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Internal Transport S ystem. SBI 3UO. Function. To circulate necessary materials to all of the cells in the body e.g. Oxygen To remove the waste products of cell metabolism To regulate body temperature To carry materials e.g. Hormones and antibodies to various organs
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Internal Transport System SBI 3UO
Function • To circulate necessary materials to all of the cells in the body e.g. Oxygen • To remove the waste products of cell metabolism • To regulate body temperature • To carry materials e.g. Hormones and antibodies to various organs • Clotting at the site of a wound to minimize blood loss
Two Types of Circulatory Systems • Open (invertebrates) – hemolymph is pumped into the body cavity • Closed (vertebrates) – blood is physically contained within vessels and separated from other body tissues See fig. 12.1 pg. 479
Structure • A closed system of blood vessels pumped by a muscular heart • It consists of: • heart: a muscular organ which pumps blood throughout the body • Artery: a vessel that carries blood AWAY from the heart – arterioles (small arteries) • Vein: carries blood TO the heart – thinner layer of muscle – venules: smaller veins • Capillaries: link arterioles and venules
Heart • http://www.youtube.com/watch?v=H04d3rJCLCE
Three subdivisions of the circulatory system (the double circulatory system) • Systemic system: blood travels through the body cells (at any time 80-90% of the blood) • Pulmonary system: blood travels through the lungs (rest of blood) • Cardiac system: Blood travels through the tissues of the heart Complete worksheet – Double circulatory system (pg. 483, fig. 12.7)
Blood Pressure • When the heart contracts blood is forced out at a high pressure (blood makes a swishing noise) this is called the “systole” • As the heart relaxes the blood is no longer being forced (noise stops) “diastole” • Pressure is measured in mm Hg • Blood pressure is measured using an instrument called a sphygmomanometer (pronounced: sfig-mow-mah-nah-meh-ter).
Blood Pressure – Contn’ • Average systolic is approx. 120 mmHg • Average diastolic is approx. 80 mmHg • Together the systole and diastole are called the “cardiac cycle” or a heartbeat
Heartbeats • Average male = 75/80 b/m • Average female = 85/90 b/m • Resting = 60 b/m • Active = 160 b/m Live Beating Heart surgery http://www.youtube.com/watch?v=Pes9O5z8efk&feature=related
Sounds of the Heart • “ LUBDUB LUBDUBLUBDUB” • LUB – ventricles contract causing the AV to slap shut • WHY? • DUB – semi-lunar valves slap shut • WHY? SinoatrialSVnode – right atrium – rhythmic signals that causes atria to contract Atrioventricular AV node – between atria and ventricles (signal reaches AV node through the specialized bundles – bundles of His Purkinje fibres initiate contraction of right and left ventricles
Heart • Large strong muscle • 4 chambers • Septum divides the oxygenated and deoxygenated blood • Beats in rhythmic contractions • Valves control the flow/back flow of blood • Pumped to 3 main areas: • Lungs = pulmonary system • Heart = cardiac system • Body = systemic system - Label the parts of the heart (pg. 480 fig. 12.2) - Draw the cross-section of the human heart (pg. 481 fig. 12.3)
Arteries • Carry blood away from the heart • Thick elastic muscle walls, small in diameter • Can withstand the great pressure that is created when the blood is forced out of the heart • When the blood is pumped into the arteries they stretch, as the blood flows away they recoil • This creates the pulse you fell in your wrist and neck • Main artery is the AORTA • Branch off into smaller arterioles • Draw fig. 12.4 pg. 482 – Arteries and Veins
Veins • Bring blood back to the heart • Thin walls, larger diameter • Not heavily muscled, elastic • Cannot handle high pressure • Very elastic and will stretch with pooled blood • Smaller veins - venules branch into veins • Muscles contract around the veins and force the blood through the veins • Veins have a one-way flap called the venous valve that stops the blood from flowing backwards • Two main veins lead to the heart: • Superior Vena Cava • Inferior Vena Cava
Capillaries • Smallest of the vessels • Join the arterioles to the venules • Form dense capillary beds, have valve that control blood flow
Heartbeat • Cardiac muscles contract by “inherent rhythm”, no other stimulus required • Can beat even if nerves are severed • In order to beat faster or slower it does receive messages from the brain • 3 types of stimuli: • Nervous stimuli – fear, excitement, tension • Physical stimuli – exercise • Chemical stimuli – drugs, alcohol, adrenalin
Pathway of the Stimulus Medulla Oblongata 2 Nerve cords 1. through spinal cord (carries stimulus to beat faster) 2. vagus nerve (inhibitor, causes to beat slower) Pacemaker right atrium
Lymphatic System • Function – drains excess fluid from the tissues and adds this fluid to the veins • EFC extracellular fluid comes from the blood and must be returned • Small capillaries called lacteals drain the excess fluid from the tissue • This fluid is now called lymph (pale yellow) • Lymph is forced through the vessels like blood in the veins (by muscle contractions) • Lymph nodes located in the lymphatic system produce white blood cells = phagocytes, leucocytes (destroy foreign substances and organisms)
DID you know? • Your heart beats 100,000 times a day. • Your heart beats 2 billion times in your lifetime! • Blood cells are formed in your bone marrow. Videos: http://www.learn360.com/ShowVideo.aspx?ID=129270&SearchText=circulatory+system&lid=13216000 Blood components: http://www.youtube.com/watch?v=R-sKZWqsUpw http://www.sciencekids.co.nz/videos/humanbody/circulatorysystem.html Once upon a time... Life - The tiny platelets (1 of 3) http://www.youtube.com/watch?v=JvOH5skxqoA&feature=fvwrel
Homework • Read pages 478-488 and answer questions #1-15 • Read pages 489-492 and answer questions #1, 2, 5, 6, 8.