Body Fluids and Circulations

Spleen is the organ that receives only oxygenated blood. Lungs and gills receive both oxygenated and deoxygenated blood. Liver receives deoxygenated blood through hepatic portal system for extracting excess quantities of digested nutrients.

Pulmonary vein carries oxygenated blood from the lungs to the left atrium of the heart.

Hepatic Vein, hepatic portal vein and renal vein carry deoxygenated blood.

According to Landsteiner and Decastello four types of blood groups (A, B, AB and O) are found in humans. Landsteiner and Veiner (1940) also discovered Rh factor which is represented by +ve  or -ve mark. AB (+ve) is the universal recipient blood group and O (+ve) is the universal donor blood group.

The gradually increasing contraction of ventricular muscles during systole first causes the closure of bicupsid and tricupsid valves (AV valves), producing a low- pitched "lubb" sound. Later, it causes the opening of the semilunar valves of systemic and pulmonary aorta. At the end of ventricular systole, semilunar valves shut, producing the second, louder heart sound, the "dup". Thus, each heart beat is accompained by a "lubb- dup" sound.

BMR or Basal Metabolic Rate is the rate at which body uses energy while at rest to maintain vital functions such as breathing and keeping warm. It can be  determined by total body weight and the amount of muscle mass. It is inversely related with the weight/ volume of an organism, i.e. smaller the organism, higher is the basal metabolic rate and vice versa.

Heart rate of six month old baby is 110-112 beats/ min. Though, it is higher than normal adult person, but it is lower than the old person. At the age of 60, a man may have maximum heart rate of 160 beats/min (avg 120 beats/min.)

For human RBC, 0.9% salt solution is isotonic. Therefore, a medium of 1.5 % salt solution would be hypertonic i.e. more concentrated. Hence, RBC shrinks due to exosmosis.

During a wound, germs are removed by the process of phagocytosis by WBCs. WBCs or whit Blood Cells accumulate at the site of wound by diapedesis. Diapedesis is the squeezing of leucocytes out from the endothelium of capillaries to fight against foreign agent.

In arthropods like prawn, the blood is colourless and contains WBCs only. The blue respiratory pigment, haemocyanin is present in the blood of molluscs. The RBCs of mammals contain the red pigment haemoglobin which carries oxygen.

Normal blood sugar level in adult human varies from 80 - 100 mg/100 ml (fasting) to 100-120 mg/100 ml (after meal).

Normal blood urea is 20 - 40 mg/dl

Total blood volume is 4 - 5 litres

ESR or Erythrocyte Sedimentation Rate in wintrobe method is 0 - 9 mm in male and 0 - 20 mm in female.

The regulation of RBC production is accomplished by the hormone erythropoietin which is secreted by the juxtaglomerular cells of kidney. This hormone circulates to the red bone marrow, where it increases stem cell (myoblasts) mitosis and speeds the development of red blood cells.