Blood, Lymphatics, and Immunity Practice Flashcards

Comprehensive question-and-answer flashcards created from lecture transcripts covering blood components, hemostasis, blood typing, leukocytes, the lymphatic system, and innate and adaptive immune responses.

What are the two main components that make up blood?

Blood consists of plasma (the fluid extracellular matrix) and formed elements (the cellular components).

What are the three categories of formed elements in blood?

Erythrocytes (red blood cells), leukocytes (white blood cells), and platelets.

What is the normal pH range of human blood?

The normal pH range of blood is $7.35-7.45$.

What are the average blood volumes for adult males and females?

Adult males have approximately $5-6\,\text{L}$ of blood, while adult females have $4-5\,\text{L}$.

What is the distinction between hematocrit and packed cell volume (PCV)?

Hematocrit is the percentage of erythrocytes in whole blood, whereas PCV is the actual volume of erythrocytes.

What are the three major plasma proteins and their relative abundances?

Albumin ($60\%$), Globulins ($35\%$), and Fibrinogen ($4\%$).

Where are plasma proteins primarily synthesized?

Plasma proteins are produced primarily by liver cells.

What are the key functions of albumin in plasma?

Albumin acts as the major contributor to plasma osmotic pressure and transports lipids such as fatty acids and steroid hormones.

What is hemopoiesis, and where does medullary hemopoiesis occur in adults?

Hemopoiesis is the process of producing formed elements. In adults, medullary hemopoiesis occurs in the red bone marrow of cranial bones, pelvic bones, vertebrae, the sternum, and proximal ends of the femur and humerus.

Which organ produces erythropoietin (EPO) and what is its function?

Erythropoietin (EPO) is a hormone produced by the kidneys that stimulates red blood cell production to counter low oxygen levels.

How many oxygen molecules can a single molecule of hemoglobin transport?

A single hemoglobin molecule contains 4 globin subunits, each with a heme group and iron ion, allowing it to carry up to 4 oxygen molecules.

What are the specific terms for hemoglobin bound to oxygen, hemoglobin lacking oxygen, and hemoglobin bound to carbon dioxide?

Oxyhemoglobin (bound to oxygen), deoxyhemoglobin (lacking oxygen), and carbaminohemoglobin (bound to carbon dioxide).

What is the average lifespan of a circulating erythrocyte?

Erythrocytes circulate for an average of $120\,\text{days}$.

How is the non-iron heme portion of hemoglobin broken down and excreted?

Heme is converted to biliverdin (green), then to bilirubin (yellow), which is transported to the liver to make bile, excreted into the intestines, and further processed by gut bacteria.

What clinical condition is characterized by bilirubin buildup causing yellowing of skin and eyes?

Jaundice.

What are the three sequential steps of hemostasis?

1) Vascular spasm, 2) Platelet plug formation, and 3) Coagulation.

How do the extrinsic and intrinsic clotting pathways differ in activation and speed?

The extrinsic pathway (tissue factor pathway) is triggered by external trauma outside the vessel and completes in seconds; the intrinsic pathway (contact activation pathway) is triggered by internal vascular damage (Factor XII contact) and takes a few minutes.

What steps occur in the common pathway of blood coagulation?

Activated Factor X activates prothrombinase, which converts prothrombin into active thrombin. Thrombin then converts soluble fibrinogen into insoluble fibrin, which stabilizes the platelet plug.

What molecule dissolves a blood clot during fibrinolysis?

Plasmin (converted from inactive plasminogen) breaks down the fibrin mesh.

What causes Hemolytic Disease of the Newborn (HDN)?

HDN occurs when an Rh- mother who was sensitized during a previous pregnancy with an Rh+ fetus produces anti-Rh antibodies that cross the placenta during a subsequent Rh+ pregnancy to destroy fetal erythrocytes.

Which leukocytes are categorized as granular, and which are agranular?

Granular leukocytes include neutrophils, eosinophils, and basophils; agranular leukocytes include monocytes and lymphocytes.

What mnemonic is used to recall the relative abundance of white blood cells from most to least abundant?

"Never Let Monkeys Eat Bananas" (Neutrophils, Lymphocytes, Monocytes, Eosinophils, Basophils).

What are the primary functions of eosinophils?

Eosinophils release granules containing histamine during allergic reactions and secrete cytotoxic chemicals to destroy parasitic worms.

What stem cell is the common precursor for all blood cell lineages?

The hemocytoblast, also known as the hematopoietic stem cell.

How much fluid enters the interstitial space from capillaries daily, and how much does the lymphatic system return to circulation?

Approximately $20\,\text{L}$ enters the interstitial space daily; $17\,\text{L}$ is reabsorbed directly into blood capillaries, and the remaining $3\,\text{L}$ is returned by the lymphatic system as lymph.

Where do the right lymphatic duct and thoracic duct empty into venous circulation?

The right lymphatic duct empties into the right subclavian vein, and the thoracic duct empties into the left subclavian vein.

What are the primary lymphoid organs and their respective cell development functions?

Red bone marrow (site of hematopoiesis and B cell development) and the thymus gland (site of T cell maturation).

What is the functional difference between afferent and efferent lymphatic vessels in a lymph node?

Afferent lymphatic vessels carry lymph arriving into the node, while efferent lymphatic vessels carry filtered lymph exiting the node.

What are the functional differences between red pulp and white pulp in the spleen?

Red pulp contains red blood cells and filters blood-borne pathogens and old RBCs; white pulp contains high concentrations of B and T cells to initiate adaptive immune responses.

How do Natural Killer (NK) cells induce cell death in infected or abnormal cells?

NK cells secrete perforin to form pores in the target cell membrane, then deliver granzymes into the cell to induce apoptosis.

How does histamine release contribute to the vascular changes seen in inflammation?

Histamine causes vasodilation (increasing local blood flow, causing redness and heat) and increases capillary permeability (allowing fluid leakage/exudate, causing swelling and pain).

How do Cytotoxic T cells and Helper T cells differ in their cell surface markers and MHC interactions?

Cytotoxic T cells possess the $CD8$ marker and interact with antigen bound to MHC class I molecules; Helper T cells possess the $CD4$ marker and interact with antigen bound to MHC class II molecules.

What distinguishes active immunity from passive immunity?

Active immunity involves the individual's own body producing an immune response and memory cells following antigen exposure; passive immunity involves the transfer of pre-formed antibodies from an outside source, providing immediate but temporary protection without memory.