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)
Hormones activation sites of hormones non-target vs. target:
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
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.
Endocrine Glands • *Handout 8.1-1*
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 • *Handout 8.1-4* • 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.
Steroid Hormones 1 3 2 4 5 • *Handout 8.1-4*
Protein Hormones 1 2 3 4 • *Handout 8.1-4*
The Pituitary Gland • *Handout 8.1-5*
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*
Posterior lobe of pituitary gland1) Hypothalamus synthesizes ADH and oxytocin2) specialized nerve cells transport ADH and oxytocin to posterior pituitary3) hormones released into blood stream as needed 1 2 3 • *Handout 8.1-5*
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 • *Handout 8.1-2* • *Handout 8.1-5* 2 3