Pathophysiology 01 - Module 1 - Stress and Adaptation module 1-4 MODULE 1: STRESS AND ADAPTATION

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MODULE 1: STRESS AND ADAPTATION “A state manifested by a specific syndrome of the body, developed in a response to any stimuli that made an intense systemic demand on it” (Selye, 1956) “A p... erson experiences stress when a demand exceeds a person’s coping abilities, resulting in reactions such as disturbances of cognition, emotion, and behaviour that can adversely affect well-being” (McCance & Huether 2006) Review of the Adrenal Gland:  There are three main layers of the adrenal gland 1. Capsule: Tough fiberous capsule enclosed in fat for protection 2. Adrenal cortex (80-90% of gland): has three zones and secretes three types of steroid hormones (synthesized from acetate & cholesterol): glucocorticoids, mineralcorticoids and adrenal androgens. 3. Adrenal medulla (10-20% of gland): contains nervous tissue which is part of the sympathetic nervous system and secretes Epi and NE Adrenal Cortex  There are three layers of the adrenal 1. Zona glomerulosa: - Outer most layer of the adrenal cortex - Produces primarily aldosterone (95% of minero-corticoid produced is in this form) 2. Zona fasciculate - Middle layer of the adrenal cortex - Produces primarily cortisol (95% of glucocorticoids), cortisone and corticosterone 3. Zona reticularis: - Inner most layer - Adrenal androgens (i.e. gonadocorticoids) are made here Downloaded by Denis Munene ([email protected]) lOMoARcPSD|16310140 NURSING 2PF3 Module 1: Stress and Adaptation 2  There are three types of adrenal cortical hormones: 1. Mineral corticoids Aldosterone - Synthesized by: the zona glomerulosa - Release is regulated by: the renin-angiotensin mechanism and by blood levels of potassium - Circulates: mostly bound to albumin - Main effects:  Sodium retention by the distal tubules of the kidney while increasing urinary losses of potassium  Regulation of volume and blood pressure control (renin-angiotensin pathway)  Facilitates the excretion of hydrogen ions  role in pH balance - Excessive aldosterone (aldosteronism [usually related to neoplasms]):  Increased sodium and water retention  hypernatremia hypertension, increased blood pressure, and edema;  Increased potassium excretion  hypokalemia  arrhythmias, muscle weakness and paralysis (potassium is important for muscle contraction and membrane depolarization) - Insufficient aldosterone:  Increased sodium and water excretion  hyponatremia  hypotension, dehydration  Increased potassium retention  hyperkalemia  again, there will be dysfunction of muscle contraction (including the heart and GI) which may cause arrhythmia and potential weight loss 2. Glucocorticoids Cortisol: - Synthesized by: the zona fasciculate and zona reticulari [Show More]

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