6.2 The Transport System Readings Pg 216, 2-4

6.2.1 Draw and label a diagram of the heart showing the four chambers, associated blood vessels, valves and the route of blood through the heart. Right ventricle  lungs  left atrium  left ventricle  body tissues  right atrium  Heart valves dictate a one-way flow of blood through the heart Blood begins its flow with the right ventricle pumping blood to the lungs In the lungs, the blood loads O 2 and unloads CO 2 Oxygen-rich blood from the lungs enters the heart at the left atrium and is pumped to the body tissues by the left ventricle Blood returns to the heart through the right atrium

Anterior vena cava Pulmonary artery Capillaries of right lung Aorta Pulmonary vein Right atrium Right ventricle Posterior vena cava Capillaries of abdominal organs and hind limbs Pulmonary vein Left ventricle Left atrium Aorta Pulmonary artery Capillaries of head and forelimbs Capillaries of left lung

Right atrium Posterior vena cava Pulmonary veins Anterior vena cava Pulmonary artery Pulmonary veins Right ventricle Aorta Semilunar valve Atrioventricular valve Pulmonary artery Left atrium Semilunar valve Atrioventricular valve Left ventricle

6.2.2 State that the coronary arteries supply heart muscle with oxygen and nutrients.

6.2.3 Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves. The heart contracts and relaxes in a rhythmic cycle called the cardiac cycle The contraction, or pumping, phase is called systole The relaxation, or filling, phase is called diastole The heart rate, also called the pulse, is the number of beats per minute The cardiac output is the volume of blood pumped into the systemic circulation per minute

6.2.4 Outline the control of the heartbeat in terms of myogenic muscle contraction, the role of the pacemaker, nerves, the medulla of the brain and epinephrine (adrenaline). Myogenic? –Muscle that stimulates itself inside the heart, independent from the brain. The sinoatrial (SA) node, or pacemaker, sets the rate and timing at which cardiac muscle cells contract The pacemaker is influenced by nerves, hormones, body temperature, and exercise Impulses from the SA node travel to the atrioventricular (AV) node Epinephrine? –From the adrenal gland, where is the adrenal gland located? Above the kidneys –Increases cardiac rate

Pacemaker generates wave of signals to contract. Signals are delayed at AV node. Signals pass to heart apex. Signals spread throughout ventricles. SA node (pacemaker) ECG AV node Bundle branches Heart apex Purkinje fibers

6.2.5 Explain the relationship between the structure and function of arteries, capillaries and veins. The “infrastructure” of the circulatory system is its network of blood vessels All blood vessels are built of similar tissues Arteries have thicker walls that accommodate the high pressure of blood pumped from the heart In the thinner-walled veins, blood flows back to the heart mainly as a result of muscle action

Endothelium Smooth muscle Connective tissue Capillary 100 µm Basement membrane Endothelium Smooth muscle Connective tissue Valve Artery Arteriole Venule Vein Artery Vein

6.2.6 State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets. Blood is a solid or liquid? –connective tissue Blood plasma is about 90% water Suspended in blood plasma are two types of cells: –Red blood cells (erythrocytes) transport oxygen, make up the majority of cells in the system –White blood cells (leukocytes) function in defense Phagocytes (phagocytosis) Lymphocytes fight off specific antigens Platelets, a third cellular element, are fragments of cells that are involved in clotting A fun note! –Erythrocytes, leukocytes, and platelets all develop from a common source, stem cells in the red marrow of bones

erythrocytes leukocytes Phagocytes Lymphocytes Platelets

6.2.7 State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat. All the items listed above are transported by the blood in the circulatory system…but What item in blood transports the oxygen and carbon dioxide? –Red blood cells (erythrocytes)