Response and the Endocrine System.docx

**[Response and the Endocrine System]** Glands can be divided into two main categories depending on how they dispense their products. Exocrine Glands -- Export their products through a duct. Some of their products are enzymes. Examples of exocrine glands;\ - Tear Glands: Produce salt water contain...

**[Response and the Endocrine System]** Glands can be divided into two main categories depending on how they dispense their products. Exocrine Glands -- Export their products through a duct. Some of their products are enzymes. Examples of exocrine glands;\ - Tear Glands: Produce salt water containing an anti-bacterial enzyme called lysosome\ - Sweat Glands -- Produce sweat onto the surface of the skin. The evaporation of sweat cools the body\ - Salivary Glands: Produce saliva, which lubricates food, and also contains the enzyme amylase, which begins the break down of starch\ - Kidneys: Pass water, urea, and salts through the ureter into the bladder\ - Liver: Produce bile, which is stored in the gallbladder before entering the duodenum through the bile duct\ - Mammary glands: Found in female breasts, develop at puberty under the influence of oestrogen. Produce milk to feed offspring\ - Pancreas: Works as exocrine and endocrine gland.\ a. Exocrine -- Produces a mixture of enzymes including lipase, protease and, amylase. Delivers these through the pancreatic duct.\ b. Endocrine -- Releases insulin (produced in Islet of Langerhans) into the bloodstream Endocrine Glands -- Ductless glands that export their products (hormones) directly into the bloodstream. A hormone is a chemical messenger that is produced in one part of the body and is transported to another part of the body, where it has an effect on its target cells, altering its function. The endocrine system works in a coordinated way with the nervous system. Nervous stimulation of an endocrine gland can lead to production of a hormone, thus the two systems are interlinked. *Comparison of Nerve Action and Hormone Action* Nerve Action Hormone Action -------------- ---------------- Fast- Acting Slow Acting Electrical Chemical Short-lived Long-lived Precise Widespread A diagram of the internal organs of a person Description automatically generated(6) [Functions of The Endocrine System\ ]- Maintains homeostasis\ - Mediates responses to external stimuli\ - Regulates reproduction, growth, and development [Pituitary Gland\ ]Located at the base of the brain just below the hypothalamus. Makes a range of hormones including;\ - Follicle-stimulating hormone (FSH): Stimulates oocyte development in the ovary producing a Graafian follicle in which the egg develops. Stimulates the production of sperm in males\ - Luteinising hormone (LH): Changes the Graafian follicle into the corpus luteum after ovulation\ - Oxytocin: Regulates milk release in response to suckling and controls contraction of the uterus\ - Prolactin: Stimulates milk production [Hypothalamus\ ]Located above the pituitary gland. Growth hormone releasing hormone (GHRH) triggers the release of growth hormone by the pituitary [Thyroid\ ]Forms two butterfly-shaped lobes in front of the trachea. Produces thyroxine which regulates, stimulates, and maintains metabolism and homeostasis [Thymus\ ]Located behind the breast bone and produces thymosin which promotes maturation of T and B- cells. [Pancreas\ ]Located beside the liver and produces insulin [Adrenal Glands\ ]Located on the top of each kidney. Produce the hormone adrenalin which diverts blood to the muscles from the intestines [Ovaries\ ]A pair of organs found only in females. They are located at either side of the uterus. They produce two hormones;\ - Oestrogen: Made by the Graafian follicle, causes a thickening of the endometrium in preparation for the possible arrival of a developing fertilised egg\ - Progesterone: Made by the corpus luteum and maintains the uterine lining until the corpus luteum degenerates [Testes\ ]A pair of male organs found outside the body in a bag called the scrotum. They produce testosterone which is responsible for the development of the male sex organs before birth [Effect of Hormone Levels -- Diabetes] \- Insulin is produced by beta cells in structures in the pancreas called the islets of Langerhans.\ - In type 1 diabetes, the beta cells that produce insulin are attacked by the body's immune system and destroyed, causing the symptoms of diabetes.\ - In type 2 diabetes, body cells build up a resistance to insulin, so more insulin has to be produced to have the same effect on blood-sugar levels. When the beta cells can no longer produce enough insulin, the symptoms of diabetes begin to appear\ *Insulin Regulation\ *- Too little insulin: Causes blood-sugar levels to rise, resulting in symptoms such as thirst, tiredness, frequent urination and an increase in weight\ - Too much insulin: Caused by injecting too much insulin, causes blood-sugar levels to drop very low, which can result in unconsciousness or death\ *Treatments\ *- Type 1: Injection of insulin\ - Type 2: Diet/Medication, followed by insulin injections if needed [Feedback Mechanism\ ]Feedback is how hormones keep themselves at just the right level. For example, the activity of the thyroid is controlled by thyroid-stimulating hormone, which is produced by the pituitary gland. Firstly, the change must be detected and then a response set in place to counter the change. If the level of thyroxine drops:\ - It is detected by the pituitary gland\ - It responds by producing more TSH\ - This stimulates the thyroid to produce more thyroxine\ - Thyroxin level rises and returns to normal If the level of thyroxine rises:\ - It is detected by the pituitary gland\ - It responds by producing less TSH\ - This stimulates the thyroid to produce less thyroxine\ - Thyroxine level drops and returns to normal [Hormone Supplements\ ]- Insulin is used to control blood-sugar levels in people with diabetes\ - Growth hormone is given to promote normal growth in children who are deficient in the hormone