Blood and Lymphatic System

acquired immunodeficiency syndrome (AIDS)

a chronic immune‑system failure caused by HIV infection, in which the virus destroys key immune cells, leaving the body vulnerable to opportunistic infections, cancers, and neurologic complications

agranulocytes

white blood cells that lack visible granules in their cytoplasm and participate in immune responses through phagocytosis or antibody production

anemia

a condition marked by reduced red blood cells or hemoglobin, resulting in decreased oxygen delivery to tissues and symptoms such as fatigue and pallor

anisocytosis

a blood abnormality in which red blood cells vary significantly in size, often indicating underlying anemia or bone marrow disorders

antibody

a protein produced by the immune system that binds to specific antigens to neutralize or destroy them

anticoagulant

a medication or substance that prevents blood from clotting by interfering with the coagulation process

antigen

any foreign substance, such as bacteria, viruses, or toxins, that triggers the body to produce antibodies

aplastic anemia

a serious disorder in which the bone marrow fails to produce adequate red blood cells, white blood cells, and platelets

autologous blood

blood that a person donates for their own future use, typically before surgery

basophil

a type of granular white blood cell that releases histamine and other chemicals during inflammatory and allergic reactions

blood

the circulating fluid composed of plasma and formed elements that transports oxygen, nutrients, hormones, and waste products throughout the body

blood chemistry

laboratory testing that measures chemical substances in the blood to evaluate organ function and metabolic status

blood chemistry panels

groups of automated blood tests used to assess multiple chemical components for diagnostic screening

blood component therapy

transfusion of specific parts of blood, such as plasma, platelets, or red blood cells, rather than whole blood

blood culture

a diagnostic test used to detect microorganisms in the bloodstream by allowing them to grow in a controlled environment

blood indices

calculated measurements of red blood cell characteristics used to classify types of anemia

blood transfusion

the administration of blood or blood components into a person’s circulation to replace lost or deficient elements

bone marrow aspiration

removal of a small sample of bone marrow using a needle to evaluate blood cell production

bone marrow biopsy

extraction and microscopic examination of bone marrow tissue to diagnose blood disorders or cancers

bone marrow transplant

infusion of healthy donor bone marrow to restore normal blood cell production in patients with damaged or diseased marrow

CD4 cell count

a measurement of CD4 T‑lymphocytes used to monitor immune function, especially in HIV infection

chemotherapy

treatment using chemical agents to destroy or inhibit the growth of abnormal or malignant cells

chyle

a milky lymphatic fluid rich in absorbed fats transported from the intestines

complete blood count

a comprehensive blood test measuring red blood cells, white blood cells, hemoglobin, hematocrit, and platelets to assess overall blood health

computed tomography

advanced x‑ray imaging that produces detailed cross‑sectional views of the body to detect abnormalities such as tumors

cross‑matching

laboratory testing that determines compatibility between donor and recipient blood before transfusion

differential count

a test that identifies the percentage of each type of white blood cell in a blood sample

eosinophil

a granular white blood cell that increases during allergic reactions and parasitic infections

erythroblastosis fetalis

a hemolytic disease of the newborn caused by Rh incompatibility between mother and fetus, leading to destruction of fetal red blood cells

erythrocyte

a red blood cell responsible for carrying oxygen and carbon dioxide throughout the body

erythrocyte sedimentation rate

a test measuring how quickly red blood cells settle in a tube over time, used to detect inflammation

erythropenia

a lower‑than‑normal number of red blood cells

granulocytes

white blood cells containing visible granules that play roles in inflammation and infection defense

hemochromatosis

a hereditary disorder causing excessive iron absorption and buildup in organs, potentially leading to organ damage

hemoglobin

the iron‑containing protein in red blood cells that binds oxygen and carbon dioxide for transport

hemolysis

the breakdown or destruction of red blood cell membranes, releasing hemoglobin into the bloodstream

hemophilia

a hereditary bleeding disorder caused by deficiency of clotting factors, resulting in prolonged bleeding

hemostatic

a drug or agent that stops bleeding by promoting clot formation

immunity

the body’s ability to resist disease through the action of antibodies, immune cells, or prior exposure

immunocompromised

having weakened immune defenses, making the body more susceptible to infections

immunosuppression

reduced ability of the immune system to respond effectively, often due to disease or medication

immunotherapy

treatment that enhances or modifies the immune system’s activity to fight disease

iron deficiency anemia

anemia caused by insufficient iron, leading to reduced hemoglobin production and small, pale red blood cells

lacteals

specialized lymphatic vessels in the small intestine that absorb dietary fats

leukemia

a malignant disease in which abnormal white blood cells proliferate uncontrollably in the blood and bone marrow

leukocyte

a white blood cell that protects the body against infection and harmful substances

lymph

the clear fluid that circulates through lymphatic vessels, carrying immune cells and waste products

lymphadenectomy

surgical removal of a lymph node

lymphadenopathy

enlargement or disease of lymph nodes

lymphadenotomy

surgical incision into a lymph node

lymphangiogram

an x‑ray image of lymph nodes or vessels obtained after injection of contrast dye

lymphatic system

the network of lymph vessels, nodes, and organs that drains excess fluid, filters pathogens, and supports immune function

lymph capillaries

tiny lymphatic vessels that collect lymph from tissues

lymph ducts

large lymphatic channels that return lymph to the bloodstream

lymph nodes

small, bean‑shaped structures that filter lymph and house immune cells

lymphocyte

an agranular white blood cell involved in immune responses, including antibody production and direct cell attack

lymph vessels

channels that transport lymph toward lymph nodes and ducts

lymphoma

a malignant cancer of lymphatic tissue

macrocytosis

the presence of abnormally large red blood cells

mean corpuscular hemoglobin

the average amount of hemoglobin per red blood cell

mean corpuscular hemoglobin concentration

the average concentration of hemoglobin within red blood cells

mean corpuscular volume

the average size of red blood cells

metastasis

the spread of cancer cells from the original site to distant organs or tissues

microcytosis

the presence of abnormally small red blood cells

monocyte

a large agranular white blood cell that performs phagocytosis and becomes a macrophage in tissues

mononucleosis

a viral infection causing increased mononuclear white blood cells, swollen lymph nodes, and fatigue

neutropenia

a decreased number of neutrophils, increasing infection risk

neutrophil

the most abundant granular white blood cell, responsible for engulfing and destroying bacteria

partial thromboplastin time

a test measuring the time it takes blood to clot, used to detect clotting disorders

pernicious anemia

a macrocytic anemia caused by vitamin B12 deficiency due to impaired absorption

phlebotomy

puncture of a vein to withdraw blood; also called venotomy

plasmapheresis

a procedure that removes plasma from blood, extracts specific components, and returns the remaining elements to circulation

platelet count

measurement of the number of platelets in the blood

platelets

small cell fragments essential for blood clotting

plasma

the liquid portion of blood and lymph containing proteins, nutrients, and waste products

polymorphonuclear leukocyte

a neutrophil with a segmented nucleus

poikilocytosis

irregularly shaped red blood cells

positron‑emission tomography

imaging combining nuclear medicine and CT to evaluate metabolic activity and detect cancers

prothrombin

a protein essential for blood clotting

prothrombin time

a test measuring how long it takes blood to clot by evaluating prothrombin activity

red blood cell

a cell that transports oxygen and carbon dioxide

red blood count

the number of red blood cells in a given blood volume

red cell morphology

evaluation of red blood cell size, shape, and appearance

reticulocytosis

increased numbers of immature red blood cells

Rh factor

an antigen on red blood cells that determines Rh compatibility

Rh negative

lacking the Rh antigen

Rh positive

having the Rh antigen

septicemia

a serious bloodstream infection caused by microorganisms and their toxins

serum

the liquid portion of blood remaining after clotting

splenectomy

surgical removal of the spleen

spleen

an organ that filters aging blood cells and supports immune responses

splenomegaly

enlargement of the spleen

thrombocytopenia

a decreased number of platelets, impairing clotting ability

thromboplastin

a substance necessary for blood coagulation

thymectomy

surgical removal of the thymus

thymus

a lymphatic gland that produces T lymphocytes and regulates immune development

vasoconstrictor

a drug that narrows blood vessels

vasodilator

a drug that widens blood vessels

venotomy

puncture of a vein to withdraw blood

white blood cell

a leukocyte that protects the body against harmful substances