stress, anxiety and aggression Flashcards
what is stress. who said this
‘physiological reaction caused by perception of aversive or threatening situations’ - Walter cannon 1871-1945
what does stress cause. is it episodic or continuous
causes physical, emotional and physiological strain. it can be both episodic and continuous
how does the SAM pathway work. what does SAM stand for
sympathetic-adrenal-medullary system. hypothalamus and Sympathetic nervous system stimulate adrenal medulla to release catecholamine transmitters epinephrine (adrenaline) and norepinephrine (noradrenaline). which increases glucose levels and blood pressure.
how does the HPA pathway work. what does it stand for
hypothalamic pituitary adrenal gland axis. process begins in paraventricular nucleus (PVN) of hypothalamus. PVN releases peptide called corticotropin releasing hormone (CRH) into blood. CRH travels to pituitary gland. pituitary gland then releases hormone: adrenocorticotropic (ACTH).
why would the HPA axis be used over SAM pathway and vice versa
SAM pathway used for immediate response to acute stressors. HPA pathway activated In response to long term chronic stressors.
what is the effect of stress on the brain
it is neurotoxic. chronic exposure to glucocorticoids destroys hippocampal neurones it can also affect the regulation of glutamate in the brain (important neurotransmitter)
what evidence supports the notion that stress can induce neurotoxicity in rats. who studied it
Diamond 1999, A rat was exposed to a cat smell and presence for 75mins. found rats suffered from impaired primed burst potentiation (lack of synaptic strengthening) in hippocampus
what evidence supports the notion that stress induces neurotoxicity in monkeys. who studied it?
monkeys have a hierarchal society. they studied the bottom rank monkey & found that was subjected to continuous stress by upper ranks. this led to enlarged adrenal glands and excessive norepinephrine production.
What is PTSD. how can its likelihood be increased?
Long lasting psychological symptoms after a traumatic event is over. PTSD likelihood can be increased if the traumatic event involved danger or violence.
what are the symptoms of PTSD. how is it triggered
flashbacks, hyper vigilance, irritability, heightened reactions to sudden noises. triggered by cues related to the traumatic event.
what brain changes can happen due to PTSD. who studied it.
can reduce the size of your hippocampus. Bremmer et al 1995 found police officers and combat veterans had reduced hippocampus size.
explain the role the hippocampus can play in PTSD
the hippocampus plays a role in distinguishing contexts. so there is instability in PTSD from detecting safe vs threatening contexts. known as Threat generalisation.
