Plasma In Blood

What is Blood Plasma?

Blood has two components: blood plasma and formed elements, which are cells. Blood is about 45% formed elements and 55% blood plasma. If a sample of blood is centrifuged in a small glass tube, the cells (which are more dense) sink to the bottom of the tube while the plasma (which is less dense) forms a layer on top.

More than 99% of the formed elements are red blood cells (RBCs). White blood cells (WBCs) and platelets occupy less than 1% of the formed elements. Because they are less dense than red blood cells but more dense than blood plasma, they form a very thin buffy coat layer between the packed RBCs and plasma.

Blood plasma in the body serves to assist other important functions of the body, such as the transportation of nutrients, hormones, and waste materials. It also assists in the regulation of blood volume and blood pressure. Plasma also plays a role in blood clotting and immune responses.

Composition of Blood Plasma

Blood plasma is a chemically complex suspension, with a wide range of elements contributing to the overall function of blood plasma.

The major components of plasma are:

Water (90%)

• Functions as the primary solvent, thus enabling the dissolution of the other components.

• Facilitates the ability to convey nutrients, hormones, and waste products.

Plasma Proteins (Albumin, Globulins, Fibrinogen)

Plasma proteins are composed of:

Albumins

• 54% of the plasma proteins

• Maintain osmotic pressure to prevent fluids from leaving the blood vessels.

• Carry hormones, vitamins, and drugs.

Globulins

• 38% of the plasma proteins

• Contains antibodies (immunoglobulins) that help in the immune defence

• Carry lipids and hormones

Fibrinogen

• 7% of the plasma proteins

• Produced in blood clotting and helps in creating the fibrin threads when blood coagulates after an injury to stabilise the blood clots.

Other Solutes (Electrolytes, Wastes, Hormones)

• Electrolytes (sodium, potassium, calcium, etc.) which help maintain osmotic pressure and play essential roles in cell functions.

• Regulatory substances such as enzymes and hormones

• Waste products such as urea, uric acid, creatinine, ammonia and bilirubin.

Functions of Blood Plasma

The different functions of plasma are essential for the maintenance of homeostasis and support of physiological processes.

Transportation of Nutrients, Hormones, and Wastes

• Transport of nutrients, hormones, gases (oxygen and carbon dioxide) and waste products

• Transports nutrients from the digestive system to the body cells.

• Transports hormones from the endocrine glands to target tissues.

• Transports waste products to the kidneys and the liver for detoxification.

• Transports gases like oxygen which is important in many cellular functions and carbon dioxide which is involved in the regulation of blood pH.

Regulation of Blood Volume and Pressure

• Role of albumins in maintaining osmotic pressure

• Prevents excess fluid loss by the blood vessels to the tissues.

• Helps to balance blood pressure and volume.

Role in Clotting and Immune Response

• Plays an essential role in blood clotting.

• It is cleaved to form fibrin, leading to the coagulation of blood and preventing bleeding.

• Globulins carry antibodies and provide immunity by neutralising pathogens and removing pathogens from the body.

Blood Plasma and Homeostasis

Plasma has a pivotal role in maintaining the internal environment of the body.

Regulation of pH

• Plasma proteins may be buffers

• This is mainly done by plasma proteins, by buffering out the extra acids and bases.

Electrolyte Balance

• Plasma maintains the balance of sodium, potassium, and other ions.

• Helps maintain the balance of the electrochemical gradients of nerve impulses and muscle contractions.

Clinical Relevance of Blood Plasma

There are many applications of the plasma clinically and is very vital in diagnosis as well as treatment

Plasma Donations and Transfusions

• Uses of plasma in medical treatments

• Plasma is used to treat clotting issues, among other diseases that require treatment and therapies that are plasma-derived.

Plasma Protein Disorders (Hemophilia, Hypoalbuminemia)

• Hemophilia is an inherited deficiency of clotting in which bleeding may occur spontaneously or after only minor trauma. It is characterized by nosebleeds, blood in the urine, and hemorrhages in joints and muscles.

• Hypoalbuminemia is a condition where the body does not produce enough albumin proteins and its level decreases in the blood. Symptoms include edema, weakness and fatigue.

Plasma Diagnostic Tests (Glucose, Lipid Profile)

• Routine Tests (like Plasma Glucose Levels and lipid Profile)

• Plasma is subject to various methods of testing for glucose levels, blood cholesterol levels and other metabolic products.

Plasma in Blood NEET MCQs (With Answers & Explanations)

Important for NEET exam are:

• Composition of Blood Plasma

• Functions of Blood Plasma

• Plasma Protein Disorder (Hemophilia)

Practice Questions for NEET

Q1. ________ maintains osmotic pressure or osmotic balance in blood vessels

1. Fibrinogen

2. Prothrombin

3. Albumin

4. Thrombin

Correct answer: 3) Albumin

Explanation:

Albumin maintains osmotic pressure or osmotic balance in blood vessels.

Function of plasma proteins - It is a protein found in blood plasma that helps retain water within the blood vessels by regulating the osmotic gradient, preventing excessive fluid leakage into tissues and maintaining blood volume. Fibrinogen and prothrombin play a role in blood clotting. Albumin maintains osmotic pressure or osmotic balance in blood vessels.

Hence, the correct answer is option 3) Albumin maintains osmotic pressure or osmotic balance in blood vessels.

Q2. Fibreless connective tissue is

1. Blood

2. Areolar

3. Adipose

4. Tendon

Correct answer: 1) Blood

Explanation:

Blood is a liquid connective tissue that contains a matrix called plasma and no fibers. Plasma is the liquid state in which blood cells are suspended, making up about 55% of the total volume of blood. It mainly consists of about 90-92% water and other dissolved substances such as proteins, electrolytes, hormones, and nutrients.
The main plasma functions involve the transport of nutrients, waste products, gases, and hormones within the body. It contains important proteins such as albumins, globulins, and fibrinogen, that respectively influence osmotic pressure, immune responses, and blood clotting. Plasma helps in maintaining body temperature and pH levels, therefore it is the most basically a part of health and homeostasis in the body as a whole.

Hence, the correct answer is option 1) Blood.

Q3. How serum is different from plasma in having

1. Excess of fibrinogen and other clotting factors

2. Absence of fibrinogen and other clotting factors

3. Absence of haemoglobin

4. Excess of haemoglobin

Correct answer: 2) Absence of fibrinogen and other clotting factors

Explanation:

The serum is similar to plasma in terms of its composition, but it does not contain clotting factors or fibrinogen, which are removed during the process of blood clotting. Serum contains a variety of important proteins, electrolytes, hormones, enzymes, and other substances that are important for various physiological functions in the body.

Plasma constitutes 55% of the total blood present in the human body.

The explanation for the Incorrect option:

Haemoglobin is a protein found in red blood cells that binds with oxygen to transport it from the lungs to the body's tissues. It is essential for oxygen delivery to cells and tissues throughout the body.

Hence, the correct answer is option 2) Absence of fibrinogen and other clotting factors.

Also Read:

• MCQs on Blood Plasma

• Components of Blood

• Connective Tissue

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