The oxygen in inhaled air passes across the thin lining of the air sacs and into the blood vessels. This is known as diffusion. The oxygen in the blood is then carried around the body in the bloodstream, reaching every cell. When oxygen passes into the bloodstream, carbon dioxide leaves it.

During internal respiration, oxygen and carbon dioxide are exchanged between the cells and blood vessels. Respiration begins at the nose or mouth, where oxygenated air is brought in before moving down the pharynx, larynx, and the trachea. The trachea branches into two bronchi, each leading into a lung.

Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body.

The partial pressure of oxygen is high in the alveoli and low in the blood of the pulmonary capillaries. As a result, oxygen diffuses across the respiratory membrane from the alveoli into the blood. Therefore, carbon dioxide diffuses across the respiratory membrane from the blood into the alveoli.

Pulmonary Gas Exchange After you inhale, there is a greater concentration of oxygen in the alveoli than in the blood of the pulmonary capillaries, so oxygen diffuses from the alveoli into the blood across the capillaries (see Figure below).

Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each person has hundreds of millions of alveoli in their lungs.

Oxygen passes quickly through this air-blood barrier into the blood in the capillaries. Similarly, carbon dioxide passes from the blood into the alveoli and is then exhaled. Then the blood is pumped through the pulmonary artery to the lungs, where it picks up oxygen and releases carbon dioxide.

alveoli

The main factors include:

• Membrane thickness – the thinner the membrane, the faster the rate of diffusion.
• Membrane surface area – the larger the surface area, the faster the rate of diffusion.
• Pressure difference across the membrane.
• Diffusion coefficient of the gas.

Figure 7 shows a situation in which one unit is without any ventilation, hence it cannot participate in gas exchange. Blood flow through this unit, therefore, constitutes an intrapulmonary shunt.

Ventilation (V) refers to the flow of air into and out of the alveoli, while perfusion (Q) refers to the flow of blood to alveolar capillaries.

State the difference between ventilation, gas exchange and cell respiration. Ventilation: Is the process of inhaling and exhaling, with oxygen entering the alveoli (large surface area). (Carbon dioxide for oxygen). Cell Respiration: The chemical process occurring in the mitochondria where energy is released as ATP.

Ventilation and oxygenation are distinct but interdependent physiological processes. While ventilation can be thought of as the delivery system that presents oxygen‐rich air to the alveoli, oxygenation is the process of delivering O2 from the alveoli to the tissues in order to maintain cellular activity.

Goal of Mechanical Ventilation: So the goals of mechanical ventilation are simply to provide adequate (not perfect) oxygenation and ventilation, reduce our patient’s work of breathing, and to minimize the damage to the lung caused by the ventilator known as ventilator induced lung injury (VILI).

Classic causes of hypoxia include hypoventilation, ventilation-perfusion mismatch, the low oxygen content in the air, right to left shunting or impaired diffusion.

Environmental factor: Heat, cold and air pollution affect oxygenation. Clients who are exposed to dust, animal dander, or toxic chemicals in the home or workplace are at increased risk for alterations in oxygenation.

Untreated hypoxia results in anaerobic metabolism, cellular acidosis, cell death and organ failure. Oxygenation may be assessed by clinical assessment, pulse oximetry and arterial blood gases.

Oxygenation is the process of oxygen diffusing passively from the alveolus to the pulmonary capillary, where it binds to hemoglobin in red blood cells or dissolves into the plasma. Oxygen delivery is the rate of oxygen transport from the lungs to the peripheral tissues.

In general, an individual patient’s hypoxemia is usually diagnosed by oxygen monitors placed on fingers or ears (pulse oximeter) and/or by determining the oxygen level in a blood gas sample (a sample of blood taken from an artery).

The pleura (plural = pleurae) is a serous membrane that surrounds the lung. The right and left pleurae, which enclose the right and left lungs, respectively, are separated by the mediastinum. The pleurae consist of two layers.

The left lung is smaller because of the space taken up by the heart (see diaphragm for an image of this). Each lung is separated into lobes branching off the main bronchus; the right lung has three lobes, while the left has only two lobes.

The right lung is five centimeters shorter than the left lung to accommodate the diaphragm, which rises higher on the right side over the liver; it is also broader. The volume, the total capacity, and the weight of the right lung is greater than that of the left. The right lung is divided into three lobes.

The lungs are enclosed in a kind of cage in which the ribs form the sides and the diaphragm, an upwardly arching sheet of muscle, Continue Scrolling To Read More Below…

In your lungs, the main airways (bronchi) branch off into smaller and smaller passageways — the smallest, called bronchioles, lead to tiny air sacs (alveoli).