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Human A&P BIO 304 · American River College ← Course home (Week 6)

BIO 304 . WEEK 6 . TUESDAY . LAB WORKBOOK

Heart Anatomy and the Cardiac Cycle

Four chambers, four valves, two circuits, and the rhythm of systole and diastole.

Print this page. You will draw your own diagrams from the directions below, then hand-label the structures listed. Drawing by hand is the integrity mechanism for this course.

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Part 1 of 2

Anatomy Lab

1A. What you will draw

The heart is two pumps in one organ: the right side serves the pulmonary circuit (to lungs), the left side serves the systemic circuit (to body). Today you'll draw the heart in frontal section, then walk through one cardiac cycle.

Box A. Heart in frontal section

Directions

  1. Draw the heart with the apex pointing down and to the patient's left. Show four chambers separated by septa.
  2. Top right: right atrium (RA). Top left: left atrium (LA). Bottom right: right ventricle (RV). Bottom left: left ventricle (LV). Label each.
  3. Show the four valves: tricuspid (between RA and RV), pulmonary (between RV and pulmonary trunk), mitral or bicuspid (between LA and LV), aortic (between LV and aorta). Label each valve with arrows showing one-way flow.
  4. Show the great vessels: superior vena cava + inferior vena cava draining into RA; pulmonary trunk leaving RV (to lungs); pulmonary veins entering LA (from lungs); aorta leaving LV.
  5. Add arrows tracing blood flow: deoxygenated blood enters RA, through tricuspid into RV, out pulmonary to lungs; oxygenated blood returns to LA, through mitral into LV, out aorta to body.
  6. Note: the LV wall is thicker than the RV wall. Show this with a thicker line. Label myocardium.

Box B. The cardiac cycle (one beat)

Directions

  1. Draw two heart silhouettes side by side, both showing all four chambers.
  2. Left silhouette: DIASTOLE (ventricles relaxed). Show atria contracting and pushing blood into ventricles. Tricuspid and mitral valves OPEN. Pulmonary and aortic valves CLOSED.
  3. Right silhouette: SYSTOLE (ventricles contracted). Show ventricles squeezing blood out to lungs and body. Tricuspid and mitral valves CLOSED. Pulmonary and aortic valves OPEN.
  4. Below the silhouettes, draw a pressure-time graph. Show LV pressure rising sharply during systole, falling during diastole. Show aortic pressure following LV during systole, holding higher during diastole (because of valve closure).
  5. Label end-diastolic volume (EDV, max ventricle volume), end-systolic volume (ESV, min volume after contraction), and stroke volume (SV = EDV minus ESV).
  6. Note: the heart sounds 'lub-dub' correspond to valve closure: lub = AV valves close at start of systole; dub = semilunar valves close at start of diastole.

1C. Structures to label (20)

After you finish each drawing, label every structure below directly on your sketch.

  1. Right atrium
  2. Left atrium
  3. Right ventricle
  4. Left ventricle
  5. Tricuspid valve
  6. Mitral (bicuspid) valve
  7. Pulmonary semilunar valve
  8. Aortic semilunar valve
  9. Superior vena cava
  10. Inferior vena cava
  11. Pulmonary trunk
  12. Pulmonary veins
  13. Aorta
  14. Interventricular septum
  15. Myocardium
  16. Systole
  17. Diastole
  18. End-diastolic volume (EDV)
  19. End-systolic volume (ESV)
  20. Stroke volume

Part 2 of 2

Physiology Lab

2A. Trace one drop of blood from RA to body

Trace one drop of blood starting in the right atrium until it reaches the systemic capillaries delivering oxygen to body tissues. List every chamber, valve, and vessel it passes through, in order. Aim for 10 to 12 steps.

2B. Synthesis questions

Answer each in 2 to 4 sentences. Use the language from this week's lecture and your drawings as evidence.

1. A patient has mitral valve regurgitation (the mitral valve doesn't close fully). Predict the effect on blood flow during left ventricular systole, and predict the symptom the patient most often reports.
2. A myocardial infarction (heart attack) damages the LV wall. Predict the effect on stroke volume, ejection fraction, and the patient's exercise tolerance. Why does LV damage cause backup of blood into the lungs (pulmonary congestion)?
3. The LV wall is much thicker than the RV wall. Explain why this difference exists, in terms of the pressure the LV must generate vs the RV. What changes in the RV wall when chronic pulmonary hypertension develops?

3. What to submit

Complete both the Anatomy Lab (your own drawings, hand-labeled, plus the structures list) and the Physiology Lab (activity and synthesis questions). Photograph or scan every page and upload to Canvas before the deadline listed on the schedule. Hand-drawn, hand-labeled work is the integrity mechanism for this course. Typed or AI-generated diagrams are not accepted.