General Biology: Circulatory and Immune Systems

Vocabulary flashcards covering the anatomy and physiology of the human cardiovascular, circulatory, and immune systems.

Circulatory System

Body system responsible for the transport of materials, acid-base buffering, and immunity.

Open Circulatory System

A circulatory system that lacks vessels, allowing blood to flow freely through body cavities, as seen in insects.

Closed Circulatory System

A circulatory system in which blood is conducted throughout the body inside vessels, as seen in vertebrates.

Pulmonary Circulation

The pathway of circulation that moves blood from the heart to the lungs to be oxygenated and then back to the heart.

Systemic Circulation

The pathway of circulation that moves blood from the heart to different parts of the body and back to the heart.

Mediastinum

The anatomical space between the lungs where the heart is located.

Base (of the Heart)

The external aspect of the heart where blood vessels connect.

Apex (of the Heart)

The pointed, left-oriented inferior part of the heart.

Epicardium

The outer visceral pericardium layer of the heart.

Myocardium

The muscular middle layer of the heart made of cardiac muscle.

Endocardium

The inner epithelial lining that lines the chambers of the heart.

Pericardial Cavity

The space located between the epicardium and the parietal pericardium.

Right Atrium

Heart chamber that receives oxygen-poor blood returning from the body and sends it to the right ventricle.

Right Ventricle

Heart chamber that pumps oxygen-poor blood to the lungs to get oxygen.

Left Atrium

Heart chamber that receives oxygen-rich blood from the lungs and passes it to the left ventricle.

Left Ventricle

Heart chamber that pumps oxygen-rich blood out of the heart to the rest of the body.

Interventricular Septum

A wall composed of cardiac muscle that divides the right and left ventricles.

Interatrial Septum

The partition that separates the right and left atria.

Tricuspid Valve

An atrioventricular valve separating the right atrium and right ventricle.

Bicuspid Valve (Mitral Valve)

An atrioventricular valve separating the left atrium and left ventricle.

Semilunar Valves

The pulmonary and aortic valves that prevent the backflow of blood away from the ventricles.

Heart Strings (Chordae Tendineae)

Connective tissue cords that regulate the opening and closing of heart valves.

Mitral Valve Prolapse

A condition in which the mitral valve fails to function properly, leading to the leaking of blood.

Sinoatrial (SA) Node

The natural pacemaker of the heart that acts as the primary source of electrical impulses.

Atrioventricular (AV) Node

Electrical conduction node located on the floor of the right atrium where action potential propagation is slower.

AV Bundle (Bundle of His)

Specialized fibers that form the electrical connection between the atria and ventricles, traveling into the interventricular septum.

Purkinje Fibers

Conduction fibers that conduct electrical impulses throughout the ventricular myocardium.

Superior Vena Cava

A large vein that collects deoxygenated blood from the upper parts of the body and returns it to the right atrium.

Inferior Vena Cava

A large vein that collects deoxygenated blood from the lower parts of the body and returns it to the right atrium.

Capillaries

Microscopic vessels composed of single epithelial cells that serve as the sites of nutrient, gas, and waste exchange.

Tunica Externa

The outermost structural layer of arteries and veins.

Tunica Media

The middle layer of arteries and veins composed of smooth muscle tissue.

Tunica Intima

The innermost lining layer of arteries and veins.

Blood Plasma

The liquid portion of blood comprising $55-60\%$ of blood volume; composed of $91\%$ water, clotting proteins, albumin, immunoglobulins, and $1\%$ ions, vitamins, amino acids, and gases.

Albumin

A plasma protein that acts as a buffer and maintains blood volume.

Fibrinogen

A plasma protein essential for blood clotting.

Erythrocytes (RBCs)

Non-nucleated formed elements containing hemoglobin that are responsible for the transport of gases.

Monocytes

Agranulocytic mononuclear leukocytes that develop into macrophages to perform phagocytosis.

T-Lymphocytes (T-Cells)

Lymphocytes responsible for cell-mediated immunity.

B-Lymphocytes (B-Cells)

Lymphocytes responsible for humoral immunity.

Neutrophils

Granulocytic white blood cells characterized by a 3-lobed nucleus.

Basophils

Granulocytic white blood cells characterized by a 2-lobed nucleus.

Eosinophils

Granulocytic white blood cells characterized by an S-shaped nucleus.

Thrombocytes (Platelets)

Formed elements of the blood that participate in clotting and hemostasis.

Hemostasis

The cessation of blood flow involving vascular spasm and platelet plug formation.

Hemophilia

A condition characterized by abnormally slow blood clotting.

Type AB Blood

An ABO blood group possessing antigens A and B with no anti-A or anti-B antibodies; designated as the universal recipient.

Type O Blood

An ABO blood group possessing no A or B antigens and having both anti-A and anti-B antibodies; designated as the universal donor.

Lymph

A colorless fluid similar to plasma lacking red blood cells and fluid tissues, containing lymphocytes.

Lymph Nodes

Lymphatic structures populated with lymphocytes that filter lymph and trap pathogens.

Spleen

The largest lymphatic organ, located at the back of the stomach, that serves as a reservoir of blood.

Thymus Gland

A lymphatic organ responsible for the maturation of lymphocytes.

Peyer's Patches

Aggregated lymphoid tissue located within the intestine.

Innate (Natural) Immunity

A non-specific defense mechanism that serves as the body's first line of defense, including skin, fever, and inflammation.

Adaptive (Acquired) Immunity

Specific immune defense developed after exposure, involving antibodies and vaccines.

Active Immunity

Adaptive immunity where the body manufactures its own antibodies following an infection or vaccination.

Passive Immunity

Immunity acquired through receiving external antibodies, such as transfer from mother to baby or via injection.