15 articles
Anastomosis
Anastomosis: a surgical connection between tubular structures such as blood vessels or intestine. Covers types (intestinal, vascular), end-to-end/side-to-side/end-to-side configurations, complications, history from Carrel to robotics.
Angiotensin
Angiotensin, especially angiotensin II, is the effector peptide of the renin-angiotensin system regulating blood pressure; discovered 1898-1958, targeted by ACE inhibitors and ARBs, whose comparative cardiovascular outcomes differ across trial populations.
Blood
Blood: specialized circulating body fluid of plasma, red blood cells, white blood cells, and platelets; about 55% plasma, carries oxygen, fights infection, clots; types A, B, AB, O with Rh factor.
Blood Flow Velocity
Blood flow velocity is the speed of blood in vessels (cm/s or m/s), measured mainly by Doppler ultrasound; flow = velocity × cross-sectional area. Key uses: stenosis grading, transcranial Doppler thresholds (vasospasm 180 cm/s, sickle cell 200 cm/s), angle-dependent errors.
Blood vessel
Blood vessels are the arteries, veins, and capillaries that carry blood through the body in pulmonary and systemic circuits; about 60,000 miles total, with three-layered walls, venous valves, and roughly 70 percent of blood volume held in veins.
Cerebral circulation
Cerebral circulation: the arterial, capillary, and venous system supplying the brain, including the circle of Willis, autoregulation (~50 mL/100 g/min, CPP 60-160 mmHg), CO2 reactivity, neurovascular coupling, and the blood-brain barrier.
Coagulation
Coagulation: blood clotting via platelet-fibrin plug formation. Modeled historically by the 1960s cascade and currently by the Hoffman-Monroe cell-based model (initiation, amplification, propagation), with anticoagulant regulation and fibrinolysis.
Ductus arteriosus
Ductus arteriosus: fetal vessel linking pulmonary artery and aorta; normally closes 24-72 hours after birth via oxygen rise and prostaglandin E2 fall. Persistent patency (PDA) affects 0.3-0.8% of term infants, up to 80% of those born before 28 weeks.
Endothelium
Endothelium: the single layer of endothelial cells lining all blood vessels and lymphatics; term coined by Wilhelm His in 1865; a dynamic organ regulating vascular tone, permeability, hemostasis, inflammation, and angiogenesis, with dysfunction central to atherosclerosis.
Fibrinogen
Fibrinogen (coagulation factor I) is a 340-kDa plasma glycoprotein that thrombin converts to fibrin for blood clotting; also an acute-phase protein and studied cardiovascular risk marker, with concentrate therapies for congenital deficiency.
Hemostasis
Hemostasis, the arrest of bleeding from injured vessels, involves vascular constriction, platelet plug formation, and coagulation; explained by the classic cascade and the modern cell-based model of Hoffman and Monroe.
Livor mortis
Livor mortis, also called postmortem hypostasis or lividity, is the gravity-dependent reddish-purple skin discoloration after death; onset within 20 minutes to 2 hours, fixed after 8 to 12 hours, useful for timing death and detecting body movement.
Oxygen–hemoglobin dissociation curve
Oxygen–hemoglobin dissociation curve (oxyhemoglobin dissociation curve, ODC): sigmoid plot of hemoglobin oxygen saturation versus oxygen partial pressure; P50 about 26 mmHg for adult blood, shifted right by low pH, high CO2, heat, and 2,3-DPG, left by fetal hemoglobin and carbon monoxide.
Reticulocyte
Reticulocyte: an immature anucleate red blood cell that matures in about 1-2 days; also called proerythrocyte. Its count (normal ~0.8-0.9%, ARC 25,000-75,000/µL) gauges marrow erythropoietic activity in anemia, with IRF and CHr parameters.
Vascular resistance
Vascular resistance: opposition of blood vessels to flow, R = (P1−P2)/Q. Covers systemic (SVR) and pulmonary (PVR) resistance, Poiseuille radius dependence, Wood units, and the >2 WU pulmonary hypertension threshold.