Thymine is exclusive amongst the four bases as it only occurs in DNA molecules. Adenine, cytosine and guanine are also found in nucleotides that make up ribonucleic acid, or RNA. Inside an RNA molecule, thymine is replaced by uracil.he order that the bases appear is insignificant in the DNA molecule. This means that there can be four different cross rungs â adenine with thymine, thymine with adenine, cytosine with guanine, and guanine with cytosine.
The pituitary gland hangs from the base of the brain by a stalk and is enclosed by bone. It consists of a hormone-producing glandular portion (anterior pituitary) and a neural portion (posterior pituitary), which is an extension of the hypothalamus.
The Hypothalamus and the Pituitary Gland. The hypothalamus is the region of the brain that controls hormone release, and is thus part of the neuroendocrine system. The pituitary gland is closely allied with the hypothalamus, both functionally and physically.Some hypothalamic neurons project directly to the neural lobe of the pituitary.Others project to the median eminence, where they connect with blood vessels that supply the pituitary.he pituitary gland is closely allied with the hypothalamus, both functionally and physically. Some hypothalamic neurons project directly to the neural lobe of the pituitary. Others project to the median eminence, where they connect with blood vessels that supply the pituitary.