| A | B |
|---|
| circulatory system | body system that transports nutrients and wastes between various body tissues; includes heart, blood, and blood vessels |
| respiratory system | body system that brings oxygen into the body and removes carbon dioxide; includes the nose, trachea, and lungs |
| trachea | long structure made of soft tissue that connects the mouth and nose to the lungs (plural: tracheae) |
| lung | organ that absorbs oxygen gas from air that an organism inhales |
| alveoli | tiny, thin-walled structure across which oxygen gas is absorbed and carbon dioxide is released in the lungs (singluar: alveolus) |
| diaphragm | thin muscle below the rib cage that controls the flow of air into and out of the lungs |
| heart | muscle in the chest that moves blood throughout the body |
| artery | large blood vessel that carries blood away from the heart |
| vein | large blood vessel that carries blood from the rest of the body to the heart |
| capillary | tiny blood vessel that transports blood between larger blood vessels and other tissues in the body |
| red blood cell | cell that carries oxygen gas from the lungs to the rest of the body |
| hemoglobin | iron-rich protein in red blood cells that allows the cell to absorb oxygen gas |
| emphysema | condition in the lungs in which the surface area of alveoli decreases, making breathing difficult |
| asthma | condition in which air pathways in the lungs constrict, making breathing difficult |
| atrium | small chamber in the human heart that receives blood from the veins (plural: atria) |
| ventricle | large chamber in the heart that receives blood from an atrium and pumps blood to the rest of the body |
| valve | flap of tissue that prevents blood from flowing backward into a blood vessel or heart chamber |
| pacemaker | collection of cells that stimulates the pumping action of the heart |
| pulmonary circulation | collection of blood vessels that carries blood between the lungs and heart |
| systemic circulation | collection of blood vessels that carries blood between the heart and the rest of the body, except for the lungs |
| blood pressure | force with which blood pushes against the wall of an artery |
| systolic pressure | measure of pressure on the walls of an artery when the left ventricle contracts to pump blood through the body |
| diastolic pressure | pressure in an artery when the left ventricle relaxes |
| platelet | cell fragment that is produced in the bone marrow and is important for blood clotting |
| plasma | clear yellowish fluid, about 90 percent water, that suspends cells in the blood |
| ABO blood group | four common blood types (A, B, AB, and O) and the protein markers that distinguish them |
| Rh factor | surface protein on red blood cells in the ABO blood group; people can be Rh+ or Rh- |
| white blood cells | cell that attacks pathogens |
| lymphatic system | body system that consists of organs, vessels, and nodes through which lymph circulates |
| lymph | collection of interstitial fluid and white blood cells that flows through the lymphatic system |
| node | organ located along the lymphatic vessels that filters bacteria and foreign particles from lymph |
| lymphocyte | white blood cell that plays a role in an immune response |
