Circulatory system

Learning objectives 1.Identify the main functions of the circulatory system. 2.Diagram the flow of blood through the heart and body. 3.Compare and contrast the major components of the blood.

Circulatory function Blood carries oxygen and nutrients to the cells. Blood carries carbon dioxide away from the cell. The circulatory system circulates important cells that are part of the immune system. The circulatory system distributes heat throughout the body.

Blood vessels Arteries carry oxygen-rich blood away from the heart. Veins carry blood back to the heart. Capillaries are microscopic blood vessels that are involved in exchange.

Diagram of the heart

Heart mechanics The heart is a muscle and movement alternates between contraction and relaxation. Heart beat is controlled by a group of cells called the pacemaker. Blood pressure measures the pressure exerted against the blood vessel walls during contraction (sistole), and when the muscles relax (diastole).

Blood flow diagram

Blood components Blood is made up of plasma (water mostly), red blood cells (hemoglobin on surface), platelets (involved in clotting), and white blood cells (fight infection).

Blood types There are 4 human blood types – A, B, AB, and O. Blood type is inherited – multiple alleles.

How does oxygen get into cells? Diffuses out of capillaries and across cell membrane. oylEshttp:// oylEs

Open response 1.Connects to pulmonary artery – to pick up oxygen and dump CO 2 in the lungs. 2.Superior/inferior vena cava – return of blood to the heart to complete the circuit. 3.Speed variation for exercise and rest – deliver more O 2 to cells when exercising to produce more ATP when needed.

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