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Questions and Answers
What is the main process involved in stopping bleeding from a broken blood vessel?
Which of the following is NOT a phase of hemostasis?
What substance do kidneys release to stimulate red blood cell production?
Erythropoietin
The three phases of hemostasis are vascular spasms, platelet plug formation, and ______.
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A thrombus is a clot that forms in an unbroken blood vessel.
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Hemophilia is an acquired bleeding disorder.
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What are the two antigens that determine the ABO blood group?
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Which blood type is considered the universal donor?
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Match the following blood types with their corresponding recipient compatibility:
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Most Americans are Rh-negative.
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What can cause a hemolytic disease of the newborn?
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What are the main components of blood?
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What percentage of blood is made up of plasma?
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Which type of blood cell is responsible for transporting oxygen?
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Blood is the only fluid tissue in the human body.
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What is the primary function of leukocytes?
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What is hematocrit?
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What is the normal range of erythrocytes per mm3 of blood?
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Blood pH is slightly __________, between 7.35 and 7.45.
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Which of the following is NOT a function of plasma proteins?
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What is erythropoietin?
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What is the normal platelet count per mm3 of blood?
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Erythrocytes contain a nucleus.
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The main function of platelets is __________.
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Study Notes
Blood
- Transports nutrients, waste, hormones, and body heat.
- Is the only fluid tissue in the human body.
- Consists of formed elements (living cells) and plasma (nonliving fluid matrix).
Blood Components
- When separated:
- Erythrocytes settle at the bottom (45% of blood, known as hematocrit).
- Buffy coat, containing leukocytes and platelets, is a thin layer between erythrocytes and plasma (less than 1% of blood).
- Plasma rises to the top (55% of blood).
Plasma
- 90% water.
- Straw-colored fluid.
- Contains dissolved substances:
- Nutrients.
- Salts (electrolytes)
- Respiratory gases.
- Hormones.
- Plasma proteins.
- Waste products.
Plasma Proteins
- Most abundant solutes in plasma.
- Primarily produced by the liver.
- Include:
- Albumin: important blood buffer and contributes to osmotic pressure.
- Clotting proteins: help stop blood loss when a blood vessel is injured.
- Antibodies: protect the body from pathogens.
Formed Elements
- Erythrocytes (red blood cells).
- Leukocytes (white blood cells).
- Platelets (cell fragments).
Erythrocytes
- Main function is to carry oxygen.
- Lack a nucleus and mitochondria.
- Contain hemoglobin.
- Shaped like biconcave discs.
- Normal count is 5 million RBCs per mm3 of blood.
Erythrocytes - Hemoglobin
- Hemoglobin is an iron-bearing protein that binds to oxygen.
- Each hemoglobin molecule can bind 4 oxygen molecules.
- Each erythrocyte contains 250 million hemoglobin molecules.
Homeostatic Imbalance of RBCs
- Anemia: decreased oxygen-carrying capacity of blood due to:
- Lower-than-normal number of RBCs.
- Abnormal or deficient hemoglobin content in RBCs.
- Sickle cell anemia (SCA): abnormally shaped hemoglobin.
Polcythemia
- Disorder resulting from excessive or abnormal increase of RBCs caused by:
- Bone marrow cancer (polycythemia vera).
- Life at higher altitudes (secondary polycythemia).
- Slows blood flow and increases blood viscosity.
Leukocytes
- Crucial in body's defense against disease.
- Complete cells with nucleus and organelles.
- Able to move in and out of blood vessels (diapedesis).
- Respond to chemicals released by damaged tissues (positive chemotaxis).
- Move by amoeboid motion.
- 4,800 to 10,800 WBCs per mm3 of blood.
Homeostatic Imbalance of Leukocytes
- Leukocytosis: WBC count above 11,000 cells per mm3 of blood, generally indicates an infection.
- Leukopenia: abnormally low WBC count, often caused by drugs like corticosteroids and anticancer agents.
- Leukemia: bone marrow becomes cancerous, producing numerous immature WBCs.
Types of Leukocytes
- Granulocytes:
- Have granules in their cytoplasm that can be stained.
- Possess lobed nuclei.
- Include neutrophils, eosinophils, and basophils.
- Agranulocytes:
- Lack visible cytoplasmic granules.
- Have spherical, oval, or kidney-shaped nuclei.
- Include lymphocytes and monocytes.
Leukocyte Abundancy
- From most to least abundant:
- Neutrophils.
- Lymphocytes.
- Monocytes.
- Eosinophils.
- Basophils.
- Easy way to remember: Never Let Monkeys Eat Bananas.
Platelets
- Fragments of megakaryocytes (multinucleate cells).
- Needed for the clotting process.
- Normal platelet count is 300,000 platelets per mm3 of blood.
Hematopoiesis (Blood Cell Formation)
- Process of blood cell formation.
- Occurs in red bone marrow (myeloid tissue).
- All blood cells are derived from a common stem cell (hemocytoblast).
- Hemocytoblasts form two types of descendants:
- Lymphoid stem cell, which produces lymphocytes.
- Myeloid stem cell, which can produce all other formed elements.
Formation of Red Blood Cells
- RBCs are anucleate, so they cannot divide, grow, or synthesize proteins.
- RBCs wear out in 100 to 120 days.
- Worn-out RBCs are eliminated by phagocytes in the spleen or liver.
- Lost cells are replaced by division of hemocytoblasts in red bone marrow.
Red Blood Cell Production
- Rate of RBC production is controlled by a hormone called erythropoietin.
- Kidneys produce most erythropoietin in response to reduced oxygen levels in the blood.
- Homeostasis is maintained by negative feedback from blood oxygen levels.
Hemostasis
- The process of stopping bleeding that results from a break in a blood vessel.
- Involves three phases:
- Vascular spasms.
- Platelet plug formation.
- Coagulation (blood clotting).
Hemostasis - Stopping Blood Loss
- Hemostasis is the process of stopping blood loss
- It involves three steps:
- Vascular Spasms: Blood vessels quickly constrict to reduce blood flow.
- Platelet Plug Formation: Platelets adhere to exposed collagen fibers, forming a sticky plug.
- Coagulation (Blood Clotting): A complex cascade of clotting factors forms a fibrin mesh that traps red blood cells and platelets, creating a clot.
- Clot Breakdown: The clot dissolves once the tissue is repaired.
Disorders of Hemostasis
-
Undesirable clotting:
- Thrombus: A clot in an unbroken blood vessel, which can be dangerous if it affects major vessels like the lungs.
- Embolus: A thrombus that breaks loose and travels through the bloodstream, potentially blocking vital organs like the brain.
-
Bleeding Disorders:
- Thrombocytopenia: Low platelet count caused by bone marrow suppression.
- Hemophilia: A hereditary condition where clotting factors are missing, leading to excessive bleeding, even from minor injuries.
Blood Groups and Transfusions
- Blood transfusions are used for significant blood loss, severe anemia, and thrombocytopenia.
- Antigens are substances that trigger the body's immune system to attack them as foreign.
- Antibodies are proteins that recognize and bind to foreign antigens.
- Blood typing identifies different antigens on red blood cells using antibodies that cause agglutination (clumping).
ABO Blood Group
- Blood types are based on the presence or absence of antigens A and B.
- Type A has antigen A.
- Type B has antigen B.
- Type AB has both antigen A and B.
- Type O has neither antigen A nor antigen B.
- Type O blood is the universal donor, as it has no antigens that would trigger an immune response.
- Type AB blood is the universal recipient, able to receive all blood types since it has no antibodies.
Rh Blood Group
- Based on the presence or absence of the Rh antigen (agglutinogen D).
- Rh+ individuals have the Rh antigen.
- Rh- individuals do not have the Rh antigen.
- Rh incompatibility: When an Rh- mother gives birth to an Rh+ baby, her immune system can develop antibodies against the Rh factor. This can become problematic in future pregnancies.
- RhoGAM: An injection given to Rh- mothers prevents the development of anti-Rh antibodies.
Blood Typing
- Blood samples are mixed with anti-A and anti-B serum.
- Agglutination (clumping) identifies the blood type.
- Cross-matching ensures compatibility between donor blood and recipient blood by testing for agglutination between donor and recipient's blood samples.
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Description
This quiz explores the various components of blood, including its functions and the significance of plasma and formed elements. Understand the roles of erythrocytes, leukocytes, platelets, and plasma proteins in the body. Test your knowledge of blood composition and its vital functions.
