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A&P II Unit 2 Exam: Heart and Circulatory System

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이 집합의 용어 (27)

  • Heart Apex Position
    The heart apex is inferior and angled to the left, causing the left lung to be smaller and the anterior view to show mostly the right ventricle.
  • Primary Function of the Heart
    Generate the pressure needed to create a pressure gradient that drives blood flow throughout the body.
  • Heart as a Dual Pump
    The heart has right and left sides that share inner ventricular walls; the right heart pumps blood to the lungs (pulmonary circuit), and the left heart pumps blood to the body (systemic circuit).
  • Generalized Blood Circuit Pattern
    Blood flows from heart side → large arteries → small arteries → arterioles → capillary beds → venules → small veins → large veins → back to the heart.
  • Layers of the Heart Wall
    Epicardium (visceral pericardium), myocardium (muscle layer), and endocardium (simple squamous epithelium lining chambers).
  • Pericardium Function
    Protects the heart from overexpansion and infection, anchors the heart, and contains fluid in the pericardial space to reduce friction.
  • Atrioventricular (AV) Valves Components
    Fibrous ring, cusps, chordae tendineae, and papillary muscles that prevent valve prolapse during ventricular contraction.
  • Semilunar Valves Function
    Open when blood flows through them and close by gravity to prevent backflow; include the pulmonic and aortic valves.
  • Coronary Circulation Origin
    All coronary arteries originate from the ascending aorta and supply the heart muscle with oxygenated blood.
  • Cardiac Muscle Characteristics
    Branching cells connected by intercalated discs, rely on aerobic respiration, self-excite, and are modulated by the autonomic nervous system.
  • Pacemaker Cells Action Potential
    Depolarization uses calcium voltage-gated channels, not sodium; rate modulated by sympathetic (norepinephrine) and parasympathetic (acetylcholine) inputs.
  • Contractile Cells Action Potential Plateau Phase
    Prolonged depolarization due to slow calcium voltage-gated channels, delaying repolarization to sustain contraction.
  • Cardiac Conduction System Components
    Sinoatrial (SA) node, atrioventricular (AV) node, AV bundle (Bundle of His), bundle branches, and Purkinje fibers.
  • Phases of the Cardiac Cycle
    1) Ventricular filling, 2) Isovolumetric contraction, 3) Ventricular ejection, 4) Isovolumetric relaxation.
  • Stroke Volume (SV) and End Systolic Volume (ESV)
    SV is the amount of blood ejected during systole; ESV is the blood remaining in ventricles after contraction.
  • Intrinsic vs Extrinsic Regulation of Cardiac Output
    Intrinsic maintains cardiac output via preload and contractility; extrinsic uses autonomic nervous system and hormones to adjust heart rate and strength.
  • Starling's Law of the Heart
    The more the cardiac muscle is stretched during filling, the stronger the subsequent contraction.
  • Tunica Intima of Blood Vessels
    Innermost layer with endothelium, subendothelium, and internal elastic lamina, directly contacting blood flow.
  • Tunica Media of Blood Vessels
    Middle layer composed of smooth muscle and external elastic lamina, responsible for vessel constriction and elasticity.
  • Vasoconstriction and Vasodilation Control
    Sympathetic nervous system releases norepinephrine causing vasoconstriction; vasodilation occurs by blocking sympathetic signals centrally.
  • Types of Capillaries
    Continuous (tight junctions, nutrient exchange), fenestrated (holes for filtration), and sinusoidal (large openings for blood cells).
  • Autoregulation of Blood Flow
    Tissues regulate their own blood flow via myogenic (stretch-induced vasoconstriction) and metabolic (vasodilation from low O2/high CO2) mechanisms.
  • Blood Pressure Gradient (ΔP)
    Difference in pressure between two points; magnitude and direction determine blood flow strength and direction.
  • Resistance Factors in Blood Flow
    Resistance increases as vessel radius decreases, blood viscosity increases, or vessel length increases.
  • Congestive Heart Failure Effects
    Right side failure causes systemic edema; left side failure causes pulmonary edema and reduced oxygen delivery.
  • Baroreceptor Reflex in Blood Pressure Regulation
    Baroreceptors detect pressure changes and adjust autonomic output to maintain blood pressure homeostasis.
  • Fetal Circulation Special Features
    Includes ductus arteriosus, foramen ovale, and ductus venosus to bypass lungs and liver before birth.