14.1.2 The Hypothalamic-Pituitary-Adrenal (HPA) Axis

• What does the HPA axis manage in the body?

  Stress response
• The HPA axis is a crucial endocrine pathway
• Steps in the activation of the HPA axis

  1️⃣ Hypothalamus releases CRH

  2️⃣ CRH stimulates the pituitary gland

  3️⃣ Pituitary gland secretes ACTH

  4️⃣ ACTH prompts the adrenal glands

  5️⃣ Adrenal glands release cortisol
• Cortisol suppresses the immune system during stress
• High levels of cortisol inhibit the hypothalamus and pituitary gland
• What are three effects of cortisol on the body?

  Mobilizes energy, suppresses immunity, increases blood sugar
• The negative feedback loop in the HPA axis reduces the release of CRH and ACTH
• Match the structure with its hormone and target:

  Hypothalamus ↔️ CRH, Pituitary Gland

  Pituitary Gland ↔️ ACTH, Adrenal Glands

  Adrenal Glands ↔️ Cortisol, Various tissues
• Steps in the activation of the HPA axis

  1️⃣ Hypothalamus releases CRH

  2️⃣ CRH stimulates the pituitary gland

  3️⃣ Pituitary gland secretes ACTH

  4️⃣ ACTH prompts the adrenal glands

  5️⃣ Adrenal glands release cortisol
• High levels of cortisol complete the negative feedback loop in the HPA axis
• What are three effects of cortisol on the body?

  Mobilizes energy, suppresses immunity, increases blood sugar
• The HPA axis consists of three primary components
• Match the structure with its function:

  Hypothalamus ↔️ Releases CRH

  Pituitary Gland ↔️ Secretes ACTH

  Adrenal Glands ↔️ Releases Cortisol
• Steps in the activation of the HPA axis

  1️⃣ Hypothalamus releases CRH

  2️⃣ CRH stimulates the pituitary gland

  3️⃣ Pituitary gland secretes ACTH

  4️⃣ ACTH prompts the adrenal glands

  5️⃣ Adrenal glands release cortisol
• What hormone is released by the hypothalamus to initiate the HPA axis activation?

  CRH
• CRH stimulates the pituitary gland to secrete ACTH
• ACTH prompts the adrenal glands to release cortisol.
• Which gland releases cortisol in response to ACTH?

  Adrenal glands
• CRH stimulates the pituitary gland to secrete ACTH
• Arrange the steps in the activation of the HPA axis in the correct order.

  1️⃣ The hypothalamus releases CRH

  2️⃣ CRH stimulates the pituitary gland to secrete ACTH

  3️⃣ ACTH prompts the adrenal glands to release cortisol
• CRH stimulates the pituitary gland to secrete ACTH
• ACTH prompts the adrenal glands to release Cortisol.
• Steps in the activation of the HPA axis in response to stress:

  1️⃣ The hypothalamus releases CRH

  2️⃣ CRH stimulates the pituitary gland to secrete ACTH

  3️⃣ ACTH prompts the adrenal glands to release Cortisol
• What hormone does the hypothalamus release to initiate the HPA axis response?

  CRH
• The pituitary gland releases ACTH, which stimulates the release of Cortisol
• High levels of Cortisol in the blood inhibit the release of CRH and ACTH through a negative feedback loop.
• What type of feedback loop is involved in regulating the HPA axis?

  Negative
• What hormone does the hypothalamus release to stimulate the pituitary gland?

  CRH
• The pituitary gland releases ACTH
• Which hormone is produced by the adrenal glands in response to ACTH?

  Cortisol
• High levels of cortisol inhibit the release of CRH and ACTH.
• Steps in the activation of the HPA axis

  1️⃣ Hypothalamus releases CRH

  2️⃣ CRH stimulates the pituitary gland

  3️⃣ Pituitary gland secretes ACTH

  4️⃣ ACTH prompts adrenal glands to release cortisol
• Which structure in the HPA axis releases CRH?

  Hypothalamus
• CRH stimulates the pituitary gland to secrete ACTH.
• Match the structure with the hormone it releases:

  Hypothalamus ↔️ CRH

  Pituitary Gland ↔️ ACTH

  Adrenal Glands ↔️ Cortisol
• What is the primary function of the HPA axis?

  Stress response
• The hypothalamus releases CRH in response to stress.
• Which hormone increases blood sugar levels during stress?

  Cortisol
• High cortisol levels inhibit the release of CRH and ACTH through a negative feedback loop.
• The HPA axis is activated in response to stress.