Post on 11-May-2015
Topic 6.2 + Option H5
Transport System
IB Biology
Components of Transport System
Blood
Heart
Blood Vessels
Types of Circulation
1) Pulmonary heart – lungs – heart
2) Systemic heart – body – heart
Types of Circulation
3) Coronary blood vessels that
supply heart muscle with oxygen and nutrients / remove waste products
BloodPlasma – 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)
Heart 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)
Heart Structure
Blood 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 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 Disease
Slow 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 ControlMyogenic muscle contraction: -Sino-Atrial Node (SAN) – specialized cells generate electrical impulse on their own with regular frequency (PACEMAKER)-Impulse spreads to both atria → atria contract together-Atrio-Ventricular node (AVN) 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 (SISTOLE)-Contraction stops – ventricles relax (DIASTOLE)
Heartbeat 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 CycleOne whole heartbeat
Sistole = 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