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Endocrine System. Function. Regulates mood Responsible for growth and development T issue function Metabolism S exual function and reproductive processes in the body. Foundations of the Endocrine System. Hormones Transfers information and instructions from one set of cells to another
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Function • Regulates mood • Responsible for growth and development • Tissue function • Metabolism • Sexual function and reproductive processes in the body
Foundations of the Endocrine System • Hormones • Transfers information and instructions from one set of cells to another • Glands • Group of cells that produces and secretes, or gives off, chemicals. A gland selects and removes materials from the blood, processes them, and secretes the finished chemical product for use somewhere in the body
Types of Glands • Glands can be divided into two groups: • Endocrine glands - glands that secrete their product directly onto a surface rather than through a duct. • Exocrine glands - secrete their products via a duct, the glands in this group can be divided into three groups: - Apocrine glands - a portion of the secreting cell's body is lost during secretion - Holocrine glands - the entire cell disintegrates and secrete its substances - Merocrine glands - cells secrete their substances by exocytosis
Major Glands of the Endocrine System • Hypothalamus • Pituitary gland • Thyroid • Thymus gland • Parathyroids • Adrenal glands • Pineal body • Reproductive glands (which include the ovaries and testes)
Hypothalamus • Collection of specialized cells that is located in the lower central part of the brain • Maintains homeostasis • (examples: heart rate, body temperature, water balance, and the secretions of the pituitary gland) • Main link between the endocrine and nervous systems • Nerve cells in the hypothalamus control the pituitary gland by producing chemicals that either stimulate or suppress hormone secretions from the pituitary
Pituitary Gland • Located at the base of the brain just beneath the hypothalamus • Often called the "master gland" because it makes hormones that control several other endocrine glands • The production and secretion of pituitary hormones can be influenced by factors such as emotions and changes in the seasons
Pituitary Gland • The pituitary is divided into two parts: • anterior lobe- regulates the activity of the thyroid, adrenals, and reproductive glands. The anterior lobe produces hormones such as: • Growth hormone- stimulates the growth of bone and other body tissues and plays a role in the body's handling of nutrients and minerals • Prolactin- activates milk production in women who are breastfeeding • Thyrotropin- stimulates the thyroid gland to produce thyroid hormones • Corticotropin- stimulates the adrenal gland to produce certain hormones
Pituitary Gland • posterior lobe • helps control the balance of water in the body • Produces oxyton: triggers the contractions of the uterus in a woman having a baby • Secretes endorphins: • chemicals that act on the nervous system and reduce feelings of pain
Thyroid • Located in the front part of the lower neck • Shaped like a bow tie or butterfly • Produces the thyroid hormones thyroxine and triiodothyronine • control the rate at which cells burn fuels from food to produce energy. • Help kids' and teens' bones grow and develop
Parathyroids • Four tiny glands that function together • Release parathyroid hormone: • which regulates the level of calcium in the blood
Adrenal Glands • Triangular shaped • Located above each kidney • Each gland has two parts: • Adrenal cortex, the outer part, produces hormones called corticosteroids that influence or regulate salt and water balance in the body, the body's response to stress, metabolism, the immune system, and sexual development and function. • Adrenal medulla, the inner part produces catecholamines such as epinephrine, also known as adrenaline. This increases blood pressure and heart rate when the body experiences stress.
Pineal Glands • Located in the middle of the brain • Secretes melatonin: • hormone that may help regulate when you sleep at night and when you wake in the morning.
Reproductive Glands • Main source of sex hormones are the gonads: • sex gland in which gametes are produced • Males • Male gonads, or testes are located in the scrotum • Secrete the hormone testosterone: • Which affect many of the male characteristics such as penis and height growth, deepening in the voice and growth in facial and pubic hair and sperm production.
Reproductive Glands • Females • Female gonads, or ovaries are located on both sides of the uterus, below the opening of the fallopian tubes • Produce the hormones estrogen and progesterone • Involved when a girl begins to experience breast growth, accumulate body fat around the hips and thighs, a growth spurt. Estrogen and progesterone are also involved in the regulation of a girl's menstrual cycle and pregnancy
Thymus Gland • Located in the upper part of the chest cavity, directly behind the sternum • Processes a type of white blood cell known as a T-lymphocyte. • They help cells recognize and destroy invading bacteria, virus, and abnormal cell growth such as cancer, and foreign tissue.
Pancreas • Also part of the digestive system • Produces two hormones: • Insulin and glucagon- work together to maintain a steady level of glucose in the blood and keep the body supplied with fuel to produce and maintain stores of energy
Negative Feedback Mechanisms • Main way to regulate blood levels of hormones. • Rising hormone levels inhibit further hormone release. • Example: The thyroid gland has secreted the right amount of thyroid hormones into the blood. The pituitary gland senses the normal levels of thyroid hormone in the bloodstream. Then the pituitary gland adjusts its release of thyrotropin, the hormone that stimulates the thyroid gland to produce thyroid hormones.
Homeostasis: • Menopause • Late middle age, ovary function declines. • Diabetes mellitus • Hypothyroidism • Hyperthyroidism • Addison’s • Hyposecretion of all adrenal cortex hormones • Cushing’s disease • Excessive output of glucocorticoids
Hypothyroidism Hyperthyroidism Acromegaly
References • http://www.becomehealthynow.com/article/bodynervousadvanced/956/ • http://kidshealth.org/teen/your_body/body_basics/endocrine.html# • http://www.innvista.com/health/anatomy/thymus.htm • http://www.umm.edu/endocrin/reproduct.htm • www.endocrineweb.com/endocrinology/your-adrenal-glands • http://parathyroid.com/parathyroid-function.htm • http://www2.estrellamountain.edu/faculty/farabee/biobk/biobookendocr.html • An Ingegrated Approach to Health Science-Book • Essentials of Human Anatomy and Physiology