Have you ever accidentally cut or scratched yourself, or had some other injury? Then, you have probably seen the red fluid leaking from the place where the skin is damaged. That red fluid is called blood. Blood is essential for life. It is a very important fluid that flows and circulates inside our body, through blood vessels, with the help of the heart. The blood provides our body's cells with nutrients and oxygen. It also removes waste products through the same cells.
In this lesson, we are going to
Human blood is an essential red fluid that circulates in our bodies and provides our body's cells with essential substances like oxygen and nutrients, as well as, transports metabolic waste products away from those same cells.
The blood circulates in the body throughout the cardiovascular system which is made up of the heart and blood vessels.
The branch of medicine, concerning the study of blood, blood-forming organs, and blood diseases, is called hematology.
What does human blood consist of? The human blood consists of plasma and formed elements (red blood cells, white blood cells, and platelets).
The liquid state of blood can be contributed to plasma as it makes up 55% of blood. The plasma is yellowish in color. It is a mixture of water, sugar, fat, protein, and salts. Its function is to transport blood cells throughout the body, along with nutrients, antibodies, waste products, hormones, and proteins.
Red blood cells, also called erythrocytes, represent 40%-45% of blood volume and are the most abundant cell in the blood.
Red cells contain a special protein called hemoglobin. Hemoglobin gives the red blood cells the red color. Because of their large number, the whole blood appears red. Hemoglobin helps carry oxygen from the lungs to the rest of the body and then returns carbon dioxide from the body to the lungs so it can be exhaled. Red blood cells are generated from the bone marrow at a rate of four to five billion per hour. Their lifespan is about 120 days in the body.
White blood cells, also called leukocytes, are much fewer in number than red blood cells, accounting for about 1 percent of the blood, but they are very important. White blood cells are essential for good health and protection of the body against infection, illness, and diseases.
They attack foreign bodies, like bacteria and viruses. Just like red blood cells, they are constantly being generated from your bone marrow. The lifespan of white blood cells ranges from 13 to 20 days. When the number of white blood cells in a person's blood increases, this is a sign of an infection somewhere in the body.
The smallest of the body cells are platelets, also called thrombocytes. Unlike red and white blood cells, platelets are not actually cells but rather small fragments of cells.
Even if they are the smallest, their role is very important. They control bleeding. Actually, they are responsible when wounds occur. They will receive a signal from the blood vessel and will travel to the area to make contact with the vessel and plug the wound until it heals. Platelets have an average lifespan of 5 to 10 days.
There are three main functions of blood: transport, protection, and regulation.
What does blood transport?
What are the blood's roles in order of protection?
What does blood regulate?
Blood circulates inside our body through the blood vessels. The average adult has about 4.5 to 5.5 liters of blood circulating inside their body. There are known three major types of blood vessels, each with a different function:
A blood type is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells. Types of blood are also known as blood groups. There are 4 main blood groups: A, B, AB, and O. The blood group is determined by the genes that we inherit from our parents. Rhesus (Rh) factor is an inherited protein found on the surface of red blood cells. If your blood has the protein, you're Rh-positive. If your blood lacks the protein, you're Rh-negative. So, blood types and Rh factor combinations make eight blood groups in total: (A+, A−, B+, B−, O+, O−, AB+, AB−), where "+" stands for Rh-positive, and "−" stands for Rh-negative.
The conditions that impact the blood’s ability to function correctly are called blood disorders. There is a range of different types. Blood disorders can affect each of the main components of blood: red blood cells, white blood cells, platelets, or plasma.
Blood disorders that affect red blood cells include anemia, iron-deficiency anemia, anemia of chronic disease, pernicious anemia (B12 deficiency), aplastic anemia, autoimmune hemolytic anemia, sickle cell anemia, polycythemia vera, malaria.
Blood disorders that affect white blood cells include lymphoma, leukemia, multiple myeloma, myelodysplastic syndrome.
Blood disorders that affect the platelets include thrombocytopenia, idiopathic thrombocytopenic purpura, Heparin-induced thrombocytopenia, thrombotic thrombocytopenic purpura, primary thrombocythemia.
Blood disorders that affect blood plasma include Hemophilia, von Willebrand disease, hypercoagulable state, deep venous thrombosis, disseminated intravascular coagulation.
Treatments and prognoses for blood diseases vary. That is depending on the blood condition and its severity.
