quiz image

Chapter 18: Blood Composition and Physical Characteristics

MagnificentComet avatar

Start Quiz

Study Flashcards

33 Questions

What is the approximate percentage of water in blood plasma?


What is the primary function of thrombocytes in the blood?

To form blood clots and stop bleeding

What is the term for the process of producing erythrocytes?


What is the average volume of blood in an adult female?

4-5 L

What is the pH range of blood?


What is the primary function of leukocytes in the blood?

To fight infection and disease

What is the primary function of albumin in blood plasma?

Acting as a buffer

Which of the following is NOT a characteristic of erythrocytes?

Presence of mitochondria

What is the primary function of globulins in blood plasma?

Producing immune responses

What is the primary site of hematopoiesis in adults?

Red bone marrow

What is the primary function of platelets in blood clotting?

Forming a platelet plug

What is the primary function of fibrinogen in blood plasma?

Initiating clot formation

What is the primary function of hemoglobin in erythrocytes?

To bind to oxygen molecules in the lungs

What is the result of too few RBCs in the blood?

Tissue hypoxia

What is the fate of the heme group after erythrocyte destruction?

It is degraded to the yellow pigment bilirubin

What is the role of testosterone in erythropoiesis?

It enhances erythropoietin production

What is the average daily production of new blood cells in the red bone marrow?

100 billion cells

What is the primary site of erythrocyte destruction?

The spleen

What is the primary component of blood plasma?


What is the primary function of erythrocytes in the transportation function of blood?

Transporting oxygen and nutrients to body cells

What is the primary function of blood in regulating body temperature?

Absorbing and distributing heat

What is the approximate percentage of plasma proteins in blood plasma?


What is the difference in average blood volume between males and females?

1-2 L more in males

What is the primary function of the biconcave shape of erythrocytes?

To increase the surface area for gas transport

What is the approximate percentage of hemoglobin in erythrocytes, excluding water?


What is the primary mechanism of ATP production in erythrocytes?

Anaerobic metabolism

Which plasma protein is responsible for maintaining osmotic pressure in the blood?


What is the primary site of hematopoiesis, where most blood cells originate?

Red bone marrow

What is the maximum number of oxygen molecules that can be bound to each hemoglobin molecule?


What is the primary stimulus for the release of erythropoietin from the kidneys?

Hemorrhage or increased red blood cell destruction

What is the fate of the globin portion of hemoglobin after erythrocyte destruction?

It is metabolized into amino acids

What is the effect of testosterone on erythropoiesis?

It increases the production of erythropoietin

What is the approximate lifespan of an erythrocyte in the bloodstream?

100-120 days

Study Notes

Blood Composition

  • Blood is a fluid connective tissue composed of:
    • Plasma (90% water, 8% plasma proteins, 2% other solutes)
    • Formed elements (Erythrocytes, Leukocytes, Thrombocytes)


  • Plasma proteins:
    • 60% albumin (substance carrier, buffer, and osmotic pressure contributor)
    • 36% globulins
    • 4% fibrinogen
  • Last 2% of plasma consists of:
    • Wastes (lactic acid, urea, creatinine)
    • Nutrients (glucose, amino acids)
    • Electrolytes (Na+, K+, Ca2+, Cl–, HCO3–)
    • Respiratory gases (O2 and CO2)
    • Hormones and enzymes

Formed Elements in Blood

  • Erythrocytes (RBCs):
    • Biconcave discs, anucleate, and essentially no organelles
    • Major factor contributing to blood viscosity
    • Filled with hemoglobin (Hb) for gas transport
    • Spectrin: a membrane protein that provides flexibility for RBC to change shape
  • Leukocytes (WBCs):
    • Only complete cells in blood
    • Defend against foreign invaders
  • Platelets:
    • Cell fragments
    • Most formed elements survive in the bloodstream for only a few days
    • Originate in red bone marrow

Erythrocyte Function

  • RBCs are dedicated to respiratory gas transport
  • Hemoglobin protein (Hb) structure:
    • Globin: 4 protein chains each containing a heme group
    • Each heme group has an iron atom in the middle
    • Each iron atom can bind to one O2 molecule
    • Each Hb molecule can transport four O2
    • Each RBC contains 250 million Hb molecules


  • O2 loading in the lungs:
    • Produces oxyhemoglobin (ruby red)
  • O2 unloading in the tissues:
    • Produces deoxyhemoglobin or reduced hemoglobin (dark red)
  • CO2 loading in the tissues:
    • Produces carbaminohemoglobin (carries 20% of CO2 in the blood)
    • Binds to the amino acid portion of the globin


  • Hematopoiesis (hemopoiesis): blood cell formation
  • Occurs in red bone marrow of axial skeleton, girdles, and proximal epiphyses of humerus and femur
  • On average, the marrow turns out an ounce of new blood containing 100 billion new cells each and every day


  • Erythropoiesis: red blood cell production
  • The number of circulating erythrocytes remains constant and reflects a balance between RBC production and destruction
  • Balance between RBC production and destruction depends on:
    • Hormonal controls
    • Adequate supplies of iron, amino acids, and B vitamins
  • Too few RBCs leads to tissue hypoxia
  • Too many RBCs increases blood viscosity

Hormonal Control of Erythropoiesis

  • Erythropoietin (EPO):
    • Direct stimulus for erythropoiesis
    • Released by the kidneys in response to hypoxia
  • Causes of hypoxia:
    • Hemorrhage or increased RBC destruction reduces RBC numbers
    • Insufficient hemoglobin (e.g., iron deficiency)
    • Reduced availability of O2 (e.g., high altitudes)
  • Effects of EPO:
    • More rapid maturation of committed bone marrow cells
    • Increased circulating reticulocyte count in 1–2 days
  • Testosterone also enhances EPO production, resulting in higher RBC counts in males

Development of Red Blood Cells

  • Erythrocytes:
    • Life span: 100–120 days
    • Old RBCs become fragile, and Hb begins to degenerate
    • Macrophages engulf dying RBCs in the spleen

Fate and Destruction of Erythrocytes

  • Heme and globin are separated:
    • Iron is salvaged for reuse
    • Heme is degraded to the yellow pigment bilirubin
    • Liver secretes bilirubin (in bile) into the intestines
    • Globin is metabolized into amino acids

Test your knowledge of the composition of blood, including the components of plasma and formed elements, as well as the physical characteristics and volume of whole blood. Learn about the different types of blood cells and their functions. This quiz is perfect for students of anatomy and physiology.

Make Your Own Quizzes and Flashcards

Convert your notes into interactive study material.

More Quizzes Like This

Use Quizgecko on...