The smaller breeds of dogs tend to have their first estrus cycle at an earlier age, while the large and giant breeds of dogs may not come into heat for the first time until they reach eighteen months to two years of age.strus is the stage of the reproductive cycle in which the dog can become pregnant; sometimes a dog that is in estrus is said to be in heat or in season. On average, puberty or sexual maturity is reached at about 6 months of age, but this can vary by breed.
What is the function of the respiratory mucosa? As with all mucus in the body, its a lubricant to keep the lungs moist, prevents the lung lining from sticking to itself and prevents foreign body's like bacterium and dust fr â¦ om in bedding into the lungs causing infection.pecialized membrane that lines the air distrubution tubes in the respiratory tree. Over 125ml of mucus produced each day forms a mucous blanket over much of the respiratory â¦ mucosa. Mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen etc.
B. pertussis colonize the cilia of the mammalian respiratory epithelium. The epithelium is a tissue composed of a layer of cells. The main purpose of the respiratory epithelium is to moisten and protect the airways. It was originally thought that B. pertussis did not invade the tissues.