Tag: zoology

The respiratory rate or breathing frequency is the rate at which the number of inhalation and exhalation cycles are  taken within a set time.  The typical respiratory rate for a healthy adult at rest is 12–20 breaths per minute. However, the average resting respiratory rates differ with age. Food stimulates the nervous system which further tends to increase respiration rate.

The lack of oxygen or a lowering of the normal level of oxygen in the blood and body fluids is known as anoxemia and is generally experienced when in high altitudes.  

The majority of carbon dioxide molecules (85 percent) are carried as part of the bicarbonate buffer system. In this system, carbon dioxide diffuses into the red blood cells. Carbonic anhydrase (CA) within the red blood cells quickly converts the carbon dioxide into carbonic acid (H$ _2$CO$ _3$). Carbonic acid is an unstable, intermediate molecule that immediately dissociates into bicarbonate ions (HCO$ _3$−) and hydrogen (H+) ions. Since carbon dioxide is quickly converted into bicarbonate ions, this reaction allows for the continued uptake of carbon dioxide into the blood, down its concentration gradient. It also results in the production of H+ ions. If too much H+ is produced, it can alter blood pH. However, hemoglobin binds to the free H+ ions, limiting shifts in pH. The newly-synthesized bicarbonate ion is transported out of the red blood cell into the liquid component of the blood in exchange for a chloride ion (Cl-). This is called the chloride shift. When the blood reaches the lungs, the bicarbonate ion is transported back into the red blood cell in exchange for the chloride ion. The H+ ion dissociates from the hemoglobin and binds to the bicarbonate ion. This produces the carbonic acid intermediate, which is converted back into carbon dioxide through the enzymatic action of CA. The carbon dioxide produced is expelled through the lungs during exhalation. 

Anaerobic respiration takes place in the absence of oxygen. So, oxidation of food does not take place. So, statement c is wrong. Gaseous exchange occurs through leaves that have minute tiny apertures over them called stomata. 

• Cardiac muscle is specialized tissue that is found only in the heart.
•  It has characteristics similar to both smooth and skeletal muscle tissue, as well as specialized properties, that allow it to function with fast but sustained contractions, rapid conduction and coordinated movement. Hence,  the property of cardiac muscle is involuntary muscles, resistant to fatigue and striated muscle.

• The two major types of muscles that make up the calf (back portion of the lower leg) are gastrocnemius and soleus muscle.
• Along with the soleus muscle, the gastrocnemius forms half of the calf muscle. Its function is plantar flexing the foot at the ankle joint and flexing the leg at the knee joint.
  
• Hence gastrocnemius muscles are found in shank(a person's leg, especially the part from the knee to the ankle).
• So, the correct answer is 'Shank'.

Agranulocytes are leukocytes that either lack granules in their cytoplasm or have granulocytes that are not as apparent as in the other cell types. Agranulocytes are basically of two types - monocytes and lymphocytes. They are both involved in the immune responses of the body.

Thus, the correct answer is 'Lymphocytes.'

Lymphocytes are one of the main types of immune cells. Lymphocytes are divided mainly into B and T cells. B lymphocytes produce antibodies - proteins (gamma globulins) that recognize foreign substances (antigen) and attach themselves to them. B lymphocytes (or B cells) are each programmed to make one specific antibody.