Adrenaline:

• function: prepares the body for "fight or flight" by increasing heart rate, expanding airways, and boosting energy levels; it helps the body respond to stress quickly

• produced in: adrenal glands, located on top of the kidneys

• examples: taking the stage at a crowded stadium, before a competitive sporting event, on a roller coaster, or in the middle of an argument

• too much: overproduction of adrenaline could have negative effects on the heart, cause difficulty sleeping, and increase anxiety

• too little: too little adrenaline rarely occurs, but if it did, it would limit the body’s ability to respond properly in stressful situations

Oxytocin:

• function: promotes emotional bonding, trust, and social interactions; also plays a key role in childbirth by stimulating uterine contractions and milk ejection during breastfeeding

• produced in: hypothalamus, released by the pituitary gland

• examples: after a baby is born, skin-to-skin contact promotes bonding between mother and baby; PDA in romantic relationships

• too much: too much oxytocin can make healthy young adults oversensitive to the emotions of others

• too little: low oxytocin levels have been linked to mental health disorders such as depression, anxiety, and eating disorders

Melatonin:

• function: regulates sleep-wake cycles (circadian rhythms), signaling the body when it’s time to sleep and helping maintain a healthy sleep pattern

• produced in: pineal gland, a small gland in the brain

• examples: a flight attendant may use melatonin after a long international flight to combat jet lag and reset their internal clock; teenagers on their phones at night may experience trouble falling asleep due to blue light

• too much: people who suffer from seasonal affective disorder (SAD) may overproduce melatonin, causing them to feel sleepy during the day

• too little: people who produce too little melatonin may experience insomnia and have difficulty falling or staying asleep

Ghrelin:

• function: stimulates hunger, increases food intake, and promotes fat storage. it signals the brain to eat when the stomach is empty

• produced in: mainly produced in the stomach, with small amounts in the pancreas and brain

• examples: around mealtimes, levels increase, and after eating, levels decrease

• too much: high ghrelin levels may cause increased hunger and appetite, leading to overeating and weight gain. it can also reduce energy expenditure and hinder weight loss efforts

• too little: low ghrelin levels may result in reduced appetite, decreased feelings of hunger, and possibly weight loss. it could also lead to difficulty maintaining adequate nutritional intake

Leptin:

• function: regulates energy balance by inhibiting hunger, signaling the brain that the body has enough stored fat, and helping to maintain body weight

• produced in: fat cells (adipose tissue)

• examples: after eating, leptin helps you feel full

• too much: high levels of leptin are linked to obesity

• too little: if leptin levels are too low, the brain may perceive starvation, leading to increased hunger and reduced energy expenditure

Pituitary Gland and Endocrine System

• endocrine system function: regulates body functions through hormones (chemical messengers)

• pituitary gland:

  • location: base of the brain, below the hypothalamus

  • function: controls other endocrine glands and regulates body functions (growth)

• regulation: hypothalamus sends signals to the pituitary gland; feedback loops adjust hormone levels