Biopsychology - Nervous/Neuron/Synaptic/Endocrine/F+F Flashcards
What are the two sub-systems of the nervous system?
- CNS (Central Nervous System)
- PNS (Peripheral Nervous System)
What is the Central Nervous System?
- made up of brain and spinal cord
- brain is the centre of all conscious awareness
- cerebral cortex (brain’s outer layer) is highly developed
- spinal cord is responsible for reflex actions
- passes messages to and from the brain and connects nerves to the PNS
What is the Peripheral Nervous System?
- transmits messages, via millions of neurons to and from the CNS
- ANS (Autonomic Nervous System) = governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal, and stress responses
- SNS (Somatic Nervous System) = controls muscle movement and receives information from sensory receptors
What is the function of the spinal cord?
- relays info between the brain and the rest of the body
- allows brain to monitor/regulate bodily processes
- contains circuits of nerve cells that allow for simple reflexes
What is the function of the brain?
- cerebrum:
- frontal, temporal, parietal, and occipital lobe
- split into two cerebral hemispheres (communicate via corpus callosum)
- cerebellum:
- controls motor skills/balance and coordinates the muscles to allow for precise movements
- diencephalon:
- divided into 4 sections: thalamus, hypothalamus, epithalamus, and subthalamus
- involved in crucial bodily functions (e.g. coordinating with endocrine system)
- brain stem:
- regulates automatic functions needed for living (breathing, heartbeat, swallowing)
- allows for impulses to pass between brain and spinal cord
What is the function of the somatic nervous system?
- made up of 12 pairs of cranial nerves/31 pairs of spinal nerves
- sensory neurons -> CNS -> motor neurons
- also involved in reflex actions (without CNS)
- facilitates communication between the CNS and outside world (carries sensory info and provides muscle responses)
What is the function of the autonomic nervous system?
- regulates involuntary actions such as heartbeats, digesting food, etc.
- ANS control centre is found in the brain stem
- plays important role in homeostasis (maintains internal processes)
- it has two parts:
- sympathetic nervous system
- parasympathetic nervous system
What is the function of the sympathetic nervous system?
- involved in processes that help deal with emergencies (fight or flight)
- neurons from SNS travel to most organs to prepare body for rapid action
- e.g. releases stored energy, dilates pupils, inhibits digestion
What is the parasympathetic nervous system?
- relaxes the individual after emergency has passed
- slows down heart rate, reduces blood pressure
- returns body to normal resting state
What is the structure of a neuron?
- dendrite
- carry nerve impulses
- cell body (nucleus)
- contains genetic material of the cell
- axon
- carries nerve impulses away from the cell body
- myelin sheath
- fatty layer that protects axon and speeds up electrical transmission of impulse
- node of ranvier
- gaps within the myelin sheath which helps speed up transmission (jumps along axon)
- schwann cell
- axon terminal
- communicate with next neuron in the chain across a synapse
What is the sensory neuron?
- found in receptors and carry nerve impulses to the spinal cord/brain
- some stop at the spinal cord for a reflex action
What is the relay neuron?
- found between sensory input and motor output (in the brain and spinal cord)
What is the motor neuron?
- found in CNS and controls muscle movements
- they release neurotransmitters that bind to muscle receptors
What are the similarities/differences between neurons?
- sensory:
- cell body in the middle of axon
- relay:
- no myelin sheath
- motor:
- large cell body/dendrites
What is synaptic transmission?
- process by which neighbouring neurons communicate with each other (send chemical messages across gap)
- nerve impulse passes from the presynaptic neuron to the postsynaptic neuron
What is the process of synaptic transmission?
- neuron in resting state:
- inside of cell = -vely charged
- neuron activated by stimulus:
- inside of cell = +vely charged
- causes action potential (creates electrical impulse)
- this is electric transmission
- once AP arrives at axon terminal, it needs to cross the synapse (end of pre/postsynaptic neuron)
- synaptic cleft = physical gap between the two neurons
- synaptic vesicle = sacs on axon terminal
- contain neurotransmitters that help to transfer AP
- as AP reaches vesicles, exocytosis takes place
- released NTs diffuse across the synaptic gap and binds to specialised receptors on postsynaptic neuron
- re-uptake = NR taken up again by the presynaptic neuron (stored for later release)
What are excitatory neurotransmitters?
- NTs that are likely to increase chances of activating/carrying out behaviour
- e.g. adrenaline, dopamine
What are inhibitory neurotransmitters?
- NTs responsible for calming the mind/body (induce sleep/filter out unnecessary excitatory signals)
- e.g. serotonin, GABA
What is excitatory post-synaptic potential?
- where the excitatory NT binds to a postsynaptic receptor causing an electrical charge in the membrane
- cell is more likely to fire
What is inhibitory post-synaptic transmission?
- where the inhibitory NT binds to a postsynaptic receptor
- cell is less likely to fire
What is summation?
- net result of whether or not the cell will fire (cell can receive both EPSPs and IPSPs)
- spatial summation:
- large no. of EPSPs are generated at many different synapses on same postsynaptic neuron
- temporal summation:
- large no. of EPSPs generated at the same synapse by series of high freq. APs by presynaptic neuron
What is the endocrine system?
- network of glands across the body that secrete hormones
- blood vessels are used to transmit info
- works alongside the nervous system to control vital bodily functions
- acts much slower than the nervous system but has much long lasting effects
- hormones enter bloodstream and affect any cell that has a receptor for that hormone
What are the main glands/hormones of the endocrine system?
- thyroid:
- thyroxine
- regulates metabolic rate and protein synthesis
- adrenal medulla:
- adrenaline
- fight or flight response
- adrenal cortex:
- cortisol = further release of stored glucose
- mineralocorticoids = regulate water balance of the body
- testes:
- testosterone
- development of male secondary sexual characteristics
- ovaries:
- oestrogen
- regulates female reproductive system
- pineal:
- melatonin
- regulation or arousal, biological rhythms, sleep-wake cycle
What are the anterior pituitary gland hormones?
- adrenocortical trophic hormone (ACTH):
- adrenal cortex
- key component in stress response
- thyroid stim. hormone (TSH):
- thyroid
- stim. release of thyroxine
- prolactin:
- mammary
- stim. milk production/release
- follicle stim. hormone (FSH):
- ovaries/testes
- stim. release of ovarian follicles
- growth hormone:
- cell growth
- melanocyte stim. hormone (MSH):
- stim. production/release of of melanin in skin/hair
What are the posterior pituitary gland hormones?
- antidiuretic hormone (ADH):
- regulates water balance of the body
- oxytocin:
- promotes uterine contractions in childbirth
What is the fight or flight response?
- when a person experiences a threatening situation, their heart beats faster, breathing is more quicker and muscles tense
What happens to the brain during the fight or flight response?
- amygdala:
- associates sensory signals with emotions associated with F or F
- hypothalamus:
- amygdala sends distress signal here
- communicates with the body through the sympathetic nervous system
How does the SNS prepare for the F+F response?
- response to acute stressors:
- prepares for rapid F or F
- adrenaline is released into bloodstream
- heart beats faster
- pushes blood to the muscles, heart and other vital organs, blood pressure increases
- faster breathing
- increases oxygen intake
- blood sugar/fats released
- supplies energy to parts of the body associated with F or F
How does the PNS respond to the F+F response?
- when the threat has passed, PN branch of ANS dampens down stress response
- slows down heartbeat
- reduces blood pressure
What are the strengths/weaknesses of F+F?
- strength:
- makes sense from evolutionary pov (helps individual to survive, F or F would have been more useful back in the day)
- weaknesses:
- reaction is not limited to F or F, freeze can also be involved
- Gray (1988) suggests first response to danger is to avoid confrontation altogether
- typically a male response
- females adopt a ‘tend and befriend’ response in stressful situations
- Taylor (2000) = women are more likely to protect their offspring and form alliances with other women
- Von Dawans (2012) = even males can tend/befriend (9/11)
- modern day life rarely requires intense biological responses
- stressors of modern day life can repeatedly activate the F or F which can -vely affect our health
- suggests that F or F is a maladaptive response in modern day life