Blood, Lymphatic, and Immune Systems Lecture Notes

Flashcards covering the physiology of blood, the anatomy and function of the lymphatic system, and the mechanisms of innate immunity based on lecture materials from late 2022.

Formed elements

The cellular components of blood making up $45\%$ of its volume, including erythrocytes, leukocytes, and thrombocytes.

Plasma

The liquid matrix of blood making up $55\%$ of its volume, composed of $92\%$ water, $7\%$ plasma proteins, and $1\%$ other solutes.

Serum

Blood plasma that does not contain clotting proteins.

Albumin

The most abundant plasma protein ($58\%$) responsible for maintaining colloid osmotic pressure.

Sodium ($Na^+$)

The most common cation in arterial plasma with a normal range of $135-145\,mEq/L$; it regulates fluid balance and neuron function.

Potassium ($K^+$)

A cation with a normal range of $3.5-5.0\,mEq/L$ essential for neuron and muscle function.

Hemopoiesis

The process of formed element production which occurs primarily in the red bone marrow of adults.

Hemocytoblasts

Blood stem cells that can differentiate into the myeloid line or the lymphoid line.

Erythrocytes

Flexible, anucleate, biconcave-shaped disks that are the most abundant formed elements, with approximately $5$ million per cubic millimeter of blood.

Hemoglobin

A red-pigmented protein made of $4$ globin subunits, each containing an iron-bearing heme molecule that binds oxygen.

Polycythemia

An imbalance due to abnormally high RBC production, causing increased blood volume and viscosity.

Diapedesis

The process by which leukocytes squeeze through blood vessel walls to reach infection sites.

Chemotaxis

The movement of leukocytes toward a higher concentration of chemicals at an infection site.

Neutrophils

The most abundant circulating WBC ($50-70\%$); also called polymorphonuclear (PMNs) cells, they phagocytize pathogens.

Basophils

Proinflammatory leukocytes that release histamine (a vasodilator) and heparin (an anticoagulant).

Monocytes

The largest circulating WBC ($2-8\%$) that transforms into aggressive macrophages upon entering tissues.

Leukopenia

A condition characterized by an abnormally low white blood cell count.

Thrombocytes

Disc-shaped fragments of megakaryocytes that play a critical role in blood clotting and have a lifespan of $8-10$ days.

Hemostasis

The three-phase process of stopping blood loss: vascular spasm, platelet plug formation, and coagulation.

Fibrinolysis

The process of breaking up a blood clot where plasminogen is activated into plasmin to digest fibrin threads.

Agglutination

The clumping of red blood cells that occurs when a recipient's antibodies bind to donor RBC antigens during an incompatible transfusion.

RhoGAM

Specialized immunoglobulins given to Rh- mothers to prevent the development of anti-D antibodies against an Rh+ fetus.

Lymph

The clear, interstitial fluid that enters lymphatic capillaries containing water, solutes, small proteins, and potentially pathogens.

Lymphedema

The accumulation of interstitial fluid resulting in swelling due to a disruption in lymphatic drainage.

Right lymphatic duct

The duct that drains lymph from the upper right side of the head, arm, and thorax into the right subclavian vein.

Thoracic duct

The major duct that drains lymph from most of the body into the left subclavian vein.

Primary lymphatic structures

Sites of lymphocyte formation and maturation, specifically the red bone marrow and the thymus.

Secondary lymphatic structures

Structures that house immune cells and serve as sites for immune surveillance, including lymph nodes, spleen, tonsils, and MALT.

Bubo

An inflamed, tender, and swollen lymph node typically caused by bacterial accumulation.

White pulp

The tissue in the spleen responsible for monitoring blood for bacteria and foreign materials.

MALT

Mucosa-associated lymphatic tissue located in the gastrointestinal, respiratory, reproductive, and urinary tracts.

Innate immunity

The immediate, nonspecific defense system that includes skin, mucosal membranes, and internal processes like inflammation and fever.

Interferons

Antimicrobial proteins released by virus-infected cells to prevent the spread of infection to neighboring cells.

Complement

A group of plasma proteins that, when activated, facilitate opsonization, inflammation, cytolysis, and the removal of immune complexes.

Opsonization

A process where complement proteins bind to a pathogen to enhance its recognition and engulfment by phagocytic cells.

MAC (Membrane Attack Complex)

A protein structure formed by the complement system that creates a hole in a bacterium's membrane to induce cytolysis.

Pyrexia

Commonly known as fever, it is an increase in body temperature above the normal $37^{\circ}C$ ($98^{\circ}F$) to inhibit pathogens and increase immune activity.