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You Gotta Have Heart The Circulatory System Circulatory System Consists of… Blood Vessels Blood Heart Functions to transport oxygen, nutrients and wastes throughout the body. Two Pathways: The heart functions as two separate pumps Pulmonary Circulation – The right side of the heart carries oxygen poor blood from the heart to lungs and oxygen rich blood back from the lungs Systemic Circulation – The oxygen rich blood is carried from the left side of the heart to body and oxygen poor blood is carried back to the heart Capillaries of head and arms Superior vena cava Aorta Pulmonary artery Pulmonary vein Capillaries of right lung Capillaries of left lung Inferior vena cava Capillaries of abdominal organs and legs Your Blood Vessels: Pathway of Circulation 3 types of vessels – Arteries – Capillaries – Veins Artery vs. Vein Arteries: carries blood Away from heart – – – – Large Thick-walled, Muscular Elastic Oxygenated blood Exception Pulmonary Artery – Carried under great pressure – Steady pulsating Arterioles: smaller vessels, enter tissue Capillaries – – – – Smallest vessel Microscopic Walls one cell thick Nutrients and gases diffuse here Veins: Carries blood to heart – Carries blood that contains waste and CO2 – – Exception pulmonary vein Blood not under much pressure Valves to prevent much gravity pull Venules: larger than capillaries Circulatory System BLOOD The Blood Body contains 4-6 L Consists of – – – – Water Red Blood Cells Plasma White blood cells and platelets Plasma Platelets White blood cells Red blood cells Whole Blood Sample Sample Placed in Centrifuge Blood Sample That Has Been Centrifuged Plasma Platelets White blood cells Red blood cells Whole Blood Sample Sample Placed in Centrifuge Blood Sample That Has Been Centrifuged Plasma Platelets White blood cells Red blood cells Whole Blood Sample Sample Placed in Centrifuge Blood Sample That Has Been Centrifuged Parts of the Blood Your Blood: Fluid Transport a connective tissue 55% plasma 45% cells Liquid Portion Carries Blood cells – Erythrocytes (RBC - red blood cells) – Leucocytes (WBC - white blood cells) Platelets (non cellular particles) Proteins – Enzymes – Hormones – Endocrine System Nutrients - Digestive System Gases - Respiratory System Inorganic salts Oxygen in the Blood Hemoglobin, iron containing molecule Loosely picks up oxygen in the lungs Loses oxygen in areas low in oxygen (diffuses) Carbon Dioxide in the Blood Hemoglobin carries CO2 also CO2 is a waste product of cellular work 70% of CO2 combines with water The rest travels to the lungs What does blood contain? 45% Packed Cells consisting of erythrocytes, leukocytes, platelets 55% Plasma which includes plasma proteins, gases, salts, nutrients, enzymes, hormones, waste products Erythrocytes (RBC) Transporters of – Oxygen – Carbon Dioxide RBC – Lack a nucleus – Contain hemoglobin – Disk-shaped RBC are produced in red bone marrow of – – – – ribs, humerus, femur, sternum, and other long bones Lives for 120 days Old RBC are destroyed in liver and spleen Leukocytes (WBC) WBC fight infection – Less abundant Large cells Some live for months – Attack foreign substances Most just a few days Several types ALL contain nuclei Platelets PLATELETS are for CLOTTING blood Cell fragments Produced in bone marrow Short life span (1 week) Fibrin (sticky network of protein fibers) – Form a web trapping blood cells 3 Types of Plasma Proteins Albumins-transport substances such as fatty acids, hormones and vitamins. Also help regulate osmotic pressure and blood volume. Globulins-transport substances and fight viral and bacterial infections. Fibrinogen-protein responsible for the ability of blood to clot Plasma Protiens Blood Clotting Break in Capillary Wall Clumping of Platelets Clot Forms Blood vessels injured. Platelets clump at the site and release thromboplastin. Thromboplastin converts prothrombin into thrombin.. Thrombin converts fibrinogen into fibrin, which causes a clot. The clot prevents further loss of blood.. Circulatory System HEART Your Heart: The Vital Pump At REST, the heart pumps about 5 QUARTS of blood a minute. During EXTREME EXERTION (exercise) it can pump 40 quarts a minute. Heart: Structure and Function Keeps blood moving Large organ composed of – cardiac muscle, – rich in mitochondria – Enclosed by a protective sac called the pericardium Myocardium-thick layer of muscle surrounded by 2 thin layers of connective & epithelial tissue The Structures of the Heart Superior Vena Cava Large vein that brings oxygen-poor blood from the upper part of the body to the right atrium Aorta Brings oxygen-rich blood from the left ventricle to the rest of the body Pulmonary Arteries Bring oxygen-poor blood to the lungs Pulmonary Veins Bring oxygen-rich blood from each of the lungs to the left atrium Left Atrium Pulmonary Valve Prevents blood from flowing back into the right ventricle after it has entered the pulmonary artery Right Atrium Tricuspid Valve Prevents blood from flowing back into the right atrium after it has entered the right ventricle Aortic Valve Prevents blood from flowing back into the left ventricle after it has entered the aorta Mitral Valve Prevents blood from flowing back into the left atrium after it has entered the left ventricle Left Ventricle Inferior Vena Cava Vein that brings oxygen-poor blood from the lower part of the body to the right atrium Septum Right Ventricle Structure of Heart (cont) Four chambers – Two upper (Atria) Walls thinner Less muscular – Two lower (Ventricles) Walls thicker More muscular Do more work Blood Flow Through the Heart ©COPY 1997 HeartPoint Bloods Path Through the Heart Both Atria fill at same time – Rt atrium receives oxygen POOR blood from body from vena cava – Left atrium receives oxygen RICH blood from lungs through four pulmonary veins After filled with blood atria contract, pushing blood into ventricle Both ventricles contract Right ventricle contracts and pushes oxygen-poor blood toward lungs, against gravity, through pulmonary arteries Bloods Path Through the Heart (cont) Left ventricle contracts and forces oxygen rich blood out of heart through aorta (largest vessel) Control of the Heart (Nervous System) Medulla oblongata regulates rate Sensory cells stretch when too fast Pressure drops when beat is too low Heartbeat Regulation Force of blood from left ventricle into arteries (pulse) Pacemaker (SA Node), group of cells at top of right atrium Electrical impulse, signals BOTH atria to contract Triggers 2nd set of cells (AV Node)-base of the right atrium to send message to ventricles, they contract EkG – record of electrical changes in the heart The Sinoatrial Node Contraction of Atria Contraction of Ventricles Sinoatrial (SA) node Conducting fibers Atrioventricular (AV) node Blood Pressure Blood against the blood vessel’s walls – The systolic pressure refers to the pressure recorded while the ventricles pump the blood. – The diastolic pressure refers to the pressure recorded as the ventricles fill with blood. A normal blood pressure is 120/80 Disorders of Circulatory System ATHEROSCLEROSIS – Fatty deposits called plaque – Builds up in walls of arteries – Obstructs flow – Also a risk if clot breaks free and blocks flow elsewhere Disorders (cont) Hypertension – High blood pressure – Hearts works harder than necessary – Increases risk of heart attack or stroke Disorders (cont) Heart Attack – Atherosclerosis in coronary artery – Heart muscle begins to die Symptoms – Nausea – Shortness of breath – Severe chest pain IMMEDIATE MEDICAL ATTENTION NECESSARY Disorders (cont) Stroke – Blood clot gets stuck in blood vessels leading to brain – Brain cells die due to lack of oxygen Or blood vessel burst – Can lead to paralysis, loss of ability to speak death The Lymphatic System A network of vessels, nodes and organs Collects the fluid that is lost by the blood – Up to 3 liters per day Returns fluid back to circulatory system Fluid is known as lymph Lymph Lymph collects in lymphatic capillaries Lymph vessels contain valves Ducts collect the lymph Lymph is returned to the circulatory system through 2 openings in the superior vena cava – Openings under the left and right clavicle bones Lymph Lymph vessels are dotted with small bean shaped enlargements called nodes Lymph nodes act as filters – Trapping bacteria and other microorganisms – Can become enlarged “swollen glands” Lymph System Lymph vessels play an important role in nutrient absorption Absorb fats and fat-soluble vitamins from the digestive tract and carry them to the blood Lymph System Lymph moves through the lymphatic system – under osmotic pressure from the blood – is pushed along by the contractions of nearby skeletal muscles – Important to have a steady flow – Edema, tissue swelling , can occur when vessels are blocked due to injury or disease Thymus Gland The thymus gland – Located beneath the sternum – Site of T cell maturation Spleen The spleen – helps to cleanse the blood and removes damaged blood cells – Harbors phagocytes that engulf and destroy bacteria and other microorganisms The Respiratory System The Respiratory System functions – To bring about the exchange of oxygen and carbon dioxide between the blood, the air, and tissues – Consists of the nose, pharynx, larynx, trachea, bronchi, and lungs Respiratory System Pharynx-serves as passageway for both air and food Trachea or windpipe carries the air, a flap of tissue called the epiglottis covers the entrance to the trachea when you swallow Entering air is warmed, moistened, and filtered – Dust is trapped by the hairs lining the nasal cavities – Mucus moistens the air and traps inhaled particles of dust or smoke. – The mucus and trapped particles are either swallowed or spit out Respiratory Larynx-contains the vocal cords – Muscles pull the cords together – Air moving between cords cause them to vibrate and produce sound Respiratory Bronchi branch from the trachea into each lung Bronchi branch into smaller bronchioles – Both are surrounded by smooth muscle that supports them and enables the ANS to regulate the size of the air passageways – Bronchioles dead end into the alveoli Respiratory Alveoli are millions of tiny air sacs – Are grouped in clusters, like grapes – Are surrounded by a network of capillaries – The real work of the respiratory system takes place here, where blood and air are side by side – The Gas Exchange is carried out here Gas Exchange 150 million alveoli in a healthy lung Enormous surface area for gas exchange The process is very efficient – Air you inhale is 21% oxygen and .04 CO2 – Exhaled air is > 15% oxygen and 4% CO2 – Hemoglobin increases the oxygen-carrying capacity of blood more than 60 times – Without hemoglobin you would need 300 liters of blood to get the same result Breathing Breathing is the movement of air into and out of the lungs. – There are no muscles connected to the lungs – The force that drives air into the lungs comes from the air pressure – Lungs are sealed in 2 sacs called the pleural membranes – A large, flat muscle known as the diaphragm contracts and relaxes causing a vacuum – The system works because the chest cavity is sealed. – A puncture may allow air to leak into the chest cavity and make breathing impossible Breathing Control By the medulla oblongata You may hold your breath but eventually the body forces you to breathe Controlled by the amount of CO2 in the breathing center More CO2 the stronger the impulses If CO2 reaches critical point you cannot keep from breathing Disorders Smoking can cause respiratory diseases such as chronic bronchitis, emphysema and lung cancer. Only 30% of male smokers live to be 80 while 55% of male nonsmokers live to be 80 Disorders Chronic Bronchitis-inflammation of the bronchi Can make even simple activities difficult Emphysema-loss of elasticity in the tissues of the lungs – Breathing is very difficult – Cannot get enough O2 to the body or get rid of the CO2 – Can use medicines or O2 to improve life Lung Cancer Lung cancer is very deadly because its cells can spread to other locations By the time it is usually detected it has spread to dozens of places 160,000 people in US diagnosed each year Few will survive 5 years Passive or second hand smoke can be a major issue for family members of a smoker, can lead to asthma in children