+ HUMAN CIRCULATORY SYSTEM

+ THE HEART - Located slightly to the left of the middle of the chest - Approximately the size of a fist - Walls are made of cardiac muscle - Allow the heart to contract and relax rhythmically and involuntarily - Blood flows in one direction only - Ensures that oxygen rich and oxygen poor blood do not mix

+ THE HEART

+ Vena Cava Blood enters the heart from the SUPERIOR VENA CAVA & INFERIOR VENA CAVA Blood is released into the right atrium

+ Right Atrium Collects blood from the SVC and IVC Blood is forced to the right ventricle

+ (Atrioventricular Valve) Tricuspid Valve Valve between the right atrium and right ventricle Prevents backflow of blood to the right atrium 3 cusps

+ Right Ventricle Receives blood from the right atrium Sends blood to the lungs

+ Semilunar Valve (Pulmonary Valve) Blood between the right ventricle and pulmonary artery Keeps blood from flowing back into the right ventricle

+ Pulmonary Artery Transfers oxygen poor blood from the pulmonary arteries to the lungs

+ Pulmonary Vein Transfers oxygen rich blood from the lungs to the left atrium

+ Left Atrium Receives oxygen rich blood from the pulmonary veins Sends blood to the left ventricle

+ Atrioventricular Valve (Bicuspid Valve) Valve between the left atrium and left ventricle Prevents blood from flowing back into the left atrium Also called the Mitral valve

+ Left Ventricle Receives blood from the left atrium Pumping chamber which forces blood through the aortic valve More muscular than the right ventricle

+ Semilunar Valve (Aortic Valve)  Valve between the left ventricle and aorta  Prevents blood from going back into the left ventricle

+ Aorta Collects blood from the left ventricle Blood flows from the aorta throughout the entire body Largest vessel in the body

+ Interventricular Septum Separates the pumping chambers of the heart

+ Path of Blood Flow Place the following items in the correct sequence: body tissue, aorta, bicuspid valve, left atrium, lungs, pulmonary trunk, pulmonary arteries, left ventricle, pulmonary veins, right atrium, right ventricle, tricuspid valve, aortic valve, pulmonary valve. Oxygen poor blood is collected from the inferior and ___________ _______ ________. It is released into the _________ _______ where it moves through the _________ valve into the ________ __________. When the right ventricle contracts, blood is forced through the _________ valve into the ____________ _______ which splits into the left & right pulmonary __________. Blood is taken via the arteries to the _____ where oxygen & carbon dioxide diffuse through the simple squamous tissue. Oxygen-rich blood then returns to the heart via the ___________ ________ which empty into the _________ ________. Once the atrium contracts, the blood passes through the __________ ________ into the _________ _________. Once the ventricle contracts blood is forced through the _________ valve and out of the _________ to travel to the _______ ________.

Path of Blood Flow: Answer Sheet 1. Superior Vena Cava 2. Right Atrium 3. Tricuspid Valve 4. Right Ventricle 5. Pulmonary Valve 6. Pulmonary Trunk 7. Pulmonary Arteries 8. Lungs 9. Pulmonary Veins 10. Left Atrium 11. Bicuspid Valve/Mitral valve 12. Left Ventricle 13. Aortic Valve 14. Aorta 15. Body Tissue

+ TYPES OF CIRCULATION 3 primary cycles Cardiac circulation: movement of blood within the heart Pulmonary circulation: path of blood from heart to the lungs and back to the heart Systemic circulation: path of blood from the heart to the body and back to the heart

+ TYPES OF CIRCULATION

+ BLOOD VESSELS There are 3 major types of blood vessels: 1. Arteries 2. Veins 3. Capillaries

+ BLOOD VESSELS 1. Arteries All carry blood AWAY from heart Flow into smaller ARTERIOLES Mostly contain oxygenated blood Thicker Aorta – principle artery in system

+ BLOOD VESSELS 2. Veins All carry blood TOWARDS the heart Flow from smaller VENULES Mostly deoxygenated blood Thinner Greater capacity for blood Vena cava -- Principle vein in system

+ BLOOD VESSELS 3. Capillary Smallest of the blood vessels Reach every corner of the body Single layer of endothelial cells – allows for gas and nutrient exchange

+ BLOOD VESSELS Exceptions: Pulmonary artery which carries DEOXYGENATED blood AWAY from the heart to the lungs Pulmonary vein which carries OXYGENATED blood from the lungs to the heart

+ BLOOD VESSELS

+

+ BLOOD THE IMPORTANCE OF BLOOD: Transport of gases (Oxygen and carbon dioxide) Transport of wastes Transport of nutrients Fighting disease and infection Blood clotting 2 DISTINCT ELEMENTS: Liquid portion – plasma (~55%) Solid portion – blood cells (~45%)

+ BLOOD PLASMA - Clear, yellowish fluid - 92% water, 7% dissolved blood proteins, 1% other organic substances and inorganic ions - Proteins: albumin (fluid balance), globulins (antibodies), fibrinogen (clotting) - Inorganic ions: bicarbonate, calcium, chloride, magnesium, potassium, sodium

+ BLOOD RED BLOOD CELLS (ERYTHROCYTES) 44% Originate from bone marrow Disk shaped Has a protein called hemoglobin (iron containing molecule) that carries oxygen to cells in body Each RBC has ~280 million hemoglobin molecules that bind oxygen to become oxyhemoglobin Each RBC contains 4 iron atoms which form the “heme” group and can bind 1-4 molecules of oxygen Has a lifespan of 3- 4 months, after which it is broken down in the liver Can stimulate growth of red blood cells when there is reduced oxygen in the blood Has no nucleus

+ BLOOD WHITE BLOOD CELLS (LEUKOCYTES) 1% (fluctuates with infection) Fights germs, foreign cells harmful to the body Macrophages: phagocytic cells that engulf pathogens (general response to infection). Innate response Lymphocytes: able to recognize and label pathogens to be engulfed by macrophages. Acquired response T Cells: Mature in the the thymus gland. Killer and Helper T cells. B Cells: Arise in Bone marrow. Memory and Plasma B cells. Have a nucleus

+ BLOOD WHITE BLOOD CELLS (LEUKOCYTES)

+ BLOOD PLATELETS (THROMBOCYTES) Less than 1% Small fragments of cells formed when larger cells in the bone marrow break apart Initiate blood clotting when there is a cut in the skin Lifespan of ~7-10 days No nucleus

+ BLOOD PLATELETS (tTHROMBOCYTES) Clotting Process 1. Blood vessel is broken 2. Chemicals are released that attract platelets to the site of injury 3. Platelets rupture and release chemicals that combine with other chemicals in the plasma to produce thromboplastin 4. When Ca+ is present, thromboplastin reacts with prothrombin to produce thrombin 5. Thrombin acts with fibrinogen to produce fibrin 6. Fibrin forms a fibrous mesh over the site of injury and solidifies into a clot

+ FUNCTIONS OF BLOOD 1. Transport materials 2. Regulate concentration of substances in body 3. Regulate temperature of the body

+ FUNCTIONS OF BLOOD 1. TRANSPORT MATERIALS - Absorb products of digestion/nutrients from the small intestine - Absorb nutrients that are synthesized by cells in other parts of the body - Nutrients are transported to the liver for storage - Picks up chemicals and gases from respiratory system and carries them to the desired location - Removes waste products of cellular processes - Carries excessive mineral ions and other waste products to kidneys for processing and excretion

+ FUNCTIONS OF BLOOD 3. TEMPERATURE REGULATION Balancing loss of heat from the body with production of heat by metabolic processes - Accomplished by changing volume of blood near body surface - Controlled by nervous system which can dilate (expand) or constrict (decrease in diameter) - In res

+ FUNCTIONS OF BLOOD 3. TEMPERATURE REGULATION VASODILATION: an increase in blood flow by widening or dilating vessels - Occurs when the core of the body becomes hot as a result of vigorous activity or high external temperature - Accompanied by perspiration

+ FUNCTIONS OF BLOOD 3. TEMPERATURE REGULATION VASOCONSTRICTION: decrease in flow of blood by narrowing or constricting the blood vessels near the surface of the skin - Reduces the amount of heat dissipated from the skin thereby conserving heat - Accompanied by shivering (waves of muscle contractions)

+ FUNCTIONS OF BLOOD Other causes for vasoconstriction and vasodilation - Increased metabolic activity - Exercise promotes vasodilation - Alcohol - Promotes vasodilation - Nicotine - - Promotes vasodilation

+ FUNCTIONS OF BLOOD Other methods of temperature regulation 1. Counter-current heat exchange system - Deep arteries leaving the core of the body lie adjacent to deep veins entering the core of the body and heat is transferred from the arteries to the veins