Worksheet III: Circulatory System-The Heart
1.   The heart is located __a__ (anterior/posterior/etc.) to the sternum and __b__ (dorsal/posterior/ etc.) to the vertebrae in the medial cavity of the larger __c__ cavity.  This medial cavity is called the __d__.  The apex of the heart points toward the __e__ (left/right) __f__ (hip/shoulder).
    a. ______________________________        d. ______________________________
    b. ______________________________        e. ______________________________
    c. ______________________________        f. _______________________________

2.  The heart is covered by a double-walled sac of connective tissue called the __a__.  The __a__ is divided into two layers called the __b__ and __c__.  The __b__ is the outermost layer composed of tough connective tissue that anchors the heart to the other organs in the thoracic cavity.  The __c__ is the innermost layer composed of a slippery membrane and is also subdivided.  The layer that lines the inner surface of the __b__ is called the __d__ layer while the layer that lines the outer part of the heart wall is called the __e__ layer.  The __e__ layer is also called the __f__.  The space between the __d__ and __e__ layers is called the __g__.
    a. ______________________________        e. ______________________________
    b. ______________________________        f. ______________________________
    c. ______________________________        g. _______________________________
    d. ______________________________

3. What is the function of the serous pericardium? ___________________________________________

4. List, from outermost to innermost, the layers of the heart wall.   
                                _______________________________
                                _______________________________
                                _______________________________

5.  The __a__ is only found in the fetal heart.  It is a shunt between the pulmonary trunk and aorta.  After birth the __a__ becomes the __b__.  Also in the fetal heart is an opening between the two atria called the __c__.  It becomes a shallow depression after birth called the __d__.
    a. ______________________________        c. ______________________________
    b. ______________________________        d. ______________________________

6. What is the purpose of the fetal modifications discussed in question #5?
                _______________________________________________________

7.  Identify the parts of the heart based on the information given below.
    a.  Wall of muscle and connective tissue that separates the ventricles.              _______________________________
    b. Outer, flap-like extensions of atria.                                                                _______________________________
    c. Valve between the right atrium and right ventricle.                                        _______________________________
    d. Valve at the base of the aorta.                                                                        _______________________________
    e. Muscles that anchor AV valves and protrude from the ventricle wall.           _______________________________
    f. Ridges of muscles in interatrial wall.                                                              _______________________________
    g. The muscle and connective tissue that separates the two atria.                      _______________________________
    h. The upper two thin-walled chambers.                                                           _______________________________
    i. Irregular muscle ridges or columns in walls of ventricles.                              _______________________________
    j.  Valve at the base of the pulmonary trunk.                                                     _______________________________
    k. Valve between the left atrium and left ventricle.                                            _______________________________
    l. The lower two thick-walled chambers.                                                           _______________________________

8.  Identify the circulation division based on the descriptions given below.
    a. Includes pulmonary arteries, lungs, and pulmonary veins. ____________________________
    b. Circuitry between the heart and body tissues.                    _______________________________
    c. Includes coronary arteries, coronary veins, and sinus.       _______________________________
    d. Circuitry between the heart and lungs.                               _______________________________
    e. Circuitry that nourishes and removes wastes from the heart muscle. ________________________

9.  What two sounds does a normal heart make? _______________________________
    a. What causes the first sound?                        _______________________________
    b. What causes the second sound?                  _______________________________
    c. Abnormal heart sounds are called:               _______________________________

10. Identify the disorder or structural defect associated with the heart.
    a. Flaps (valves) are stiff and constrict openings between chambers.             _______________________________
    b. The foramen ovale does not close after birth.                                             _______________________________
    c.  Valve does not close tight and allows blood to backflow.                         _____________________________
    d. Valves are weak and billow into atrial chambers during ventricular systole. ______________________________
    e.  Cardiac muscle tissue dies and is replaced with scar tissue.                       __________________________
    f.  Heart beat is irregular.                                                                                _______________________________
    g. Heart rate is above 100beats/min. when at rest.                                          _______________________________
    h. Heart rate is below 60 beats/min. when at rest.                                           _______________________________
    i. The ventricular septum has an opening that connects the right and left ventricles. __________________________
    j. An additional pacemaker occurs in the heart causing an arrhythmic heart beat.  ____________________________
    k. A fluttering or any abnormal heart rate or rhythm.                                      _______________________________
    l. Atrial beat at a rate of 240-360 beats/min.                                                    _______________________________
    m. Asynchronous contractions of atrial muscles; impulses
    arrive at AV node so fast that all cannot get through.                                      _______________________________
    n. Asynchronous ventricular contractions; impulses travel
    to parts of ventricle at different rates.                                                               _______________________________
    o. Right side of the heart pumps inefficiently compared
    to left side; blood and fluids build up in organs.                                              _______________________________
    p. Left side of heart pumps inefficiently compared to
    right side; blood and fluids build up in lungs.                                                  _______________________________
    q. Disease of the vessels; narrowed with fatty deposits and less elastic.          _______________________________

11.  List 10 structural features of the heart muscle.    
                            ______________________________________
                            ______________________________________
                            ______________________________________
                            ______________________________________
                            ______________________________________
                        _____________________________________________
                        _____________________________________________
                        _____________________________________________
                        _____________________________________________
                        _____________________________________________

12.  Name, in the correct sequence of impulse travel, the 4 major components of the heart's nodal system.                                                                                ________________________________
                                ________________________________
                                ________________________________
                                ________________________________

13.  The heart beat is initiated by the __a__ (Give the more scientific name for this structure.).  However, it can be regulated by cardiovascular centers in the brain via the __b__ nerve.   The __a__ is located in the __c__ (right/left/lower/upper) atrial wall just below the entrance of the vena cavae.  It self-depolarizes at an average rate of __d__ beats/minute.  This wave of depolarization spreads __e__ (across and up/across and down) the atrial muscles causing the atrial muscles to contract and force the blood __f__ (downward/upward) into the ventricles.   Next, the wave of depolarization arrives at the __g__ in the __h__ (lower/upper/middle) portion of the interatrial septum.  This area is also self-depolarizing, but its rate is normally set by the __a__.  Impulses sent out from the __g__ __i__ (descend/ascend) along heavily insulated muscle fibers called the __j__.  These __j__ fibers branch  __k__ (upward and downward/downward and upward) to become the __l__ fibers.  As the __l__ fibers stimulate muscle cells to contract, the ventricles contract from __m__ (apex toward atria/atria towards apex) driving the blood __n__ (down and out/up and out) through the __o__ (exit point from left ventricle) and __p__ (exit from right ventricle).
    a. ______________________________        i. ______________________________
    b. ______________________________        j. ______________________________
    c. ______________________________        k. ______________________________
    d. ______________________________        l. ______________________________
    e. ______________________________        m. ______________________________
    f. ______________________________        n. ______________________________
    g. ______________________________        o. ______________________________
    h. ______________________________        p. ______________________________

14. A graphical recording of the electrical changes in heart muscle is called a(n):  ________________________

15. Identify the waves or periods of a normal EKG based on the information given below.
    a. Represents ventricular repolarization.            ______________________________
    b. From beginning of ventricular depolarization thru
    repolarization.                        ______________________________
    c. Last significant wave of EKG.                ______________________________
    d. Represents depolarization of SA node.        ______________________________
    e. Represents ventricular depolarization.            ______________________________
    f. Largest, in amplitude, of the 3 waves.            ______________________________
    g.  Where the wave for atrial repolarization is hidden.    ______________________________
    h.  The smallest and first wave.                ______________________________
    i. Represents ventricular repolarization.            ______________________________
    j. Time period from atrial depolarization to ventricular
    depolarization.                        ______________________________
16.  Identify the site (vessel, chamber, or organ) that blood travels to next and also if the blood is oxygenated or deoxygenated.
    a. Vessel that exits left ventricle.                ______________________________
    b. Vessel(s) that empty into the left atrium.        ______________________________
    c. Organ receiving blood from the pulmonary artery.    ______________________________
    d. The chamber that receives blood from the pulmonary
    veins.                            ______________________________
    e. The chamber that blood goes to from the right atrium.    ______________________________
    f. The chamber that receives blood from the vena cavae.    ______________________________
    g. The chamber that blood goes to from the left atrium.    ______________________________
    h.  The vessel that exits from the right ventricle.        ______________________________
    i. The chamber that the aorta exits from.            ______________________________
    j. The chamber that the pulmonary trunk exits from.    ______________________________
17. All the events associated with flow of blood through the heart during one heart beat is called the:
                                ______________________________.










18.  Two major divisions of the cardiac cycle are __a__ and __b__.  __a__ is contraction of the heart muscle and is divided into a contraction of the upper two chambers called __c__  __a__ and a contraction of the lower two chambers called __d__  __a__.  Likewise, __b__ , or relaxation of the heart, is also divided into __e__  __b__ and __f__  __b__.  Pressure changes are usually described in reference to the __g__ (right/left) side of the heart.  Pressures in the __h__ (right/left) side are 1/5 those in the __i__ side.
    a. ______________________________        f. ______________________________
    b. ______________________________        g. ______________________________
    c. ______________________________        h. ______________________________
    d. ______________________________        i. ______________________________
    e. ______________________________
19. Name, in the correct sequence, 5 events of the cardiac cycle starting with the heart completely relaxed stage.                            ___heart completely relaxed______
                                _____________________________
                                _____________________________
                                _____________________________
                                _____________________________
20.  Identify the stage of the cardiac cycle (Use your answers in question #19.) using the information given below.
    a.  SA node depolarizes; wave of depolarization spreads
    out and down through atria.                _____________________________
    b. This is longest of all the stages; occurs during        
    the other stages.                    _____________________________
    
    c.  Atria contract and drive blood into ventricles.        _____________________________
    d. 70% of ventricular filling occurs during this stage.    _____________________________
    e. AV node depolarizes; ventricles contract from apex
    superiorly.                        _____________________________
    f.  This is also a very long stage occurring during the other
    stages, but is characterized by the dicrotic notch.    _____________________________
    g.  Isovolumetric contraction occurs here.        _____________________________
    h. AV valves open initially; semilunar valves closed;
    AV valves close toward the end of this stage.        _____________________________
    i. Ventricular pressure drops under 80 mmHg.        _____________________________
    j.  Semilunar valves burst open; blood forcefully ejected.    _____________________________
    k. Pressure rises to 120 mmHg.                _____________________________
    l. Ventricles bulge with blood being forced into them.    _____________________________
21. Average heart rate = _________ beats/minute.
22.  Answer the following questions concerning cardiac output.
    a. The volume of blood pumped by a ventricle during
    one contraction. (Give term.)                ______________________________
    b. Volume of blood that remains in the ventricles after maximum filling. (Give term.) ______________________________
    c. Volume of blood found in ventricles after atrial systole. Give term._________________________
    d.  Average EDV =                    ______________________________
    e. Average ESV =                    ______________________________
    f. Amount of blood pumped out by each ventricle in one
    minute. (Give term.)                    ______________________________
    g. Average SV =                    ______________________________
    h. If EDV = 130 ml, ESV = 60 ml, and heart rate = 80
    beats/min., what is this persons SV?            ______________________________
    i. What is that (Use information given in h) person's CO? ______________________________
    j. The heart's ability to push CO above normal levels is called: __________________________
23. What 2 factors regulate cardiac output?            _______________________________
                                _______________________________
24. Of the 2 factors listed in question #23, which is the most important and why? ___________________
___________________________________________________________________________________
25.  Name 2 autonomic controls that affect or adjust heart rate.    _______________________________
                                _______________________________



26.  The __a__ body is located where the common carotid artery forks and gives rise to the internal and external carotid arteries.  Pressure receptors, called __b__, in this __a__ body are sensitive to __c__.  If the heart rate increases, blood flow through the __a__ body __d__ (increases/decreases/stays the same).  This __d__ in pressure causes __b__ to fire a nerve impulse to the __e__ center in the medulla.  The __f__ center fires nerve impulses back to the heart via the __g__ nerve.  These impulses __h__ (increase/decrease/do not change) heart rate.
     a. ______________________________        e. ______________________________
    b. ______________________________        f. ______________________________
    c. ______________________________        g. ______________________________
    d. ______________________________        h. ______________________________
27. List 6 other factors, besides autonomic controls that affect heart rate.
                                ______________________________
                                ______________________________
                                ______________________________
                                ______________________________
                                ______________________________
                                ______________________________
28.  Name 3 hormones that increase heart rate.            ______________________________
                                ______________________________
                                ______________________________
29. Name 3 ions that increase or decrease heart rate.        ______________________________
                                ______________________________
                                ______________________________
30. How does increasing temperature affect heart rate?  Why? ________________________________
31. What is the average heart for males?  for females?  ___________________     _________________
32. How does aging  (from infancy to old age) affect heart rate?

33.  Name two factors that influence stroke volume.        _______________________________
                                _______________________________
34. How does ventricular filling affect SV? _________________________________________________
35. The critical factor that controls SV is the amount of stretch before contraction.  This statement is known as the _________________________________________.  Explain. ______________________
___________________________________________________________________________________

36. Which would be more serious:  atrial septal defect or ventricular septa defect.  Why? ____________
___________________________________________________________________________________
___________________________________________________________________________________

37. Why is the left ventricle thicker than the right ventricle? ____________________________________
___________________________________________________________________________________

38. Why is it important for heart muscle to have a very long refractory period? _____________________
___________________________________________________________________________________

39.  Why do both atria contract at the same time when the SA node is located in the wall of the right atrium? _____________________________________________________________________________

40.  What is myogenic tissue and what is the cause of its activity? _______________________________
___________________________________________________________________________________

41. Calculate a person's cardiac output from the following information:  EDV = 150 ml; ESV = 60 ml; pulse rate is 50 pulses/minute. _______________________________________________________________

42. Why is a person's heart rate the most important force affecting cardiac output? __________________
___________________________________________________________________________________

43.  Why are ventricular filling and venous pressure important in affecting the strength of the heart's contraction? _________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________

44. The AV and semilunar valves have unique designs to direct blood flow and prevent backflow.  Explain.
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________

45.  What is an ectopic heart beat and how does it interfere with the heart's normal rhythm? __________
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________

46.  What is the relationship between heart rate and ventricular filling time and stroke volume? Why can athletes increase their heart rates 3 times and not perform at a higher level during events? ____________
___________________________________________________________________________________
___________________________________________________________________________________
___________________________________________________________________________________




































Answers:  Worksheet III-The Heart.

1.      a. posterior                    d. mediastinum
    b. anterior                    e. left
    c. thoracic                    f. hip

2.     a. pericardium                    e. visceral
    b.  fibrous pericardium                f.  epicardium
    c. serous pericardium                g.  percardial cavity
    d. parietal
3. It secretes a lubricate to prevent the heart from creating too much friction against other tissues.
4.  epicardium/myocardium/endocardium
5.     a. ductus arteriosus                c. foramen ovale
    b. liagmentum arteriosum            d. fossa ovalis
6. Both are shunts that take most blood away from the nonfunctioning lungs.
7.     a. Interventricular septum            g. Interatrial septum
    b. Auricles                    h. Atria
    c. Tricuspid valve                i. Trabeculae carneae
    d. Aortic semilunar valve            j. Pulmonary semilunar valve
    e. Papillary muscles                k. Mitral or bicuspid valve
    f. Musculi pectinati                l. Ventricles

8.     a. Pulmonary circuit                d. Pulmonary circuit
    b. Systemic circuit                e. Coronary circuit
    c. Coronary circuit
9.  Lup-dup
    a. AV valves closing
    b. Semilunar valves closing
    c. Murmurs

10.     a. Stenosis                    j. Ectopic pacemaker
    b. Atrial septal defect                k. Palpitation
    c. Valvular insufficiency                l. Atrial flutter
    d. Valvular prolapse                m. Atrial fibrillation
    e. Myocardial infarction                n. Ventricle fibrillation
    f. Arrhythmia                    o.  Systemic edema
    g. Tachycardia                    p. Pulmonary edema
    h. Bradycardia                    q. Atherosclerosis
    i.  Ventricular septal defect
11.  Anastomosing fibers/Cells connected by intercalated discs/Very large numbers of mitochondria/T tubules wider and fewer than in skeletal muscle/SR less elaborate than in skeletal muscle/Totally aerobic-uses mainly fatty acids even when very active/All-or-none law applies to whole organ because of gap junctions that unite cells/Some cells are myogenic-self-depolarizing/Refractory period 100-200 times as long as in skeletal muscle/Cells are uninucleate/Endomysium is loaded with capillaries.
12.  SA node/AV node/Bundle of His/Purkinje fibers.
13.     a. sinoatrial node                i. descend
    b. vagus                    j. Bundle of His
    c. upper                    k. downward and upward
    d.  between 65-80                l. Purkinje
    e. across and down                m. apex towards atria
    f. downward                    n. up and out
    g.  atrioventricular node                o. aorta
    h. lower                        p. pulmonary trunk (arteries)
14. EKG
15.     a. T wave                    f. QRS complex
    b. Q-T interval                    g. QRS complex
    c. T wave                    h.  P wave
    d. P wave                    i. T wave
    e. QRS complex                j. P-R interval


16.     a. Aorta, oxygenated                f. RA, deoxygenated
    b. Pulmonary veins, oxygenated            g. LV, oxygenated
    c. Lungs, ----                    h. Pulmonary trunk, deoxygenated
    d. LA, oxygenated                i. LV, oxygenated
    e.  RV, deoxygenated                j. RV, deoxygenated
17. cardiac cycle
18.     a. systole                    f. ventricular
    b. diastole                    g. left
    c. atrial                        h. right
    d. ventricular                    i. left
    e. atrial
19.  Heart completely relaxed/Atrial systole/Atrial diastole/Ventricular systole/Ventricular diastole.
20.     a. Atrial systole                    g. Ventricular systole
    b. Atrial diastole                    h. Heart completely relaxed
    c. Atrial systole                    i. Ventricular diastole (heart completely relaxed)
    d. Heart completely relaxed            j. Ventricular systole
    e. Ventricular systole                k. Ventricular systole
    f. Ventricular diastole                l. Atrial systole
21.  75

22.     a. SV                        f.  CO
    b. EDV                        g. ~ 70ml
    c. EDV                        h. 70 ml
    d. ~120 ml                    i.  5600 ml/min
    e.  ~ 50 ml                    j. Cardiac reserve
23. Heart rate and stroke volume
24. Heart rate. Because it can vary as much as 3X while SV can only vary 1.5X.
25. Carotid sinus reflex and Aortic reflex.
26.     a. carotid                    e.  cardioregulatory
    b. baroreceptors                f. cardioinhibitory
    c. stretch                    g. vagus
    d. increases                    h. decrease
27.  Chemicals (ions and hormones)/Temperature/Exercise/Emotions/Sex/Age
28. NE, E, and TH
29. Na+, K+, and Ca++
30. Increase temperature, increase cellular metabolism which increases heart rate.
31. 64-72 beats/min males and 72-80 beats/min females
32. Infants have highest heart rates gradually decreases until ~ age 30 and gradually increases until death.
33. Ventricular filling and ventricular emptying.
34. The longer time to fill, the greater the SV.
35. Frank-Starling law of the Heart. With maximal stretching, up to limits of muscle tissue, muscles make the maximal number of cross-bridges and therefore can generate more tension.
36. Ventricular septal defect is much more serious because of the higher pressures that are created by ventricular muscles.  When the ventricles contract blood would be propelled with much greater force between the ventricles and cause greater mixing of oxygenated and deoxygenated blood.
37. The left side of the heart pumps blood throughout the entire body (to the head, arms, body torso, and legs) while the right side of the heart only sends blood to the lungs, a very shorter distance away.  Greater distances require more muscle.
38. Long refractory periods make tetanic contractions less likely.  A heart muscle that undergoes tetany would result in a heart attack and possibly death.
39. Even though the SA node is in the wall of the right atrium, transmission of the impulse travels to both atria at nearly the same time because connective tissue can act as insulator and fiber diameter varies.  The impulse travels more slowly throughout the right atrium because of more connective tissue giving the spreading impulse time to 'catch up' and stimulate the left atrium.
40. Myogenic tissue are self-depolarizing.  The SA and AV nodes are examples in the heart, but many smooth muscle cells also have this ability.  The cause is leaky Na+ gated channels.
41.  EDV (150 ml)  -  ESV (60 ml)  =  SV (90 ml);  CO  = HR (50 beats/min)  X SV (90 ml) = 4500 ml/min.
42.  Heart rate can vary as much as 3 times while SV only varies by one and half times.
43.  Frank-Starling's Law of the Heart states that the critical factor that controls SV is the amount of stretch before contraction.  Therefore, if the ventricles have more blood they will stretch more and more blood, the SV, will be propelled out.  If ventricular diastole is lengthened, allowing more time for filling, and greater pressure in the vena cavae occur, allowing more blood to be delivered during diastole, more blood enters the ventricles and a greater SV results.  
    Once the heart rate triples, the rate of filling declines because of the shortening of diastole to the point that, even under increased venous pressure, less filling is then occurring.