BIOL 1104: 4.1 Hormones and Feedback Loops

What are hormones?

Signaling molecules that communicate messages within cells and to different parts of the body

Explain protein hormones

Protein hormones are water soluble, so protein hormones are not able to get into the cell. They bind to receptors on the cell surface, and they directly stimulate a cytoplasmic response. The cytoplasmic response is carried out by a series of molecular interactions called signal transduction.

Explain steroid hormones

Lipid-based hormones that are able to pass through cell membranes to bind to receptors in the cell. Once passed through the cell membrane, it will bind to a receptor, and the receptor-hormone complex enters the nucleus to bind to DNA in a specific region to activate protein synthesis.

What is the endocrine system?

the network of glands and organs that use hormones to send messages to parts of the body via the circulatory system. The endocrine glands produce hormones for the signaling.

Explain the positive feedback?

change in a parameter in one direction triggers a response that moves that parameter in the same direction. In other words, the enhancement or amplification of an effect caused by its own influence on the process that gives rise to it.

Explain negative feedback?

change in a parameter in one direction triggers a response that moves that parameter in a the opposite direction. The counteraction of an effect by its own influence on the process that gives rise to it.

Explain the steps of signaling transduction

Reception: hormone binds to the receptor on cell surface

Transduction: signal is relayed through other molecules via a series of chemical reactions

Response: the cellular response to the hormone is activated

What is the hormone cascade?

A hormone stimulates another cell to release another hormone. Tropic hormones are hormones that regulate the release of other hormones.

Who are the major players of the hormone cascade?