Anatomy & Physiology of Hematologic and Lymphatic Systems – Comprehensive Bullet Notes

What is bone marrow?

Soft, spongy tissue inside sternum, vertebrae, ribs, and pelvis, where red marrow is actively hematopoietic.

What are Hematopoietic Stem Cells (HSCs)?

Self-replicating cells capable of differentiating into any blood cell (totipotent), first committing to myeloid or lymphoid lines.

What is the normal pH of blood?

The normal pH 7.35 - 7.45 range for blood, maintained by buffer systems.

What are Erythrocytes (RBCs) and what is their life-span?

Mature erythrocytes; life-span is approximately 120 days, removed by the spleen/liver.

What is erythropoiesis and what governs it?

RBC production in marrow, governed by nutrient supply and erythropoietin (EPO) from kidneys.

What is the primary function of Leukocytes (WBCs)?

Primary defense against pathogens.

What does a "Left Shift" indicate?

An increase in immature neutrophil forms (bands), indicating a bacterial infection.

Where do B and T lymphocytes mature?

B cells mature in the marrow, while T cells mature in the thymus.

What is the function and life-span of Thrombocytes (Platelets)?

Key to hemostasis (prevent blood loss), with a life-span of 5\text{–}9 days.

What are the steps of Hemostasis?

Vessel spasm, platelet plug formation, and clot (full coagulation cascade).

What are the functions of the Lymphatic System?

Fluid balance, fat absorption, immune defense, and waste/abnormal cell transport.

What is the function of Lymph Nodes?

They filter lymph and house immune cells.

What is the Spleen and its main functions?

Largest lymphoid organ, with red pulp filtering aged RBCs and white pulp performing immune surveillance.

What is the Thymus responsible for?

Organ where thymocytes mature into T cells.

What components are measured in a Complete Blood Count (CBC)?

A test that measures RBCs, WBCs, platelets, Hb, Hct, and RBC indices.

What is the Schilling Test used for?

A test to diagnose \text{B}\_\text{12} malabsorption, specifically to differentiate dietary lack from pernicious anemia.

What are the two types of Hematopoietic Stem-Cell Transplants (HSCT)?

Transplant using a donor (allogeneic) or the patient's own cells (autologous).

What is a Hemolytic Transfusion Reaction and its management?

Recipient antibodies binding donor RBC antigens, causing hemolysis, with symptoms like fever, chills, and hypotension. Requires immediate transfusion cessation.

What is Anemia and its causes?

A decrease in RBC/Hb/Hct leading to reduced oxygen carrying capacity, caused by impaired production, blood loss, or destruction.

What is Aplastic Anemia?

Pancytopenia from stem-cell damage.

How is Iron-Deficiency Anemia characterized?

Characterized by decreased MCV and ferritin, often due to chronic blood loss or inadequate diet.

What are two types of Megaloblastic Anemias?

Anemias caused by pernicious anemia (lack of intrinsic factor) or folate deficiency.

What is Sickle Cell Disease?

A homozygous Hb-S mutation leading to Hb-S polymerization and sickling upon hypoxia, causing vaso-occlusive crisis.

What is Polycythemia?

Increased RBC count, leading to thick viscous blood and hypercoagulability.

What is Agranulocytosis?

Often drug-induced, characterized by a severe lack of granulocytes.

What is Leukemia?

Malignant proliferation of abnormal leukocytes in marrow/lymph.

What is Thrombocytopenia and its main symptoms?

Platelet count below 150{,}000/\text{mm}^3, leading to symptoms like petechiae/purpura when below 50{,}000.

What is Hemophilia and its hallmark symptoms?

X-linked recessive bleeding disorder (A = factor VIII, B = factor IX, C = factor XI deficiency) characterized by prolonged bleeding and hemarthrosis.

What is Disseminated Intravascular Coagulation (DIC)?

Simultaneous micro-thrombosis and bleeding, triggered by conditions like sepsis or trauma.

What is Multiple Myeloma?

Malignant plasma-cell proliferation in marrow leading to bone destruction, hypercalcemia, and renal damage.

What is Lymphangitis?

Acute infection of lymph channels, presenting as red tender streaks and enlarged painful nodes.

What is Lymphedema?

Primary or secondary blockage of lymph flow, resulting in protein-rich edema and fibrosis.

What is Hodgkin Lymphoma (HL)?

Lymphoma characterized by painless node enlargement and the presence of Reed-Sternberg cells.

What is Non-Hodgkin Lymphoma (NHL)?

B- or T-cell neoplasms without Reed-Sternberg cells, varying from indolent to aggressive.

What is the formula for Hematocrit?

=\frac{\text{Packed RBC volume}}{\text{Total blood volume}}\times100\%

=\frac{\text{Hct (\%)\,}\times10}{\text{RBC (millions/µL)})}