Railway Science (Biology – Circulatory System)

Vein:- It carries blood towards the heart. Type of blood - Carries deoxygenated blood. Transport direction - Carries blood towards the heart. Human circulatory system (blood vascular system) - It consists of a muscular chambered heart, a network of closed branching blood vessels and blood.

Part A (Right Ventricle) receives the deoxygenated blood from the right atrium and pumps it to the pulmonary artery. Part B (Valves) prevent the backward flow of blood. Valves are actually flaps (leaflets) that act as one-way inlets for blood coming into a ventricle and one-way outlets for blood leaving a ventricle. Normal valves have 3 flaps (except the mitral valve). The human heart is made of four chambers, two auricles and two
ventricles.

Single circulation - Blood flows through the heart only once during one cycle of passage through the body exhibited by Hippocampus, Exocoetus and Anabas. Class- Pisces, Kingdom- Animalia, Phylum- Chordata, Superclass- Gnathostomata. Characteristics - The body has three regions - head, trunk, and tail. The circulatory system is of close type. The sexes are separate.

Blood Coagulation - Process of forming a clot in order to prevent excess loss of blood from the body. Red blood cells (Erythrocyte): Origin - Bone marrow. Function - transfer oxygen from the lungs to the tissues and transporting carbon dioxide from the tissues to the lungs.
White blood cells (Leukocytes): Origin - Bone marrow and found in the blood and lymph tissue. Function - Protecting and fighting against invading pathogens. Blood plasma - liquid component of blood contributes to 55% of blood’s total volume.

There are 4 main blood groups defined by the ABO system: Blood group A – It has A antigens on the red blood cells with anti-B antibodies in the plasma. Blood group B – It has B antigens with anti-A antibodies in the plasma. Blood group O – It has no antigens, but both anti-A and anti-B antibodies in the plasma. Blood group AB – It has both A and B antigens, but no antibodies.

Double circulation - We have two loops (One is oxygenated and the other is deoxygenated) in our body in which blood circulates. Amphibians and the reptiles (except crocodiles - 4-chambered heart) have a 3-chambered heart with two atria and a single ventricle. Frogs respire through their skin. The human heart has four chambers.

Pulse is the rhythmic throbbing of arteries. Arteries experience a pressure wave as blood is pumped from the heart. Since arteries have muscular walls, throbbing is experienced due to the expansion of their walls. Pulse rate is the direct measure of the heartbeat rate.

Position 2 - Tricuspid Valve, Position 3 - Pulmonary Valve, Position 4 - Aortic Valve, Position 5 - Mitral Valve. Tricuspid valve (three leaflets) - Allow blood to flow from the right atrium to the right ventricle.
Pulmonary valve (three leaflets) - Allow blood to pump from the right ventricle to the pulmonary artery. Mitral valve (two leaflets) - Allow blood to flow from the lungs into the left atrium. Aortic valve (three leaflets) - Open to let blood flow from heart’s left ventricle to the aorta.

Blood is made up of red blood cells, white blood cells, platelets, and plasma. white blood cells account for only about 1% of blood, but their impact is big. White blood cells are also called leukocytes. They protect against illness and disease.

Direction of flow of blood - Right Ventricle (Pumps blood into the pulmonary artery). Pulmonary Veins (Brings oxygenated blood from the lungs to the heart). Pulmonary artery (Takes deoxygenated blood). Left Ventricle (Pumps blood into the aorta). Right Auricle (Receives blood from different parts of the body).