Endocrine System Flashcards
Endocrine System
Set of organs that secrete hormones directly into the circulatory system.
Hormones
Chemicals released into the blood and act as signals to target organs to perform various functions.
Functions of the Endocrine System
Regulates many body functions. All body systems are regulated by endocrine system in some way. Regulation of blood production, apetite, reproduction, brain function, sleep cycle, electrolyte balance, growth, sexual development, and response to stress and injury. Glands and organs secrete hormones into the blood to be transported to target organs and tissues to control their function. Example, pancrease releases hormone insulin, which signals to cell to uptake sugar and pineal gland releases melatonin, which regulates sleep cycles.
Glands of the Endocrine System
Complex network of glands and organs. A gland is a specific type of organ that secretes hormones into the blood to target and affect other organs. Major glands in the endocrine system are: the pineal, pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, ovaries and testes, hypothalamus.
Functions of the Endocrine System
Regulates many body functions by controlling amount of hormone being released for all body systems. Regulates blood production, appetite, reproduction, brain function, sleep cycle, electrolyte imbalance, growth, sexual development, and response to stress or injury. Secrete hormones to target organs. Example, pancrease releases insulin hormone, which signals cells to uptake sugar. Pineal gland releases hormone melatonin, which regulates sleep cycles.
Endocrine Glands I
Glands that secrete hormones that have different chemical structures. A duct-less gland. Ex: Lipid based enter cell regulate DNA, nonpolar, fat-soluble hormones, such as estrogen and progesterone release by according to age and development. Reproductive hormones for gamete production. Estrogen production increases puberty and leads to development of secondary sex characteristics.
Endocrine Glands II
Polar water-soluble hormones, such as epinephrine are released in response to stress. Hormone receptors regulate and control body functions.Ex: when adrenal glands secrete epinephrine into the bloodstream, heart rate, blood pressure, muscle strength, and metabolism increase, called “fight or flight” response.
Hormone imbalance
Hormone imbalance can cause metabolic diseases such as diabetes, hyperthyroidism, gigantism. Hypothyroidism, thyroid gland produces too much thyroxine, which leads to increase weight loss and heartbeat. Gigantism occurs in the pituitary making too much growth hormone, making excessive growth. Too much growth hormone in adults is called acromegaly.
Homeostasis
Is the maintenance of a constant internal environment. Work through feedback systems, which are controlled by endocrine glands. Bring physiological and behavioral changes, which maintain internal constancy. Ex: Maintaing concentration of glucose in the blood controlled by insulin and glucagon. Also maintaining the right amount of water in the blood controlled by Antidiuretic hormone (ADH) secreted by pituitary gland.
Positive and Negative Feedback mechanisms
Positive feedback causes an increase in the secretion of a hormone. Ex: secretion of hormone oxytocin. Cervical stretching and fetus pressure triggers release of oxytocin from posterior pituitary. Oxytocin stimulates uterine contractions cause fetus to be expelled. Negative feedback most hormone levels are regulated through this process, influenced by releasing and inhibiting hormone. Maintains homeostasis. Beta Cells of pancreas release hormone insulin when blood sugar levels too high. Alpha cells secrete Glucagon is secreted in when blood glucose levels are too low. Breaksdown glycogen, which is stored in the liver and muscle cells into glucose to raise blood sugar levels. When homeostasis is reached hormone secretion is stopped.
The Central Nervous System and the Endocrine System
Endocrine system is generally involved with more slower and more long-lasting responses to stimuli than nervous system. Integration of these two systems is called the, “activation of the neuroendocrine system.” Ex: Hypothalmus directs activities of the pituitary gland. Biochemical messages turn on or off messages to pituitary gland from hypothalmus. Hypothalmus secrete hormones called “releasing hormones” or “inhibiting hormones” to pituitary. Pituitary makes specific hormones to target organs. Ex: Pituitary secretes follicle-stimulating hormone (FSH), which functions in egg development in ovaries. Pressure of fetus on cervix sends signal to hypothalmus results in increase in oxytocin to expell fetus.
Negative Feedback
Relationship between endocrine system and central nervous system. Most hormone levels in the body are regulated through negative feedback. A mechanism that includes the monitoring for specific homeostatic levels and a signal to a gland. This signal stimulates or inhibits the glands secretion in order to maintain homeostasis or cause compensations that return the level to homeostasis. Function through releasing hormone and inhibiting hormone . Ex: pancrease to release more insulin so cells can uptake sugar, which lowers blood sugar levels in the blood.
Positive Feedback
A mechanism that stimulates glandular secretions to continue to increase, temporarily pushing levels further out of homeostasis, until a particular biological affect is reached (expulsion of fetus during birth)). The increase of hormones. Ex: Secretion of oxytocin by posterior pituitary because of cervical stretching and fetal pressure.
Releasing hormones
Chemical messengers that stimulate the production of certain hormones. Come from specialized cells in the Hypothalmus to pituitary, so pituitary can make specific hormones to target organs. Ex. Pituitary excretes FSH for egg development in ovaries and sperm production in testes.
Inhibiting Hormones
Chemical messengers that restrict the production of certain hormones. Come from the hypothalmus to the pituitary, so pituitary can make less of a hormone. Ex: FSH hormone for egg development in ovaries. Hypothalmus signals posterior pituitary to make oxytocin due to pressure of fetus on cervix.
