The four important characteristics of respiratory surface are:
1. Thin walls
2. Moisture
3. Large surface area
4. Blood supply
Respiratory system or respiratory tract is divided into upper and lower tract. Upper respiratory tract includes nose and its cavities, sinuses, pharynx and the part of the larynx. Lower respiratory tract consists of the trachea, bronchi, bronchioles and the alveoli.
Alveoli are the ends of the respiratory tract the smallest units in it. Alveoli are small folded air sacs that are branching off from alveolar ducts and providing an extremely large surface area for the gas exchange. Gas exchange occurs thanks to small blood vessels – capillaries that surround alveoli and it occurs via the process of diffusion.
So, respiratory surface is thin membrane also known as the blood–air barrier that consists of the alveolar epithelial cells, their basement membranes and the endothelial cells of the alveolar capillaries.
Scientific validity is the applicability of a conclusion drawn in the context of a scientific experiment to the world at large.
Muscle cells do not form different types of tissues, the muscle tissue is one of the 4 basic categories of tissues found in humans
They can keep organ tissue alive for transplantation.
One of the reasons for the success of the smallpox eradication campaign was that small pox only occurred in humans. Smallpox is an extremely contagious and deadly virus for which there is no known cure. it is caused by two variants, Variola major and Variola minor. it is a disease of the past that was eliminated by worldwide vaccination.
