Many organs best known for other functions also release hormones that help regulate blood pressure, digestion, and blood-cell production. This lesson explores the endocrine contributions of the heart, gastrointestinal (GI) tract, and kidneys.
When blood volume or pressure rises, the walls of the heart’s atria stretch. Specialized atrial cells respond by releasing atrial natriuretic peptide (ANP), a peptide hormone that helps reduce blood volume and blood pressure.
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What is ANP, and what is its overall effect?
Atrial natriuretic peptide is released by stretched atrial cells. It promotes sodium and water loss, inhibits renin secretion, and supports vasodilation, helping reduce blood volume and pressure.
What stimulates gastrin release, and what does gastrin do?
Stomach distention stimulates gastrin release. Gastrin stimulates secretion of hydrochloric acid by the stomach.
How do secretin and CCK differ?
Secretin responds to acidic chyme by promoting pancreatic bicarbonate release and inhibiting further stomach acid secretion. CCK promotes pancreatic enzyme secretion and bile release from the gallbladder.
What happens when the kidneys release renin?
Renin initiates the RAAS pathway, which promotes sodium and water reabsorption and helps restore blood flow and blood pressure.
What are the functions of calcitriol and EPO?
Calcitriol supports calcium regulation, including intestinal calcium absorption. EPO stimulates red blood cell production in the bone marrow when oxygen levels are low.
Quiz questions
What change causes atrial cells to release ANP?Answer: Increased atrial stretch from higher blood volume or pressure.
Which hormone responds to acidic chyme by promoting pancreatic bicarbonate release?Answer: Secretin.
What digestive response does CCK promote?Answer: Pancreatic enzyme secretion and gallbladder bile release.
What is a key effect of renin initiating the RAAS pathway?Answer: It promotes sodium and water reabsorption.
Which kidney hormone response to low oxygen helps improve oxygen delivery?Answer: EPO release stimulates red blood cell production.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.