The Physiology Of The Lungs

Oxygen is drawn into the lungs by a process called inhalation, (breathing in), which occurs when the diaphragm and intercostal muscles are contracted which causes the lungs to expand, giving a larger volume and therefore causing a lower pressure differential between the lungs, alveolar pressure, and the outside atmosphere. This inverse relationship between volume and pressure is called Boyle’s law. (Tortora & Derrickson, 2011)

During inspiration, the diaphragm and the surrounding muscles contract. The diaphragm moves down increasing the volume of the chest cavity, and the surrounding muscles pull the rib up to allow further increase in volume. This increase of volume decreases the air pressure in the alveoli

The bronchi and bronchiole tubes are loosely wrapped with muscle. During regular breathing, the muscles around these airways are relaxed (5). This allows air to flow freely through these passageways to the alveoli. However, during an asthma attack, air has trouble reaching the alveoli, which prevents the body from receiving oxygen. This is because the airways become smaller. Firstly, the muscles around the airways spasm and contract. This then causes inflammation of the bronchioles and bronchi themselves, which causes a mucus to be produced.

There is also a large increase in airway resistance and a collapse of the lower airways during expiration and a decrease in the elastic recoil of the

D. The lung has special membranes that surround it. Those membranes are known as the parietal and visceral membranes. They serve as shields to help with defense, absorption and secretion (Thompson). When large amounts of liquid enter the lung membrane, it creates enough pressure to squeeze your lung to the point that it partially or completely collapses (Mayo Clinic). A partial or complete collapsed lung will reduce the amounts of oxygen, therefore causing difficulty breathing (Mayo

The air pressures and volumes are essential to breathing. During inhalation the diaphragm contracts allowing the

The main organs of the respiratory system are the lungs – they are the location where the gas exchange between oxygen and carbon dioxide takes place. The lungs therefore expand when you breathe in, and retract when you breathe out. This is done through the diaphragm – a sheet of muscle that is positioned under the lungs. As one inhales, their diaphragm contracts and moves itself downward, increasing the space for your lungs to expand to. The ribs also move to enlarge the possible area the lungs can expand to. This pressure causes air to be sucked through the body to the lungs. When one exhales, the opposite takes place – the diaphragm moves upwards and returns to normal, allowing the process to happen again.

This causes further damage to the lung. This hyperinflation of the lung is known as emphysema. In emphysema, the alveoli are permanently enlarged leading to a dramatic decline in the alveolar surface area available for gas exchange (Workman, 2013). The permanent enlargement of the alveoli is caused by the overabundance of proteases. When proteases are present in higher-than-normal levels, alveoli is damaged as the proteases break down the elastin located within the lung. When elastin is broken down, lung elasticity is decreased and air is permanently trapped within the air spaces (Workman, 2013). These overall changes from both bronchitis and emphysema lead to hypoxemia, decreased oxygenation, and respiratory

The lower respiratory system contains the lower trachea, bronchi, bronchioles and alveoli in the lungs. The bronchi form as the lower part of the trachea and branch into two in the left and right lung. The upper segments of the bronchi have C shaped cartilage rings which keep the bronchi open for airflow. The bronchi divide into smaller bronchioles inside the lungs. They are made up of smooth muscle (without cartilage). The bronchioles continue to divide into alveoli; small grape shaped air sacs. Each alveoli is surrounded by pulmonary capillaries. The function of the alveoli is to perform the exchange of oxygen and carbon dioxide. There are millions of alveoli in the lungs, they have thin walls so the diffusion of oxygen and carbon dioxide can move across the membrane without resistance to the pulmonary capillaries.

The respiratory system changes in many ways as one ages. These gradual changes begin at age twenty to thirty (Miller, 2015, p. 443) and function starts to weaken at age forty (El-Kader, and El-Den Ashmawy, 2013, p. 15). Changes occur in the upper respiratory structures, chest wall and musculoskeletal structures, and lung structures and function. The upper respiratory structures in the nose become less supportive, due to less connective tissue, and smaller, because of decreased blood flow (Miller, 2015, p. 443). Also, degenerative changes in the submucosal glands of the nasopharynx produce thicker mucus (Miller, 2015, p. 443). Cough and gag reflex are decreased (Miller, 2015, p. 443). Because of chest wall and musculoskeletal changes, elderly spend more energy on breathing. This occurs as a consequence of chest wall stiffness, weakened muscles, and changes in the shape of the chest (Miller, 2015, p. 444). The lungs become less elastic and smaller, the alveoli enlarge and thin out, the pulmonary artery becomes stiffer, wider, and thicker, the pulmonary capillaries decrease and have less blood flow, and the mucosal bed thickens (Miller, 2015, p. 445). Elastic recoil diminishes and can cause air trapping and less gas exchange (Miller, 2015, p. 445). Due to changes, elderly do not always respond in a compensatory manner and can have mental changes instead (Miller, 2015, p. 445).

Desperately, my eyes search for light. My ears craving the sound of life, activity, even the mice scurry away from me. I am currently spending my first day in the heart of this ‘correctional facility’ as they say. I am sitting in an eternity of darkness and silence. The Warden can’t be serious about this, I’m sure any minute he;’s going to clarify what Tommy said about that hell forsaken inmate of his killing my wife. He has to believe me. After all I’ve done for him, he needs to just consider it. My lungs are craving the fresh air, the musty, damp cell is slowly suffocating me.

“I know and you're going to be ok.” I said even though I knew he wasn't going to be ok. We all knew he was going to die in a matter of a few minutes. And during those last few minutes we had with him we prayed to the lord that he would take care of the officer and watch over us during the rest of our journey ahead. I couldn't stand there looking at his dead body so we covered it with a blanket we found in a car. Next we heard more gunshots and they wouldn't stop. There were tons of cars around us getting hit with bullets and the bullets kept bouncing off.

• Respiration begins when air enters the nasal cavity and makes its way into the pharynx.

Asthma causes may include allergens, environmental irritants, respiratory illnesses, sulphites in food, reflux, or medications like beta blockers.2 The airways of asthmatics are narrowed due to the plugging by accumulated mucus, and smooth muscle contraction. During inspiration, the diaphragm moves downwards into the abdomen, and the ribs move upward and outward movement due to diaphragm and inspiratory intercostal muscles’ contraction respectively. This enlarges the lungs due to the changes in intrapleural pressure, and expands the alveoli. Hence, airway resistance decreases during inspiration, because, as the lungs enlarge, the airways within the lung are subject to the same forces as the alveoli, becoming widened. During passive expiration, the inspiratory intercostal muscles relax, causing the lungs to recoil. During active expiration, expiratory intercostal muscles and abdominal muscles contract, decreasing thoracic dimensions, and increasing

As we breathe in, the muscles in the chest wall force the thoracic area, ribs and connective muscles to contract and expand the chest. The diaphragm is contracted and moves down as the area inside the chest increases as air enters the lungs. The lungs are forced open by this expansion and the pressure inside the lungs becomes enough that it pulls