Breathing and Exchange of Gases Test 27

Alveoli are the primary sites of exchange of gases. Exchange of gases also occur between blood and tissues. $$O_ 2$$  and $$CO_ 2 $$ are exchanged in these sites by simple diffusion mainly based on pressure/ concentration gradient. Solubility of the gases as well as the thickness of the membranes involved in diffusion are also some important factors that can affect the rate of diffusion.

The oxygen dissociation curve plots the percentage saturation against the partial pressure of oxygen, and its contribution to the total oxygen content. This is an S-shaped curve due to the alterations in hemoglobin's affinity for oxygen in response to other physiologic factors. 

At high altitudes, there is a decrease in oxygen hemoglobin saturation. This hypoxic condition causes hypoxia-inducible factor 1 (HIF- 1) to become stable and stimulates the production of erythropoietin (EPO), a hormone secreted by the kidneys. EPO stimulates red blood cell production from bone marrow in order to increase hemoglobin saturation and oxygen delivery. Thus, the total number of RBC increases.

Different organisms have different structures which act as the respiratory organ. In the crustaceans, there are gills to exchange the gases. There is a tracheal system in the insects which has developed to allow the exchange of gases. There are book lungs in the arachnids like the spiders. 

•  In a tracheotomy, the tube is inserted through a cut in the neck below the vocal cords this allows air to enter the lungs. 
• Breathing is then done through the tube, bypassing the mouth, nose, and throat. Air from your nose and mouth passes down through your throat to the larynx and into the trachea.
•  The trachea is the big air tube leading to the lungs. When you breathe out, air leaves your lungs through this tube. Hence, During tracheotomy (a tube inserted directly into the trachea), colder and drier air enters the lungs than normal which can cause lung crusting and infection. The primary cause for this is air does not flow through the nasal passageways.

The digestive system includes alimentary canal and associated glands to carry out the digestion of food and release the energy stored in these food substances. The primary function of the respiratory system is to allow atmospheric oxygen from the air to enter the blood and carbon dioxide from the blood to exit into the air. The endocrine system includes endocrine glands and maintains the homeostasis of the body through hormonal actions. Nervous system serves in the reception of sensory input followed by their integration in the brain and spinal cord and generation of motor output to produce the response. Thus, the correct answer is B.

• Carbon dioxide is the waste gas that is produced when carbon is combined with oxygen as part of the body's energy-making processes.
• The lungs and respiratory system allow oxygen in the air to be taken into the body, it also helps the body to get rid of carbon dioxide in the air breathed out.
• When the blood from the heart flows through the capillaries and collects oxygen from the alveoli. At the same time, carbon dioxide passes out of the capillaries and into the alveoli. These blood brings oxygen to the body cells and takes away their carbon dioxide.  Hence, the circulatory system and respiratory system eliminates carbon dioxide from the body.

The larynx is known as voice box or sound producing organ. A pair of membranous folds called vocal cords, stretch across the laryngeal cavity. In normal condition, the vocal cords lie apart so that the glottis remains widely open to allow free passage of respiratory air. For sound production, vocal cords come close together, they vibrate when air rushes out through glottis and produce voice.