Tag: respiration and associated structures

The blood pumped by the right ventricle enters the pulmonary artery, whereas the left ventricle pumps blood into the aorta.The deoxygenated blood pumped into the pulmonary artery is passed onto the lungs from where the oxygenated blood is carried by the pulmonary veins into the left atrium. This pathway constitutes the pulmonary circulation. 

Altitude sickness is also known as acute mountain sickness (AMS), altitude illness, hypobaropathy, "the altitude bends" or soroche is a pathological effect of high altitude on humans, caused by acute exposure to low partial pressure of oxygen at high altitude. It commonly occurs above 2,400 metres (8,000 feet). 

The breathing centre in the brain responds to changes in the carbon dioxide concentration of the blood.

Respiration is a process based on chemical reaction and takes place  in all living cells. In this process, energy is released from glucose, for the functioning of our cells. Sugars used as a substrate for respiration comes from the hydrolysis of starch which results in loss of dry matter. 

The main respiratory surface in humans is the alveoli, which are small air sacs branching off from the bronchioles in the lungs. They are one cell thick and provide a moist and extremely large surface area for gas exchange to occur. Capillaries carrying deoxygenated blood from the pulmonary artery run across the alveoli. Due to the enormous number of alveoli (approximately 300 million in each human lung), the surface area of the lung is very large (75 m2). Having such a large surface area increases the amount of gas that can diffuse into and out of the lungs.

Not all cells use oxygen to produce energy. Aerobic cells use oxygen to produce energy. Anaerobic organisms do not require oxygen to produce energy. They obtain energy from metabolism in absence of oxygen. For example, yeasts in absence of oxygen convert sugar into alcohol and produces energy. This energy is then utilized for their survival.

The rate of respiration is highly dependent on concentration of carbon dioxide. The higher the concentration of carbon dioxide, less is the rate of respiration. Less the concentration of oxygen and more is the concentration of carbon dioxide, respiration rate increases.

• The combination of oxygen with haemoglobin is called oxyhaemoglobin and this oxygenated blood is carried away from the lungs through the bloodstream to all the tissues of the body. 
• Carbon monoxide can also bind to haemoglobin but does so about 240 times more tightly than oxygen, forming a compound called carboxyhaemoglobin. 
• This means that if both carbon monoxide and oxygen are inhaled, carbon monoxide will preferentially bind to haemoglobin. 
• This reduces the amount of haemoglobin available to bind to oxygen, so the body and tissues become starved of oxygen.

The characteristics of a respiratory surface are thin walls, a moist inner surface, a huge combined surface area, a rich blood supply each alveolus is sounded by capillaries. Surfaces which dries out easily, thick and easily damaged are not a characteristic of good respiratory surface.