Q.23. Write short note on open and closed type of circulatory system. (2014)
Ans. Open Circulatory System: -
Open circulatory systems are the more basic type of circulatory system and are referred to as open because the blood is not contained within an enclosed circuit of vessels. Instead, the blood flows from the heart through open-ended vessels and when the blood reaches the end of the vessels it flows directly over the tissues. While the tissues are bathed in blood gas exchange occurs. The blood then freely flows back into vessels that direct the blood back to the heart. Overall, you could describe an open circulatory system as being more free flowing and passive. There are many organisms that have open circulatory systems, including grasshoppers, snails and clams.
Closed Circulatory System: -
The closed circulatory system may be of particular interest to you because it is the type of system that humans have. Unlike an open circulatory system, a closed circulatory system is more structured and controlled and the blood of a closed system always flows inside vessels. These vessels make up the plumbing circuit of the body and can be found throughout the entire body. This plumbing circuit can be broken down into three different types of vessels or tubes that transport blood throughout the body: arteries, capillaries, and veins.
The first type of vessel is the arteries, which are responsible for moving blood away from your heart and to your tissues. When the blood gets to the tissues it is contained within capillaries, which are very small vessels with thin walls. These thin walls make it possible for gas and waste exchange to occur between your blood and your tissues. The blood then leaves the capillaries and goes into the veins which bring the blood back to your heart.
As you already know, humans have a closed circulatory system, but we share this type of system with such animals as birds, cats, frogs and earthworms.
Q.24. Write short note on Blood cells. (2016)
Related Questions -
Q. Write short note on red blood corpuscles. (2019)
Ans. A blood cell, also called a haematopoietic cell, hemocyte, or hematocyte, is a cell produced through hematopoiesis and found mainly in the blood. In mammals, these fall into three general categories:
(i) Red blood cells – Erythrocytes
(ii) White blood cells – Leukocytes
(iii) Platelets – Thrombocytes.
Together, these three kinds of blood cells add up to a total 45% of the blood tissue by volume, with the remaining 55% of the volume composed of plasma, the liquid component of blood. The volume percentage of red blood cells in the blood (hematocrit) is measured by centrifuge or flow cytometry and is 45% of cells to total volume in males and 40% in females.
Haemoglobin (the main component of red blood cells) is an iron-containing protein that facilitates transportation of oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs.
Q.25. Write short note on composition and function of bile. (2017)
Related Questions -
Q. Write short note on function of bile. (2019)
Ans. Bile or gall is a dark green to yellowish brown fluid, produced by the liver that aids the digestion of lipids in the small intestine. In humans, bile is produced continously by the liver (liver bile), and stored and concentrated in the gallbladder (gall bladder bile). After eating, this stored bile is discharged into the duodenum.The composition of gallbladder bile is 97% water, 0.7% bile salts, 0.2% bilirubin, 0.51% fats (cholesterol, fatty acids and lecithin), and 200 meq/l inorganic salts.
Function -
1. Bile increases the absorption of fats, it is an important part of the absorption of the fat-soluble substances, such as the vitamin A, D, E and K.
2. Besides its digestive function, bile serves also as the route of excretion for bilirubin, a by product of red blood cells recycled by the liver. Bilirubin derives from hemoglobin by glucuronidation.
Bile tends to be alkali on average. As an alkali, it also has the function of neutralizing any excess stomach acid before it enters the duodenum, the first section of the small intestine Bile salts also act as bactericides destroying many of the microbes that may be present in the food.
Q.26. Write short note on Structure and function of white blood corpuscles found in human being. (2017)
Ans. Structure and function of white blood corpuscles found in human being: -
White blood cells, also called leukocytes, play an important role in the body’s immune response by identifying and targeting pathogens.
White blood cells, also called leukocytes (leuko = white) make up approximately one percent, by volume, of the cells in blood. The role of white blood cell is different from that of red blood cells. They are primarliy involved in the immune response to identify and target pathogens, such as invading bacteria, viruses, and other foreign organism. White blood cells are formed continually; some live only for hours or days, while some live for years.
The morphology of blood cells differs significantly from red blood cells. They have nuclei and do nbot contain hemoglobin. The different types of white blood cells are identify by their microscopic appearance after histologic staining.