What is a suprachiasmatic nucleus?
Suprachiasmatic nucleus (SCN) is a pair of structure of the size of the Pinhead hypothalamus, part of the brain located above the optical chiasm, an area where optical nerves pass. It controls the circadian rhythm, the rhythmic repetition of certain phenomena at about the same time every day. Also known as the biological clock, it contains about 20,000 neurons that create neuronal and hormonal signals that regulate different body functions in an approximately 24 -hour cycle. Some signals generated by neurons of the suprachiasmatic nucleus include gamma-aminobutylic acid, vasopressin, vasoactive intestinal peptide and somatostatin. Different functions synchronized with generated signals are a cycle of sleep and waking, body temperature, blood pressure changes, urine production and hormone secretion. Once the light coming from the environment reaches the eyes, the specificized light sensitive retinal cells known as photoreceptors convert light into electrical signals and then transfer it to the brain. These signals that travel along retinOhypothalamic tract, cause pulling. Stretching is a shift of the phase of the suprachiasmatic core of the activity to synchronize with the light and the dark cycle of the environment of the same frequency. During the subjective day, pulling is mediated by cyclic adenosine monophosphate and pituitary adenylcyclory -activating peptide, while cyclic guanosine monophosphate and acetylcholine are mediated during a subjective night.
In addition to the light signals, the suprachiasmatic core is affected by melatonin. Melatonin is a hormone synthesized from the neurotransmitter serotonin pineal gland. It is an agent and a regulator of the suprachiasmatic core. His synthesis is a circadian, where he is inhibited by light and stimulated by darkness. As its level increases during environmental darkness, melatonin sends information to the brain when the night arrived and the function of the body is appropriately evoked.
Has been identified by severalIk of genes that regulate the circadian rhythm. It is timeless, period, DCLOCK and cycle. It controls protein expression, leading to a complex intracellular system of negative feedback. The negative feedback system is responsible for the periodicity of the suprachiasmatic nucleus.variations in the rhythm of neuronal and hormonal signaling occurs seasonally. It can reflect the effect of variation of length, tide, temperature and sunlight of daylight. In Jet Lag, the biological clock is disrupted due to a sudden artificial change in the time of hours from travel to another time zone, leading to a sharp shift in neuronal and hormonal signals. Often it requires a few days to do a body working on a normal 24 -hour cycle.