MICROANATOMY

Detailed explanation-1: -prolactin and oxytocin. The two hormones involved in lactation are oxytocin and prolactin. The hormone prolactin is responsible for the production of milk in the system while the hormone oxytocin is responsible for the release of milk.

Detailed explanation-2: -Insulin secretion by the cells of the islets of Langerhans is primarily regulated by the d-glucose level in the extracellular fluid bathing the cells.

Detailed explanation-3: -Final Answer: Constriction of skin blood vessels and contraction of skeletal muscles when it is too cold is an example of a negative feedback loop in humans.

Detailed explanation-4: -Many types of cells have the identical intracellular receptor, but the set of genes that the receptor regulates is different in each cell type. This is because more than one type of gene regulatory protein generally must bind to a eucaryotic gene to activate its transcription.