Hypothalamus, and its relation to the Pituitary

Disorder Hypothalamus gland PituitaryHypothalamus, and its relation to the Pituitary.The hypothalamus is the portion of the anterior part of the diencephalon that lies below the hypothalamic sulcus and in front of the interpenduncular nuclei in the brain. It is divided into a variety of nuclei and nuclear areas. It lies directly below the thalamus and laterally is continuous with the subthalamic regions. The gland itself is very important as it contains neurosecretions that are of importance in the control of certain metabolic activities such as maintenance of water balance, sugar and fat metabolism, regulation of body temperature and secretion of releasing and inhibiting hormones. It is the chief sub cortical region for the integration of sympathetic and parasympathetic activities. Basically meaning that, it controls your voluntary and involuntary bodily functions.Hypothalamus in relation to the pituitary There are neural connections between the hypothalamus and the posterior lobe of the pituitary gland and vascular connections between the hypothalamus and the anterior lobe. The pituitary is no longer considered the master gland. The hypothalamus is the final common pathway that receives input from virtually all other areas of the central nervous system and directs input to the pituitary. The hypothalamus modulates the activities of the anterior and posterior lobes of the pituitary in two distinct ways. The neurohormones synthesized in the hypothalamus reach the anterior pituitary directly through a specialized portal vascular system and regulates the synthesis and secretion of six major peptide hormones of the pituitary. The pituitary hormones in turn regulate the peripheral endocrine glands ( the thyroid, adrenal and the gonads) as well as growth and lactation. No direct neural connections exists between the hypothalamus and the anterior pituitary. In contrast, the posterior pituitary comprises axons, originating in neural cell bodies located in the hypothalamus. These axons serve as storage site for two peptide hormones synthesized in the hypothalamus, which act in the periphery to regulate the water balance, milk ejection, and uterine contraction. An intermediate lobe locate between the anterior and posterior lobes is present in some, but the specific cells are scattered throughout the anterior and posterior lobes in the adult humans. Virtually all hormones secreted by the hypothalamus and the pituitary are pulsatile that is in a burst lie fashion, interspersing brief periods of inactivity and activity. In addition some of the hormones lie(ACTH, growth hormone, and prolactin) have definite circadian or diurnal rhythms with increased secretion during specific hours of the day. Other hormones for example the leutinizing hormone and the follicle stimulating hormone which are involved in the menstrual cycle for women have, month long rhythms with evidence of superimposed circadian cycles.The major functions of the hypothalamus are fairly clear cut. From being involved in controlling thirst , hunger and sexual activity to some of the most basic functions of the body being regulated through the hypothalamus, some being visceral reflexes and others include complex behavioral and emotional reactions, however, all involve a particular stimulus. It is important to keep this in mind in considering hypothalamic function.