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Topic Option H5 Transport System

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Presentation on theme: "Topic Option H5 Transport System"— Presentation transcript:

1 Topic 6.2 + Option H5 Transport System
IB Biology

2 Components of Transport System
Blood Heart Blood Vessels

3 Types of Circulation 1) Pulmonary 2) Systemic heart – lungs – heart
heart – body – heart

4 Types of Circulation 3) Coronary
blood vessels that supply heart muscle with oxygen and nutrients / remove waste products

5 Heart Structure 2 sides with different functions:
right: to receive + pump blood to the lungs left: to receive + pump blood to the body 2 types of chambers: atrium + ventricle 4 chambers: 2 atria/2 ventricles Cardiac muscle: involuntary Ultimate control: Autonomic Nervous System (ANS)

6 Heart Valves Allow blood to flow in only one direction Four valves
Atrioventricular valves – between atria and ventricles Bicuspid valve (left) Tricuspid valve (right) Semilunar valves between ventricle and artery Pulmonary semilunar valve Aortic semilunar valve

7 Vessels of the heart Aorta Pulmonary arteries Vena cava
Leaves left ventricle Pulmonary arteries Leave right ventricle Vena cava Enters right atrium Pulmonary veins (four) Enter left atrium

8 Blood in the heart chambers does not nourish the myocardium
The heart has its own nourishing circulatory system Coronary arteries Cardiac veins Blood empties into the right atrium via the coronary sinus

9 Heart contractions

10 The Heart: Cardiac Cycle
Atria contract simultaneously Atria relax, then ventricles contract Systole = contraction Diastole = relaxation Cardiac cycle – events of one complete heart beat Mid-to-late diastole – blood flows into ventricles Ventricular systole – blood pressure builds before ventricle contracts, pushing out blood Early diastole – atria finish re-filling, ventricular pressure is low

11 Blood Plasma – fluid Red blood cells or erythrocytes – produced in the bone marrow of large bones / transport O2 and CO2 White blood cells (lymphocytes and phagocytes) – produced in the bone marrow / belong to immune system Platelets - cell fragments that help blood clotting

12 (antibodies) urea + HEAT



15 Blood Vessels Arteries Veins Capillaries
carry blood Away from heart; strong thick walls; smooth muscle (elastic); fibrous coat; small lumen = ↑ pressure Veins carry blood back to heart; large lumen; thin wall/muscle; ↓ elastic; valves Capillaries connect arteries and veins; no valves; pores; no muscle/not elastic extremely thin (1 cell thick) = fast exchange

16 Blood Pressure Blood applies pressure to the walls
If it is too low - cells might not get enough O2 If it is too high - vessels can rupture (heart attack, stroke) Salt can increase blood pressure Normal blood pressure: 120/80 mm Hg

17 Coronary Heart Disease
Slow build up of plaque (lipids, cholesterol) = ATHEROSCLEROSIS Arteries become harder, less flexible Less space for blood Coronary arteries supply O2 to heart cells Thrombosis = clot = heart attack = heart cells die Factors affecting coronary heart disease (CHD): Age, race, heredity, gender, cholesterol levels, blood pressure, obesity, diabetes, smoking, sedentary lifestyle, stress


19 Heartbeat Control Myogenic muscle contraction:
Sino-Atrial Node (SA) – specialized cells generate electrical impulse on their own with regular frequency (PACEMAKER) Impulse spreads to both atria → atria contract together Atrio-Ventricular node (AV) picks up the impulse in lower right atrium septum and conduces to the ventricles through fibers Ventricles contract: AV valves close / semi-lunar valves open (SYSTOLE) Contraction stops – ventricles relax (DIASTOLE)

20 Heartbeat Control Autonomic Nervous System and hormones can modify myogenic rhythm: Nerves from brain stem (medulla) have involuntary control over heart rate = affect SA node Exercise = ↑CO2 / ↓O2 = medulla oblongata (brainstem) takes over Chemoreceptors detect ↑CO2 = H+ causes decrease in pH Adrenaline targets sino-atrial node (SAN): stimulant


22 Cardiac Cycle One whole heartbeat Sound = valves closing
Systole = contraction / Diastole = relaxation Valves prevent backflow Sound = valves closing 1st = atrio-ventricular valves (mitral, tricuspid) 2nd = semilunar valves (aortic, pulmonary) Important = valves open and close depending on pressure inside chambers/blood vessels Atria systole = pressure not too great (thin walls, most blood already moved to ventricles) Ventricular systole = pressure great inside both ventricles

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