Flashcards in this deck (112)

• What are the two main components of the circulatory system?

  • Blood vascular system
  • Lymphatic vascular system
  anatomy circulatory_system
• What is the function of the circulatory system?

  • Transport of nutrients
  • Transport of gases
  • Transport of wastes
  • Transport of hormones
  • Transport of immune cells
  function circulatory_system
• What are the three layers of blood vessel walls?

  • Tunica intima
  • Tunica media
  • Tunica adventitia
  anatomy blood_vessels
• What is the tunica intima composed of?

  • Endothelium
  • Basal lamina
  • Subendothelial connective tissue
  anatomy blood_vessels
• What specialized structure may be present in arteries at the intima–media border?

  • Internal elastic lamina
  anatomy blood_vessels
• What is the tunica media composed of?

  • Smooth muscle cells
  • Elastic fibers
  anatomy blood_vessels
• What is the main component responsible for vasoconstriction?

  • Smooth muscle cells of the tunica media
  physiology blood_vessels
• What is the tunica adventitia composed of?

  • Connective tissue with collagen and elastic fibers
  • Contains vasa vasorum
  anatomy blood_vessels
• What are vasa vasorum?

  • Small vessels supplying the outer layers of large vessels
  anatomy blood_vessels
• Where are vasa vasorum most prominent?

  • Large arteries
  • Large veins
  anatomy blood_vessels
• What is the role of endothelial cells?

  • Provide a barrier
  • Regulate exchange
  • Prevent clotting
  • Regulate tone
  • Modulate inflammation
  physiology cells
• What cell type lines all blood vessels?

  • Simple squamous endothelial cells
  anatomy cells
• What is the function of nitric oxide released by endothelial cells?

  • Vasodilation by relaxing smooth muscle
  physiology blood_vessels
• What is prostacyclin's role?

  • Vasodilation
  • Inhibition of platelet aggregation
  physiology blood_vessels
• What is endothelin’s role?

  • Potent vasoconstriction
  physiology blood_vessels
• What is the function of von Willebrand factor?

  • Mediates platelet adhesion during clot formation
  physiology blood_vessels
• What is the main difference between arteries and veins?

  • Arteries have thicker walls and thicker tunica media
  • Veins have larger lumens and thicker adventitia
  anatomy blood_vessels
• Why do veins have valves?

  • To prevent backflow due to low pressure
  physiology blood_vessels
• What are the three types of arteries?

  • Elastic arteries
  • Muscular arteries
  • Small arteries/arterioles
  anatomy arteries
• What characterizes elastic arteries?

  • Numerous elastic lamellae in the tunica media
  anatomy arteries
• What is the function of elastic arteries?

  • Maintain continuous blood flow by smoothing pressure fluctuations
  physiology arteries
• How does an elastic artery appear on slides?

  • Thick wall
  • Many wavy pink elastic layers
  • Relatively small lumen
  anatomy histology
• What characterizes muscular arteries?

  • Prominent internal elastic lamina
  • Many smooth muscle layers in tunica media
  anatomy arteries
• How can you recognize a muscular artery on slides?

  • Clear internal elastic lamina
  • Thick smooth muscle media
  anatomy histology
• What defines small arteries?

  • Up to 8 layers of smooth muscle in the tunica media
  anatomy arteries
• What defines arterioles?

  • 1–2 layers of smooth muscle in the tunica media
  anatomy arteries
• Why are arterioles important?

  • Major regulators of systemic blood pressure
  • Flow into capillaries
  physiology arteries
• How do arterioles appear on histology?

  • Very small lumen
  • 1–2 smooth muscle layers
  • Round profile
  anatomy histology
• What is microcirculation?

  • Blood flow through arterioles, capillaries, and venules
  physiology circulation
• What are capillaries?

  • Thin-walled vessels allowing exchange of gases, nutrients, and wastes
  anatomy blood_vessels
• What is the diameter of most capillaries?

  • 7–9 µm
  anatomy capillaries
• What are the three types of capillaries?

  • Continuous
  • Fenestrated
  • Discontinuous (sinusoidal)
  anatomy capillaries
• What characterizes continuous capillaries?

  • Tight junctions
  • No fenestrations; found in muscle, CNS, lung
  anatomy capillaries
• How do continuous capillaries appear on slides?

  • Very thin wall
  • Only endothelium and basal lamina
  anatomy histology
• What characterizes fenestrated capillaries?

  • Circular pores with or without diaphragms; found in endocrine glands, kidney, intestines
  anatomy capillaries
• How do fenestrated capillaries appear on slides?

  • Endothelial cells with dot-like fenestrations
  anatomy histology
• What characterizes discontinuous capillaries?

  • Large gaps between cells
  • Discontinuous basal lamina; found in liver, spleen, bone marrow
  anatomy capillaries
• Why are sinusoidal capillaries important?

  • Allow passage of large molecules and cells
  anatomy capillaries
• What are pericytes?

  • Contractile support cells around capillaries and venules
  anatomy cells
• What are postcapillary venules?

  Vessels that collect blood from capillaries; main site of leukocyte extravasation.
  vascular blood
• Why are postcapillary venules important in inflammation?

  Endothelial cells respond to histamine and allow leukocyte migration.
  inflammation blood
• How do postcapillary venules appear on slides?

  Thin-walled, larger lumen than capillaries, little smooth muscle.
  histology vascular
• What distinguishes venules from arterioles?

  Venules have larger, irregular lumens and thinner walls.
  vascular anatomy
• What are small veins characterized by?

  Wider lumen, thin tunica media, thick tunica adventitia.
  vascular anatomy
• How do small/medium veins appear on slides?

  Irregular lumen, thin smooth muscle, often collapsed.
  histology vascular
• What characterizes large veins?

  Very thick adventitia with longitudinal smooth muscle.
  vascular anatomy
• What are the superior and inferior vena cava composed of?

  Very thick tunica adventitia with longitudinal smooth muscle bundles.
  vascular anatomy
• What is the endocardium?

  Inner lining of the heart composed of endothelium and subendothelial connective tissue.
  anatomy cardiology
• What is the myocardium?

  Thick middle layer composed of cardiac muscle.
  anatomy cardiology
• Why is myocardium thicker in the ventricles?

  Higher pressure required for systemic and pulmonary circulation.
  cardiology physiology
• What is the epicardium?

  Outer layer consisting of mesothelium and connective tissue with fat, vessels, and nerves.
  anatomy cardiology
• What is the cardiac skeleton?

  Dense connective tissue framework supporting heart valves and muscle attachment.
  anatomy cardiology
• What structures are part of the cardiac skeleton?

  • Annuli fibrosi
  • Trigona fibrosa
  • Septum membranaceum
  anatomy cardiology
• What is the function of the cardiac skeleton?

  Electric insulation between atria and ventricles.
  function anatomy
• What are heart valves composed of?

  Fibrous connective tissue covered by endocardium.
  anatomy cardiology
• How do valves appear on slides?

  Avascular flaps of dense connective tissue.
  histology cardiology
• What are Purkinje fibers?

  Specialized cardiac muscle cells forming the conduction system.
  anatomy electrophysiology
• How do Purkinje fibers appear on slides?

  Large pale cells with glycogen-rich cytoplasm, fewer myofibrils, peripheral nuclei.
  histology electrophysiology
• Why do Purkinje fibers stain pale?

  High glycogen content displaces myofibrils.
  histology anatomy
• What is the function of the SA node?

  Initiates the heartbeat (pacemaker).
  cardiology electrophysiology
• What is the function of the AV node?

  Delays conduction to allow ventricular filling.
  cardiology electrophysiology
• What is the AV bundle (Bundle of His)?

  Conducting fibers connecting AV node to ventricles.
  cardiology electrophysiology
• What are bundle branches?

  Right and left pathways descending into ventricles.
  cardiology electrophysiology
• What is the function of sympathetic innervation of the heart?

  Increases heart rate and contractility.
  physiology cardiology
• What is the function of parasympathetic innervation of the heart?

  Decreases heart rate.
  physiology cardiology
• What is the main difference between arteries and veins on slides?

  Arteries have round lumens and thick walls; veins have collapsed lumens and thin walls.
  histology vascular
• How do you differentiate elastic vs muscular arteries histologically?

  Elastic arteries have many elastic lamellae; muscular arteries have prominent smooth muscle layers.
  histology vascular
• How do you identify arterioles on slides?

  Small vessel with 1–2 layers of smooth muscle and round lumen.
  histology vascular
• How do you identify capillaries on slides?

  Extremely thin walls—only endothelial cells and basal lamina.
  histology vascular
• How do lymphatic capillaries differ from blood capillaries?

  They have discontinuous basal lamina and lack RBCs.
  anatomy lymphatic
• How do lymphatic vessels appear on slides?

  Very thin walls, irregular shape, valves, no RBCs.
  histology lymphatic
• Where are lymphatic vessels abundant?

  Loose connective tissue beneath epithelium.
  anatomy lymphatic
• What is the function of lymphatic vessels?

  Return excess interstitial fluid to the bloodstream.
  function lymphatic
• What is the thoracic duct?

  Largest lymphatic vessel draining most of the body into the venous angle.
  anatomy lymphatic
• What prevents backflow in lymphatic vessels?

  Internal valves.
  function lymphatic
• What cell junction in endothelial cells modulates permeability?

  Tight junctions (zonula occludens).
  anatomy endothelium
• What are Weibel-Palade bodies?

  Endothelial storage granules containing von Willebrand factor.
  anatomy endothelium
• What is the flow in lymphatic vessels?

  Flow is facilitated by internal valves.
  anatomy lymphatic
• What cell junctions in endothelial cells modulate permeability?

  Tight junctions (zonula occludens).
  cell_biology endothelium
• What are Weibel-Palade bodies?

  Endothelial storage granules containing von Willebrand factor and P-selectin.
  anatomy granules
• What is the main function of the tunica media?

  Regulates vascular tone and blood pressure.
  vascular anatomy
• Which cells synthesize elastic fibers in vessels?

  Smooth muscle cells.
  cell_biology vascular
• Which vessels have the thickest tunica adventitia?

  Large veins.
  anatomy veins
• Which vessels have the thickest tunica media?

  Arteries, especially elastic arteries.
  anatomy arteries
• What is the function of the internal elastic lamina?

  Provides elasticity and separates intima from media.
  vascular anatomy
• Where is the external elastic lamina found?

  Between the tunica media and tunica adventitia in muscular arteries.
  anatomy elastic
• How do elastic lamellae appear on H&E?

  Wavy eosinophilic sheets.
  histology vascular
• What is the role of smooth muscle in veins?

  Weak contraction; assists in venous return.
  anatomy veins
• What is the function of arteriovenous shunts?

  Regulate body temperature by bypassing capillaries.
  anatomy regulation
• Where are AV shunts found?

  Skin of fingers, toes, and ears.
  anatomy shunts
• What are metarterioles?

  Transitional vessels between arterioles and capillaries.
  vascular anatomy
• What are precapillary sphincters?

  Smooth muscle regulators controlling capillary flow.
  vascular regulation
• What happens when precapillary sphincters contract?

  Blood bypasses capillary beds.
  vascular flow
• What is transcytosis?

  Transport of macromolecules across endothelium via vesicles.
  cell_biology transport
• What promotes leukocyte adhesion to postcapillary venules?

  Expression of P-selectin and E-selectin.
  immunology adhesion
• What is edema?

  Excess interstitial fluid due to impaired lymphatic drainage.
  pathology fluid
• Which vessels are most permeable?

  Sinusoidal capillaries.
  vascular permeability
• Which chamber of the heart has the thickest myocardium?

  Left ventricle.
  anatomy heart
• What are intercalated discs?

  Specialized junctions between cardiac muscle cells for electrical coupling.
  cardiology cells
• Which layer of the heart contains coronary vessels?

  Epicardium.
  anatomy heart
• What is the endothelium of the endocardium?

  Simple squamous epithelium.
  anatomy endocardium
• Where are Purkinje fibers located?

  Subendocardial layer of ventricles.
  cardiology fibers
• Why do veins have thinner tunica media?

  Lower pressure system requires less smooth muscle.
  vascular veins
• Why do large arteries require elastic recoil?

  To maintain continuous blood flow during diastole.
  vascular arteries
• Which vessels serve as blood reservoirs?

  Veins.
  anatomy reservoirs
• How do lymphatic valves appear on slides?

  Two leaf-like flaps protruding into the lumen.
  histology valves
• Which vessels commonly collapse in histological sections?

  Veins and lymphatic vessels.
  histology collapse
• Which vessels maintain a round shape in histology?

  Arteries due to thick smooth muscle walls.
  histology shape
• What is the best slide clue for identifying an elastic artery?

  Multiple thick elastin sheets in the tunica media.
  histology elastic
• What is the best slide clue for identifying a muscular artery?

  Prominent internal elastic lamina and thick smooth muscle.
  histology muscular
• What is the best slide clue for identifying a vein?

  Thin wall, collapsed lumen, thick adventitia.
  histology vein
• What is the best slide clue for identifying a lymphatic vessel?

  Thin irregular wall, no RBCs, visible valves.
  histology lymphatic