Circulatory System

The Heart A muscular organ that pumps blood throughout your body. Four chambers: Atria (left/right): move the blood from the body into the heart. They pump the blood into the ventricles Ventricles(left/right): pump the blood out of the heart Left ventricle pumps the blood out to the body. Right ventricle pumps the blood to the lungs

The Heart Between the chambers are valves. Valves allow the blood to flow in only one direction “lub dub” is the opening and closing of the valves

Circulatory System The circulatory system is made up of blood vessels All your blood vessels lined up would be about 100 000 km

Types of Blood Vessels Arteries are blood vessels that carry blood away from your heart. Most carry oxygenated blood. Arteries are thick walled and elastic to handle the pressurized flow. The largest artery is the aorta. Arteries branch into arterioles, and finally capillaries. Capillaries are where gases and nutrients are exchanged with the cells

After leaving the capillaries, the blood is deoxygenated Blood is carried back to the heart through tiny venules and into the veins. Veins have valves that prevent the backflow of blood. Blood returns to the heart through the major veins; the superior vena cava, and the inferior vena cava.

Components of Blood Blood transports oxygen, nutrients, and water to your cells and carries carbon dioxide and wastes away from your cells. Blood also carries cells that fight infection and heal wounds. 55% of the 5L of blood is plasma. Plasma: water, proteins and minerals, dissolved salts. 45% of the 5L of blood are the Red blood cells, white blood cells, and platelets.

Red blood cells: carry oxygen and carbon dioxide. Formed in bone marrow, liver, and spleen. Hemoglobin carries the oxygen. White blood cells: fight infection. Much larger than RBC’s Platelets: help clot the blood by forming a scab.

Respiratory System When you breathe, you inhale oxygen and exhale carbon dioxide. Your lungs deliver the oxygen, and excrete carbon dioxide. Breathing brings the oxygen in, the air is filtered by cilia and mucus. Air travels down the pharynx and larynx (voice box), and then the trachea. At the base of the trachea are the bronchi, which branch into smaller tubes called bronchioles. Finally, the air reaches tiny sacs called alveoli.

Gas Exchange Alveoli are tiny, thin-walled sacs. Each alveolus is surrounded by capillaries. O2 diffuses out of the alveolus into the blood and binds with red blood cells, and CO2 diffuses into the alveolus.