Lesson 6- The Heart

What is atrial systole?

As the signal spreads through the atria, it causes the atria to contract which sends additional blood (atrial kick) into the ventricle in addition to the majority of the blood that flows passively.

Compare and contrast the work of the left and right atria.

Both work at the same moment in time. They both fill with blood coming from the outside of the body and as they fill with blood they both exist relaxed. The difference is that the right atrium is picking up deoxygenated blood and the left atrium is picking up oxygenated blood.

Calculate the cardiac output

CO= HB x SV (Heart beat times the strove volume) Cardiac output is how much volume of blood is released per minute.

The blood exists in a deoxygenated form in the: a. right pump b. left pump c.pulmonary artery d. pulmonary vein e. aorta f. veins g. vena cava h. arteries

Deoygenated is going to be in the veins, right pump, pulmonary artery, vena cava

True or False. The interventricular septum has a uniform thickness.

False. The interventricular septum starts off very thin in what is known as the membrane region and then becomes very thick in the muscular region.

True or False. The SA node is activated by the nervous system.

False. Your heart can beat without the input of the nervous system.

The thicker the myocardium, the greater the ______________.

Hydrostatic pressure it can generate through a contraction. Thus, the left ventricle is the thickest.

What is the role of the visceral layer of the pericardium?

Lubricates the heart together with the pericardial fluid.

What are the two major functions of the valves?

Prevent backward flow and allow the buildup of pressure

What is occurring in the time between the lub and the dub?

Pumping to the body-systole

Order the structures involved in the electrical signal of the heart: AV node, perkinje fibers, bundle of his, SA node

SA node then the AV node then the Bundle of HIs then the Perkinje Fibers

Compare and contrast the state of the heart during systole and diastole

Systole- the semilunar valve is open, the ventricle is contracting, the atria is relaxed and the atrioventircular valves are closed. Blood is being pumped out of heart. Diastole- the atria are contracting, the atrioventricular valves are open, the semilunar valves are closed, the ventricles are relaxed.

Why is your average heart beat 60-100 beats per minute

That is the number of signals that initiate in the SA node

What generates the opening and reciprocal closing of the atrioventricular and semilunar valves

The contraction of the ventricles. The contraction of the ventricle will force the atrioventricular valve closed and the semilunar open.

Why does the blood pressure not just become 0 during diastole

The elasticity of the myocytes allow for a maintenance of pressure even if the ventricle is relaxed.

Describe the interaction between the heart and the nervous system

The heart can pump by itself, but the heart beat can be regulated by the autonomic nervous system. the sympathetic nervous system will speed up the contractions while the parasympathetic will send a signal to the heart via the vagus nerve slowing down the heart beat.

What is occurring in the time between a dub and the next lub?

The heart is filling with blood again-diastole

A patient has a disorder where the blood is now in contact with the myocardium. Which layer of the heart is damaged?

The inner-most layer that is in contact with the blood vessels is the endocardium. Thus, there is probably a hole in the endocardium which is reasonable since the endocardium is very thin.

A patient has a disorder where the heart cannot generate strong enough contractions. which layer of the heart is probably affected?

The myocardium. The myocardium is the thickest layer of the heart and contains the muscles. This is where the contraction occurs and the energy is wasted.

Which layer of the heart contains a gap?

The pericardium. The inner layer which aligns the heart is called the visceral pericardium and then the outer layer is called the parietal pericardium. The gap in between is called the pericardial cavity and it contains fluid. The visceral pericardium may also be called the epicardium. There is also an outermost layer of fibrous protein for protection and connection.

As the atria fill with blood, the ____________ increases resulting in _________________.

The pressure in the atria increases resulting in contraction of the atria and the blood flowing to the ventricle.

The two atrioventricular valves are?

The tricuspid valve and the mitral valve.

Why is the visceral layer of the pericardium sometimes referred to as the epicardium?

The two layers fuse together.

Describe the consequence of broken chordae tendinae or papillary muscles

The valves would not prevent backward flow as efficiently. Valves are connected to the walls of the ventricles through these tendons and the muscle at the end and that is what prevents them from just flopping backwards and opening up.

Compare and contrast the systemic and pulmonary circulation of the lungs.

There is a lot of mixing between systemic circulation and pulmonary circulation. In terms of systemic circulation, there are bronchial arteries bringing oxygen to the lungs for the lungs and bronchial veins taking away deoxygenated blood back to systemic veins. On the pulmonary side, the pulmonary artery brings deoxygenated blood to become oxygenated (but not for the actual lungs) and then pulmonary veins carry the oxygenated blood to the heart. There are mixing. The bronchial arteries which carry oxygen may then dump into the pulmonary veins and take some oxygen back into the heart.

The atrioventricular valves are closed when ____________________ and are open when ______________.

They are closed when the ventricle is going to contract and they are open when the ventricle is relaxed.

The semilunar valves are closed when _______________ and are open when ____________.

They are closed when the ventricle is relaxed and open when the ventricle contracts.

How do the lungs receive oxygen?

They have bronchial arteries that bring the oxygen from the heart.

The tricuspid valve separates _____________________ while the mitral valve separates ______________________.

Tricuspid-right atria from right ventricle (RT) Mitral- Left atria from left ventricle (LM)

The blood exists in a oxygenated form in the: a. right pump b. left pump c.pulmonary artery d. pulmonary vein e. aorta f. veins g. vena cava h. arteries

left pump, pulmonary vein, aorta, arteries

Lub sound occurs when _________ closes and the dub sound occurs when ___________ closes.

the atrioventricular valves close and then the dub sound is when the semilunar valves close.

The pericardium has how many functions?

three. It protects the heart, lubricates the heart (reduce friction of contraction), and connects it to other parts of the body.