What is the process when nervous system makes you feel hungry or thirsty?

Hunger

1. Stomach: When your stomach is empty or partially empty, it produces a hormone called ghrelin. Ghrelin signals the hypothalamus, a part of the brain that controls appetite and other bodily functions.

2. Hypothalamus: The hypothalamus receives the ghrelin signal and triggers a series of responses that make you feel hungry. These responses include:

* Increased activity in the lateral hypothalamus, which is involved in stimulating hunger.

* Decreased activity in the ventromedial hypothalamus, which is involved in suppressing hunger.

* Activation of the sympathetic nervous system, which increases the heart rate and blood pressure and releases stress hormones like adrenaline and cortisol. These hormones can also increase hunger.

3. Other factors: In addition to ghrelin, several other factors can affect hunger, including:

* Insulin: Insulin is a hormone that helps the body use glucose (sugar) for energy. When insulin levels are low, the body may produce more ghrelin, which can increase hunger.

* Leptin: Leptin is a hormone that is produced by fat cells. Leptin signals the hypothalamus to suppress hunger and increase energy expenditure. When leptin levels are low, the body may produce more ghrelin, which can increase hunger.

* Stress: Stress can increase the production of cortisol, which can increase hunger.

* Exercise: Exercise can increase the production of ghrelin, which can increase hunger. However, exercise can also increase energy expenditure, which can help reduce hunger over time.

Thirst

1. Kidneys: The kidneys are responsible for regulating the body's water balance and electrolyte levels. When the body is dehydrated, the kidneys produce a hormone called angiotensin II. Angiotensin II signals the hypothalamus, a part of the brain that controls thirst and other bodily functions.

2. Hypothalamus: The hypothalamus receives the angiotensin II signal and triggers a series of responses that make you feel thirsty. These responses include:

* Increased activity in the lateral hypothalamus, which is involved in stimulating thirst.

* Decreased activity in the ventromedial hypothalamus, which is involved in suppressing thirst.

* Activation of the sympathetic nervous system, which increases the heart rate and blood pressure and releases stress hormones like adrenaline and cortisol. These hormones can also increase thirst.

3. Other factors: In addition to angiotensin II, several other factors can affect thirst, including:

* Blood volume: When blood volume is low, the body may produce more angiotensin II, which can increase thirst.

* Sodium levels: When sodium levels are high, the body may produce more angiotensin II, which can increase thirst.

* Potassium levels: When potassium levels are low, the body may produce more angiotensin II, which can increase thirst.

* Stress: Stress can increase the production of cortisol, which can increase thirst.

* Exercise: Exercise can increase fluid loss, which can increase thirst.