For a human organism to survive in a variable and hostile environment, regulatory mechanism are essential. We have two major regulatory systems:

The nervous system, and The endocrine system

 Both the systems are not mutually exclusive but overlap in form and function. Hypothalamus acts as an integrating centre for both the systems (particularly the autonomic) and is the major site at which their activities combine.

The endocrine or ductless glands are so called because they secrete substances directly into the blood stream. The active principle which they secrete are called hormones which are transported into the blood to exert specific effects on cells remote from the site of origin.

A harmone is a chemical substance that is secreted into the body fluids by one cell or group of cells and that exerts a physiological control effect on other cells of the body. The basic types of harmones are:

Proteins or derivative of proteins or amino acids, and Steroids.

There are eight endocrine glands, which together weigh only about two ounces (60 grams). The harmones they secrete are very powerful beyond belief. A drop more or a drop less can have earth-shaking effect on the glands we mean. The endocrine system consists of:

(a) Thyroids (b) Pineal (c) Pituitary (d) Parathyroids (e) Thymus (f) Adrenals (g) Pancreas (h) Ovaries (in the female) and (i) Testes (in the male).

Soma Juice: The saadhakaa will get this juice early in his tapas. It is secreted by the hypophysis cerebri (the pituitary gland). It is a small gland about 1cm in diameter and about 0.5 to 1gm in weight. This gland lies in the hypophyseal fossa of the sphenoid bone at the base of the brain, almost in the centre of the head. It is connected with the hypothalamus by the hypophyseal stalk. 50,000 or more nerve fibres enter this fragment of tissue, while enormously rich blood supply carry its chemical messengers - harmones - to the rest of the body.

The hypophysis cerebri is divisible into two distinct portions:

Adenohypophysis (anterior pituitary), and Neurohypsphysis (posterior pituitary)

Adenohypophysis produces six major harmones, which play major roles in the control of metabolic functions throughout the body. Neurohypophysis produces two hormones.

All secretions by this gland are controlled by either normal or nervous signals from the hypothalamus. Hypothalamus is a collecting centre for information concerned with the well-being of the organisms and in turn this information is used to control the secretions of the hypophysis cerebri. Its hormones act as the stimulants on specific thyroid, adrenal cortex, ovaries, the testis and the mammary glands. Thus the pituitary is the most remarkable component of the organism. A master indeed among the glands.

Soma juice is often mentioned in the scriptures. It is said to be the expressed juice of a climbing creeper, sarcostemma viminalis, used in yajnaas. It is also referred to as a liquour.