IB Biology: Circulation

16 flashcards · Other · by Gabrielle Wong

  1. Characteristics of cardiac tissue

    Similar to skeletal muscle - individual cells fused to make fire, actin/myosin form sacromeres, but tend to be shorter/wider Quick passing of electrical signals - due to intercalated discs and cytoplasm Prevention of fatigue with high levels of blood supply and high numbers of mitochondria Myogenic - involuntary (not controlled by nerves) contraction)

  2. 2 different systems circulating blood

    Pulmonary, systemic

  3. Heart: 2 atria, 2 ventricles blood flows from veins into atria, then ventricles, then is propelled through to the arteries

  4. Veins: blood vessels through which blood comes from body tissues back to the heart

    Key characteristics: less muscle and fibres becuase of lower blood pressure thinner walls due to lower blood pressure pocket valves to prevent the backward flow of blood valves are one way to keep slower blood moving through veins

  5. Capillaries: blood vessels that form a network for the transport of blood and gas exchange

    Key characteristics: form a bed/network to allow for travel of blood to all parts of the body, facilitates efficent gas exchange thin cells - efficient movement of molecules, plasma can leak out from tissue and re-enter after removing waste

  6. Arteries: thick blood vessels that carry blood away from the heart

    Key characteristics: thick outer layer to maintain pressure, withstand it (prevents bursting) narrow lumen also for maintenance of pressure no valves because valves would inhibit high pressure flow of blood smooth ANS muscle to reduce friction elastic muslce with fibres/collagen to adjust pressure, preventing bursting, and for contraction to propel blood

  7. Heart rate control is myogenic, meaning that it is controlled by cardiac muscle

    Process: SA node fires, atria contract 0.1 second delay AV node fires Electrical signal travels down bundle of His and Purknje fibres ventricles contract

  8. Systole: contraction Diastole: relaxed

    The atria contract due to the firing of the SA node, which ensures blood that was already passively flowing to the ventricles continues to do so; change in pressure is minimal due to thin walls The ventricles contract after the signal from the AV node travels down the bundle of His and Purknje fibres, which then lads to the closing of the AV valve, semilunar valve remains closed as pressure builds until pressure within ventricles is greater than that of the artery, causing the semilunar valve t…

  9. Heart sounds:

    "lub dub" Caused by the closing of valves due to pressure differences caused by the cardiac cycle

  10. ECGs: electrocardiograms, tracks the electrical signals of the cardiac cycle

    Parts: P wave: firing of the SA node, atria in systole AV node sends signal at Q QRS complex: movement through fibres T-wave: repolarization of AV node

  11. Factors that affect heart rate

    Exercise - chemosensors of the medulla oblongta detect increased need for O2 and CO2 removal Chemicals (adrenaline increases, acetylcholine decreases)

  12. Thrombosis: blood clot in vessel, may lead to blockage of larger, major vessels (coronary thrombosis), can be treated with anticoagulants

    Deep vein thrombosis can be caused by prolonged sitting

  13. Pacemakers: used by individuals who have issues with heartbeat (too fast/slow/irregular), a battery operated device implanted underneath skin in the upper chest area to regulate the frequency of the cardiac cycle through the sending of tiny electrical shocks (connected to wires in the heart's interior)

    Pacemakers last for about 7 years

  14. Defibrilators: device that sends electrical shocks to the heart to reset electrical signals that control it, used in the event of a heart attack

    AED: automated external defibrilators, are made to be portable, easy to handle, and have audible instructions

  15. Astherosclerosis: condition caused by the narrowing of arterties due to the buildup of plaque, leading to harder, less flexible arteries Plaque = cholesterol, lipids, debris, occurs slowly over many years due to diet and lifestyle

    This is a problem because on of the three major artiers may be blocked, leading to inability of oxygen to flow to those aarea, leading to a myocardial infarction (heart attack)

  16. Hypertension: persistently high blood pressure

    Hypertension is often a mix of genetic and lifestyle factors