HPA axis
This glucocorticoid hormone, released by the adrenal cortex, provides negative feedback to both the hypothalamus and pituitary.
Cortisol
Name one main target organ of the SAM response.
Heart, lungs, blood vessels, adrenal glands
What is one way chronic stress can affect learning and memory?
Impaired formation of new memories and decreased spatial/contextual memory due to hippocampal atrophy and reduced neurogenesis
Cortisol increases plasma glucose primarily through what hepatic process?
Gluconeogenesis
The concept describing “wear and tear” from prolonged stress is called what?
Allostatic load
In acute stress, cortisol helps maintain blood glucose by antagonizing the action of this hormone.
Insulin
Which types of behavioural responses/ activation does the SAM axis cause?
Behavioral AdaptationAdaptive redirection of behaviorIncreased arousal and alertnessIncreased cognition, vigilance and focused attentionSuppression of feeding behaviorSuppression of reproductive behaviorInhibition of gastric motility; stimulation of colonic motilityContainment of the stress responsePhysical AdaptationAdaptive redirection of energyOxygen and nutrients directed to the central nervous system and stressed body site(s)Altered cardiovascular tone; increased blood pressure and heart rateIncreased respiratory rateIncreased gluconeogenesis and lipolysisDetoxification from toxic productsInhibition of reproductive and growth axesContainment of the stress responseContainment of the inflammatory/immune response
Impaired formation of new memories and decreased spatial/contextual memory due to hippocampal atrophy and reduced neurogenesis
Locus coeruleus (LC)
Elevated cortisol disrupts which phase of sleep most prominently?
REM
Chronic cortisol elevation may cause these two changes in the musculoskeletal system (name one for muscular and one for skeletal).
Prolonged exposure to elevated levels of cortisol can lead to muscle wasting and decreased bone density by inhibiting osteoblast activity and promoting osteoclast function
Cortisol acts via two receptor types with differing affinities; name both.
Mineralocorticoid receptor (MR) and Glucocorticoid receptor (GR)
Which brainstem nucleus helps regulate sympathetic outflow to the body during stress?
ventrolateral medulla (VLM), particularly its rostral ventrolateral medulla (RVLM), caudal ventrolateral medulla (CVLM), paraventricular nucleus of the hypothalamus (PVN)
Chronic stress reduces neurogenesis in this hippocampal region.
Dentate gyrus of the hippocampus
These two hormones involved in height development are affected in children raised in stressful environments.
GH and STS
Over time, chronic stress can reduce the sensitivity of glucocorticoid receptors, leading to what effect on feedback?
Impaired negative feedback of the HPA axis → cortisol levels remain elevated
This structure of the pituitary is directly connected to the hypothalamus via neuronal axons (as opposed to the portal blood system).
Posterior pituitary (neurohypophysis)
What type of receptors in target tissues mediate most of epinephrine’s effects on heart rate and bronchodilation?
Beta-adrenergic receptors
Explain how chronic stress alters amygdala connectivity.
Increased dendritic growth and hyperactivity in the amygdala
Enhanced connectivity with the prefrontal cortex and hippocampus in a way that biases towards threat detection and fear responses
This contributes to heightened anxiety, emotional reactivity, and impaired emotional regulation
Name two gastrointestinal pathologies that may worsen under chronic stress.
Peptic ulcers, IBS, Crohn's, GERD
Chronic stress alters immune function by suppressing which type of immune cell proliferation?
Lymphocytes
Explain why chronic HPA axis activation can lead to immune suppression.
Inhibit cytokine production
Reduce lymphocyte proliferation
Decrease antibody synthesis
Suppress inflammatory responses
Explain how chronic overactivation of the SAM system can contribute to cardiovascular disease.
Persistent high heart rate and blood pressure → increases cardiac workload
Vascular remodeling and endothelial dysfunction → promotes atherosclerosis
Increased catecholamine exposure → can trigger arrhythmias and cardiac hypertrophy
During stress, CRH can both engage prostanoid-mediated hypothalamic circuits and suppress NPY-driven behaviors. What are the 2 physiological functions affected?
Appetite and thermoregulation
Repetitive activation of the sympathetic nervous system stiffens arterial walls and promotes low-grade inflammation through this biological process, linking emotional strain to heart attack risk.
Endothelial dysfunction
Name one of the 3 stages of the general adaptation syndrome.
alarm reaction stage, resistance stage, and exhaustion stage.