Question

2. Describe briefly the ways in which hormones can exert a controlling action in the regulation of physiological systems.

Answer 1

Hormones are the chemical messengers produced by endocrine glands and secreted into blood, which act on the target cell and produce some physiological change in the body.

Two type of receptor are present in the target cell for hormones
1. Membrane receptor
2. Cytoplasmic or nuclear receptor

1) Action of hormones via membrane receptor ( protein hormones) :

Hormones  
attaches to the membrane receptor ( present in the cell membrane) -> Response 1 -> generation of secondary messenger (cAMP or Calcium ion) -> biochemical responses -> physiological responses
Eg - FSH causkng ovarian growth

2)Hormone action via intracellular receptors
(Steriod hormones)

Hormone -> passes to cell membrane -> attaches to intranuclear/ intracytoplasmic receptor -> receptor hormone complex -> stimulate transcription and translation -> physiological response
Eg- estrogens causing uterine tissue growth and differentiation