Important Notes on Body Fluids and Circulation for NEET

During the last-minute preparation for NEET, revision is the most important activity. It not only helps memorize the topic but also increases your accuracy. However, during this time, revising entire chapters may not seem feasible due to the vastness of the NEET syllabus. Thus, a chapter-wise note, like important notes of biology for NEET body fluids and circulation, can be helpful for your final revisions.

This post includes important notes on body fluids and circulation. It covers all the necessary body fluids and circulation class 11 notes that are vital for NEET 2025 exam.

Body Fluids and Circulation Notes

• Body fluids are a type of fluid within an organism that helps the cells to transport substances via body cavities. They can be blood, lymph, urine, tissue fluid, etc. 

• Two types of fluid circulation can be observed – intracellular circulation and extracellular circulation.

• Single-celled organisms like amoeba perform intracellular circulation inside their cell via cyclosis.

• In the extracellular circulation process, body fluids circulate across the cells.

• Through the circulatory system, body fluids distribute different substances like hormones, gasses, nutrients, etc. throughout the body and eliminate waste materials like urine from the body. 

• The circulatory system has two types – open and closed.

Blood

Blood is a connective tissue that consists of plasma, formed elements, and fluid matrix.

Plasma

• Constituting 55% of the entire blood volume, this viscous fluid contains 90%-92% of water and 6%-8% proteins, glucose, amino acids, and electrolytes.

• The major protein elements are albumins, fibrinogens, and globulins.

• The electrolytes like  \[Na^{+}, Ca^{++}, Cl^{-}\] etc. are found in small amounts.

Formed Elements

These formed elements are composed of thrombocytes, erythrocytes, and leukocytes.

Thrombocytes

• Thrombocytes or blood platelets help in the process of blood clotting.

• A specific cell in the bone marrow called megakaryocyte produces blood platelets.

• Count – 1.5-3.5 lakh per mm-3 blood.

Erythrocytes

• They are commonly known as red blood cells or RBC.

• Colour – Red due to hemoglobin.

• Count – 50-55 lakh per mm-3 blood in adult humans.

• Created in - Bone marrow.Shape – Biconcave.Nucleus – mostly absent.

• Lifespan - 120 days on average.

• Wrecked in – the spleen that is known as the RBC graveyard.

• The primary function of RBC, the most abundantly available cell in blood, is to transport the respiratory gasses in cells.

Leucocytes

• Commonly known as white blood cells.

• Colour – Colourless.

• Count – 6-8 thousand per mm-3 blood in adult humans.

• Nucleus – Present.

• Lifespan – 3-4 days on average. 

• Majorly two types – agranulocytes and granulocytes.

• Granulocytes consist of basophils, eosinophils, and neutrophils.

• Agranulocytes consist of lymphocytes and monocytes. Both neutrophils and monocytes have the phagocytic ability.

• Basophils secrete serotonin, histamine, etc., and thus, present in inflammatory reactions.

• Eosinophils help in resisting infections and are also, present in allergic reactions. Lymphocytes help to build up the immune response of organisms.

Important Notes on Body Fluids and Circulation for NEET Exam

Revision notes can be very helpful during the exam preparations. They are short, meaningful, and to the point and help you attain the accuracy level for your competitive exam. Below is the note is given on body Fluids and circulation which will be beneficial for you as per the NEET exam.

Body Fluids

• Human body consists of various fluids which are essential for the smooth functioning of tissues that carry  an important function by providing nutrition to living cells and eliminating the harmful substances that are produced in our bodies.

• Blood is a connective tissue that comprises a plasma fluid matrix and formed elements

• Fluid matrix is also known as Plasma. These cells cater to a special function and consist of highly specialized cells.

• Plasma is a viscous fluid that consists of almost 50 to 55% of the blood volume. It is 90 to 92 % of water.

• Plasma also contains small amounts of minerals like \[Na^{+}, Ca^{++}, Mg^{++}, HCO{_{3}}^{-}, Cl^{-}\]

• Formed elements constitute about 45% of blood and comprise enterocytes, leukocytes, thrombocytes.

• Enterocytes are also known as RBCs are formed in the red bone marrow. It is Biconcave and devoid of any nucleus.

• Leukocytes are also known as WBC which are much less in number and are nucleated.

• Thrombocytes are also known as platelets that release substances that help in the coagulation and circulation of blood.

• ABO Grouping

There are four types of blood groups A, B, AB and O. Given below are the detail about blood groups:-

Blood Groups

• RH Group

RH antigen is present in 80% of human beings and forms an important part of Fluids and circulation. Those with RH antigen are RH positive and those without RH antigens are RH negative.

• Lymph

Lymphs are released as the blood passes through the capillaries in tissues. It is also a fluid connective tissue. In this liquid, the mineral distribution is the same as in plasma. The exchange of nutrients and gases  between the blood and cells is facilitated by this fluid connective tissue.

This was all about body fluids. Given below are the important points of the human circulatory system.

The circulatory system supplies the body with oxygen and nutrients while removing waste and carbon dioxide. It is a network of blood vessels and can either be open or closed which depends on the free movement of blood in a cavity or the containment of the same in vessels.

Circulatory System

So, these were some of the important notes that may help you in the preparation for your NEET exam. Below are some of the frequently asked questions that may help you clear your doubts and provide you with additional information on the topic of body Fluids and circulation.