Control of Our Bodies Homeostasis Endocrine System Control of Our Bodies Homeostasis

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

Exocrine or Endocrine Exocrine – release products (enzymes) into ducts Ex) Sweat, tears, digestive juices 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 Pineal gland The hypothalamus makes hormones that control the pituitary gland. In addition, it makes hormones that are stored in the pituitary gland. 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. Pituitary gland The pituitary gland produces hormones that regulate many of the other endocrine glands. Pancreas The pancreas produces insulin and glucagon, which regulate the level of glucose in the blood. Parathyroid glands These four glands release parathyroid hormone, which regulate the level of calcium 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. Thymus During childhood, the thymus releases thymosin, which stimulates Tcell development. Testis The testes produce testosterone, which is responsible for sperm production and the development of male secondary sex characteristics Adrenal glands The adrenal glands release epinephrine and nonepinephrine, which help the body deal with stress.

Pituitary Gland Master gland Growth Hormone (GH) Too much – gigantism Controls the other endocrine glands Growth Hormone (GH) Too much – gigantism Too little – dwarfism Antidiuretic (ADH) Stimulates kidneys to keep water

Hypothalamus Part of brain and attached to pituitary Controls pituitary secretions

Thyroid

THYROID GLAND Regulates Metabolism and energy balance

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

Parathyroid

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

Negative Feedback Mechanism Our body uses feedback mechanism to maintain homeostasis within our body. Regulation of calcium is one example of this process. Can you think of another one? Hint: Role Play Activity

Adrenal Gland Releases hormones to deal with stress

Adrenal Gland Cont. Cortex Medulla Produces more than 2 dozen steroid hormones corticosteriods Medulla “fight or flight” Epinephrine and norepinephrine

Glucose Regulation Two Ways: Eating Regularly Hormone Adjustments

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. Islets; clusters of cells in pancreas Alphasecrete glucagon – increases sugar Beta secrete insulin – decreases sugar

What Happens? Between meals Blood glucose lowPancreas secretes glucagonLiver changes glycogen to glucose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

Diabetes Diabetes High sugar levels in blood Do not produce enough insulin to control blood sugar Some take insulin injections to regulate

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