Railway Science (Biology – Circulatory System)

It is considered to be between 120/80 mmHg and 140/90 mmHg. It is measured in millimetres of mercury (mmHg). Systolic pressure: The pressure when the heart beats and pushes blood out to the arteries.
Diastolic pressure: The pressure when the heart is at rest between beats. The red blood cells contain a red coloured pigment because of Haemoglobin (carry oxygenated blood inside the body from lungs and gills).

Capillaries: Capillaries are the smallest of blood vessels. They serve to distribute oxygenated blood from arteries to the tissues of the body and to feed deoxygenated blood from the tissues back into the veins.
Calories: Amount of energy released when body breaks down, digests and absorbs food. Cell: Basic structural and functional unit of life.
Types: Prokaryotic cells and Eukaryotic cells. Corpuscle is an unattached cell, especially of a kind that floats freely, as a blood or lymph cell.

Red Blood Cell (RBC) or Erythrocyte is a type of blood cell that is made in the bone marrow and found in the blood. It contains a protein called hemoglobin, which carries oxygen from the lungs to all parts of the body.

ECG (Electrocardiogram) finds any irregularities in the heart rhythm. Invented by Willem Einthoven. Heart problems - Heart attack, Heart failure, Arrhythmia, Cardiac arrest.

Globin are a superfamily of heme-containing globular proteins, involved in binding and transporting oxygen. Albumin is the most abundant circulating protein found in plasma. Heme proteins are strongly coloured proteins, usually reddish-brown, which is due to the presence of the heme moiety. The globulins are a family of proteins in the blood that are insoluble in pure water but dissolve in dilute salt solutions.

Purkinje fibres are named after the Czech scientist Jan Evangelista Purkyne, who discovered them in 1839. Purkinje fibres (or Purkyne tissue) are located in the inner ventricular walls of the heart, just beneath the endocardium. These fibres are specialised myocardial fibres that conduct an electrical stimulus or impulse that enables the heart to contract in a coordinated fashion.

Calcium (Ca, Atomic number - 20). Blood clotting or coagulation is a crucial mechanism that prevents excessive bleeding following blood vessel injuries. Platelets (a type of blood cell) collaborate with proteins in the plasma (the liquid part of blood), to form a clot at the site of injury, effectively halting the bleeding process. Sodium (Na), Chlorine (Cl), and Potassium (K) helps in maintaining the right balance of fluids in the body.

The azygos vein carries blood from the back of the chest and abdomen to heart. This vein carries blood upward through diaphragm and the mediastinum. The internal jugular vein is a paired venous structure that collects blood from the brain, superficial regions of the face, and neck, and delivers it to the right atrium.

Angioplasty is a procedure performed on the human heart to open a blocked blood vessel and improve blood flow to the heart muscle. The human heart is a fist-sized organ that pumps blood throughout the body.
It is the primary organ of our circulatory system. The average human heart beats at 72 times per minute. Number of heart chambers in: Mammals and Birds - 4, Reptiles (Exception: Crocodile - 4) and Amphibians - 3, Fish - 2, Cockroach - 13, Octopus - 3.

Capillaries - tiny vessels that transport blood, nutrients and oxygen to cells . It completes the circulatory system by connecting arteries with veins.
Nerves - bundle of fibers that receives and sends messages between the body and the brain. Vein - blood vessel that carries de - oxygenated blood towards the heart except pulmonary vein.