The Adrenals

• The paired Adrenal glands or Suprarenal glands lie superior to each kidney in the retroperitoneal space.
• In an adult, each adrenal gland is 3–5 cm in height, 2–3 cm in width, and a little less than 1 cm thick, with a mass of 3.5–5 g.
• The Adrenal gland has an outer cortex and an inner medulla.
• The outer cortex of the Adrenal gland comes from the intermediate mesoderm (mesodermal mesenchyme derivative).
• The inner medulla of the Adrenal gland is neuroectodermal in origin.
• The Adrenal Cortex is subdivided into three zones, each of which secretes different hormones.
• Hypothalamus-Pituitary-Adreno Axis and Sympatho-Adreno-Medullary Axis Responses to stressors during the stress response.
• The Adrenal Cortex, which composes 90% of the gland by weight, functions to regulate metabolism and maintain normal electrolyte balance.
• The outer zone of the Adrenal Cortex, called the Zona Glomerulosa, is just deep to the connective tissue capsule and its cells are closely packed and arranged in spherical clusters and arched columns.
• Racing thoughts, dizzy or lightheaded, quick and shallow breathing, bladder urgency, and sweaty palms can occur during fight or flight response.
• Decrease in digestive processes, including slowing down of food movement in the bowel, can occur during fight or flight response.
• Nausea or “butterflies” can occur during fight or flight response, as less blood is going to the gastrointestinal tract.
• Adrenergic receptors are involved in the physiological responses during SNS stimulation.
• The adrenal medulla secretes the hormones epinephrine and norepinephrine into the bloodstream.
• The Zona Glomerulosa secretes hormones called Mineralocorticoids because they affect mineral homeostasis.
• Cortisol exhibits the permissive or tropic effects on the target tissue, sensitizing the target tissue to the Glucagon and Epinephrine, permitting them to have glucose elevating effects.
• Cortisol only causes a slight increase in blood glucose levels.
• During fight or flight response, there is an increase in heart rate.
• Steroids can either increase or decrease certain blood cell lines.
• Signals are also sent to the adrenal cortex to produce the stress hormone cortisol.
• Steroids are used in the treatment of IgE-mediated allergies, and Cortisol and Hydrocortisone are examples of steroids.
• Tunnel vision occurs during fight or flight response, where peripheral vision is diminished and visual attention is focused on a narrow, central field.
• Individuals who have had a heart attack may present with elevated white blood cell (WBC) counts, not necessarily due to infection but due to the stress caused by the myocardial infarction leading to Cortisol secretion.
• Cortisol causes a decrease in Eosinophils.
• During fight or flight response, blood is redirected from less critical areas to more vital areas that are crucial for immediate survival.
• Adrenal glands release epinephrine during fight or flight response.
• Glucagon and Epinephrine cause an additive increase in blood glucose levels.
• Epinephrine and Norepinephrine cause several physiological changes to prepare the body for fight or flight.
• Elevation of WBC is mainly due to drastically increased polymorphonuclear cells or Neutrophils.
• The SNS then stimulates the adrenal medulla.
• Cortisol can also cause a decrease in lymphocytes and basophils.
• Fight or Flight Response: A person enters a stressful or dangerous situation, the amygdala is activated, sending a distress signal to the hypothalamus.
• The purpose of tunnel vision is to concentrate and enhance focus on potential threats.
• During fight or flight response, blood vessels in the skin contract to force blood toward the muscles.
• Pupils dilate to help see better during fight or flight response.
• The hypothalamus activates the sympathomedullary pathway (SAM pathway), a pathway running to the adrenal medulla and the sympathetic nervous system (SNS).
• Pressure natriuresis and pressure diuresis are when the pressure increases, the kidney will start dumping sodium and fluid in order to maintain a normal blood pressure.
• 11 Beta-Hydroxysteroid Dehydrogenase-2 (11BHSD2) converts Cortisol to Cortisone in the kidney, colon, sweat and salivary glands.
• Cortisol can either increase or decrease protein expression.
• Cortisol has some mineralocorticoid potency and can also attach to the Mineralocorticoid Receptor (MR) and induce mineralocorticoid effects.