The Circulatory System

1. The Circulatory System Gaiser Life Science

2. Know What do you know about the circulatory System? “I don’t know anything.” is not an acceptable answer. Use complete sentences. Evidence After listening to the PowerPoint lecture, come back here and list evidence to explain why your answer to the above question is or is not a good answer. You may also use other outside sources to help you respond. Page 81

3. Circulatory System Functions Information Clarifying ?s 1. Transports and delivers necessary materials to muscles and organs Examples: Vitamins, minerals, nutrients, oxygen 2. Expels waste Examples: carbon dioxide, ammonia, lactic acid, and others 3. Carries red and white blood cells through the body; White blood cells help the body fight infections and red blood cells store oxygen. The heart It is a hollow organ made mostly of muscle that pumps blood through the body. It is about the size of your fist. Blood can only go one direction through the heart. Heart Structure The heart has four hollow cavities called chambers. These can be divided into the two upper chambers called atria and two lower chambers called ventricles. They can then be divided into left and right sides. The left and right sides are not connected and entirely separated by a wall of muscle. The ventricles are connected by passageways to the atria. These passageways are blocked by one way valves, which allow blood to only flow from the atria to the ventricles. Page 82

4. Circulatory System How the heart works Information Clarifying ?s FYI: All warm blooded vertebrates (Birds and mammals) have four chambered hearts. All cold blooded vertebrates (except crocodilians) have three chambered hearts. Fish have 2 chambered hearts Since the heart and circulatory system is a closed repeating pathway, it’s hard to say where it all starts. Let’s start with the noise it makes - Lub-Dub. Phase 1: The tricuspid and mitral (or bicuspid) valves close making a sustained “Lub” sound. This begins the high pressure stage when the blood is pumped out of the Ventricles. The right ventricle pumps oxygen depleted blood to the lungs. The left ventricle pumps oxygen enriched blood to the head and body. Phase 2: The semilunar (or aortic) and pulmonary valves close making a shorter “Dub” sound. This begins the low pressure stage when the atria pump blood into the ventricles as they relax and dilate. The right atrium receives oxygen depleted blood from the head and body. The left atrium receives oxygen enriched blood from the lungs. Then it all starts over again, and again, and again, and again ……. Page 82

5. Circulatory System Information Clarifying ?s - Properly called the sinoatrial node, it regulates the beating of the heart. It’s located in the right atrium. It works together with the atrio-ventricular node, located at the junction of the four chambers, to control heart rate. Pacemaker Arteries - blood vessels that carry blood away from the heart. Blood is under greater pressure in the arteries - wounds spurt blood. Blood in arteries is bright red. Veins - blood vessels that carry blood toward the heart. There is less pressure in the veins - wounds ooze blood. Blood in veins is bluish because of carbon-dioxide content. - tiny vessels where necessary substances are exchanged between the blood and body cells Capillaries - Anywhere the arteries pass close to the skin, there is a pulse, which replicates the steady beat of the heart. Pulse Examples: wrist, neck, temple, behind the knees Blood Pressure 2 levels: high pressure or systolic when the ventricles contract and low pressure or diastolic when the ventricles relax and dilate. Blood pressure readings are taken with a sphygmomanometer. Page 82

6. Circulatory System Information Clarifying ?s The blood follows a pathway from the heart to the biggest artery in the body - the aorta, to smaller arteries, and finally to the tiniest capillaries. Along this pathway, the blood does many things: 1. When the blood passes through the kidneys, wastes are filtered out of the blood 2. When the blood flows through the liver, toxins such and medicine, alcohol, and chemicals are filtered out of the blood. 3. When the blood flows the the organs, muscles and other parts of the body, nutrients and oxygen are delivered and wastes are picked up. 4. When the blood flows through the lungs, carbon dioxide is left behind and oxygen is absorbed. The pathway continues. From the tiny capillaries, the blood goes through the smaller veins, then through the largest vein in the body - the superior vena-cava, and back into the heart again. Summary: Page 82

8. This PowerPoint was created by Tim Paterek. All pictures came from Google Image Search. To fall within the Fair Use Guidelines, this PowerPoint must be used within the confines of the classroom and may not be published back onto the Internet unless the pictures are removed.