Mucous secretion and Sputum

Mucous secretion noun - Protective secretion of the mucus membranes; in the gut it lubricates the passage of food and protects the epithelial cells; in the nose and throat and lungs it can make it difficult for bacteria to penetrate the body through the epithelium.

Sputum and mucous secretion are semantically related. In some cases you can use "Sputum" instead a noun phrase "Mucous secretion".

Sputum noun - Expectorated matter; saliva mixed with discharges from the respiratory passages; in ancient and medieval physiology it was believed to cause sluggishness.

Mucous secretion and sputum are semantically related. You can use "Mucous secretion" instead a noun "Sputum".