Chapter 45 Hormones and the Endocrine System Hormones

Chapter 45 - Hormones and the Endocrine System

Hormones • Chemical signals that are released into the extracellular fluid and carried by the circulatory system in order to regulate functions of the body. • Will stimulate slower, but longer lasting responses to stimuli than the nervous system will (ie: hormones will not remove your hand from the burning stove…) – Local regulators- Act only on local cells for a quicker response.

Hydrophilic based hormones (proteins) CANNOT pass directly into cell and MUST bind to receptors OUTSIDE cell. This creates a cascading signal transduction pathway of chemical chain reaction to cause a cellular response. Hydrophobic based hormones (steroids) CAN pass directly through cell membrane & bind to receptors INSIDE cell nucleus. This can affect DNA transcription and protein synthesis which alter cellular response.

Glands • Hypothalamus and Pituitary Glands- Control most of the rest of the endocrine system. o Hypothalamus- Integrates the endocrine and nervous system together o Pituitary- Attached to the bottom of the hypothalamus and produces/releases many important hormones (ie: growth hormones)

Glands o Thyroid Gland- Releases T 3 and T 4 which are important in human development, maturation, and homeostasis. - Iodine needed for proper functioning

Glands o Parathyroid Gland- Maintains levels of blood calcium

Negative Feedback system

Glands • Pancreas with associated Islets of Langerhans - Produces glucagon and insulin (antagonists) *meaning one increase blood glucose and the other one works to do the to maintain glucose levels in the blood opposite)

Click “play” button below to watch animation!

Diabetes Mellitus - Type 1 - Cannot produce insulin at all; need to give artificial insulin - Type 2 - Deficiency in the production of insulin; insulin or receptors ineffective

Glands - Adrenal Glands- Production of Epinephrine (adrenaline) and Norepinephrin (nonadrenaline) * “epi-” sit on top of kidneys - Rapid bioenergetic boost

Bozeman. Fight or Flight Response

Glands - Gonadal Glands- Sex hormones (all humans have all of these hormones, just in different concentrations) Ovaries = fmales Ovaries = females Testes = males

Glands - Androgens- Testosterone- High concentration in males - Estrogens- Maintains female reproductive system – Progesterone- Prepares the uterus for an embryo

Glands - Pineal Gland- Produces melatonin which maintains our biological clocks.

Know the glands AND their functions!