1. Importance of the Endocrine System

2. Hormones Chemical regulators produced by cells that affect cells in another part of the body. Endocrine hormones are produced by endocrine glands and are secreted into the blood. Transported by blood to cells in another part of the body. By contrast exocrine glands secrete substances through ducts or tubes, onto a body surface or into a cavity (ex. Sweat glands, mucous glands, digestive glands)

3. Hormones activation sites of hormones non-target vs. target: Non-targetTarget Location of activationAffect many cells throughout the body Affect specific cells or target tissues Examples Somatotropin- stimulates growth of body (aka growth hormone) Parathyroid hormone – regulates calcium levels in body Insulin- regulates blood sugar by increasing permeability of cells to glucose Gastrin – stimulates cells of stomach to produce digestive enzymes Epinephrine- produced in times of stress, accelerates body reactions during crisis

4. Chemical Control Systems Nervous system & endocrine system work together to control organs & tissues. –Nervous system  rapid, short-term adjustments. Neurotransmitters –Endocrine system  slower, long-term adjustments. Hormones Handout 8.1-3

5. Chemical Control Systems Nervous system and endocrine system both operating in the hypothalamus… The hypothalamus regulates the pituitary gland through nerve signals. The pituitary gland stimulates the endocrine glands which secrete hormones that affects the hypothalamus.

6. Endocrine Glands GlandExample of Hormones Produced HypothalamusAntidiuretic – H 2 O regulation Oxytocin - labour Both produced in hypothalamus but released by posterior pituitary Pituitary “Master Gland” Growth hormone Prolactin FSH and LH Thyroid-stimulating hormone ThyroidThyroxine – metabolic rate Triodothyronine ParathyroidParathyroid hormone (Ca + and PO 4 3- ) PancreasInsulin (high blood sugar) Glucagon (low blood sugar) Ovary (female)Estrogen (devel. 2o sex charac.) Progesterone (maintains uterine lining) Testes (male)Testosterone Andostrone Adrenal GlandEpinephrine (medulla) Norepinephrine (medulla) Glucocorticoids (cortex) *Handout 8.1-1*

7. Chemical Signals: Steroid and Protein Hormones Steroid Hormones Made from cholesterol. Fat soluble  diffuses into cell E.g., sex hormones and cortisol Hormone-receptor complex acts in nucleus to influence transcription Protein Hormones Made from amino acids. Water soluble – attaches to receptor cell on target cell membrane Changes activity of enzymes inside cell E.g., insulin and growth hormones. *Handout 8.1-4*

8. Steroid Hormones 1 Hormone diffuses from cell and travels through blood stream to interstitial fluid 2 Hormone diffuses across cell membrane into target cell 3 Hormone attaches to receptor molecule forming hormone- receptor complex 4 Hormone-receptor complex attaches to DNA 5 Hormone activates a gene initiating transcription of a specific protein 1 2 3 4 5 *Handout 8.1-4*

9. Protein Hormones 1 Hormone diffuses from cell and travels through blood stream to interstitial fluid 2 Hormone (1 st messenger) binds to receptor on cell membrane 3 Hormone-receptor complex promotes formation of cyclic AMP 4 cAMP acts 2 ndary messenger and activates an enzyme 1 2 3 4 *Handout 8.1-4*

10. The Pituitary Gland *Handout 8.1-5*

11. The Pituitary Gland Referred to as the “master gland”. Posterior lobe stores and releases hormones produced by the hypothalamus. Anterior lobe produces its own hormones, but the release is regulated by the hypothalamus. *Handout 8.1-5*

12. Posterior lobe of pituitary gland 1) Hypothalamus synthesizes ADH and oxytocin 2) specialized nerve cells transport ADH and oxytocin to posterior pituitary 3) hormones released into blood stream as needed 1 2 3 *Handout 8.1-5*

13. Anterior lobe of pituitary gland 1) Hormones secreted by nerve ends of hypothalamus 2) Hormones transported in the blood to pituitary gland 3) Pituitary gland stimulated to release pituitary hormones, which are carried by blood to target tissues 1 2 3 *Handout 8.1-5* *Handout 8.1-2*