1、Chapter 17Adrenal GlandThe adrenal glands are organs that control chronic and acute stress(急性应激 ) in the body by regulating blood pressure, heart rate, bronchodilatation, electrolyte balance, and emergency blood sugar levels. The adrenal glands are small peanut-shaped glands that sit cranial to both
2、 left and right kidneyA,adrenal cortexThe adrenal cortex is the outer tissue layer responsible for producing different types of steroids for maintenance of blood sugar, electrolytes, and sex steroid production.1, Zona granulosa(粒状带粒状带 ):This is the outermost area of the cortex,which is responsible f
3、or producing a steroid hormonecalled aldosterone, also called a mineralocorticoid(盐皮质激素 ).2, Zona fasciculata(束状带束状带 ):This layer is the inner region of the ad-renal cortex that produces a prednisone-like steroid called cortisol(皮质醇 ).3, Zona reticularis(网状带网状带 ): The zona reticularis is the inner r
4、egionof the adrenal cortex that produces a prednisone-like steroid called cortisol(皮质醇 ).B,adrenal medullaThe adrenal medulla is the section of tissue in the middle of the gland that is responsible for Producing epinephrine(肾上腺素 ) to assist the body in Times of crisis or life and death concerns(figh
5、t or flight).B,adrenal medullaEpinephrine has the following effects on the body: Increases heart rate; Increases blood vessel constriction, thus increases blood pressure; Dilates bronchial airways; Decreases intestinal secretion and movement; Dilates the eyes;Adrenal GlandIn general, the adrenal gla
6、nd serves the body in three functions to aid in normal maintenance and response to stress: 1. Adrenal cortisol production, 2. Adrenal mineralocorticoid production, 3. and Epinephrine production.1,Adrenal cortisol production, 1,Cortisol is produced by the adrenal cortex to take protein and fat and tu
7、rn them into glucose in times of low blood sugar. The process is controlled by a small gland in the brain called the pituitary gland, also called the master gland. When the brain senses low blood sugar, the pituitary gland releases a hormone called adrenocorticotropic hormone (ACTH) to stimulate the
8、 adrenal gland to produce cortisol. ACTH is released into the bloodstream until it encounters specific protein receptors in the adrenal cortex to stimulate the release of cortisol. Cortisol is then released into the bloodstream to stimulate the breakdown of protein and fat into sugar. As cortisol le
9、vels rise in the body, the pituitary decreases the amount of ACTH release. This is called a negative feedback loop.2, Adrenal mineralocorticoid productionAdrenal Mineralocorticoid(盐皮质激素 ) Production The adrenal cortex also produces a mineralocorticoid() Called aldosterone (醛固酮 )that is responsible f
10、or the reabsorption of sodium and expulsion of potassium in the proximal convoluted tubules in the kidney.This hormone,above all other adrenal hormones, is needed for normal handling of stress and body maintenance. Without sufficient levels of this hormone, an animal can get into a life-threatening crisis.
