TOPIC 3: CIRCULATION :TOPIC 3: CIRCULATION Mr. Tony Dura Year 9 2008-2009


1. THE BODY’S TRANSPORT SYSTEM :1. THE BODY’S TRANSPORT SYSTEM The cardiovascular system, also called the circulatory system, consists of the heart, blood vessels and blood. Functions: Delivering needed materials (O2, glucose…) Removing waste products (CO2) Fighting disease (it transports cells that attack disease-causing microorganisms)


The Heart :The Heart Is the hollow, muscular organ that pumps blood throughout the body. Size of your fist Located in the center of your chest, behind the sternum and inside the rib cage Each time it beats, it pushes blood through the blood vessels of the cardiovascular system.


Slide 5:4 chambers (or compartments): 2 upper chambers (receive blood) Left Atrium Right Atrium 2 lower chambers (pump blood out) Left Ventricle Right Ventricle The chambers are separated by a wall of tissue called the septum Atria and ventricles are separated by valves. A valve is a flap of tissue that prevents blood from flowing backward


Lub :Lub If you listen to your heartbeat, it makes a lub dub sound. The lub is when blood is pushed out of the heart into the body and the dub is the reloading of the heart with more blood ready to push it out to the body Dub


Slide 8:The contraction of the left ventricle exerts much more force (to the lungs) than the right one (throughout the body) A group of heart cells called the pacemaker sends out signals that make the heart muscle contract, according to the oxygen requirement. It is located in the right atrium In the 1950s doctorns and engineers developed an artificial, battery-operated pacemaker


Two Loops :Two Loops After leaving the heart, blood ravel in blood vessels through the body Arteries: blood away from the heart Capillaries: tiny narrow vessels, where the blood flows into Veins: blood back to the heart 1st loop: (right side of the heart) blood from heart lungs  heart 2nd loop: (left side of the heart) blood from heart  body  heart


Slide 11:Our circulatory system is a double circulatory system. This means it has two parts parts. the right side of the system deals with deoxygenated blood. the left side of the system deals with oxygenated blood.


Slide 12:How does the Heart work? blood from the body blood from the lungs The heart beat begins when the heart muscles relax and blood flows into the atria. STEP ONE


Slide 13:The atria then contract and the valves open to allow blood into the ventricles. STEP TWO


Slide 14:The valves close to stop blood flowing backwards. The ventricles contract forcing the blood to leave the heart. At the same time, the atria are relaxing and once again filling with blood. The cycle then repeats itself. STEP THREE


Slide 15:http://es.youtube.com/watch?v=xagOnC6sZEU Systemiccirculation Systemiccirculation


2. A closer look at blood vessels :2. A closer look at blood vessels Some of them are as wide as your thumb, but most of them finer than a human hair. If all of them were hooked together, you could wrap the earth more than twice. ARTERIES CAPILLARIES VEINS


ARTERIES :ARTERIES When blood leaves the heart, it travels through arteries. RV pumps blood  arteries  lungs LV  aorta (Artery)  branch into smaller arteries (i.e.: coronary arteries)  heart itself, brain, intestine… Structure Thick walls, made up of 3 layers Innermost  epithelial cells, smooth (blood flows easily) Middle layer  muscle tissue Outer wall  connective tissue


Slide 18:The expansion and relaxation of the artery wall causes the pulse. (movement of the spurt of blood pushes and expands the wall) The layer of muscle in an artery acts as a control gate, adjusting the amount of blood sent to different organs (I.e.: eating or running)


Capillaries :Capillaries Blood flows from small arteries into the tiny capillaries. In there, materials are exchanged between the blood and the body’s cells. They are only one cell thick. Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration. I.e.: glucose


Veins :Veins After blood moves through capillaries, it enters larger blood vessels called veins, which carry blood back to the heart. Veins are made up of three layers, with muscle in the middle layer, but walls much thinner than arteries. Movement (pushing force of the heart dicreases) Contraction of muscles helps push the blood along Veins contain valves to prevent blood from flowing backward. Breathing movements force blood toward the heart


Bloodvessels :Bloodvessels Veins Arteries Capillaries


Blood Pressure :Blood Pressure Blood exerts a force, called blood pressure, against the walls of blood vessels (I.e.: hose/faucet) It is caused by the force with which the ventricles contract We measure it with a sphygmomanometer. Healthy person is 120/80 or lower.


3. BLOOD AND LYMPH :3. BLOOD AND LYMPH Blood is a complex tissue that has several parts. Average human 5 liters It is made up of: Plasma Red blood cells White blood cells Platelets 45% of the blood is cells, the rest 55% is plasma


Slide 27:PLASMA (55%) RED BLOOD CELLS (5 or 6 million per ml) WHITE BLOOD CELLS (5000 per ml) PLATELETS


PLASMA :PLASMA Liquid part of the blood 90% water and 10% dissolved materials: Glucose Fats Vitamins and minerals Chemical messengers Wastes Proteins give plasma this yellow color Types of proteins: Regulate water in blood Help fight desease Interact with platelets to form blood clots


RED BLOOD CELLS :RED BLOOD CELLS Take up O2 in the lungs and deliver it to cells elsewhere in the body Produced in bone marrow Look like disks with pinched-in centers. They can bend and twist easily, enable them to squezze through narrow capillaries. Made mostly of hemoglobin (Fe protein that binds chemically to O2 molecules) They can pick up CO2, but its a plasma job Matture RBC no nucle. They live 120 days


WHITE BLOOD CELLS :WHITE BLOOD CELLS Produced in the bone marrow Body´s disease fighters Some recognize invaders, other produce chemicals to fight them and other surround and kill the organisms. Fewer than RBC (1 each 500 or 1000 ) Larger, contain nuclei and live for months or years


PLATELETS :PLATELETS Cell fragments that play an imporatant part in forming blood clots Form “scabs” when you cut yourself Helps stop the bleeding Platelets produce tiny fibrin (protein) threads These form a web-like mesh that traps blood cells.


BLOOD TYPES :BLOOD TYPES Blood transfusion is the transfer of blood from one person to another There are four major types of blood, determined by proteins knwon as markers found in the RBC: 1. A 2. B 3. AB 4. 0


Slide 33:Cross matching: doctors check first your blood type and then blood that you can safely receive, will be found Rh factor, is another protein on the RBC. If you have it, you are positive, if not, you are negative.


THE LYMPHATIC SYSTEM :THE LYMPHATIC SYSTEM It is a network of veinlike vessels that returns the fluid to the bloodstream (I.e.: rain gutters after a rainstorm, carrying excess fluid away) Lymph consists of water and dissolved materials such as glucose and WBC Lymph moves slowly (no pumps) Lymph nodes filter lymph, trapping bacteria and other microorganisms in the fluid. When body fights and infection, the nodes enlarge.


4. CARDIOVASCULAR HEALTH :4. CARDIOVASCULAR HEALTH Cardiovascular disease is the leading cause of death in most of the countries. They include: Atherosclerosis: a condition in which an artery wall thickens as a result of the buildup of fatty materials (cholesterol) If it happens in the coronary arteries, it may lead to a heart attack (blood does not reach part of the heart and kill it) Treatment includes low fat diet and moderate exercise. Medications or surgery for severe cases.


Slide 38:Hypertension or high blood pressure is a disorder in which a person´s blood pressure is consistently higher than normal (greater than 140/90) Heart works harder to pump blood It is called the “silent killer”, because people have no obvious symptoms. Relate with atherosclesis, as the arteries narrow, blood pressure increases. Reduce intake of Na, which can increase blood pressure (found in salt, noodles, soups, snack foods...)


Keeping healthy :Keeping healthy Exercise regularly Eat a balanced diet low in: Saturated fats (butter, whole milk and ice cream) Trans fats (margarine, chips, doughnuts) Cholesterol (eggs, red meat, cheese...) Na Avoid smoking