Physio_23.txt

vibration of the taut valves immediately after closure along wont vibration of adjacent walls of the heart and major vessels

• first 0.14
• second 0.11
• the second os hotter because the semilunar valves are more taut than the AV valves so they vibrate for a shorter time

• the second usually has a higher frequency
• 1 the tautness
• 2 greater elastic coefficient of the arterial walls that provide the principle vibrating chamber

• first is longer with a lower frequency
• second is shorter with a higher frequency

• weak rumble in the middle third of diastole
• oscillation of blood between the walls of the ventricle
• reason it does not appear until the middle of diastole is that in the early part of diastole the ventricles are not filled enough to create the elastic tension needed to reverberate
• very low frequency

• the atrial heart sound
• heard when the atria contract and blood rushes into ventricle

special microphone to record heart sounds

rheumatic fever

• autoimmune disease
• begins with infection by Group A hemolytic streptococci; sore throat, scarlet fever, middle ear infection
• the streptococci release proteins which antibodies are formed
• the antibodies react not only with the proteins but also with other proteins of the body
• Inflammation occurs along the edges of the heart valves
• mitral>aortic
• The inflammation on adjacent leaflets cause them to become stuck and fuse together. the edges also become solid, scarred masses

• because of resistance to ejection LV pressure can reach 300, this creates a nozzle effect.
• this turbulent blood vibrates the walls of the aorta and causes the murmur
• If severe may cause a thrill, being able to feel the vibration on the chest

• during diastole blood flows backward from the aorta into the ventricle
• blowing murmur

• blood flows backward through the mitral valve during systole
• pansystolic murmur heard at the apex of the heart

• left atrial pressure can rise to 30 mmHg
• not heard until middle third of systole with an increase at the end due to atrial contraction

• Ao stenosis id loudest
• mitral stenosis is softest

• they both decrease stroke volume
• stenosis does not allow the LV to empty entirely
• regurge allows blood to flow back into the ventricle

• hypertrophy of the LV; due to increased workload. In regurge the LV also enlarges to hold the extra blood. Allows the LV the generate a much higher pressure and stroke volume
• Increases in blood volume; results from an initial drop in arterial blood pressure and circulatory reflexes that are induced by the drop in pressure

• the LV finally cannot keep up with the workload
• as a consequence the LV dilates and output begins to fall
• blood dams up in the left atrium and in the lungs
• left atrial pressure rises and causes pulmonary edema

the lung lymphatic system enlarges and carries fluid away

• the enlargement increases the distance that the impulse must travel in the atrial wall
• may become so long it causes a circus rhythm
• mitral disease usually cause atrial fib

• problems become exacerbated due to increased return to the heart
• can lead to lethal pulmonary edema or left heart failure
• diminished cardiac reserve
• muscles fatigue rapidly

• stenosis of some point in the heart or a major vessel; valve or coarctation of the aorta . pulmonary edema and reduced cardiac output
• left to right shunt
• right to left shunt

• the lungs inflate during the first breath reducing the pulmonary resistance
• at the same time the aortic pressure increases from the cessation of blood through the umbilical artery
• blood begins to flow backward through th ductus causing it to close, the blood now flowing through it has a much higher O2 concentration causing this constriction

• during early life no effect
• as the child grows the pressure gradient between the aorta and pulmonary artery grows which increases flow backward to the lungs
• no cyanosis until later in life when the heart fails or the lungs become congested

• decreased cardiac reserve and respratory reserve
• LV must pump much more blood and become hypertrophied, when exercising the heart can never pump enough blood as needed
• will faint from moderate activity
• The extra flow through the lungs leads to high pulmonary pressure and to congestion and edema
• no murmur at birth van be heard then will become a machine type murmur through the entire cardiac cycle. waxes and wanes with each beat

tetralogy of fallout

• overriding aorta, originates from the RV or a hole in the septum
• pulmonary valve stenosis
• VSD
• right ventricle hypertrophy

right to left shunt, right ventricle directly to the aorta

• cyanotic
• high systolic RV pressure
• enlarged RV on xray
• angiogram shows VSD

• viral infection during pregnancy, first trimester
• german measles
• some are hereditary