Physiology of Digestion Quiz

Atropine, a muscarinic receptor antagonist, inhibits peristalsis in the intestines by blocking the action of acetylcholine (Ach) on the myenteric plexus, which is responsible for regulating intestinal muscle contractions.

The vago-vagal reflex is a key reflex in the stomach that primarily helps in the relaxation of the stomach wall, allowing for the ingestion and accommodation of food.

The gastrocolic reflex is triggered by the distention of the stomach, leading to the urge to defecate. It is an example of how the digestive system coordinates different processes.

Lysozymes are enzymatic components of saliva that play a role in breaking down bacterial cell walls, contributing to the antibacterial properties of saliva.

The bicarbonate secreted by the salivary glands helps neutralize the acidic chyme that might reflux from the stomach into the esophagus, protecting the esophageal lining.

The process of producing red blood cells (RBCs) in the bone marrow.

The liver synthesizes lipoproteins, which are carriers for lipids (fats) in the bloodstream.

The liver breaks down amino acids into keto-acids, a process called deamination.

The liver converts non-carbohydrate molecules, like amino acids and glycerol, into glucose, a process called gluconeogenesis.

The liver produces various clotting factors vital for blood coagulation.

Bile is produced by the liver and stored in the gallbladder. It contains conjugated bilirubin, cholesterol, and pigments.

Enterochromaffin-like cells (ECL cells) are found in the stomach lining and secrete histamine, a chemical that stimulates gastric acid production.

Pepsin is a digestive enzyme produced in the stomach that breaks down proteins. It works best in acidic conditions and can digest collagen.

Erythrocytes, also known as red blood cells, are responsible for transporting oxygen from the lungs to the tissues throughout the body.

Megaloblastic anemia is a type of anemia caused by a deficiency of vitamin B12 or folate, which are essential for the production of healthy red blood cells. This deficiency leads to the formation of abnormally large, immature red blood cells, called megaloblasts.

White blood cells (WBCs) are crucial for the body's immune system. They defend the body against infection and inflammation. These cells travel to areas of infection and inflammation, providing a rapid and robust defense against infectious agents. Granulocytes, monocytes, and B-lymphocytes are formed in the bone marrow.

Fructose is transported across the luminal cell membrane of an enterocyte in a normal adult human by facilitated diffusion. Facilitated diffusion is a type of passive transport where a carrier protein helps the molecule move across the membrane down its concentration gradient without using energy.

Iron absorption in the duodenum primarily occurs through the action of a transport protein called the DMT1 (divalent metal transporter 1). This is an active transport process, requiring energy to move iron across the intestinal lining.

Collagen is a fibrous protein found in connective tissues, such as skin, bones, and tendons. It is not a plasma protein, which are proteins found in the liquid portion of the blood (plasma).

Pepsin, an endopeptidase, cleaves peptide bonds between specific amino acids in proteins. It particularly targets the bonds between a tyrosine or phenylalanine and the next amino acid in the sequence.

Trypsin is an example of an endopeptidase. Endopeptidases are enzymes that break down proteins by cleaving peptide bonds within the protein chain. Other examples of endopeptidases include chymotrypsin and elastase.