Hormones Produced by Organs Other Than the Major Endocrine Organs

Question 1

Prostaglandins (PGs); several groups indicated by letters A–I (PGA–PGI)

Answer 1

Chemical composition
• Derived from fatty acid molecules
Source
• Plasma membranes of virtually all body cells
Stimulus for secretion
• Various (local irritation, hormones, etc.)
Target organ/Effects
• Have many targets but act locally at site of release. Examples of effects include the following: increase blood pressure by acting as vasoconstrictors; cause constriction of respiratory passageways; stimulate muscle of the uterus, promoting menstrual pain and labor; enhance blood clotting; promote inflammation and pain; increase output of digestive secretions by stomach; cause fever

Question 2

Gastrin

Answer 2

Chemical composition
• Peptide
Source
• Stomach
Stimulus for secretion
• Food
Target organ/Effects
• Stomach: stimulates glands to release hydrochloric acid (HCL )

Question 3

Intestinal gastrin

Answer 3

Chemical composition
• Peptide
Source
• Duodenum (first segment) of small intestine
Stimulus for secretion
• Food, especially fats
Target organ/Effects
• Stomach: stimulates gastric glands and motility

Question 4

Secretin

Answer 4

Chemical composition
• Peptide
Source
• Duodenum
Stimulus for secretion
• Food
Target organ/Effects
• Pancreas: stimulates release of bicarbonate-rich juice
• Liver: increases release of bile
• Stomach: reduces secretions and motility

Question 5

Cholecystokinin (CCK)

Answer 5

Chemical composition
• Peptide
Source
• Duodenum
Stimulus for secretion
• Food
Target organ/Effects
• Pancreas: stimulates release of enzyme-rich juice
• Gallbladder: stimulates expulsion of stored bile
• Duodenal papilla (entry point at the small intestine): causes sphincter to relax, allowing bile and pancreatic juice to enter duodenum

Question 6

Erythropoietin

Answer 6

Chemical composition
• Glycoprotein
Source
• Kidney
Stimulus for secretion
• Hypoxia (low oxygen level)
Target organ/Effects
• Bone marrow: stimulates production of red blood cells

Question 7

Active vitamin D3

Answer 7

Chemical composition
• Steroid
Source
• Kidney (activates provitamin D made by epidermal cells)
Stimulus for secretion
• PTH
Target organ/Effects
• Intestine: stimulates active transport of dietary calcium ions across intestinal cell membranes

Question 8

Atrial natriuretic peptide (ANP)

Answer 8

Chemical composition
• Peptide
Source
• Heart
Stimulus for secretion
• Stretching of atria (receiving chambers) of heart
Target organ/Effects
• Kidney: inhibits sodium ion reabsorption and renin release
• Adrenal cortex: inhibits secretion of
aldosterone, thereby decreasing blood volume and blood pressure

Question 9

Leptin

Answer 9

Chemical composition
• Peptide
Source
• Adipose tissue
Stimulus for secretion
• Fatty foods
Target organ/Effects
• Brain: suppresses appetite and increases energy expenditure

Question 10

Resistin

Answer 10

Chemical composition
• Peptide
Source
• Adipose tissue
Stimulus for secretion
• Unknown
Target organ/Effects
• Fat, muscle, liver: antagonizes insulin’s action on liver cells