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.
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. 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.
Glands Hypothalamus and Pituitary Glands- Control most of the rest of the endocrine system. Hypothalamus- Integrates the endocrine and nervous system together Pituitary- Attached to the bottom of the hypothalamus and produces/releases many important hormones (ie: growth hormones)
Glands Thyroid Gland- Releases T3 and T4 which are important in human development, maturation, and homeostasis. - Iodine needed for proper functioning
Glands 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 opposite) to maintain glucose levels in the blood
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!