Human Anatomy Self-Assessment Review Questions and answers

Human Anatomy  Self-Assessment Review Questions and answers on Cardiovascular System

1. Which of the following is not important in preventing backflow of blood?

1. AV valves
2. endocardium
3. papillary muscles
4. chordae tendineae

2. Which valve separates the left atrium from the left ventricle?

1. tricuspid
2. aortic
3. mitral
4. pulmonary

3. Which of the following lists the valves in the order through which the blood flows from the vena cava through the heart?

1. mitral, pulmonary semilunar, bicuspid, aortic semilunar
2. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar
3. bicuspid, aortic semilunar, tricuspid, pulmonary semilunar
4. aortic semilunar, pulmonary semilunar, tricuspid, bicuspid

4. Which chamber initially receives blood from the systemic circuit?

1. left atrium
2. right atrium
3. left ventricle
4. right ventricle

5. The ________ layer secretes chemicals that help to regulate ionic environments and strength of contraction and serve as powerful vasoconstrictors.

1. myocardium
2. pericardial sac
3. endocardium
4. epicardium

6. The myocardium would be the thickest in the ________.

1. right atrium
2. right ventricle
3. left ventricle
4. left atrium

7. In which septum is it normal to find openings in the adult?

1. all of the above
2. interatrial septum
3. atrioventricular septum
4. interventricular septum

8. Which of the following is unique to cardiac muscle cells?

1. Only cardiac muscle has gap junctions.
2. Only cardiac muscle is capable of autorhythmicity
3. Only cardiac muscle has a high concentration of mitochondria.
4. Only cardiac muscle contains a sarcoplasmic reticulum

9. The influx of which ion accounts for the plateau phase?

1. chloride
2. sodium
3. potassium
4. calcium

10. Which portion of the ECG corresponds to repolarisation of the atria?

1. T wave
2. none of the above: atrial repolarisation is masked by ventricular depolarisation
3. QRS complex
4. P wave

11. Which component of the heart conduction system would have the slowest rate of firing?

1. Purkinje fibres
2. bundle branches
3. atrioventricular bundle
4. atrioventricular node

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Critical questions 

1. Describe how the valves keep the blood moving in one direction.
2. Why is the pressure in the pulmonary circulation lower than in the systemic circulation?
3. Why is the plateau phase so critical to cardiac muscle function?
4. How does the delay of the impulse at the atrioventricular node contribute to cardiac function?
5. How do gap junctions and intercalated disks aid contraction of the heart?
6. Why do the cardiac muscles cells demonstrate autorhythmicity?

Answers

1. endocardium
2. mitral
3. tricuspid, pulmonary semilunar, bicuspid, aortic semilunar
4. right atrium
5. pericardial sac
6. left ventricle
7. atrioventricular septum
8. Only cardiac muscle is capable of autorhythmicity
9. calcium
10. none of the above: atrial repolarisation is masked by ventricular depolarisation
11. Purkinje fibres

Answers to Critical Questions  

1. When the ventricles contract and pressure begins to rise in the ventricles, there is an initial tendency for blood to flow back (regurgitate) to the atria. However, the papillary muscles also contract, placing tension on the chordae tendineae and holding the atrioventricular valves (tricuspid and mitral) in place to prevent the valves from prolapsing and being forced back into the atria. The semilunar valves (pulmonary and aortic) lack chordae tendineae and papillary muscles, but do not face the same pressure gradients as do the atrioventricular valves. As the ventricles relax and pressure drops within the ventricles, there is a tendency for the blood to flow backward. However, the valves, consisting of reinforced endothelium and connective tissue, fill with blood and seal off the opening preventing the return of blood.
2. The pulmonary circuit consists of blood flowing to and from the lungs, whereas the systemic circuit carries blood to and from the entire body. The systemic circuit is far more extensive, consisting of far more vessels and offers much greater resistance to the flow of blood, so the heart must generate a higher pressure to overcome this resistance. This can be seen in the thickness of the myocardium in the ventricles.
3. It prevents additional impulses from spreading through the heart prematurely, thereby allowing the muscle sufficient time to contract and pump blood effectively.
4. It ensures sufficient time for the atrial muscle to contract and pump blood into the ventricles prior to the impulse being conducted into the lower chambers.
5. Gap junctions within the intercalated disks allow impulses to spread from one cardiac muscle cell to another, allowing sodium, potassium, and calcium ions to flow between adjacent cells, propagating the action potential, and ensuring coordinated contractions.
6. Without a true resting potential, there is a slow influx of sodium ions through slow channels that produces a prepotential that gradually reaches threshold.