Hematology Lecture 1
40 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of albumin in plasma?

  • Maintaining osmotic pressure (correct)
  • Transporting nutrients
  • Acting as an antibiotic
  • Facilitating clotting

During which trimester does the liver primarily contribute to haemopoiesis?

  • First trimester
  • Second trimester (correct)
  • Third trimester
  • Postnatal period

What percentage of the total solids in plasma do plasma proteins account for?

  • 70% (correct)
  • 80%
  • 60%
  • 50%

What is the main component of the buffy coat in centrifuged blood?

<p>White blood cells (B)</p> Signup and view all the answers

Which of the following best describes serum?

<p>Liquid without clotting factors (B)</p> Signup and view all the answers

Where does haemopoiesis primarily occur during the third trimester and throughout life?

<p>Bone marrow (C)</p> Signup and view all the answers

Which of the following best characterizes haemopoietic stem cells?

<p>Capable of replication into multiple blood cell types (A)</p> Signup and view all the answers

What is the likely outcome if blood is collected into a tube containing no anticoagulant?

<p>It forms a clot, leaving serum above (B)</p> Signup and view all the answers

What is the percentage of reticulocytes normally found in the blood?

<p>2.5% (B)</p> Signup and view all the answers

Which type of hemoglobin has the highest affinity for oxygen?

<p>Fetal hemoglobin (Hb F) (C)</p> Signup and view all the answers

What leads to an increased reticulocyte count in the peripheral blood?

<p>Acute hemorrhage (A)</p> Signup and view all the answers

What percentage of oxygen can each gram of pure hemoglobin combine with?

<p>1.34 milliliters (C)</p> Signup and view all the answers

What is the primary globin chain composition of adult hemoglobin (Hb A)?

<p>2α and 2β chains (A)</p> Signup and view all the answers

What happens to the iron from the degraded heme portion after red blood cell destruction?

<p>It is taken by plasma transferrin to be reused for RBC synthesis. (B)</p> Signup and view all the answers

Which enzyme catalyzes the reversible reaction between CO2 and water to form carbonic acid?

<p>Carbonic anhydrase (B)</p> Signup and view all the answers

Which type of hemoglobin is normally present at very low concentrations in adults?

<p>Hemoglobin A2 (A)</p> Signup and view all the answers

What is the normal hemoglobin concentration range in women?

<p>12-15 g/dl (D)</p> Signup and view all the answers

What occurs to red blood cells at the end of their life span?

<p>They are destroyed by macrophages in the reticuloendothelial system. (B)</p> Signup and view all the answers

What structure forms the core of each heme group in hemoglobin?

<p>Protoporphyrin ring (D)</p> Signup and view all the answers

How many iron atoms are there in each hemoglobin molecule?

<p>4 (A)</p> Signup and view all the answers

What compound is formed from the breakdown of the protoporphyrin ring in hemoglobin?

<p>Bilirubin (D)</p> Signup and view all the answers

What is the earliest recognized erythroid precursor in the bone marrow?

<p>Proerythroblast (B)</p> Signup and view all the answers

How does hemolytic anemia typically affect bilirubin levels in the body?

<p>Indirect bilirubin is elevated, causing jaundice. (D)</p> Signup and view all the answers

What is the role of regulatory factors in stem cell biology?

<p>They promote the self-renewal and differentiation of stem cells. (B)</p> Signup and view all the answers

What is the predominant cause of RBC death as they age?

<p>Gradual degradation of enzymes without replacement. (D)</p> Signup and view all the answers

In which anatomical location does haemopoiesis primarily occur after three months of intrauterine life?

<p>In the bone marrow (A)</p> Signup and view all the answers

What change occurs in bone marrow from newborns to elderly individuals?

<p>The amount of red bone marrow decreases while yellow marrow increases. (A)</p> Signup and view all the answers

Which stem cell type does not possess self-renewal capabilities?

<p>Precursor cells (A)</p> Signup and view all the answers

What characterizes the transition from pluripotent stem cells to myeloid and lymphoid stem cells?

<p>The influence of growth factors causing cell separation. (C)</p> Signup and view all the answers

What is the main function of the stroma in red bone marrow?

<p>It provides structural support and a supportive environment for hematopoietic cells. (A)</p> Signup and view all the answers

Which substance is NOT typically found in the composition of red bone marrow?

<p>Adipocytes (A)</p> Signup and view all the answers

How is yellow bone marrow converted back to red bone marrow?

<p>In response to conditions like severe bleeding or hypoxia. (C)</p> Signup and view all the answers

What structural features define sinusoidal capillaries?

<p>A discontinuous layer of endothelial cells and reticular fibers. (C)</p> Signup and view all the answers

What is the primary reason that erythrocytes can easily pass through small capillary pores?

<p>Their flexibility and lack of a nucleus facilitate shape change. (D)</p> Signup and view all the answers

What differentiates integral proteins from peripheral proteins in the RBC membrane?

<p>Integral proteins span the membrane, while peripheral proteins are found only on the inner surface. (A)</p> Signup and view all the answers

Which statement correctly describes hemoglobin in relation to erythrocytes?

<p>It is the main protein in RBCs, accounting for over 95% of their dry weight. (B)</p> Signup and view all the answers

What process describes the series of developmental stages leading to mature RBCs?

<p>Erythropoiesis. (D)</p> Signup and view all the answers

Which of the following is a characteristic of pro-erythroblasts?

<p>They produce hemoglobin until maturity. (A)</p> Signup and view all the answers

What happens to the nucleus of an erythrocyte as it matures?

<p>It gets progressively smaller and is eventually extruded. (A)</p> Signup and view all the answers

What percentage of the RBC membrane's composition is made up of carbohydrates?

<p>10% (C)</p> Signup and view all the answers

Flashcards

Self-renewal

The ability of a cell to divide and create more cells of the same type.

Differentiation

The process by which a less specialized cell becomes a more specialized cell.

Regulatory Factors

Factors that regulate the growth and development of stem cells.

Suitable Microenvironment

The environment within bone marrow that supports stem cell growth and differentiation.

Signup and view all the flashcards

Pluripotent Stem Cell

The earliest type of stem cell, capable of producing all cell types in the body.

Signup and view all the flashcards

Hematopoietic Stem Cells

Stem cells that can only produce blood cells.

Signup and view all the flashcards

Bone Marrow

The bone marrow found in the cavities of long bones and cancellous bones.

Signup and view all the flashcards

Bone Marrow with Age

The change in bone marrow from red to yellow with age.

Signup and view all the flashcards

Blood

The liquid connective tissue that transports oxygen, nutrients, and waste products throughout the body.

Signup and view all the flashcards

Haemopoiesis

The process of blood cell formation, starting from stem cells.

Signup and view all the flashcards

Erythrocytes (Red Blood Cells)

Cells responsible for carrying oxygen throughout the body, giving blood its red color. They are formed in the process of erythropoiesis.

Signup and view all the flashcards

Erythropoiesis

The process of red blood cell formation, starting from stem cells. It occurs mainly in the bone marrow.

Signup and view all the flashcards

Plasma

The liquid component of blood, containing water, proteins, and other dissolved substances.

Signup and view all the flashcards

Hematocrit (PCV)

The percentage of red blood cells (erythrocytes) in a given volume of blood. It is a measure of the blood's oxygen-carrying capacity.

Signup and view all the flashcards

Serum

Plasma without clotting factors. Obtained from blood that has been allowed to clot.

Signup and view all the flashcards

Reticulocytes

Immature red blood cells that still contain some ribosomal RNA. They are released from the bone marrow and mature into erythrocytes within 1-2 days.

Signup and view all the flashcards

Retic Count

The percentage of reticulocytes in the blood. It reflects the bone marrow's production of red blood cells.

Signup and view all the flashcards

Decreased Reticulocyte Count

A decrease in the number of reticulocytes in the blood, indicating a reduced production of red blood cells. Common in conditions like bone marrow failure.

Signup and view all the flashcards

Increased Reticulocyte Count

An increase in the number of reticulocytes in situations like blood loss or hemolytic anemia, where the body needs to replace red blood cells quickly.

Signup and view all the flashcards

RBC Function: Oxygen Transport

The primary function of red blood cells is to carry oxygen from the lungs to the tissues throughout the body.

Signup and view all the flashcards

RBC Function: CO2 Transport

Red blood cells also transport carbon dioxide (CO2) from the tissues back to the lungs to be exhaled.

Signup and view all the flashcards

What is Hemoglobin?

Hemoglobin is a protein found in red blood cells that binds to oxygen. It's what makes blood red!

Signup and view all the flashcards

Hemoglobin Function

Hemoglobin's ability to bind to oxygen is crucial for transporting oxygen throughout the body.

Signup and view all the flashcards

Hemoglobin Oxygen Affinity

The type of globin chain present in a hemoglobin molecule directly influences its oxygen affinity. For example, Hb F (fetal hemoglobin) has a higher affinity for oxygen compared to Hb A (adult hemoglobin).

Signup and view all the flashcards

What is Embryonic Hemoglobin?

Embryonic hemoglobin is the primary type of hemoglobin found in the developing embryo. This form of hemoglobin has a unique structure and properties.

Signup and view all the flashcards

What is Fetal Hemoglobin (Hb F)?

Fetal hemoglobin (Hb F) is the main hemoglobin present in the fetus during pregnancy. It has a higher affinity for oxygen compared to adult hemoglobin, ensuring efficient oxygen transfer from the mother to the developing baby.

Signup and view all the flashcards

What is Adult Hemoglobin (Hb A)?

Adult hemoglobin (Hb A) is the primary hemoglobin found in adults. It consists of two alpha and two beta globin chains.

Signup and view all the flashcards

What is the Lifespan of RBCs?

Red blood cells (RBCs) have a lifespan of approximately 120 days. After that, they are phagocytized by macrophages in the spleen, liver, and bone marrow, which constitute the reticuloendothelial system.

Signup and view all the flashcards

What Happens to Hemoglobin After RBC Breakdown?

When RBCs break down, the hemoglobin is phagocytozed by macrophages, primarily in the liver, spleen, and bone marrow.

Signup and view all the flashcards

What Happens to Heme After Hemoglobin Breakdown?

The heme portion of hemoglobin is broken down into two components: iron, which is recycled for new RBC production, and protoporphyrin, which is converted into bilirubin.

Signup and view all the flashcards

What are sinusoidal capillaries?

Sinusoidal capillaries are a type of blood vessel found in the liver, spleen, and bone marrow. They are characterized by their discontinuous endothelial lining, which allows for the passage of large molecules and cells.

Signup and view all the flashcards

Describe the structure and function of red blood cells.

Red blood cells (RBCs) are biconcave discs that lack a nucleus. This shape maximizes their surface area to volume ratio, enhancing their ability to transport oxygen.

Signup and view all the flashcards

What is the normal range of red blood cells in males and females?

The normal RBC count for females ranges from 3.9 to 5.5 million per microliter of blood, while the count for males is slightly higher, ranging from 4.1 to 6 million per microliter.

Signup and view all the flashcards

What is the composition of the red blood cell membrane?

The RBC membrane is composed of proteins, lipids, and carbohydrates. The membrane proteins are integral or peripheral, giving the RBC its flexible shape.

Signup and view all the flashcards

What is hemoglobin, and what is its role in red blood cells?

Hemoglobin is the major protein found inside red blood cells, responsible for oxygen transport. The presence of hemoglobin is what gives red blood cells their characteristic pink color when stained.

Signup and view all the flashcards

Where are red blood cells produced?

Red blood cells are produced in the bone marrow from pluripotent stem cells, undergoing a series of differentiation stages.

Signup and view all the flashcards

What is the earliest stage of red blood cell development?

The earliest recognizable precursor of a red blood cell is called a pro-erythroblast. This cell undergoes a sequence of differentiations until it becomes a mature red blood cell.

Signup and view all the flashcards

What happens to the nucleus and hemoglobin content during red blood cell development?

As a red blood cell develops, it accumulates hemoglobin, reaching a maximum concentration of 34%. The nucleus shrinks until it is eventually expelled from the cell.

Signup and view all the flashcards

Study Notes

Hematology Lecture (1)

  • Blood is a liquid connective tissue
  • It's composed of two parts: formed elements (blood cells) and plasma
  • Formed elements include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes)
  • Plasma is the liquid in which the formed elements are suspended
  • It's an aqueous solution composed of 90% water and 10% solids (solutes)
  • Plasma proteins account for 70% of the total solids
  • Albumin is the most abundant plasma protein and maintains osmotic pressure of the blood
  • The hematocrit (PCV) estimates the volume of packed erythrocytes per unit volume of blood
  • If blood is collected without an anticoagulant, it clots, separating into a clot containing formed elements and a clear yellow liquid called serum
  • If blood is collected with an anticoagulant, it will not clot and when centrifuged separates into three layers:
    • Lower layer (red): erythrocytes (about 40-45%)
    • Middle layer (white): buffy coat (WBCs and platelets) (about 1%)
    • Upper layer (translucent/yellowish): plasma (about 55%)

Haemopoiesis

  • It's the process of forming new blood cells from hematopoietic stem cells
  • Sites of haemopoiesis:
    • First trimester: yolk sac
    • Second trimester: mainly liver, with spleen and lymph nodes contributing
    • Third trimester and later: bone marrow
  • A graph shows relative contributions of yolk sac, liver, and bone marrow over time

Stem Cells

  • These are the cells from which all hematopoietic cells originate
  • Characteristics: self-renewal and differentiation
  • Requirements for proliferation and differentiation: regulatory factors (Hemopoietic Growth Factors) and a suitable microenvironment (marrow space)
  • Earliest stem cell is pluripotent, capable of producing all types of blood cells
  • Pluripotent stem cells differentiate into:
    • Myeloid multipotent stem cells
    • Lymphoid multipotent stem cells
  • Differentiation leads to production of mature blood cells

RBC Production (Erythropoiesis)

  • RBCs are produced from pluripotent stem cells that develop into myeloid multipotent stem cells
  • Stages in erythropoiesis:
    • proerythroblast
    • basophilic normoblast
    • polychromatic normoblast
    • orthochromatic normoblast
    • reticulocyte
    • erythrocyte
  • Proerythroblast is the earliest precursor, only producing RBCs and goes through intermediate forms
  • During differentiation, cells become progressively more committed until they only produce one type of mature cell
  • Precursors lack self-renewal capacity and are restricted to one lineage
  • The proerythroblast is the earliest identified precursor of the RBC. (It only produces RBCs, not other blood components)
  • RBCs mature and accumulate hemoglobin until they reach 34%.
  • The nucleus is expelled, forming reticulocytes which contain residual RNA
  • Reticulocytes are released into the blood and develop into mature erythrocytes within 1 to 2 days
  • Normal reticulocyte count is typically less than 2.5% of total RBCs

RBC Function

  • Carry oxygen from lungs to tissues via hemoglobin
  • Hemoglobin combines with 1.34 milliliters of oxygen per gram
  • Transport CO2 from tissues to lungs as bicarbonate ions (HCO3-)
  • Carbonic anhydrase catalyzes the reversible reaction between CO2 and water to form carbonic acid (H2CO3)
  • Hemoglobin plays a role in maintaining acid-base balance

Hemoglobin Structure and Function

  • Normal hemoglobin concentration: 13-17 g/dL (men), 12-15 g/dL (women)
  • Hemoglobin production starts in the proerythroblast stage of RBC development; continues into the reticulocyte stage but stops at the mature stage.
  • Hemoglobin molecule consists of four heme groups, each with an iron atom capable of binding four oxygen molecules
  • Different forms of hemoglobin exist (embryonic, fetal, adult hemoglobin A, adult hemoglobin A2) varying in globin chain composition
  • These differences affect oxygen affinity

Life Span and Destruction of RBCs

  • Lifespan is about 120 days
  • Destroyed by macrophages in spleen, liver, and bone marrow
  • No nucleus, cellular metabolism progressively deteriorates, becoming non-viable after 120 days
  • Hemoglobin is phagocytosed immediately by macrophages
  • Iron from hemoglobin is taken up by transferrin, primarily going to the bone marrow, for usage in new RBC synthesis
  • The protoporphyrin ring is degraded, converting to bilirubin. Liver conjugates and excretes as stercobilin
  • The stercobilin is excreted into the feces and some goes into the bloodstream where it is converted to urobilin and is excreted in the urine

Fate of Hb after RBC Destruction

  • The heme portion of hemoglobin breaks down into iron, that is taken up by transferrin and reused; and protoporphyrin which is converted into bilirubin, conjugated, excreted into bile then as stercobilin into the feces.
  • Stercobilin and some bilirubin are reabsorbed into the bloodstream and converted to urobilinogen and finally into urobilin which is excreting the urine.
  • Globin chains are broken down to amino acids used for general protein synthesis in the body.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Hematology Lecture (1) PDF

Description

Explore the essential components of blood, including its composition and the roles of red blood cells, white blood cells, and plasma. This lecture provides insights into hematocrit and the effects of anticoagulants on blood samples. Gain a foundational understanding of this vital liquid connective tissue.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser