Sulci or known as fissures
When an egg is not fertilized by sperm, this causes the breakdown of the uterus lining. It is known as menstruation.
The reticulum is the second stomach in the set of four, its main function is to interact with the rumen to initiate the mixing activity of the rumen and providing and additional area for fermentation. This stomach is generally known as the honeycomb due to the lining of small compartments in the shape of honeycombs. It is also known as the Hardware Stomach since it is the main compartment where foreign objects like nails, stones, wire, and other objects are collected and degraded by the gastric juices of the cow's GI tract.
On a small scale this is known as structural geology. On a global scale this is known broadly as rheology (folding) and tectonics (faulting).
The inner lining of the stomach contains wrinkles known as gastric folds. These gastric folds allow the stomach to stretch to accommodate large amounts of food. There are also mucous cells and gastric pits in the inner lining that mucous to protect the stomach.
The internal lining of the stomach is known as the mucous membrane or the gastris mucosa. This lining can be described as being thick and velvet like with a soft smooth surface. When the stomach is empty or contracted this lining is floded into many folds known as rugae. The purpose of the cells in this lining is to secret digestive juices and mucus. The mucus protects the mucosa , the digestive juices contain a digestive enzyme known as pepsin. There are also parietal cells which are able to secrete hydrochloric acid which is used in the digestion of food.
Nothing happens- alcohol is not an acid capable of eating through the mucosa. Stomach acid is, but the mucosa is constantly renewed. In some cases, the mucosa is not enough and the acid irritates the stomach lining- thats known as an ulcer.
When the bladder is empty it's lining is thrown into folds called rugae. It allows the stomach and other tissues to expand when needed.
Melanotic mucosa of the colon means that the inner lining of the colon is dark in color. It is often a result of chronic laxative use. It's also known as melanosis coli.