Essay on Downtown: Lungs

Submitted By dylanwalford
Words: 1612
Pages: 7

Snjskaamakis he cardiovascular system cannot carry outs normal duties, unless the respiratory system contributes it'd share faithfully. Respiration is the overall process of exchanging oxygen and carbon dioxide, which is between the environment and blood.
It is broken up into three stages:
Stage 1: the breathing process which involves the movement of air in and out of the lungs.
Stage 2: he cardiovascular system cannot carry outs normal duties, unless the respiratory system contributes it'd share faithfully. Respiration is the overall process of exchanging oxygen and carbon dioxide, which is between the environment and blood.
It is broken up into three stages:
Stage 1: the breathing process which involves the movement of air in and out of the lungs.
Stage 2:

Respiration may be broken into three stages: (1) the process of breathing, which involves the movement of air into and out of the lungs (the pulmonary system); (2) the exchange of gases between the internal surface of the lungs and the blood; and (3) the exchange of gases between the blood and the cells of the body. The combined system with the heart and lungs working together is often called the cardiopulmonary system (Figure 12a).
Movement of air from the external environment into the lungs is accomplished by the action of two groups of muscles. The first is the diaphragm, a muscular wall that divides the trunk's body cavity into two parts, the chest and the abdomen. The second consists of the rib muscles (intercostal muscles). These muscles act together to change the size of the chest cavity. The rib muscles are attached to your ribs, which in turn encircle the lungs and chest cavity. Together, this system is often referred to as the rib cage.

The respiratory tract is the pathway for air to enter the body. It is one of only three main gateways that connect the "outside" of the body to the "inside" of the body (the other two are the digestive tract and the urinary tract). The process of respiration involves many interactions. Let us begin with inspiration (inhaling). Air is drawn into the lungs as a result of the combined expansion of the rib cage and the lowering of the diaphragm; in normal breathing it is lowered about 1 cm; in heavy breathing it can be lowered up to 10 cm. When the lungs are expanded in this state, atmospheric pressure, the pressure outside the body, is higher than the pressure in the lungs. Air flows from the higher to the lower pressure areas and into the lungs through a system of channels that begins with the oral cavity (mouth) and the nasal cavity (nose). The air flow then continues through the trachea (the windpipe) and into the bronchi which are two large tubes, one for each lung. Finally, stemming from the main bronchi are smaller bronchi and tiny bronchioles, much like branches and twigs stemming from a tree trunk.

Figure 12b. The exchange of gases occurs between the membranes ofthe alveoli and the surrounding capillaries. The red blood cells are thevehicles that carry the carbon dioxide to and oxygen away from thealveoli.

Arriving at the bronchioles, the air has yet to unload its cargo of oxygen. The start of this task is taken on by vast armies of tiny, expandable, thin-walled, clustering sacs called alveoli. There are estimated to be about 300 million of these small air sacs in an average-sized adult. The alveoli constitute the bulk of lung tissue; it is their substance that makes the lungs soft and spongy. When the lungs expand or contract, it is the alveoli that are expanding or contracting. It is from the alveoli that the blood receives its oxygen.

Every alveolus in your lungs is covered with capillaries (Figure 12b). Every single red blood cell (RBC) in your bloodstream flows through these pulmonary capillaries so they can pick up an oxygen molecule and give up carbon dioxide. Layers of capillary and alveolar cells lie in direct contact side by side with a double membrane, almost unimaginably thin,…