1. a. First line of defense: These external, nonspecific (innate) defenses include our physical and biochemical barriers, as well as the normal flora that live on our skin. The barriers are made up of the the epithelial cells on the skin and our body tract conditions, like the linings of the respiratory, urinary, and gastrointestinal systems. When exposed to pathogenic substances, these allow the body to expel the harmful particles by coughing, sneezing, vomiting, and other methods of flushing them out. The first line of defense is also composed of our natural, beneficial bacteria, which train and develop the immune system and protect against microbes by producing chemicals that are toxic to foreign invaders.
b. Second line of defense: These …show more content…
a. Red blood cells: Erythrocytes, also known as red blood cells, contain hemoglobin. It is the main vessel that transports oxygen across the bloodstream and oxygenates tissues. These cells are responsible for carrying gas to and from the tissues and the lungs. b. Hemoglobin: Hemoglobin is a substance inside the red blood cells. This protein molecule contains globin, a protein, and heme, a pigment, which contains iron and releases the oxygen from the lungs and into the tissues. It also transports some carbon dioxide from the tissues and back into the lungs. c. White blood cells: Leukocytes, or white blood cells, remove dead or injured cells and fight infection and foreign invaders that may enter the body. There are many types of leukocytes and they respond to the presence of these pathogens by producing antitoxins, creating antibodies, and using the process of phagocytosis (where the cell ingests the harmful/useless particle).
d. Neutrophils: Neutrophils travel around the bloodstream and is often the first type of white blood cell that reaches the infection site. They are the most abundant type of leukocyte and can kill the microbes through phagocytosis. They also have antimicrobial proteins in their granules which allow them to attack the pathogenic particles