Explore

06. Human Circulatory System

Key Terms

Prepared by: learnloophq@gmail.com

Last edited 25 days ago by Learn LoopHQ.

Chapter: 06. Human Circulatory System

⁠

Circulatory system: The transport system in our body that provides body cells with food and oxygen and removes waste products.

Blood: A red-coloured viscous fluid that flows in blood vessels and reaches every cell of the body.

Plasma: The liquid, yellowish part of blood that makes up more than half of blood volume and contains dissolved substances.

Blood corpuscles / Blood cells: The three kinds of cells found in blood: Red blood corpuscles (RBCs), white blood corpuscles (WBCs), and blood platelets.

Red blood corpuscles (RBCs) / Erythrocytes: The most numerous blood cells, without a nucleus, containing haemoglobin for oxygen transport.

Haemoglobin: The oxygen-carrying red pigment in RBCs that gives blood its red colour.

Oxyhaemoglobin: The compound formed when haemoglobin combines with oxygen, transporting oxygen to body cells.

White blood corpuscles (WBCs) / Leucocytes: Colourless blood cells with a nucleus that defend the body against diseases and provide immunity.

Blood platelets / Thrombocytes: Minute cell fragments in blood that help to stop bleeding by clotting the blood.

Blood vessels: A system of tubes through which blood flows to connect all parts of the body.

Arteries: Distributing blood vessels that carry blood away from the heart to other parts of the body, usually oxygenated.

Pulmonary arteries: The arteries that carry deoxygenated blood from the heart to the lungs.

Aorta: The largest artery in the body, which distributes oxygenated blood from the heart to all body parts.

Arterioles: Smaller vessels formed when arteries divide, which further divide into fine capillaries.

Veins: Collecting blood vessels that bring blood from body organs to the heart, usually deoxygenated.

Pulmonary veins: The veins that carry oxygenated blood from the lungs to the heart.

Vena cava: The largest vein in the body, which brings deoxygenated blood from the body to the heart.

Capillaries: The finest blood vessels, one cell thick, that connect arteries and veins and facilitate the exchange of substances.

Heart: A muscular organ located in the chest cavity that acts as a living pump for our body.

Cardiac muscles: Specialized muscles that form the walls of the heart and contract and relax tirelessly.

Auricles / Atria: The upper two receiving chambers of the heart, with thin walls.

Ventricles: The lower two distributing chambers of the heart, with thicker walls, that pump blood into blood vessels.

Tricuspid valve: The valve located between the right auricle and right ventricle, preventing the backflow of blood.

Bicuspid valve (Mitral valve): The valve located between the left auricle and left ventricle, preventing the backflow of blood.

Semilunar valves: Half-moon-shaped valves located between ventricles and the great arteries (aorta and pulmonary aorta), preventing backflow of blood.

Heartbeat: The rhythmic contraction and relaxation of the auricles and ventricles.

Heartbeat rate: The number of heartbeats in one minute, typically 72 times per minute for a normal human.

Systole: The phase of contraction of the heart muscles when the heart pumps blood into blood vessels.

Diastole: The phase of relaxation of the heart muscles when the heart receives blood.

Cardiac cycle: The events (systole and diastole) that occur during one heartbeat, completed in 0.8 seconds.

Blood pressure: The pressure exerted by blood on the wall of arteries.

Sphygmomanometer: The instrument used to measure blood pressure.

Systolic pressure: The highest blood pressure exerted when ventricles contract and pump blood into arteries (normal ~120 mm Hg).

Diastolic pressure: The lowest blood pressure exerted when ventricles relax (normal ~80 mm Hg).

Pulse: The rhythmic jerks felt in arteries due to the rhythmic contraction of the heart.

Pulse rate: The number of pulses felt in one minute, equal to the heartbeat rate.

Antigens: Special types of proteins found on the surface of RBCs that determine blood groups.

Antibodies: Special types of proteins found in blood plasma that react against specific antigens.

ABO system of blood groups: A classification system of human blood into A, B, AB, and O based on the presence or absence of specific antigens.

Blood group A: Blood group characterized by the presence of Antigen A on RBCs and Anti-B antibody in plasma.

Blood group B: Blood group characterized by the presence of Antigen B on RBCs and Anti-A antibody in plasma.

Blood group AB: Blood group characterized by the presence of both Antigens A and B on RBCs and no antibodies in plasma.

Blood group O: Blood group characterized by the absence of both antigens on RBCs and the presence of both Anti-A and Anti-B antibodies in plasma.

Anti-A antibody: An antibody in plasma that reacts against Antigen A.

Anti-B antibody: An antibody in plasma that reacts against Antigen B.

Clumping reaction: The formation of lumps when incompatible antigens and antibodies interact in mixed blood.

Blood transfusion: The transfer of blood from one person (donor) to another (recipient).

Donor: A person who gives blood during a blood transfusion.

Recipient / Acceptor: A person who receives blood during a blood transfusion.

Universal recipients: Persons with blood group AB who can receive blood from all four blood groups because they have no antibodies.

Universal donors: Persons with blood group O who can donate blood to any blood group because their RBCs have no antigens.

Blood bank: A centre where blood collected from donors is stored and preserved for later use after testing.

Enucleated: A term meaning “without nucleus,” describing mature mammalian red blood cells.

Radial artery: The artery passing over the radius bone of the arm, where the pulse is commonly felt.

Stethoscope: An instrument used by doctors to listen to internal body sounds, especially heartbeats.

Want to print your doc?
This is not the way.

Try clicking the ⋯ next to your doc name or using a keyboard shortcut (

CtrlP

) instead.