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Chapter 15:
The parietal pericardium has a tough outer fibrous layer. Why is this good? When can it be a problem?
Normally, it prevents the heart from overfilling. But, if fluid accumulates in the pericardial space, then the fibrous sac does not stretch and the pressure is placed on the heart, preventing it from filling properly. This is called cardiac tamponade.
Your lab partner dissected the sheep heart in lab before you had a chance to look at it. He really butchered it, to boot. How can you tell what valve you are looking at?
If you see chordae tendineae, then you know you have a AV valve. If it has three flaps it is the tricuspid valve, and if it has two it is the bicuspid or mitral valve. If it does not have chordae tendineae attached, then it is one of the semilunar valves. If there is any ventricle wall left, remember that the tricuspid valve is on the right side where the wall of the ventricle is thinner, and the mitral valve is on the left where the wall is very thick ( high pressure pump!).
You hear an abnormal sound associated with the first heart sound, or lub. What is wrong?
There is some abnormality in one of the AV valves, most likely the mitral valve.
What is the pacemaker of the heart?
The sinoatrial node.
Where is the wave for atrial relaxation (diastole) in the ECG?
It is hidden in the QRS complex. The ventricular contraction completely overwhelms the small wave we would see for atrial diastole.
What part of the brain regulates heart rate?
The medulla oblongata.
What effect would acetylcholine have on the heart? Epinephrine ?
Acetylcholine is the neurotransmitter used by the postganglionic cells of the parasympathetic nervous system, and like that system, would slow down heart rate and decrease the force of contraction. Epinephrine related to norepinephrine, which is the neurotransmitter used by the sympathetic (fight or flight) nervous system, which speeds up heart rate and increases the force of contraction.
What happens if baroreceptors in the arteries detect an increase in blood pressure? If the blood pressure increases in the great veins (vena cavae)?
Barorecptors in the arteries would initiate a negative feedback system to slow the heart and decrease the force of contraction of the heart. However, if the pressure increases on the venous side of the heart, the only thing we can do to decrease that pressure and allow more blood to return to the heart is to increase the rate and force of contraction of the heart to move that blood into the arterial system.
Why would you want a cold operating room if you were doing open heart surgery?
Cold decreases both the heart rate and cellular metabolism. This gives you a longer time to work on the heart.
Name an artery that carries poorly oxygenated blood.  The pulmonary arteries.
What kind of blood do the pulmonary veins carry? Well oxygenated blood- they are returning to the heart from the lungs. Remember the basic definitions of arteries and veins has nothing to do with the kind of blood they carry.
What structure is always found at the start of a true capillary?
A ring of smooth muscle called the precapillary sphincter.
What is the difference in structure between continuous capillaries, fenestrated capillaries, sinusoids, and the capillaries found in the brain?
Continuous capillaries are "normal" capillaries. They have small slits between cells that can expand and allow white blood cells to pass into tissues in case of an infection. Fenestrated capillaries have "windows" or pores in their membranes, and they act like sieves or leaking garden hoses. They are very useful when we want to filter blood to make urine, or cerebrospinal fluid. Sinusoids are capillaries that are just barely held together. Gaps allow cells to pass in and out. These are found in the liver. The capillaries in the brain and testes are held together with tight junctions. Any substances that want to leave the capillary must pass through the cell itself to get into the tissues. This is a protective function.
 What can happen if you lock your knees, as when standing at attention?
You do not need to contract your leg muscles to hold yourself up since you have locked your bones. Without the "milking action" of muscle contraction, the blood is not squeezed toward your heart, and just pools in the veins in your legs. After a while your blood pressure falls, and the amount of blood flowing to your brain decreases and you faint. Once you are horizontal, it is easier for the blood to get back to your heart (it is not fighting the pull of gravity) and you will wake up again.
In what vessels does blood travel the fastest? The big arteries leaving the heart- all the blood is traveling through a relatively small space.
The slowest? The capillaries. If we took the cross-sectional area of all of the capillaries in the body (they are small, but many) and added them together, we would have a very large area for the blood to travel through. This means it moves slowly and allows time for the exchange of nutrients, wastes and gasses.
What is a normal systolic blood pressure? 100-120 m Hg for young, healthy persons, but as high as 140 mm Hg
What is a normal diasystolic blood pressure? 60-80 mm Hg for young, healthy persons, but as high as100 mm Hg
 Besides telling you whether or not a person's heart is beating, what can you tell from a pulse?
You can determine the rate of the heart beat, the regularity of the rhythm, and also get a rough idea of blood pressure depending on where you do and do not feel a pulse.
If a person's heart is beating 70 times per minute, his blood pressure is 110/80 and his left ventricle pumps out 80 ml of blood with every beat, what is his cardiac output?
It is 80ml/beat X 70 beats/min. = 5600 ml/min. or 5.6 L/min. (You don't use blood pressure.)
What is the normal central venous pressure and where is it measured? It is usually measured in the right atrium, and should be close to 0 mm Hg to allow blood to flow back into the heart.
What does the ductus venosus, bypass? The developing liver of the fetus.
 What do thethe ductus arteriosus and the foramen ovale bypass? The ductus arteriosus shunts blood from the pulmonary trunk into the aorta and the foramen ovale allows blood to pass from the right atrium into the left atrium. Both bypass the developing lungs of the fetus.
What kind of blood does the umbilical vein carry? The umbilical vein is carrying blood from the placenta back to the inferior vena cava of the fetus, so it is carrying well-oxygenated blood. The umbilical arteries carry poorly-oxygenated blood from the fetus to the placenta where the blood picks up oxygen. Notice the similarities with the pulmonary circulation in an adult.