Blood Cells and Functions

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Questions and Answers

What is the primary regulator of erythropoiesis?

Erythropoietin (EPO) (correct)

Iron

Vitamin B12

Hemoglobin

What does a hematocrit measurement reflect?

Total white blood cell count

Total lipid levels in blood

Ratio of red cell mass to whole blood volume (correct)

Concentration of electrolytes in plasma

Which of the following is NOT a factor required for mature red blood cells?

Iron

Folic acid

Vitamin B12

Hemoglobin (correct)

Which type of hemoglobin is typically found in adult humans?

HbA Signup and view all the answers

What is the expected mean corpuscular volume (MCV) range for healthy red blood cells?

82-98 Signup and view all the answers

What percentage of the total leukocyte count do lymphocytes constitute?

36% Signup and view all the answers

Which of the following is a function of the spleen?

Filter blood and act as a blood reservoir Signup and view all the answers

What is the primary role of macrophages in the body?

Engulf and destroy microorganisms Signup and view all the answers

Where do T cells mature before entering the bloodstream?

Thymus gland Signup and view all the answers

What specific function do Peyer's patches serve in the immune system?

Development of B cells and IgA production Signup and view all the answers

What happens to the thymus gland during adolescence?

Atrophies and is replaced by fibrous tissue Signup and view all the answers

What is the primary role of the tonsils?

Phagocytosing microorganisms in the mouth and throat Signup and view all the answers

Which of the following statements about lymph formation is true?

Lymph is formed through protein extravasation from microcirculation Signup and view all the answers

What is the role of oncogenes in cancer development?

They may be expressed at high levels or mutated, leading to cancer. Signup and view all the answers

Which type of mutation involves a change at a single nucleotide level?

Point mutation Signup and view all the answers

How do tumor suppressor genes function in normal cells?

They inhibit unnecessary cell division and promote cell death of damaged cells. Signup and view all the answers

Which of the following explains the concept of genomic amplification?

The increase in copies of a chromosomal region containing oncogenes. Signup and view all the answers

What can lead to the formation of tumors?

Inflammation, infection, or benign growths Signup and view all the answers

What are the primary components that make up blood?

Plasma and blood cells Signup and view all the answers

Which type of blood cells are responsible for immunity?

Leukocytes Signup and view all the answers

What factor primarily stimulates the production of red blood cells (RBCs)?

Erythropoietin Signup and view all the answers

Which pathway is involved in clot initiation within the coagulation process?

Both intrinsic and extrinsic pathways Signup and view all the answers

What is the primary role of plasma proteins in blood?

Clotting and immune response Signup and view all the answers

What is hematopoiesis?

The formation of blood cells Signup and view all the answers

Which cell type is responsible for forming platelet plugs during coagulation?

Thrombocytes Signup and view all the answers

What percentage of body weight does total blood volume represent?

6-8% Signup and view all the answers

What is a common clinical manifestation of leukemia related to bone marrow expansion?

Pain and tenderness in the bones Signup and view all the answers

Which leukemias are commonly associated with chromosomal translocations?

Chronic Myeloid Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL) Signup and view all the answers

What is the primary treatment goal for leukemia?

To reduce the number of blast cells Signup and view all the answers

What type of leukemia is primarily characterized by the proliferation of T-cell precursors?

Acute Lymphoblastic Leukemia (ALL) Signup and view all the answers

What is the common cause of Chronic Myeloid Leukemia (CML)?

Chromosomal abnormality in stem cells Signup and view all the answers

Which type of lymphoma contains Reed-Sternberg cells?

Hodgkin lymphoma Signup and view all the answers

In relation to lymphocyte types, what percentage of Non-Hodgkin lymphomas are B cell lymphomas?

80% Signup and view all the answers

Which laboratory test identifies myeloblasts and lymphoblasts for leukemia diagnosis?

Peripheral blood smear Signup and view all the answers

What is the relationship between Down syndrome and leukemia?

It is associated with both AML and CML. Signup and view all the answers

Which type of leukemia leads to a risk of infections due to neutropenia?

Acute Lymphoblastic Leukemia (ALL) Signup and view all the answers

Study Notes

Blood Cells

Blood is composed of plasma and cells like red blood cells (RBCs), white blood cells (WBCs), and platelets.
Blood accounts for 6-8% of body weight.
Hematopoiesis (blood cell formation) occurs in red bone marrow.

Blood Constituents

Plasma makes up 55% of blood volume and contains water, ions, plasma proteins, immunoglobulins, and fibrinogen.
Cellular components make up 45% of blood volume and include erythrocytes, WBCs, and platelets.

Blood Function

Blood ensures homeostasis through cellular metabolism.
Transports oxygen, hormones, nutrients, and heat throughout the body.
Plays a role in hemostasis, hematocrit, and differentiation of blood cells.
Maintains acid-base balance and defends against invading microorganisms and injuries.

Erythropoiesis

Erythropoiesis is the process of red blood cell formation.
Erythropoietin (EPO) is the primary regulator of erythropoiesis.
Factors essential for mature RBC production include iron, folic acid, and vitamin B12.

Hemoglobin Structure

Hemoglobin is the pigment responsible for the red colour of blood.
It contains four heme molecules (inorganic) and one globin protein.
Each heme molecule contains an iron (Fe2+) atom.
Hemoglobin types include embryonic Hb1, 2, Portland, fetal HbF (2 alpha and 2 gamma chains), and adult HbA (2 alpha and 2 beta chains).

RBC destruction

RBCs have a lifespan of 110-120 days and are destroyed through phagocytosis.
Hemoglobin breakdown produces bilirubin, which is conjugated by the liver and excreted in bile.
Anemia is a condition characterized by decreased red blood cell mass, while polycythemia is characterized by increased red blood cell mass.

Hematocrit

Hematocrit is the percentage of red blood cells in the total blood volume.
It is an indicator of red blood cell size, hemoglobin synthesis, and red blood cell count.
MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Hemoglobin), and MCHC (Mean Corpuscular Hemoglobin Concentration) are red blood cell indices measured in blood smears.

Peripheral Blood Smear

A peripheral blood smear is a test that examines the size and shape of red blood cells.
It assesses red blood cell production levels through reticulocyte counts.
It also measures nutrient levels like iron, vitamin B12, and blood cell counts.

Agranulocyte - Lymphocytes

Lymphocytes are primary cells of the immune response.
They constitute 36% of the total white blood cell count.
They initially circulate in blood but eventually reside in lymphatic tissue as mature T cells, B cells, or plasma cells.
Natural Killer cells (NK cells) resemble lymphocytes and can kill tumor cells and virus-infected cells without prior exposure.

Spleen

The spleen is the largest lymphatic organ located in the left upper quadrant of the abdomen.
It is composed of red pulp (RBCs) and white pulp (WBCs).
It contains macrophages and lymphocytes and functions as a blood filter and reservoir.

Thymus Gland

The thymus gland is a bilobed gland located in the thoracic cavity.
It contains lymphoid tissue and promotes the maturation of lymphocytes into T cells.
It atrophies during adolescence, replaced by fibrous and fatty tissue.

Tonsils

Tonsils are located in the pharynx.
They phagocytose microorganisms in the mouth and throat regions.
Chronic infections may require tonsillectomy.

Peyer’s Patches

Peyer's patches are located in the distal end of the small intestine.
They contain follicles of B cells that differentiate into IgA-producing plasma cells.
Macrophages in Peyer's patches provide a defensive barrier against microorganisms.

Macrophages/Locations

Macrophages are found in various tissues, including the liver (Kupffer cells), bone (osteoclasts), skin (Langerhans cells), bone marrow/blood (monocytes), CNS (microglia), and kidney (mesangial cells).

Lymph Node

Lymph nodes filter lymph and are the primary site for lymphocyte production.
They contain B cells in cortical follicles and T cells in the paracortical areas.
Lymphocytes enter the bloodstream through lymphatics.
Swollen lymph nodes indicate infection.

Lymph Formation

Interstitial fluid forms as protein extravasates from microcirculation into the interstitial fluid.
Lymph is a clear fluid containing water and white blood cells, mainly lymphocytes.
It plays a role in immunologic tolerance, autoimmunity, inflammation, cancer metastasis, and cardiovascular and metabolic disorders.

Lymphatic Trunks/Collecting Ducts

Lymphatic trunks are formed by merging lymphatic vessels and drain lymph from large body regions.
Collecting ducts are responsible for returning lymph to the bloodstream.

Cancer: pathophysiology

Cancer is a disease caused by uncontrolled cell division and spreading into surrounding tissues.
Changes to DNA underlie cancer development caused by genetic changes, oncogenes, tumor suppressor genes, genomic amplification, and point mutations.
Translocation is an abnormal fusion of two chromosomal regions, like the Philadelphia chromosome found in chronic myeloid leukemia (CML).
Myelodysplastic syndrome is a condition characterized by defective maturation of myeloid cells, leading to the development of blasts in bone marrow.

Leukemia: clinical manifestations

Leukemia is characterized by an increase in abnormal white blood cells, leading to symptoms like fatigue, bleeding, infections, bone pain, hepatosplenomegaly, lymph node pain, gingival swelling, and mediastinal growth.
Diagnosis involves peripheral blood smear, bone marrow biopsy, and immunophenotyping.
Treatment aims to reduce the number of blast cells through chemotherapy and stem cell or bone marrow transplant.

Chronic Leukemia

Chronic leukemia is characterized by an increase in abnormal white blood cells over a prolonged period, interfering with the function and development of healthy blood cells.
Cells in chronic leukemia undergo partial maturation, leading to delayed cell death and a weakened immune system.
Chromosomal abnormality in stem cells destined to become leukocytes is a common cause.

Lymphoma

Lymphoma is characterized by a collection of white blood cells, either due to their failure to die or due to uncontrolled replication.
Hodgkin lymphoma is characterized by the presence of Reed-Sternberg cells.
Non-Hodgkin lymphoma accounts for 85% of lymphomas and can be B cell or T cell lymphoma.

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Description

Explore the essential components and functions of blood, including red blood cells, white blood cells, and platelets. Learn about hematopoiesis, plasma constituents, and the vital roles blood plays in maintaining homeostasis and fighting infections.