Answer: A mucous membrane is a layer of epithelial tissue which lines an area of the body which comes into contact with air. Mucous membranes are moist because of the presence of glands which secrete a thick fluid known as mucus, and they are important for a number of bodily functions. Mucous membranes line the urogenital tract, digestive tract, and respiratory tract, with one of the more well known mucous membranes being the lining of the interior of the nose.
The moisture found in a mucous membrane acts to protect the body by creating a barrier and preventing the inside of the body from drying out. Mucus also traps pathogens, dirt, and particulate matter so that they can be sequestered and eliminated by the body. The nose is particularly famous for this, using mucus as a barrier between many harmful substances and the respiratory tract. Some sections of mucous membrane also have small hairs known as cilia which act as traps, and can move to push things across the surface of the membrane.
Answer: The respiratory membrane is formed by a combination of the walls ofalveoli and walls of capillaries. It consists of type 1 alveolarcells, a basement membrane, capillary endothelium, alveolarepithelium and macrophages.
Answer: The visceral membrane is a type of serous membrane, which covers the outer layer of organs (such as the intestines). It secretes small amounts of a serous fluid, which reduces friction between organs and other structures.
Answer: Viscera denotes the organs in the body cavities.(The heart confined in the Pericardial cavity, the lungs in the Pleural cavity, and the abdominal organs in the Peritoneal cavity).Visceral membrane (visceral serosa) covers those organs.More info could be find onhttp://en.wikipedia.org/wiki/Serosa
Answer: The nucleus is surrounded by a nuclear envelope composed of two membranes. The nuclear envelope is dotted with thousands of nuclear pores, which allow material to move into and out of the nucleus. Like messages, instructions, and blueprints moving in and out of a main office, a steady stream of proteins, RNA, and other molecules move through the nuclear pores to and from the rest of the cell. --Biology textbook
All cells have a membrane that distinguishes their internal contents from the surrounding fluid or tissue.
Remember, smaller entities such as virus or prions are not cells, but rather just protein complexes.