight or flight
- amygdala then sends distress signal to hypothalamus => command centre in brain which communicates with rest of body through sympathetic nervous system
- different response for acute and chronic stressors
How is the parasympathetic nervous system used in the fight or flight response
- when threat has passed, parasympathetic nervous system dampens stress response
- slows heartbeat and reduces blood pressure
What is the role of the sympathetic nervous system in response to acute stressors
- when SNS is triggered, it begins process of preparing body for rapid action necessary for fight or flight
- sends signal to adrenal medulla to release hormone adrenaline
What does adrenaline do in response to acute stressors
- makes heart beat faster, pushing blood to muscles, heart and other vital organs, and blood pressure increases
- breathing becomes faster so more oxygen can be taken in
- blood sugar released as well as fats, which flood bloodstreams, supplying energy to parts of body associated with fight or flight response
What is the role of the sympathetic nervous system in response to chronic stressors
- if brain continues to perceive something threatening, second system kicks in
- as the initial surge of adrenaline subsides, the hypothalamus activates a stress response system called the HPA Axis
- H => hypothalamus, P => pituitary gland, A => adrenal glands
Explain the role of the hypothalamus in the HPA axis
- HPA relies on series of hormonal signals to keep SNS working
- in response to continued threat, hypothalamus releases chemical messenger CRH
- released into bloodstream in response to stressor
Explain the role of the pituitary gland in the HPA axis
- on arrival at pituitary gland, CRH causes pituitary to produce and release ACTH
- ACTH is transported in bloodstream to target sites in adrenal glands
Explain the role of the adrenal glands in the HPA axis
- ACTH stimulates adrenal cortex to release various stress related hormones => cortisol
- cortisol is responsible for several effects in body that are important for fight or flight
How does feedback happen for chronic stressors in the fight or flight response
- HPA axis system is efficient at regulating itself
- both hypothalamus and pituitary gland have special receptors that monitor cortisol levels
- if these rise above normal, they initiate reduction in CRH and ACTH levels => brings cortisol back to normal
What are positive evaluation points for the fight or flight response
- makes sense from evolutionary psychology point of view as it would have helped individual to survive by fighting or fleeing a threat
- studies supports claim that adrenaline is essential in preparing body for stress, people who have malfunctioning adrenal glands do not have a normal fight or flight response to stress
What are negative evaluation points for the fight or flight response
- Gray (1988)
- Taylor (2000)
- Von Dawans (2012)
How is Gray (1988) a negative evaluation point for the fight or flight response
- states first reaction to stress is freeze
- involves person stopping, looking and listening and being hyper vigilant to danger
How is Taylor (2000) a negative evaluation point for the fight or flight response
- found females tend and befriend in times of stress
- tend and befriend refers to protection of offspring and seeking out social groups for mutual defence
- women have hormone oxytocin which means they are more likely to stay and protect offspring