Question

Angiotensinogen is a protein produced and secreted by:

• A. Juxtaglomerular (JG) cells.
• B. Macula dense cells
• C. Endothelial cells.
• D. Liver cells.

Answer 1

The correct option is D

Liver cells.

The correct option is D.

Explanation for the correct option:

1. The liver produces angiotensinogen, a ∝-globulin protein.
2. Renin is an enzyme that helps to convert the plasma protein angiotensinogen into angiotensin.
3. This protein causes the adrenal cortex to create aldosterone, which acts on the ascending limb cells of the loop of Henle and increases the rate of Na reabsorption.
4. The uptake of an osmotically comparable volume of water occurs when Nal is reabsorbed.
5. Blood volume and pressure rise as salt and water are absorbed.

Explanation for the incorrect options:

Option A:

1. The macula densa and juxtaglomerular cells are the two types of cells that make up the juxtaglomerular apparatus.
2. The macula densa is a group of specialized epithelial cells in the distal convoluted tubule that detect the sodium concentration of the fluid in the tubule.
3. At the glomerular vascular pole, it is situated immediately close to the afferent and efferent arterioles.
4. The macula densa is located where the distal convoluted tubule meets the glomerulus's afferent arteriole.

Option B:

1. At this junction, there is a dense layer of these cells on the DCT lining.
2. The macula denisa's job is to act as salt checkers.
3. When they detect a change in blood sodium levels, they release substances that allow the body to reabsorb or release sodium to restore the usual level.

Option C:

1. Epithelial tissues are tissues that have a free surface that faces either a body fluid or the outside environment and thus provides a coating or lining for a component of the body.
2. There is a little intercellular matrix and the cells are densely packed.

Final answer: Angiotensinogen is a protein produced and secreted by liver cells.