Hormones and endocrine system Chapter 45 Hormones and endocrine system

Hormones You only need a little bit of the hormone to cause a response (remember how the signal gets amplified! Look back at chapter 11) Protein-based hormones Receptor on the plasma membrane (don’t go inside!) Water-soluble Lipid-based hormones Receptor is inside the cell (go inside the cell!)

Signaling Review

Receptors Same receptor, same hormone, different cell - different pathways (first two) Same type of cell, same hormone, different receptor - different response

The Master Gland (Pituitary) Under the hypothalamus Posterior Pituitary Directly connected to hypothalamus by neurosecretory cells Only STORES hormones that are produced by the hypothalamus Anterior Pituitary Indirectly connected to hypothalamus (still under its control) by capillary portal system Makes its own hormones and releases them POST PITUITARY DOES NOT MAKE HORMONES

Posterior Pituitary Antidiuretic Hormone (ADH) Oxytocin Targets kidney tubules Retention of water Oxytocin “Swift birth” Targets mammary glands, uterine muscles Let down of milk

Anterior Pituitary Adrenocorticotrophic Hormone Assists in synthesizing corticosteroids, which are responsible for stress response Thyroid Stimulating Hormone Regulates body temperature, thirst and hunger Follicle Stimulating Hormone Stimulates the maturation of egg and sperm Luteinizing Hormone Stimulates secretion of sex steroids from the gonads Prolactin Stimulates milk production in breasts Melanocyte Stimulating Hormone Regulates the function of skin pigment cells (melanocytes) Growth Hormone Growth in bones, tissues, and other body systems

Tropic vs nontropic Tropic Nontropic Both Target endocrine glands Ex. TSH stimulates the thyroid to produce thyroxine Nontropic Direct effect on target cells, tissues Ex. Melanocyte Stimulating Hormone (MSH)- affects skin cells, Prolactin- Affects cells in the mammary glands to make milk, Thyroxine Both Ex. Growth hormone – tells bone and tissue cells to grow (nontropic), causes liver to make insulin- like growth factors which tell other cells to grow (tropic)

Issues Acromegaly Too much Human Growth Hormone You can see it in the hands, jaw, and brow ridge Can by caused by a pituitary tumor, which causes the production of too much growth hormone