Question

Currently studying for a final for cell biology.

The topic is on hydrophobic (hormone) signaling molecules that provoke a slow lasting response.

The professor said hormones are hydrophobic and must be carried around by soluble protein. They are membrane diffusible and far-reaching (systemic)...

what does far-reaching systemic mean in cell biology? What is systemic??

Answer 1

Hormones are biological messengers that are secreted by specialized tissues or organs and are transmitted to the target site via the blood stream. Based on their molecular structure , hormones can be classified as 1. steroidal and 2.non-steroidal.

Steroidal hormones are hydrophobic , fat soluble and diffuse through the cell membrane and act on the cytoplasm which brings about desired metabolic modifications. Whereas non steroidal hormones are hydrophilic and hence bind to receptors in the cell membrane to mediate the required metabolic action.

Hormones are secreted in very little amount but can bring about the desired action. Hormones can travel through the blood systemically but yet remain active until it reaches its target site. Pituitary , for example , secretes hormones , that are transported by the blood systemically to reach other endocrine glands. This ability of hormones to act at distant target sites is referred as "far - reaching systemic".