Endocrine System Overview Physically disconnected Controls growth, development, environmental responses Glands: Major organs of the endocrine system – makes hormones – Hormones: chemical signals that move through blood Hormones attach to cell receptor – Cause target cells produce proteins

Steroid and Non-Steroid Hormones Naturally produced by the body Travel through blood Attach to receptor of target cells Target cell creates proteins

Differences Between Steroid & Nonsteroid Hormones –Steroid hormones enter into the cell. –Nonsteroid hormones do not enter the cell. Steroid hormone diffuses through the cell membrane Steroid hormone binds to a receptor within the cell. The hormone and receptor enter the nucleus and bind to DNA Steroid hormone causes DNA to make proteins. Nonsteroid hormone binds to receptor on the cell membrane. Receptor stimulates a second messenger with in the cell. Second messenger starts a series of chemical reactions in the cytoplasm. Second messenger reactions activate enzymes. Steroid hormone receptor nucleus DNA proteins Non-steroid hormone receptor second messenger Chemical reactions activated enzymes

HYPOTHALAMUS PITUITARYTHYROID THYMUS ADRENAL GLANDS PANCREAS FEMALE GONADS :OVARIES MALE GONADS : TESTES Major Glands All the below create hormones Hypothalamus – Stimulates the pituitary gland to release hormones – Controls growth, reproduction, body temp Pituitary gland – Controls cell growth and [H2O] in blood – Stimulates other glands Thyroid gland – Regulates metabolism, growth, development Thymus – Allows WBCs to mature to fight infection Adrenal Glands – Controls “fight or flight” response – Increases breathing, alertness, blood pressure Pancreas – Controls glucose level in blood – Insulin, glucagon Gonads: influence sexual development – Testes (males): testosterone – Ovaries (females): Estrogen, progesterone

Releasing hormones stimulate other glands to produce hormones –Allow glands to communicate with one another –Are used in temperature regulation

Hormonal imbalances can cause severe illness Abnormal hormone levels affect homeostasis. Hormonal imbalances might be treated with surgery or medicine. Steroids, a pituitary tumor, or some prescription drugs can make the pituitary overactive and indirectly cause problems.

Hypothalamus Pituitary gland Thyroid Thymus Adrenal glands Pancreas Ovaries Testes

REview 1)What are glands and what do they release? 2)What do steroid and nonsteroid hormones direct cells to create? 3)Examine the diagram of the endocrine system on slide #7. Practice answering the 8 different glands. 4)Which gland….  releases insulin to lower blood sugar levels?  increases your alertness and blood pressure?  helps your white blood cells mature?  is located atop your kidneys?  are found in your brain (two answers)?  is considered your body’s thermostat?