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General Biology: Circulatory System Review

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  • General functions of a circulatory system

    The circulatory system transports nutrients, gases, hormones, and wastes throughout the body and helps regulate temperature and pH balance.

  • Difference between gastrovascular cavities, open and closed circulatory systems

    Gastrovascular cavities have a single opening for digestion and circulation; open systems pump hemolymph into body cavities; closed systems circulate blood within vessels.

  • What is hemolymph?

    Hemolymph is the fluid equivalent to blood in open circulatory systems, mixing blood and interstitial fluid.

  • Three main types of vessels in closed circulatory systems

    Arteries carry blood away from the heart, veins return blood to the heart, and capillaries facilitate exchange between blood and tissues.

  • What is single circulation?

    Single circulation is a blood flow system where blood passes through the heart once per circuit, typical in fish.

  • What is double circulation?

    Double circulation has two circuits: pulmonary (heart to lungs) and systemic (heart to body), seen in amphibians, reptiles, birds, and mammals.

  • Difference between frog and human circulation

    Frogs have a three-chambered heart with some mixing of oxygenated and deoxygenated blood; humans have a four-chambered heart with complete separation.

  • Number of heart chambers in mammals, birds, and amphibians

    Mammals and birds have four chambers; amphibians have three chambers in their hearts.

  • Pathway of blood through the mammalian cardiovascular system

    Blood flows from body → right atrium → right ventricle → lungs → left atrium → left ventricle → body.

  • Why do ventricles have thicker muscle tissue than atria?

    Ventricles pump blood out of the heart, requiring more force; the left ventricle is thickest because it pumps blood to the entire body.

  • What is the cardiac cycle?

    The cardiac cycle is the sequence of heart muscle contraction and relaxation during one heartbeat.

  • What is systole?

    Systole is the phase when the heart ventricles contract and pump blood out.

  • What is diastole?

    Diastole is the phase when the heart muscle relaxes and chambers fill with blood.

  • Function of the SA Node and AV Node

    The SA Node initiates the heartbeat and sets the pace; the AV Node delays the signal to allow ventricles to fill before contracting.

  • What does an EKG measure?

    An EKG measures the electrical activity of the heart during the cardiac cycle.

  • Definition of a heart attack and cardiovascular disease

    A heart attack is damage to heart muscle from blocked blood flow; cardiovascular disease includes conditions affecting heart and blood vessels.

  • Structure and function of arteries, veins, and capillaries

    Arteries have thick muscular walls for high pressure; veins have valves to prevent backflow; capillaries have thin walls for exchange.

  • Why do arteries have thicker smooth muscle than veins?

    Arteries withstand higher pressure from the heart's pumping, requiring thicker smooth muscle and connective tissue.

  • How does blood pressure change as blood moves from the heart?

    Blood pressure is highest in arteries near the heart and decreases as blood moves through arterioles, capillaries, and veins.

  • How is blood moved back to the heart?

    Blood returns via veins aided by valves, skeletal muscle contractions, and pressure changes during breathing.

  • How is blood pressure measured?

    Blood pressure is measured with a sphygmomanometer; normal is around 120/80 mmHg, high is above 140/90 mmHg.

  • How is blood flow through capillaries regulated?

    Precapillary sphincters control blood flow into capillary beds based on tissue needs.

  • How does capillary structure relate to function?

    Capillaries have thin, porous walls to allow exchange of gases, nutrients, and wastes between blood and tissues.

  • Why does blood flow slow near capillaries?

    Blood flow slows due to increased total cross-sectional area of capillaries, allowing time for exchange.

  • What is systolic pressure?

    Systolic pressure is the maximum pressure during ventricular contraction.

  • What is diastolic pressure?

    Diastolic pressure is the minimum pressure during ventricular relaxation.