Hypothalamus of the autonomic nervous system. It synthesizes and secretes certain neurohormones, called releasing hormones or hypothalamic hormones, and these in turn stimulate or inhibit the secretion of hormones from the pituitary gland. The hypothalamus controls body temperature, hunger, important aspects of parenting and attachment behaviours, thirst, fatigue, sleep, and circadian rhythms. The hypothalamus derives its name from Greek ὑπό, "under" and θάλαμος, thalamus. The hypothalamus is a brain structure made up of distinct nuclei as well as less anatomically distinct areas. It is found in all vertebrate nervous systems. In mammals, magnocellular neurosecretory cells in the paraventricular nucleus and the
Medulla (hair) The medulla's presence in human hair and its patterns differ both from person to person and from strand to strand on a single person's head. One hair may have an absent medulla while another from the same person may have a complete or fragmented medulla. For this reason, medulla patterns are not very useful as forensic evidence and are typically only used for determining the species of the subject. The medulla contains large amounts of mitochondrial (as opposed to nuclear) DNA. Mitochondrial DNA is passed from the mother to her offspring. As such, mtDNA may be of forensic value. Medulla