Our lives hang on a thread. A constant flow of blood must reach cells throughout the body, delivering oxygen, while removing carbon dioxide. If the flow stop, we will die. We are walking miracles!
Quote of the Day: “I [God] will give you a new heart and put a new spirit within you; I will take the heart of stone out of your flesh and give you a heart of flesh” (Ezekiel 36:26).
cardiovasculary system, atria, pulmonary, aorta, sedentary, ventricle
Your heart and circulatory system;
The Cardiovascular System: Your heart is located between your lungs in the middle of your chest, slightly to the left of your sternum. A sac called the pericardium surrounds your heart protecting it and keeping it in place.
Your heart has four chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart.
Your heart works as a pump that pushes blood to the organs, tissues, and cells of your body. Blood delivers oxygen and nutrients to every cell and removes the carbon dioxide and waste products made by those cells. Blood is carried from your heart to the rest of your body through a complex network of arteries, arterioles, and capillaries. Blood is returned to your heart through venules and veins.
Arteries carry oxygen-rich blood away from your heart, and veins carry oxygen-poor blood back to your heart. The pulmonary artery brings oxygen-poor blood into your lungs and the pulmonary vein brings oxygen-rich blood back to your heart. Arterioles further branch into capillaries, the true deliverers of oxygen and nutrients to your cells. Most capillaries are thinner than a hair. In fact, many are so tiny, only one blood cell can move through them at a time. Once the capillaries deliver oxygen and nutrients and pick up carbon dioxide and other waste, they move the blood back through wider vessels called venules. Venules eventually join to form veins, which deliver the blood back to your heart to pick up oxygen.
Four types of valves regulate blood flow through your heart:
- The tricuspid valve regulates blood flow between the right atrium and right ventricle.
- The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries, which carry blood to your lungs to pick up oxygen.
- The mitral valve lets oxygen-rich blood from your lungs pass from the left atrium into the left ventricle.
- The aortic valve opens the way for oxygen-rich blood to pass from the left ventricle into the aorta, your body's largest artery, where it is delivered to the rest of your body.
Discovering The Heart:
What are the top two chambers of the heart?
What are the bottom two chambers of the heart?
What are the veins leading from the lungs into the heart called?
What is the artery leading from the heart to the lungs called?
What is the main artery that takes blood out of the heart to the body?
What are the names of the two veins that bring deoxygenated blood from the tissues of the body back to the heart?
Try This: build a model of the heart
Materials: 2 grahams crackers, 6 large marshmallows, 20 small marshmallows, 7 toothpicks, red & blue paint
Using one square graham cracker for each chamber, paint/frost the right atrium and ventricle blue and then paint/frost the left atrium and ventricle red. Add thepulmonary veins to the heart model. Push some small marshmallows onto a toothpick and paint them red, Place them so they attach to the left atrium. They should be red because they come from the lungs and are full of oxgenated blood. These four pulmonary veins lead into the backside of the heart, directl ino the left atrium. Add an aorta to the modeal. Put three large mashmallows on a toothpick and paint them red. The marshmallow aorta will exit from the bottom of the heart. Put large marshmallows on a toothpick and paint them blue. Add this vein to the upper blue graham cracker to symbolize deoxgenated blood flowing from the inferior and superior vewna cava. Put large marshmallows on another toothpick and paint them blue. Add thi sartery to the bottom blue graham cracker to represent the pulmonary arteries leading away from the right ventricle.