thick middle muscle layer of the heart
upper chamber of the heart that receives blood from the rest of the body
lower chamber of the heart that pumps blood out of the heart to the rest of the body
flap of connective tissue located between an atrium and a ventricle, or in a vein, that prevents back flow of blood
path of circulation between the heart and lungs
path of circulation between the heart and the rest of the body
small group of cardiac muscle fibers that maintains the heart's pumping rhythm by setting the rate at which the heart contracts the sinoatrial (SA) node
large blood vessel that carries blood away from the heart to the tissues of the body
blood vessel that carries blood from the body back to the heart
4 Things that the Circulatory System Does
1. Transports oxygen
2. Transports nutrients
3. Transports other substances throughout the body
4. Removes wastes from tissues
Which arteries are the only ones that carry oxygen-poor blood?
thick elastic walls; 3 layers of tissue (connective tissue, smooth muscle, and endothelium); carry oxygen-rich blood
smallest blood vessels; so narrow that blood cells pass through single file; allow gas exchange
located near/between skeletal muscles; contain valves; move blood towards the heart
a wave of fluid pressure in the arteries when the heart contracts
the force in the arteries when the ventricles contract; pressure when heart beats; top number
the force in the arteries when the ventricles relax; pressure when heart rests; bottom number
straw-colored liquid portion of the blood
red blood cell (erythrocyte)
blood cell containing hemoglobin that carries oxygen; most numerous blood cell; made in bone marrow; live 120 days; filtered out by liver and spleen
iron-containing protein in red blood cells that binds oxygen and transports it to the body
white blood cell (leukocyte)
type f blood cell that guards against infection, fights parasites, and attacks bacteria; may live for years; engulf invaders; produce antibodies; release chemicals against infection
cell fragment released by bone marrow that helps in blood clotting; made in bone marrow; live 5-9 days
fluid that is filtered out of the blood
condition in which fatty deposits called plaque build up inside artery walls and eventually cause the arteries to stiffen
What happens to platelets when the come in contact with broken blood vessels?
they become sticky and cluster around the wound; they release clotting factors (proteins) that start reactions
Describe the 3-Step Process of Blood Clotting
1. Capillary Wall Breaks: a blood vessel is injured by a cut or scrape
2. Platelets Take Action: platelets clump at the site and release the clotting factor thromboplastin, which triggers a series of reactions; thromboplastin converts the protein prothrombin into the enzyme thrombin
3. Clot Forms: thrombin converts the soluble plasma protein fibrinogen into insoluble, sticky fibrin filaments, which from the clot; the clot seals the damaged area and prevents further loss of blood
3 Roles of the Lymphatic System
2. Nutrient Absorption
Where does lymph collect?
in a system of lymphatic capillaries that become large lymph vessels
Is lymph pumped?
no; vessels have valves that prevent lymph from back flow
What is the purpose of the ducts in the lymphatic system?
return lymph to blood through openings in subclavian veins below shoulders
What do lymph vessels pick up alongside the intestines? Where do they transport these nutrients to?
fats and fat-soluble vitamins from the digestive tract; the bloodstream
What do lymph nodes do?
filters that trap microorganisms, stray cancer cells, and debris as lymph flows through them; white blood cells in lymph nodes engulf/destroy cellular "trash"
What are the roles of the thymus and spleen in the lymphatic system?
T lymphocytes mature in thymus to function in the immune system; spleen filters blood and removes old/damaged blood cells and stores platelets
specific, y-shaped molecules; receptors fit antigens on invader
small dose of infection is given to the body to produce antibodies and prevent the disease from affecting the person again
additional dose of an immunizing agegiven at a time period of weeks to years after the initial dose to sustain the immune response elicited by the first dose