Circulatory System (Blood Vascular and Lymphatic Systems) - ICSE Biology 8

Vocabulary flashcards covering key terms related to the circulatory and lymphatic systems, including heart anatomy, blood vessels, cardiac physiology, and blood group concepts.

Circulatory System

System that distributes oxygen, nutrients, and wastes; consists of the blood vascular system and the lymphatic system.

Blood Vascular System

The part of the circulatory system consisting of the heart, blood vessels, and blood that circulates blood.

Lymphatic System

Network of lymph, lymph vessels, and lymph nodes; returns tissue fluid to blood and defends against pathogens.

Heart

Muscular pumping organ about the size of a fist; lies between the lungs; pumps blood through vessels.

Pericardium

Double-layered sac enclosing the heart; contains pericardial fluid to reduce friction.

Atria

Receiving chambers of the heart with thinner walls than the ventricles.

Ventricles

Lower chambers that pump blood; right ventricle to the lungs, left ventricle to the body.

Interventricular septum

Muscular wall that separates the right and left ventricles.

Tricuspid valve

Right atrioventricular valve; prevents backflow from ventricle to right atrium.

Bicuspid/Mitral valve

Left atrioventricular valve; prevents backflow from ventricle to left atrium.

Semilunar valves

Valves at the bases of the aorta and pulmonary artery; prevent backflow into the ventricles.

Aorta

Largest artery; carries oxygenated blood from the left ventricle to the body.

Pulmonary artery

Carries deoxygenated blood from the right ventricle to the lungs for oxygenation.

Pulmonary veins

Carry oxygenated blood from the lungs to the left atrium; the only veins carrying oxygenated blood.

Superior vena cava

Vein that returns deoxygenated blood from head and upper body to the right atrium.

Inferior vena cava

Vein that returns deoxygenated blood from the lower body to the right atrium.

Coronary arteries

Arteries arising from the aorta that supply oxygen to the heart muscles.

Coronary veins

Veins that drain blood from the heart muscle into the right atrium (via the coronary sinus).

Double circulation

Two separate circulations (pulmonary and systemic) in which blood passes through the heart twice per cycle.

Pulmonary circulation

Circulation of blood between the heart and lungs; deoxygenated blood to lungs, oxygenated blood back to heart.

Systemic circulation

Circulation of oxygenated blood from the left ventricle to the body and back to the right atrium.

Cardiac cycle

One heartbeat sequence: atrial systole, ventricular systole, diastole; about 0.8 second.

Systole

Contraction phase of the heart; ventricles contract to pump blood into arteries.

Diastole

Relaxation phase of the heart; chambers fill with blood.

Heart sounds

Lub-dub sounds produced by closure of heart valves during the cardiac cycle.

Sino-atrial node (SA node)

Natural pacemaker of the heart; initiates heartbeat and sets rhythm in the right atrium.

Atrioventricular node (AV node)

Receives impulses from the SA node and passes them to the ventricles via the Bundle of His.

Bundle of His

Conduction pathway from AV node to ventricles through the septum.

Purkinje fibers

Fibers that distribute the electrical impulse through the ventricles to cause contraction.

Arteries

Blood vessels that carry blood away from the heart; thick, elastic, muscular walls; usually carry oxygenated blood.

Veins

Blood vessels that carry blood toward the heart; have valves to prevent backflow; carry deoxygenated blood (except pulmonary veins).

Capillaries

Tiny one-cell-thick blood vessels where exchange of gases, nutrients, and wastes occurs between blood and tissues.

Blood

Fluid that transports substances; consists of plasma, red blood cells, white blood cells, and platelets.

ABO blood groups

Blood groups A, B, AB, and O determined by antigens on RBCs and antibodies in plasma.

Antigen

Molecule (often a glycoprotein) that triggers an immune response; A and B are antigens on RBCs in ABO system.

Antibody

Proteins in plasma that bind specific antigens (e.g., anti-A, anti-B) in the ABO system.

Clumping reaction

Agglutination of RBCs due to incompatible antigen-antibody interaction during transfusion.

Blood transfusion

Transfer of blood from a donor to a recipient; requires compatibility between donor and recipient.

Donor

Person who gives blood during a transfusion.

Recipient

Person who receives blood during a transfusion.

Universal donor

Blood type O (no antigens) can be given to any blood group, but can receive only type O.

Universal recipient

Blood type AB (no anti-A or anti-B antibodies) can receive from any ABO group.

Lymph

Clear fluid that circulates in the lymphatic system; drains from tissue spaces and returns to blood.

Lymph vessels

Vessels that carry lymph; start as lymphatic capillaries and drain into larger ducts, returning lymph to blood.

Lymph nodes

Structures that filter lymph and are sites of lymphocytes; part of immune defense.