How the Body Controls the Production of Thyroxine
The thyroid gland can be taken to illustrate the basic principles of hormonal communication and action. Situated in the neck, the thyroid gland secretes thyroxine,…
The thyroid gland can be taken to illustrate the basic principles of hormonal communication and action. Situated in the neck, the thyroid gland secretes thyroxine,…
All endocrine structures develops from epithelia or nervous tissues, or from both. It is noteworthy that some structures described here have other important functions, e.g.,…
There is good reason to suppose that life began in the sea. Many animals, notably marine invertebrates such as sea anemones, spider crabs and star…
This brief account of the kidney illustrates its two principal function, excretion and osmoregulation. In that it totally removes urea from the blood, it is…
Marine elasmobranchs such as shark, dogfish and rays overcome their osmotic difficulties in a unique way. They have a similar chloride content to marine teleosts…
Migratory fishes: Osmotic independence can be maintained only if the salinity of the external medium remains constant. If the salinity of this external medium fluctuates…