Tag: human respiratory system

The normal respiration rate in an adult rabbit is 30 - 60/minute, but some breathe faster than this if they are hot or stressed.

In fermentation, the carbohydrate gets broken down, but instead of making pyruvate, the final product is a different molecule depending on the type of fermentation. Fermentation is most often triggered by a lack of sufficient amounts of oxygen to continue running the aerobic respiration chain. Humans undergo lactic acid fermentation. Instead of pyruvate, lactic acid is created instead. Other organisms can undergo alcoholic fermentation where the end product is neither pyruvate nor lactic acid. The organism makes ethyl alcohol as an end product. 

The respiratory surface needs moisture for maximum efficiency. Oxygen from the air dissolves in the water on the surface momentarily and this allows the oxygen more time to cross the alveolar membrane. If the surface dries out, gas exchange will happen at a very reduced rate since fast-moving gaseous oxygen molecules do not efficiently cross the alveolar membrane. The reduced gas exchange is mostly likely not enough to support blood oxygenation for vital functions. 

Diffusion is insufficient to meet the oxygen requirement of multicellular organisms like human because all the cells are not direct contact in environment and diffusion is a slow process. Diffusion is too slow to cover the distance between the gas exchange surface and the sites where the oxygen is required. That is why we need a gas transport system - the bloodstream. It would be difficult to allow passive diffusion to transfer oxygen because there would need to be gradients across each and every cell. In the end, it would be too slow and impractical for any multicellular organism to use.

• Trachea consists of C-shaped cartilaginous rings that support the walls of the trachea and prevent its collapse during inspiration. 
• Respiratory centre is located in the medulla oblongata. 
• Yeast undergoes anaerobic respiration to produce ethanol and $CO _{2}$. 
• The type of respiration in insects and fish is tracheal respiration and branchial respiration respectively. 
• ATP is a biologically useful energy produced during respiration. 
• The partial pressure of $O _{2}$ in alveolar air is approximately 104 mm Hg. 
• Vocal cords are present inside the larynx.
  

NAD+ and FAD are co-enzymes required for the completion of many biochemical pathways. However, there is no need for an enormous amount of synthesis of either of these co-enzymes as there as a mechanism of recycling the co-enzymes after completion of one step in the metabolic pathway. These co-enzymes are predominantly required for the synthesis of ATP (energy currency of the cell) and will be used in the electron transport chain for the production of the same. So, they are not required to be synthesized in huge quantities but they play a crucial role in cell energetics.

There are two types of the carotid artery; one in left and one in the right. The external carotid artery supplies blood to the face and neck whereas internal carotid artery supplies blood to the brain.

Larynx (voice box) is located between the pharynx and the trachea. It is the upper modified part of trachea and leads to trachea or windpipe. It has a framework of cartilage that protrudes in the front of the neck and sometimes is referred as the Adams apple. The larynx is considerably larger in males than in females; hence, the Adams apple is much more prominent in males. At the upper end of the larynx, vocal cords are present which help in production of speech. They are set into vibration by the flow of air from the lungs. A difference in the size of the larynx is what accounts for the difference between male and female voices; because male larynx is larger than a female larynx, usually male voice is lower in pitch. The nasal cavities, the sinuses, and the pharynx all serve as resonating chambers for speech, just as the cabinet does for a stereo speaker.

Whale is a mammal and mammals breathe with lungs. The whale’s lungs contain more alveoli and is surrounded by two layers of capillaries increasing the surface area for more efficient gas exchange.