Human Body Water and Blood Composition

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Questions and Answers

Total Body Water is approximately ______% of body weight.

The Extracellular Fluid (ECF) is composed of Interstitial Fluid (ISF) and ______.

plasma

Mature Red Blood Cells (RBCs) are ______-nucleated.

non

RBC production begins in ______.

utero Signup and view all the answers

Adequate ______ is essential for RBC production.

nutrition Signup and view all the answers

Erythropoietin is a hormone released by the ______.

kidney Signup and view all the answers

A lack of RBC or hemoglobin can lead to ______.

anaemia Signup and view all the answers

Erythropoietin levels increase in response to reduced ______ availability at high altitudes.

oxygen Signup and view all the answers

Synthetic EPO is used in patients with Chronic ______ failure.

renal Signup and view all the answers

The shape of RBCs is described as ______, which aids their function.

biconcave Signup and view all the answers

RBCs contain ______, which is essential for oxygen transport.

hemoglobin Signup and view all the answers

The lifespan of red blood cells is approximately ______ days.

120 Signup and view all the answers

Sickle Cell Disease is a genetic disorder characterized by ______ cells that can obstruct blood flow.

sickled Signup and view all the answers

Each heme molecule in hemoglobin contains one ______ atom.

iron Signup and view all the answers

Blood group O Rhesus negative is known as the 'Universal ______'.

Donor Signup and view all the answers

Excess bilirubin in the blood can cause ______.

jaundice Signup and view all the answers

Haemoglobinopathies refer to ______ forms of hemoglobin, such as HbS.

abnormal Signup and view all the answers

Red blood cells are also referred to as ______.

erythrocytes Signup and view all the answers

The process of forming a blood clot involves the creation of the protein ______.

fibrin Signup and view all the answers

The ______ is a term that refers to the percentage of blood volume that is occupied by red blood cells.

hematocrit Signup and view all the answers

Study Notes

Total Body Water

Approximately 60% of the body weight is water.
This is about 40-45 liters in a 70kg male.
The water is split between Extracellular Fluid (ECF) and Intracellular Fluid (ICF).
ECF is further divided into Interstitial Fluid (ISF) and plasma.

Composition of Blood

Plasma is a component of the ECF compartment.
Plasma is a straw-colored liquid that makes up 55% of the blood volume.
Its components include water, proteins, electrolytes, nutrients, and waste products.

Cellular Content of Blood

Erythrocytes (Red Blood Cells) compose 45% of the cellular content of blood.
Leukocytes (White Blood Cells) compose less than 1% of the cellular content.
Platelets compose less than 1% of the cellular content.

Red Blood Cells

Mature red blood cells are non-nucleated.
They are biconcave, which increases their surface area and allows for more efficient oxygen transport.

Red Blood Cell Production (Erythropoiesis)

Begins in utero.
From 6-7 months, the bone marrow takes over.
Children use all bone marrow.
Later in life, only sternum, vertebrae, ribs, and pelvis are used.
Requirements for production:
- Adequate nutrition, including proteins and vitamins such as B12 and folic acid.
- Erythropoietin, a hormone released by the kidneys.

Sequence of Events in Red Blood Cell Production

Proerythroblast: The earliest stage of red blood cell development.
Basophilic erythroblast: The cell begins to synthesize hemoglobin, giving it a blue color.
Polychromatophilic erythroblast: The cell continues to synthesize hemoglobin and develops a mixed blue and pink color.
Normoblast: The cell loses its nucleus, but still retains some residual RNA, giving it a pink color.
Reticulocyte: The cell matures and enters the bloodstream, where it continues to synthesize hemoglobin.
Mature erythrocyte: The cell is fully mature and able to transport oxygen.

Role of Erythropoietin in Red Blood Cell Production

Erythropoietin is a hormone that stimulates the production of red blood cells.
High altitude can initiate an increase in red blood cell production to compensate for lower oxygen levels.
Synthetic EPO is available for treatment of Chronic Renal Failure.
Abuse of EPO in sport can result in dangerous polycythemia, increasing blood viscosity and potential for heart failure or stroke.

Functions of Red Blood Cells

Transport oxygen via hemoglobin.
Transport carbon dioxide.
Act as a blood buffer, maintaining a normal blood pH of 7.4.

Structure of Hemoglobin

A protein comprising 4 polypeptide chains, two Alpha (α) chains and two Beta (β) chains in adult hemoglobin (Hb A).
Each chain is linked to a heme molecule.
Each heme molecule has one iron atom, to which oxygen binds.
Fetal hemoglobin (HbF) consists of two Alpha chains and two Gamma (γ) chains.
HbF binds oxygen more readily than HbA, which is important during fetal development.
Haemoglobinopathies are disorders caused by abnormal hemoglobin, such as sickle cell disease and thalassaemias.

Anaemia

Anaemia is a condition characterized by a low number of red blood cells or a reduced amount of hemoglobin.
Sickle cell disease is a genetic disorder that causes red blood cells to become rigid and sickle-shaped.
These sickle cells are fragile and can be trapped in the microcirculation, obstructing blood flow and causing severe pain, stroke, jaundice, and respiratory symptoms.
This can lead to severe pain, stroke, jaundice, and respiratory problems.

Red Blood Cell Breakdown

Red blood cells have a lifespan of about 120 days.
They become fragile with age and are trapped in the spleen, which is sometimes referred to as the "red cell graveyard."
Heme is separated from globin.
Globin is recycled as amino acids.
Iron from heme is recycled.
Heme breakdown also produces biliverdin and bilirubin.
Bilirubin is a yellow pigment transported to the liver and excreted in bile.
Jaundice results from high levels of bilirubin in the blood and can also be caused by liver disease.

Hematocrit, Red Blood Cell and Hemoglobin Concentration

Hematocrit is the percentage of red blood cells in the whole blood.
Normal hematocrit levels vary between men and women.

Blood Groups

Blood groups are determined by the antigens present on the red cell membrane.
All blood groups have either Rhesus-positive or Rhesus-negative status.
Blood type O, Rhesus-negative is considered the universal donor as it does not have any antigens that will react with potential antibodies in the recipient’s plasma.

Blood Transfusion

A patient’s blood is typed and crossmatched to ensure compatibility between donor cells and recipient serum.
An incompatibility occurs when the antigen on the donor's red blood cells reacts with a corresponding antibody in the recipient’s serum.

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Description

Explore the essential concepts regarding total body water and the composition of blood. This quiz covers topics such as the roles of extracellular and intracellular fluids, the components of plasma, and the cellular content of blood including red and white blood cells. Test your understanding of these fundamental physiological concepts.