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7th Grade Science Chapter 7 Notes The Circulatory System 7.1 – Circulation Cardiovascular system – includes the heart, arteries, veins, & capillaries “cardio” – means heart “vascular” – means vessel (like indoor plumbing) Heart – made up of 4 chambers - 2 atria and 2 ventricle - valves separate the chambers to help direct flow o 1 – Tricuspid valve – right atrium o 2 – pulmonary (semilunar) valve – right ventricle o 3 – mitral valve - left atrium o 4 – aortic (semilunar) valve – left ventricle Heart flow: - Blood (deoxygenated) comes to the heart thru the vena cava o Superior & inferior vein - Enters the right atrium & is pumped to the right ventricle - Right ventricle pumps blood to pulmonary artery to the lungs - Lungs give O2 for blood to pick up - Blood comes back from lungs to heart thru pulmonary veins - Pulmonary veins bring blood to heart thru left atrium o Oxygenated blood - Left atrium pumps blood to the left ventricle - Left ventricle pumps blood to the aorta - Aorta disperses blood to the rest of the body Diffusion – higher concentration to lower concentration until equilibrium is reached - occurs between blood & body cells - exchanges nutrients, O2 , & waste products - capillaries connect arteries to veins & the body cells so that the blood used (deoxygenated & full of wastes) will go to veins & refreshed blood (from arteries) will get to the cells Types of Circulation Pulmonary From heart to lungs & back to the heart Coronary Blood movement in the tissues of the heart Systemic Blood from heart to the rest of the body & back Blood Vessels Veins Brings all blood to the heart heart Arteries Carries blood away from the Pressure is lower Has a valve to keep one way flow Higher pressure Gives us our heart beat (blood Pressure) Both are connected by capillaries Blood pressure – blood exerting a force on the walls of the vessels - highest in arteries - normal range from 65-80 beats per min 7.2 Blood Functions of the blood – is a tissue - Blood carries O2 from lungs to body cells & gets rid of COs from body cells - Picks up waste products from cells & delivers to kidneys - Transports nutrients from digestive tract to body cells - blood fights infections Makes up 8% of body Amt of blood in adults equals about 5 – 1L bottles If blood drops below 8%, your body goes into shock Parts of Blood Plasma – liquid part of blood-mostly water o contains nutrients & oxygen o makes up more than half the volume of blood Red Blood cells – have no nucleus o Contains hemoglobin o Acts as a chemical that can carry oxygen and carbon dioxide o In 1 mm3 – contains 5,000,000 red blood cells o Life span is 4 months o Produced in bond marrow Particularly in femur and humerus o Reproduce @ 2-3 million/sec White Blood Cells – makes up to 5000 to 10000 count in blood o job is to fight bacteria, viruses, and other foreign substances o When detects a foreign substance, white blood cell count will increase o Life span from a few days to months o They attach and absorb the foreign body Platelets – help with blood clotting o contain 400.000 in drop of blood o life span of 5-9 days Blood clotting – platelets make your blood clot & forms a natural bandage -Fibrin – threadlike fibers form a sticky net - hemophiliac – genetic disease that lacks clotting factors Blood types – A, B, AB, & O Antigens – each type has a chemical identifying tag Antibodies – specific proteins that destroy or neutralize foreign substances - located in the plasma Rh factor – give your blood +/- + , if Rh marker is present - - , if Rh marker is not present - Inherited - Cannot be mixed Anemia – Too few red blood cells - makes it harder for tissues to receive O2 - can result from disease, sickness, severe injury Leukemia – white blood cells rapidly reproduce immature cells - do not function properly - can cause death - typically need a bone marrow transplant 7.3 Lymphatic system Lymphatic system – collects fluid from body and tissue spaces and returns it to The blood thru a system of lymph capillaries and larger lymph Vessels - contains cells that help your body defend itself against disease-causing organisms - blood passes nutrients and o2 to cells - some becomes part of tissue fluid in-between cells - the lymph vessels collects and moves those molecules Organs – Lymph nodes, Lymph, Lymphocytes - Lymph nodes o Filter out microorganisms and foreign materials o Lymphocytes transports these organisms to the node o At sign of infection, over production of lymphocytes are found in nodes o Makes glands tender to touch - Lymph o Water (most of it), dissolved substances like nutrients and proteins and lymphocytes - Lymphocytes o Type of white blood cell o Is not pumped by heart – relies on muscular contractions of skeletal system Diseases HIV – Human Immunodeficiency Virus - attacks and destroys Helper T cells (type of lymphocyte) - Helper T Cells o Produce antibodies to fight infections o Less T cells, less fight against pathogens o Can lead to death