Hypothalamic–pituitary–adrenal_axis

⭐ Core Definition: Hypothalamic–pituitary–adrenal axis

The hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis) is a complex set of direct influences and feedback interactions among three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a pea-shaped structure located below the hypothalamus), and the adrenal (also called "suprarenal") glands (small, conical organs on top of the kidneys). These organs and their interactions constitute the HPA axis.

The HPA axis is a major neuroendocrine system that controls reactions to stress and regulates many body processes, including digestion, immune responses, mood and emotions, sexual activity, and energy storage and expenditure. It is the common mechanism for interactions among glands, hormones, and parts of the midbrain that mediate the general adaptation syndrome (GAS).

↓ Menu

>>>PUT SHARE BUTTONS HERE<<<

👉 Hypothalamic–pituitary–adrenal axis in the context of Stress (biology)

Stress, whether physiological, biological or psychological, is an organism's response to a stressor, such as an environmental condition or change in life circumstances. When stressed by stimuli that alter an organism's environment, multiple systems respond across the body. In humans and most mammals, the autonomic nervous system and hypothalamic-pituitary-adrenal (HPA) axis are the two major systems that respond to stress. Two well-known hormones that humans produce during stressful situations are adrenaline and cortisol.

The sympathoadrenal medullary axis (SAM) may activate the fight-or-flight response through the sympathetic nervous system, which dedicates energy to more relevant bodily systems to acute adaptation to stress, while the parasympathetic nervous system returns the body to homeostasis.

↓ Explore More Topics

In this Dossier

⭐ Core Definition: Hypothalamic–pituitary–adrenal axis
👉 Hypothalamic–pituitary–adrenal axis in the context of Stress (biology)
Hypothalamic–pituitary–adrenal axis in the context of Gut–brain axis

Hypothalamic–pituitary–adrenal axis in the context of Gut–brain axis

The gut–brain axis is the two-way biochemical signaling that takes place between the gastrointestinal tract (GI tract) and the central nervous system (CNS). The term "microbiota–gut–brain axis" highlights the putative role of gut microbiota interacting with brain functions, according to preliminary research. Broadly defined, the gut–brain axis includes the central nervous system, neuroendocrine system, neuroimmune systems, the hypothalamic–pituitary–adrenal axis (HPA axis), sympathetic and parasympathetic arms of the autonomic nervous system, the enteric nervous system, vagus nerve, and the gut microbiota.

Chemicals released by the gut microbiome can influence brain development, starting from birth. A review from 2015 states that the gut microbiome influences the CNS by "regulating brain chemistry and influencing neuro-endocrine systems associated with stress response, anxiety and memory function".

↑ Return to Menu

Hypothalamic–pituitary–adrenal axis in the context of "Stress (biology)"

Play Trivia Questions online!

Skip to study material about Hypothalamic–pituitary–adrenal axis in the context of "Stress (biology)"

⭐ Core Definition: Hypothalamic–pituitary–adrenal axis

👉 Hypothalamic–pituitary–adrenal axis in the context of Stress (biology)

Hypothalamic–pituitary–adrenal axis in the context of Gut–brain axis