**Important Biology Notes on Human Blood for SSC and Railway Exams**
**Composition of Blood**
Blood is a fluid connective tissue that circulates throughout the body, transporting nutrients, oxygen, and hormones to the cells and removing waste products. It also plays a role in immunity and defense against infection.
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| Biology Notes: Blood and its Components - Exam Prep |
- * **Plasma:** The liquid portion of blood, which makes up about 55% of blood volume. Plasma contains water, proteins, carbohydrates, fats, vitamins, minerals, and hormones.
- * **Blood cells:** The solid portion of blood, which makes up about 45% of blood volume. There are three types of blood cells: red blood cells, white blood cells, and platelets.
**Red blood cells (RBCs)**
- also known as erythrocytes, are the most common type of blood cell. They contain a protein called hemoglobin, which binds to oxygen and transports it to the cells.
**White blood cells (WBCs)**
- also known as leukocytes, play a role in the immune system. They help to defend the body against infection.
**Platelets**
- are small fragments of cells that help to clot blood.
**Functions of Blood**
Blood has many important functions in the body, including:
* **Transporting nutrients and oxygen to the cells and removing waste products:
Blood carries nutrients and oxygen from the lungs and digestive system to the cells throughout the body. It also carries waste products, such as carbon dioxide and urea, from the cells to the lungs and kidneys for excretion.
* **Regulating body temperature:
Blood helps to regulate body temperature by absorbing and releasing heat.
* **Protecting against infection:
Blood contains white blood cells, which help to defend the body against infection.
* **Maintaining fluid balance:
Blood helps to maintain fluid balance in the body by regulating the movement of water between the blood and tissues.
* **Clotting blood:
Platelets in the blood help to clot blood, which prevents excessive bleeding when an injury occurs.
**Blood Groups**
Blood groups are classified based on the presence or absence of certain antigens on the surface of red blood cells. There are four main blood groups: A, B, AB, and O.
People with the same blood group can donate blood to each other, but people with different blood groups cannot. This is because the antibodies in a person's blood will attack the antigens on the red blood cells of a person with a different blood group.
**Blood Disorders**
There are many different types of blood disorders, including:
* **Anemia:**
A condition in which the blood does not have enough red blood cells or hemoglobin.
* **Leukemia:**
A type of cancer that affects the white blood cells.
* **Thrombosis:**
A condition in which a blood clot forms in a blood vessel.
* **Hemophilia:**
A genetic disorder that prevents the blood from clotting properly.
Key features:
Name: **Important Biology Notes on Human Blood : SSC & Railway
Type : Pdf File
Language: English
Useful for Exams: Railway RRC Group D, RRB NTPC, SSC, CDS, UPSSSC, UPPSC, UPSC & other Govt Competitive Exams.
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| Components of Blood - Biology Notes for SSC CGL |
**Conclusion**
Blood is an essential body fluid that plays a vital role in many important functions. It is important to understand the composition and functions of blood, as well as the different types of blood disorders.
