17.7 The Pineal Gland

what is the pineal gland

endocrine gland that secretes melatonin, which is important in regulating the sleep wake cycle

where is the pineal gland located

inferior but somewhat posterior to the thalamus

what are pinealocyte

cell of the pineal gland that produces and secretes the hormone melatonin

what hormone is melatonin classified as

amine

what is melatonin

a hormone derived from serotonin produced by the pineal gland

what hormone is produced and secreted by the pineal gland

melatonin

what affects the secretion of melatonin

the level of light received from the environment

what happens to melatonin production when photons of light stimulate the retinas

melatonin production is inhibited

what is the effect of increase melatonin levels

drowsiness

what should you avoid doing in the middle of your sleep cycle to prevent lowering melatonin

exposure to light

what rhythms does melatonin influence

circardian rhythms, including sleepiness, wakefulness, appetite, and body temperature

why do children have higher melatonin levels than adults

it may prevent the release of gonadotropins, thereby inhibiting the onset of puberty

what is jet lag

a condition that occurs when traveling across multiple time zones disturbs the light dark cycle regulated by melatonin

how do some air travelers manage jet lag

by taking melatonin supplements to induce sleep

what do you need more of at night and what do you need more of in the daytime

melatonin and cortisol

what is the suprachiasmatic nucleus (SCN)

a region in the hypothalamus that is important in regulating biological rhythms

what happens after the signal leaves the SCN

nerve is carried to the spinal cord and eventually to the pineal gland where production of melatonin is inhibited

where is melatonin also known to be produced

in the gut by enterochromaffin cells

when do melatonin levels increase

in the evening and decrease in the morning