70 likes | 193 Views
Endocrine system. Human Systems Biology. Hormones “ Chemical Messengers”. Produced and secreted directly into the blood by endocrine glands Endocrine gland hormones are spread by blood stream throughout body to target organs (each hormone has a specific target)
E N D
Endocrine system Human Systems Biology
Hormones “Chemical Messengers” • Produced and secreted directly into the blood by endocrine glands • Endocrine gland hormones are spread by blood stream throughout body to target organs (each hormone has a specific target) • Target organs have hormone-receptor proteins that bind to hormones that arrive in blood • Neurotransmitters are different because they send signals between cells
Page 65 • The main glands in the Endocrine system are: • Pituitary Gland • Thyroid Gland • Parathyroid Glands • Adrenal Glands • Pancreas • Ovaries • Testes Refer to page 65, write a brief function for each gland!
Types of Glands Exocrine Glands Endocrine Glands • Have ducts • Secrete products into body cavities • E.g. salivary glands secrete salivary amylase enzyme into mouth via salivary ducts • No ducts! • Secrete hormones directly into bloodstream • E.g. • Hypothalamus • pituitary • thyroid • pancreas
Salivary Gland Duct
Control of Endocrine Glands Endocrine glands are controlled by a “cause and effect” feedback system with inputs (reactants) and outputs (products). This is what maintains “Homeostasis” (balance) Negative Feedback Positive Feedback • If the feed back output opposes the input • Pancreas: See page 66 about blood glucose. • Kidney: See page 64 about ADH. • If the output (i.e. hormone) fed back is increasing the input