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
6.2.2 State that the coronary arteries supply heart muscle with oxygen and nutrients
The coronary arteries supply oxygenated and nutrient filled blood to the heart. There are two main coronary arteries: 1) the right coronary artery (RCA) and 2) the left main coronary artery (left main trunk).
The right coronary artery divides itself into the 1) right marginal artery and 2) posterior descending artery. They are able to supply the 1) right atrium, 2) right ventricle, and 3) bottom portion of both ventricles and septum.
The left main coronary artery divides itself into the 1) circumflex artery and 2) left anterior descending (LAD) artery. The circumflex artery supplies blood not only to the left atrium but also to the left ventricle – both its side and back. The LAD artery supplies the left ventricle – front and bottom – and the septum´s front.
6.2.3 Explain the action of the heart in terms of collecting blood, pumping blood, and opening and closing of valves
The flow of blood is done so by two ways: 1) the pulmonary circulation through your heart´s right side or 2) the systematic circulation through your heart´s right side.
The pulmonary cirulation starts in both the superior and inferior vena cava and goes through the right atrium – where a volume of blood is collected. It then continues into the right ventricle and passes through the right atrioventricular valve. After that, the right atrium then contracts in order to force any remaining blood into the right ventricle. Once there is enough volume of blood in the right ventricle, it starts contracting. The contraction iniates the processes of 1) closing the atrioventricular valve to prevent blood from backflowing into the right atrium, 2) dramatically increasing the blood pressure inside the right ventricle leading to the opening of the right semilunar valve and allowing blood to enter the pulmonary artery, and 3) blood leaving the heart through the pulmonary artery due to its great increase in pressure.
The systematic cirulation starts in the pulmonary vein and goes through the left atrium – where a volume of blood is collected. It then continues into the left ventricle and passes through the left atrioventricular valve. After that, the left atrium contracts in order to force any remaining blood into the left ventricle. Once there is enough volume of blood in the left ventricle, it starts contracting. The contraction initiates the processes of 1) closing the atrioventricular valve to prevent blood from backflowing into the left atrium, 2) dramatically increasing the blood pressure inside the left ventricle leading to the opening of the left semilunar valve and allowing blood to enter the aorta, and 3) blood leaving the heart through the aorta due to its great increase in pressure.
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 adrenaline
Myogenic muscle contraction is when a heart muscle can contract by itself without the stimulation of a nerve. These contractions are initiated by the pacemaker everytime it sends a signal. While one nerve carries messages from the medulla of the brain to the pacemaker and speeds up the beating of the heart; the other nerve carries messages from the medullla of the brain to the pacemaker and slows down the beating of the heart. The adrenaline is then carried by the blood and reaches the pacemaker, signaling it to increase the beating of the heart.
6.2.5 Explain the relationship between the structure and function of arteries, capillaries and veins
Arteries: 1) have thick wall and elastic fibers to withstand high pressures, 2) narrow lumen to maintain high pressure, and3) thick layers of circular elastic fibers and muscle fibers to pump blood.
Veins: 1) wide lumen to facilitate blood flow, 2) thin outer layer of longitudinal collagen and elastic fibers as pressure is low, 3) valves to prevent backflow between pulses, and 4) thin walls so that nearby muscles can help push blood towards the heart.
Capillaries: 1) small lumen so that various can fit in one place, 2) wall is one cell layer thick in order for diffusion´s distance to be small, and 3) no valves since pressure is low.
6.2.6 State that blood is composed of plasma, erythrocytes, leucocytes (phagocytes and lymphocytes) and platelets
Erythrocytes are red blood cells that cotain hemoglobin. They allow efficient transportation of oxygen and carbon dioxide in the body despite not having a nucleus and living only for 100 days.
Leucocytes are white blood cells present in the bloodstream that can identify and eliminate threats to the body once they are inside the circulatory system by phagocytosis.
Platelets are small, colorless cells that last an average of 4 days and lack a nucleus because they play an important but integral role in blood clotting.
6.2.7 State that the following are transported by the blood: nutrients, oxygen, carbon dioxide, hormones, antibodies, urea and heat
Nutrients are transported by glucose and amino acids. Oxygen is the reactant needed for aerobic cell respiartion. Carbon dioxide is a waste product of aerobic cell respiration. Hormones are transported from gland to target cells. Antibodies are protein molecules involved in immunity. Urea is a nitrogenous waste filtered out of the blood by kidneys. Heat are skin arterioles that can change diameter in order to lose or gain heat.