Chapter 20 - Heart and Neck Vessels Flashcards
Precordium
the area on the anterior chest overlying the heart and great vessels
Mediastinum
where the heart and great vessels are located in the thoracic cage
How is the heart positioned?
so the right side is anterior and the left side is mostly posterior
Where is the right ventricle located?
immediately behind the sternum, greatest area of cardiac surface
Which ventricle forms the apex?
left
Which portion of the left atrium shows anteriorly?
the left atrial appendage
Which part of the heart beats on the chest wall producing an apical impulse?
the apex
Pericardium
the tough, fibrous, double-walled sac that surrounds the heart
Myocardium
the muscular wall of the heart, it does the pumping
Endocardium
the thin layer of endothelial tissue that lines the inner surface of the heart
Atrium
thin-walled reservoir for holding blood
Ventricle
thick-walled muscular pumping chamber
Main purpose of valves:
prevent backflow of blood
Valves open and close __________ in response to pressure gradients
passively
Atrioventricular valves
separate the atria and ventricles
Tricuspid valve
the right AV valve
Mitral (aka bicuspid) Valve
left AV valve
Chordae Tendineae
collagenous fibres that anchor valves to the muscle wall
When do the AV valve open?
when the heart is filling (diastole)
When do the AV valves close?
during the pumping phase (systole)
Semilunar Valves
located between the ventricles and pulmonary arteries
How many cusps do the semilunar valves have?
3
Pulmonic Valve
semilunar valve in the right side of the heart
Aortic Valve
semilunar valve in the left side of the heart
When do semilunar valves open?
during pumping so blood can be ejected
Cardiac Cycle
the rhythmic movement of blood through the heart
Diastole
ventricles relax and fill with blood
Systole
heart contracts
Diastole takes up _____ of the cardiac cycle
2/3
Systole takes up ____ of the cardiac cycle
1/3
What happens during diastole?
-ventricles are relaxed
-AV valves are open
What is the heart sound that is heard?
valves closing
Protodiastolic (early) Filling
the first passive filling phase
Presystole (Atrial systole, Atrial kick)
active phase when the atria contract and push out the last amount of blood
What signals the beginning of systole?
closure of the AV valves
Atrial systole occurs during…
ventricular diastole
Atrial kick causes a small rise in _____ ventricular pressure
left
What happens during systole?
-ventricular pressure increases
-mitral and tricuspid valves swing shut
Isometric Contraction
when all 4 valves are closed, ventricular walls contract and pressure builds up
Heart sounds:
lubb - av valves close
dubb -sl valves close
Where can you hear S1?
over all the precordium, usually loudest at the apex
Where is S2 heard loudest?
at the base
What does “MoRe to the Right, Less to the Left” mean?
during inspiration, intrathoracic pressure is decreased, pushing more blood into the venae cavae, thus increasing venous return to the right side of the heart
When is S3 heard?
when the ventricles are resistant to filling during the early filling phase
When does S4 occur?
at the end of diastole when the ventricle is resistant to filling
What can cause murmurs?
-increase in velocity of blood flow
-decrease in VIScosity of blood
-structural defect in the valves or unusual openings in chambers
What are the 4 characteristics of a heart sound?
-frequency (pitch)
-intensity (loudness)
-duration
-timing
Automaticity
heart can contract by itself, independently of any signals or stimulation
Where is an electrical impulse initiated?
cells in the SA node near the superior vena cava
The SA node is the…
pacemaker of the heart
Where does the bundle of His transmit impulses?
to the point of the apex
P wave
depolarization of the atria
P-R interval
interval from P wave to QRS complex
QRS complex
depolarization of the ventricles
T wave
repolarization of the ventricles
Electrical events _______ precede mechanical events in the heart
slightly
How many L of blood are pumped through the body per minute?
4-6L
Cardiac Output
the volume of blood in each systole (stroke volume) x number of bpm
Preload
the venous return that builds during diastole
Frank-Starling law says that the…
greater the stretch, the stronger the contraction
Afterload
the opposing pressure that the ventricle must generate to open the aortic valve
Carotid Artery
located between the trachea and the sternomastoid muscle
Jugular Vein Pulse
results from movement of a waveform backward as a result of events upstream
When does the fetal heart begin to beat?
end of 3 weeks gestation
Where does fetal oxygenation take place?
the placenta
2/3 of fresh oxygenated blood is shunted through the ______ ______
foramen ovale into the left side of the heart
Ductus Arteriosus
where the other 1/3 of the fresh blood is shunted to the aorta
The fetal heart is equal in…
weight and muscle wall thickness
The foramen ovale closes when?
within the first hour after birth
When does the ductus arteriosus close?
within 10-15 hours after birth
When does the left ventricle increase in side?
1 year of age
What is the adult ratio of left ventricle to right ventricle?
2:1
How does the position of the heart vary in infants?
-more horizontal
-apex is higher
When does the heart reach adult position?
by 7 years of age
Blood volume increased by ___ to ____% during pregnancy
30-40%
How is the pulse rate affected in pregnant women?
beats 10-15bpm faster due to blood volume expansion
The pulse rate returns to baseline within first ____ days postpartum
10
Arterial BP __________ in blood pressure during pregnancy due to…
decreases; peripheral vasodilation
When does the blood pressure drop to the lowest point?
during second trimester then rises
With aging _______ blood pressure increases due to…
systolic; thickening and stiffening of large arteries
Arteriosclerosis
stiffening of arteries
Does the overall heart size increase with age?
no
Which ventricle thickens with aging?
left (an adaptive mechanism)
Diastolic BP may decrease after age __
60
No change in ______________ occurs with aging
resting HR
Does CO at rest change with aging?
no
look at subjective, objective assessment and pathology
