Human Respiratory System

Human Respiratory System The drive to breathe is involuntary and generally automatic, although one can change breathing patterns, and they change when we sleep or are doing different activities. The lungs and respiratory system function to move air 24/7/365 because the body cannot 'store' oxygen that it needs for cellular respiration and energy production. Thus air is constantly flowing in and out of the lungs (Healthline Editorial Team).

Respiration, in terms of human physiology, has more than one definition: it includes cellular respiration, a process ongoing within the mitochondria, where glucose is broken down to ultimately produce ATP (adenosine triphosphate), providing energy to the body. As well, the body is capable of brief periods of internal anaerobic respiration, which produces lactate in muscles for example. However, the focus of this report is on respiration as the process through which air moves into and out of the lungs, in processes of inhalation and exhalation.

Respiration using the physiological respiratory system is a process whereby gases are transferred from the lungs to the blood vessels and from the blood vessels to the lungs; with blood vessels carrying the gases to the various bodily tissues (The Respiratory System). The majority of the respiratory system functions for intake and outtake of air, particularly oxygen and carbon dioxide; the smaller alveoli and alveolar conduits are the locales where gases are exchanged. As well as functioning for air intake exchange, the respiratory framework directs, warms, and humidifies the air.

Organs in the respiratory framework also function in smell and speech. The respiratory framework is also involved in physiological homeostasis of the internal environment of the body; indeed it can be argued that the respiratory system is one of the most important for the body's proper functioning (Healthline Editorial Team).

The respiratory system includes the following: left and right lungs, both within the thoracic cavity; the right lung has three lobes whereas the left lung has only two lobes, and is partially compressed because the heart is on the left side of the body. Air enters and exits the lungs through a diverse system of upper airways. The respiratory system also involves the diaphragm as well as being supported by muscles and bones making up the thoracic cavity (DiGiovanna).

The remaining portion of this paper focuses on the human respiratory system and addresses illnesses that influence the respiratory system and affect our well-being. Lastly, some preventive measures are given. The anatomy of the human respiratory system The respiratory framework includes the respiratory tract, the pulmonary circulation, other components including the central nervous system (CSN), and the chest wall. The entire framework of the respiratory system is housed in the thorax, head, and neck.

The upper respiratory tract is found in the head and neck, while the lower respiratory tract is found as the trachea through the lungs (Person and Mintz). The anatomy of the respiratory tract includes the following: the naso-oropharynx, the alveoli, the respiratory bronchioles, and the directing airways. As well, the lungs can considered as directing airways and respiratory units. The trachea, bronchi, and bronchioles bring in and transport air from the outside world and convey it to the alveoli, which are the respiratory units.

Gas exchange is the process occurring at the level of the alveoli, delivering oxygen to the blood to be transported throughout the body to the cells for normal cellular functions (Person and Mintz). Air enters through the nose and/or mouth and then moves through the pharynx and larynx and trachea into the lungs. In the lungs the air moves into primary bronchi, bronchioles, and then the alveoli/respiratory membrane. These organs can likewise be subdivided into: upper respiratory tract where [nose-pharynx-larynx], and the lower respiratory tract [thoracic respiratory organs].

Nose Air in the nasal cavity enters through the nose's two nares (nostrils). On the superior side you have the nasal bones, and the plates of hyaline ligaments sit toward the end of the nose and are in charge of shaping the nose. Nasal Cavity A division of the nasal entrances into left and right sides is accomplished by the nasal septum. The septum is framed by an inferior vomer bone, a superior ethmoid bone, and a septal cartilage that sits anteriorly.

Inside the nose, the sticky mucous membrane that lines the nasal cavities serves to traps dust particles. Then small hairs called cilia help move the dust to the nose to be removed; these also function to prevent debris from entering the respiratory system (Healthline Editorial) Pharynx The pharynx, usually called the throat, is generally described in terms of anatomy as being separated into three areas based on their location in the body. The three segments are called the oro-pharynx, the naso-pharynx, and the laryngo-pharynx.

The naso-oro-pharynx begins at the nostrils and includes the nasal section, glottis, and sinuses up to the trachea. This airway is lined by special cells which have tiny hairs called cilia; and it is made up of ciliated pseudo-stratified columnar epithelial tissue. The hairs function to move bodily fluids and trapped debris so that they can avoid entering the lungs. One function of the naso-oro-pharynx is warm and humidify the air before it enters the lungs; another is to trap and/or filter out 'large' particles (Person and Mintz).

The oro-pharynx is the section of the pharynx that is located just behind the naso-pharynx. The oro-pharynx is used not only as part of the respiratory system, but is also the route whereby food and liquids enter into the body, as part of the digestive system. The oro-pharynx has a tougher variety of cells, called stratified squamous epithelial cells, because of the large variety of substances that enter the body through the mouth (The Respiratory System).

The laryngo-pharynx section of the pharynx is defined as the area from the epiglottis to the very start of the throat. In analogy to the oro-pharynx, the cellular tissue of the laryngo-pharynx is made up of stratified squamous epithelial tissue; this area handles not only air intake but also intake of fluids and foods as part of the digestive system. Solids and fluids move from the laryngo-pharynx to the throat.

However, once the breathing reflex is stimulated, air travels into the larynx through an opening called the glottis (The Respiratory System). Larynx The larynx is the fundamental part of the anatomy involved with speech. The manner in which it functions is that the epiglottis remains in a position that is vertical and separates air, which flows from the laryngo-pharynx to the larynx and trachea, and food/fluids into the throat (The Respiratory System).

Trachea Once air is in the larynx, air flows to the trachea; this is a tube that is generally inflexible, being comprised of some 18-20 C-shaped hyaline cartilage supports. These pieces of cartilage function to hold the trachea open. As well, there is smooth muscle in the trachea, at the rear anatomically. The soft tissue of the smooth muscle in the trachea permits expansion of the upper end of the esophagus during swallowing.

The trachea is the primary airway to the lungs, and is located just beneath the larynx (Healthline Editorial Team). The trachea is lined with ciliated pseudo-stratified columnar epithelial cells and tissue, just as was the case for the naso-pharynx and the nasal cavity. Some of these cells also release bodily fluids. It turns out that, even though we cannot see them, air that we routinely breathe in contains a large number of particles such as smoke, pollen, and dust.

The cilia that line the trachea function all of the time, even when we are asleep, to move bodily fluids, and entrapped 'junk' up to the pharynx to be removed. This is a route to protect the respiratory system from materials that should not enter it. The trachea then goes to a division called the right and left fundamental bronchi, each then entering the respective right and left lung (The Respiratory System).

The Lungs The lungs function to intake oxygen, deliver it to the blood vessels and to eliminate carbon dioxide by exhalation (Healthline Editorial Team). The right lung is comprised of three sections, from top-to-bottom these are the upper, center and lower projections; each of these sections is further divided into sub-sections, each having its own airway. The left lung has only two sections, as the heart takes up a portion of the thoracic cavity (Person and Mintz).

Each of the two primary bronchi enters the left and/or right lung at a location called the hilum, which is also where other vessels enter and leave the lung. The left bronchus is marginally flatter than the right bronchus because of the area of the heart. The main bronchi and the majority of its branches make up the bronchial tree. The bronchus that goes to a separate lobe of the lung is called lobar bronchi and stems from branches of the main bronchus.

There are three lobar bronchi on the right lung and only two on the left (The Respiratory System). Cartilage plates support all of the bronchi, holding them open for continuous airflow. Bronchioles are the smallest branches of bronchi splitting into even smaller tubes. The bronchioles have no cartilage, but are instead lined with smooth muscle. The smooth muscle lining the bronchioles functions to allow these airways to dilate and constrict as a part of the breathing reflex. Air goes from the bronchioles to the alveoli (Person and Mintz).

Alveoli The alveoli are very tiny vessels at the end of each bronchiole, and could be described as looking like tiny grape clusters. The alveoli are covered by a network of capillaries, which is where the gaseous exchange of oxygen into the blood vessels and carbon dioxide out of the blood vessels is made. Estimates indicate as many as 150 million alveoli within each of the two lungs.

The walls of the alveoli are comprised of simple squamous epithelial cells; these are important for gas exchange; as well, the alveoli have alveolar cells. Most of the cell walls of the alveoli are comprised of the very thin squamous cells that permit the exchange of gas molecules (The Respiratory System).

The surface wall of the alveoli has only one layer of epithelial cells; many immune system cells are also found in this location, including macrophages, neutrophils, and eosinophils that give way to the cells that exist on the alveoli lining. The alveoli cell wall creates an air-blood interface with the capillary system (Person and Mintz). Diaphragm The main respiratory muscle that allows for breathing is the diaphragm. Figure 1. Diagram of the respiratory system.

Physiological functions of the respiratory system: Breathing Surprisingly, air flow in the body is neither pushed nor forced; rather it is transported by changes in pressure. Within the chest, there are a variety of muscles that act to expand the rib cage -- these include the pectoralis minor, external intercostal, and sternocleidomastoid muscles, which function to bring in air as the rib cage is expanded. As well, when the diaphragm is flattened as it contracts, the volume of the chest cavity is increased (The Respiratory System).

When this happens, inhalation occurs, as air rushes in through the nose and mouth. When these muscles relax, exhalation naturally occurs as the cavity is depressed. Normally, breathing is passive and requires no deliberate effort. However, when the abdominal wall and intercostal muscles are flexed, forced exhalation takes place. This action causes the air cavity to compress more quickly to force air out (The Respiratory System). Figure 2.

Respiratory system during inhalation and exhalation (Source: The Respiratory System) Tuberculosis: A Disease of the Respiratory System Mycobacterium tuberculosis is the bacterial species that causes tuberculosis, a disease that usually attacks the lungs. There are, however, cases where the tuberculosis bacteria attack the spine, kidney, and/or brain. Tuberculosis (TB) is a dangerous disease, first, because it can be fatal, and second, because it is highly infectious. While many do not realize it, TB was at one time the primary cause of fatalities in the United States.

This disease was once the number one cause of death in America (CDC). What Causes Tuberculosis? The exact origin of TB is infection by mycobacterium tuberculosis. The current problem is that there are now many strains of this bacteria, and some of them have become antibiotic resistant. The disease is very easily spread through the air by coughing, singing, speaking, and sneezing, and unfortunately also by spit.

It was once against the law to spit in public, during the early 1900's when TB was rampant, for example in New York City. But there are a great variety of strains. Even if someone sneezes and then leaves the room, the bacteria may remain in the air and/or on surfaces where others can come into contact with them. In some cases, a person may be a TB carrier, yet have no symptoms themselves; this is called latent or inactive TB. Luckily, latent TB is non-contagious.

However, just because the TB is latent does not mean that the person will not become ill; at least 10% of individuals having latent TB will go on to develop a case of active TB (Nall). What Are the Symptoms of Tuberculosis? When TB is active there are a variety of different symptoms. The majority of these are respiratory in nature, such as coughing. As the disease spreads or worsens, the coughs may produce a bloody and/or mucous-filled discharge.

Officially, TB symptoms include at least three weeks of persistent coughing, night sweats, weight loss, fever, chills, fatigue, weakness, bloody or mucous discharge in coughs, and chest pain. (CDC). How Is Tuberculosis Diagnosed? There are a variety of different tests for TB, including a blood test. One type of TB test includes injection of a tiny amount of TB bacteria to determine if there is an antibody reaction. Swelling at the site of the injection is generally.