topic 6.2 + option h5 transport system ib biology
TRANSCRIPT
Topic 6.2 + Option H5 Topic 6.2 + Option H5
Transport SystemTransport System
IB Biology
Components of Transport SystemComponents of Transport System
Blood
Heart
Blood Vessels
Types of CirculationTypes of Circulation
1) Pulmonary heart – lungs – heart
2) Systemic heart – body – heart
Types of CirculationTypes of Circulation
3) Coronary blood vessels that
supply heart muscle with oxygen and nutrients / remove waste products
Heart StructureHeart Structure2 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 + ventricle4 chambers: 2 atria/2 ventricles
Cardiac muscle: involuntary Ultimate control:
Autonomic Nervous System (ANS)
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Heart ValvesHeart Valves Allow blood to flow in only one direction Four valves Atrioventricular valves – between atria and
ventriclesBicuspid valve (left)Tricuspid valve (right)
Semilunar valves between ventricle and artery
Pulmonary semilunar valveAortic semilunar valve
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Vessels of the heartVessels of the heartAorta Leaves left ventricle
Pulmonary arteries Leave right ventricle
Vena cava Enters right atrium
Pulmonary veins (four) Enter left atrium
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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
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Heart contractionsHeart contractions
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The Heart: Cardiac CycleThe Heart: Cardiac Cycle
Atria contract simultaneously
Atria relax, then ventricles contract
Systole = contraction
Diastole = relaxation
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
Cardiac cycle – events of one complete heart beat
BloodBloodPlasma – 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
urea+ HEAT
(antibodies)
Blood VesselsBlood VesselsArteries
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
Blood PressureBlood 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
Coronary Heart DiseaseCoronary Heart DiseaseSlow build up of plaque (lipids, cholesterol) = ATHEROSCLEROSISArteries become harder, less flexibleLess space for bloodCoronary arteries supply O2 to heart cellsThrombosis = 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
Heartbeat ControlHeartbeat ControlMyogenic 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)
Heartbeat ControlHeartbeat ControlAutonomic Nervous System and hormones can modify myogenic rhythm:
oNerves from brain stem (medulla) have involuntary control over heart rate = affect SA node Exercise = ↑CO2 / ↓O2 = medulla oblongata (brainstem) takes overChemoreceptors detect ↑CO2 = H+ causes decrease in pH
oAdrenaline targets sino-atrial node (SAN): stimulant
Cardiac CycleCardiac CycleOne whole heartbeat
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 vesselsAtria systole = pressure not too great (thin walls, most blood already moved to ventricles)Ventricular systole = pressure great inside both ventricles