BIOL 320 1st EditionLecture 6Outline of Last Lecture I. LeukocytesA. ProductionB. DisordersII. PlateletsIII. HemostasisA. PhasesB. DisordersIV. Human Blood GroupsA. Transfusion ReactionsOutline of Current Lecture V. Rh FactorA. Homeostatic ImbalanceVI. Developmental AspectsVII. Cardiovascular SystemA. HeartCurrent LectureRh Factor- Descriptions:o Rh(-): means no antigens are present on the surface of the erythrocyteo Rh(+): means at least one antigen is present on the surface of the erythrocyteo There are several antigens for Rh Factor but there are eight common antigens (C, D, and E)o Rh(-) make anti-Rh antibodieso First exposure: when Rh(-) is first exposed to Rh(+) either by transfusion or pregnancy, Rh(-) is ok because the body has not made the anti-Rh antibodies.o Second exposure: when Rh(-) is re-exposed to Rh(+), Rh(-) will now have the anti-Rh antibodies to attach the Rh(+) blood, causing agglutination (clumping of the blood). This clumping will lead to a thrombus or embolism and when blood is filtered in the kidneys could cause renal failure.- Homeostatic Imblance:o Erythroblastosis Fetalis (Hemolytic disease of the newborn)o Description:o Mother is Rh(-) and baby is Rh(+) first pregnancy will be ok. Second pregnancy with Rh(-) mother and Rh(+) baby is a problem because the mother now is sensitized and agglutination occurs when mother and baby’s blood mix. The baby becomes anemic and hypoxic. In severe cases, brain damage and even death may result.o Treatment:o The baby can be treated with prebirth transfusions and exchange transfusions after birth.o RhoGAM serum containing anti-Rh antibodies (agglutinins) can prevent the Rh(-) mother from becoming sensitized. By agglutinating the Rh factor, it blocks the mother’s immune response and prevents her sensitization.- Developmental Aspectso Early fetal development: blood cells produced in yolk sac, liver, and spleen.o Late fetal development: blood cells produced in “blood islands” (mesenchyme cells, where bonemarrow comes from), which occurs in third trimester (around month 7). Fetal blood also has specific kind of hemoglobin (HbF). HbF has a higher affinity for oxygen (consequently CO2 as well). This higher affinity ensures the developing baby will get enough oxygen.- Hemopoiesis: formation of blood cells.o In younger children, most bones produce blood cells.- Aging Effects:o Leukemia, anemia, clotting disorders result from heart, vessel, and immune conditions.o Older bone Marrow: Structure changes. Marrow gets replaced with adipose tissue. Fewer leukocytes get produced. See more prevalence of immune attack. Thrombus more prevalent due to worsening heart and vessel tissue damage.Cardiovascular System- Hearto Characteristics: Orientation: diagonal Mediastinum: medial cavity of the thorax Midline Anatomical relationships:- Superior to the diaphragm- Deep to the sternumo Pericardium: double-walled sac Fibrous pericardium: fibrous connective layer Serous pericardium: thin, slipper, two-layer serous membrane Pericardium fluid: lubricates to reduce friction Myocardium: heart muscle Endocardium: seals off muscle from blood…gases can’t diffuse between layers, meaning muscle needs its own vascular (can’t steal from the blood that is being pumped through atria and ventricles). Pericarditis: infection or inflammation of pericardial tissue…build up of fluid sheath around heart creating more pressure on heart to beat, resulting in heart failure.o Flow of Blood (briefly): Right atrium: receive blood from body and fill right ventricle Tricuspid valve: prevents back-flow between right atrium and ventricle Right ventricle: pump blood to pulmonary system to re-oxygenate blood (via pulmonary artery) Left atrium: receive blood from pulmonary system (via pulmonary vein) and fill left ventricle Mitral (bicuspid) valve: prevents back-flow between left atrium and ventricle Left ventricle: pump blood to whole bodyo Important Terms/Structures: Fossa ovalis: shallow depression that marks the spot where an opening, the foramen ovale, existed in the fetal heart Trabeculae carneae: muscle found in the ventricles of the heart Pectinate muscles: muscle found in the atria of the hearto Valves Atrioventricular (AV) valves: located at each atrial-ventricular junction, prevent backflow into the atria when the ventricles are contracting. [Includes the tricuspid and mitral valves.]- Chordae tendinae: tiny white collagen cords, “heart strings” which anchor the cusps to the papillary muscles protruding the from the ventricular walls- Papillary muscles: contract with the other ventricular musculature so that they take up the slack on the chordae tendinae as the full force of ventricular contraction hurls the blood again the AV valve flaps Semilunar (SL) valves: guard the bases of the large arteries issuing from the ventricles (aorta and pulmonary trunk) and prevent backflow into the associated ventricles. Function of Valves:- Relaxed heart: gravity pulls blood from atria to ventricles…AV valves are open- Atria contract: squeeze remaining blood into ventricles…- Ventricles contract:o Pressure pushes AV flaps closedo Papillary muscles contract (keep AV flaps shut)o Blood finds another path out (SL valves)- Relaxed heart: cusps of semilunar (SL) valves catch blood and the weight shuts themo Heart Sounds “Lub-dub” = valves closing- Lub: AV valves closing- dub: SL valves closing Heart Murmur: leakage through the valves due to congenital disorder or infection…the incomplete closing of valves Valve Stenosis: narrowing or stiffening of the valves due to scarring of heart valves (from genetic pre-disposition or calcium deposits)…resulting in the heart having to work harder…heart wearing out…replace valves with cadaver valves, synthetic