**Question:** Hormones secreted by adrenal medulla are:

A. Adrenaline
B. Cortisol
C. Estrogen
D. Progesterone

**Correct Answer:** A. Adrenaline

**Core Concept:** The adrenal medulla is part of the adrenal gland, located on top of the kidneys. It plays a crucial role in the body's stress response and regulation of blood pressure. The adrenal medulla produces and releases two main hormones: adrenaline (also known as epinephrine) and noradrenaline (also known as norepinephrine). These hormones are released in response to stress or increased demand for energy, contributing to the "fight or flight" response.

**Why the Correct Answer is Right:** Adrenaline is the hormone primarily secreted by the adrenal medulla, specifically by the chromaffin cells. It is responsible for numerous physiological changes in preparation for a stress response, such as increased heart rate, blood pressure, and glucose levels. Adrenaline also stimulates glycogenolysis and gluconeogenesis to generate glucose for the increased energy demand.

**Why Each Wrong Option is Incorrect:**

B. Cortisol: Cortisol is a hormone secreted by the adrenal cortex, the outer layer of the adrenal gland. It plays a vital role in the body's response to stress, immune system regulation, and maintaining blood glucose levels.

C. Estrogen: Estrogen is a hormone primarily produced by the ovaries in females and the testes in males. It is involved in the development and maintenance of secondary sexual characteristics and plays a role in bone growth and breast development.

D. Progesterone: Progesterone is another hormone primarily produced by the corpus luteum during pregnancy and the ovaries in non-pregnant females. It plays a crucial role in preparing the uterine lining for implantation and maintaining pregnancy.

**Clinical Pearl:** The adrenal medulla and cortex work together in a delicate balance to regulate the body's response to stress and maintain homeostasis. When there is a stressful event, the hypothalamus and pituitary gland stimulate the adrenal glands to secrete cortisol and adrenaline (epinephrine), which act synergistically to prepare the body for a stress response.