Final answer:
True, the posterior lobe of the pituitary gland is comprised mostly of nervous tissue, with nerve fibers and neuroglial cells supporting the transmission of hormones from the hypothalamus to the posterior pituitary for storage and release.
Step-by-step explanation:
The statement that the posterior pituitary consists mainly of nervous tissue is true. The posterior lobe of the pituitary gland, also known as the neurohypophysis, is significantly different from the anterior pituitary lobe. It is an extension of the brain and is connected to the hypothalamus via nerve axons. The structure predominantly consists of nerve fibers and neuroglial cells, which support the axons that transport hormones secreted by the hypothalamus to the posterior pituitary for storage and later release into the bloodstream. Hormones stored here include vasopressin and oxytocin, which are then released as needed.