Endocrine System Control of Our Bodies Homeostasis Explain

Endocrine System Control of Our Bodies Homeostasis

Explain Section 39 -2 The Endocrine System regulates Metabolism Calcium and glucose levels Response to stress by means of the Testes Thyroid Growth Water balance Reproduction by means of the Pituitary Ovaries Pancreas Parathyroids Adrenals

Exocrine or Endocrine • Exocrine – release products (enzymes) into ducts – Ex) Sweat, tears, digestive stomach acids • Endocrine – directly to bloodstream; NO DUCTS – Ex) Hormones

Endocrine System • Glands – release products to bloodstream directly. • Horomones – products deliver messages to body • Target cells – have specific receptors for specific hormones

Endocrine Glands Section 39 -1 Hypothalamus The hypothalamus makes hormones that control the pituitary gland. In addition, it makes hormones that are stored in the pituitary gland. Pituitary gland The pituitary gland produces hormones that regulate many of the other endocrine glands. Parathyroid glands These four glands release parathyroid hormone, which regulate the level of calcium in the blood. Thymus During childhood, the thymus releases thymosin, which stimulates Tcell development. Adrenal glands The adrenal glands release epinephrine and nonepinephrine, which help the body deal with stress. Pineal gland The pineal gland releases melatonin, which is involved in rhythmic activities, such as daily sleep-wake cycles. Thyroid The thyroid produces thyroxine, which regulates metabolism. Pancreas The pancreas produces insulin and glucagon, which regulate the level of glucose in the blood. Ovary The ovaries produce estrogen and progesterone. Estrogen is required for the development of secondary sex characteristics and for the development of eggs. Progesterone prepares the uterus for a fertilized egg. Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics

Pituitary Gland • Master gland – Controls the other endocrine glands • Growth Hormone (GH) – Too much – gigantism – Too little – dwarfism

Hypothalamus • Part of brain and attached to pituitary • Controls pituitary secretions

THYROID GLAND • Regulates – Metabolism and energy balance

Thyroid Hormones • Thyroxine – Regulates body energy usage • Calcitonin – One hormones that regulates calcium and phosphate in blood

Calcium Regulation PARAthyroid Glands • PTH-Parathyroid hormones • Increases calcium, phosphate, and magnesium absorption in intestines. • Causes bones to release calcium and phosphate • Causes removal of calcium and magnesium from urine by kidneys • Increases the making of Vitamin D in body

Adrenal Gland • Releases hormones to deal with stress

Pancreas: Endocrine and Exocrine • What did the pancreas do in digestion? Secreted Enzymes Pancreas also secretes hormones Endocrine glands - ductless organ that releases hormones DIRECTLY into the bloodstream.

Blood Glucose Level • Pancreatic Hormones regulate blood sugar level before and after meals. – Alpha secrete glucagon – increases sugar – Beta secrete insulin – decreases sugar

Glucose Regulation Two Ways: 1. Eating Regularly 2. Hormone Adjustments

What Happens? • Between meals Blood glucose low Pancreas secretes glucagon Liver changes glycogen to glucose sent to target tissues • After a meal Blood glucose high Pancreas secretes insulin Glucose goes to the Liver(Glygogen) and goes to Target tissues

Reproductive Glands • • Production of gametes Secretion of sex hormones: Female – Ovaries - Estrogen Males – Testes - Testosterone