1. Chapter 19: The Circulatory System: The Heart
Gross Anatomy of the Heart and Blood Flow

2. Lab: Gross Anatomy of the Heart and Blood Flow
External Structure
Internal Structure
Blood Flow
Through the Heart
To the Heart - Coronary Circulation
Arterial Supply
Venous Return

3. Is this an Anterior or Posterior view of the Heart?
Fig. 19.6a
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4. A. External Anatomy - Anterior
Ligamentum
arteriosum
Aortic arch
Ascending
aorta
Superior vena cava
Left pulmonary
artery
Branches of the
right pulmonary
artery
Pulmonary trunk
Left pulmonary
veins
Right pulmonary
veins
Left auricle
Right auricle
Right atrium
Coronary sulcus
Anterior
interventricular
sulcus
Right ventricle
Inferior vena cava
Left ventricle
Apex of heart
Fig. 19.5a
(a) Anterior view
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5. A. External Anatomy - Anterior
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Atrioventricular sulcus - separates atria and ventricles
Interventricular sulcus - overlies the interventricular septum that divides the right ventricle from the left
Sulci contain coronary arteries
Ligamentum
arteriosum
Aortic arch
Ascending
aorta
Superior vena cava
Left pulmonary
artery
Branches of the
right pulmonary
artery
Pulmonary trunk
Left pulmonary
veins
Right pulmonary
veins
Left auricle
Right auricle
Right atrium
Coronary sulcus
Anterior
interventricular
sulcus
Right ventricle
Inferior vena cava
Left ventricle
Apex of heart
(a) Anterior view
Figure 19.5a
19-12

6. B. External Anatomy -Posterior
Aorta
Left pulmonary
artery
Superior
vena cava
Right pulmonary
artery
Left pulmonary
veins
Right pulmonary
veins
Left atrium
Coronary sulcus
Right atrium
Coronary sinus
Inferior vena cava
Fat
Posterior
interventricular
sulcus
Left ventricle
Apex of heart
Right ventricle
(b) Posterior view
Fig. 19.5b
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7. B. Internal Anatomy- Heart Chambers
Four Chambers
Right and Left Atria
two superior chambers
receive blood returning to heart
auricles enlarge chamber
Right and Left Ventricles
two inferior chambers
pump blood into arteries
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Aorta
Right pulmonary
artery
Left pulmonary artery
Superior vena cava
Pulmonary trunk
Right pulmonary
veins
Left pulmonary veins
Pulmonary valve
Interatrial
septum
Left atrium
Right atrium
Aortic valve
Fossa ovalis
Left AV (bicuspid) valve
Pectinate muscles
Left ventricle
Right AV
(tricuspid) valve
Papillary muscle
Tendinous cords
Interventricular septum
Endocardium
Trabeculae carneae
Myocardium
Right ventricle
Epicardium
Inferior vena cava
Figure 19.7
19-11

8. Internal Anatomy - Anterior
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Aorta
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Superior vena cava
Right pulmonary
veins
Left pulmonary veins
Pulmonary valve
Interatrial
septum
Left atrium
Right atrium
Aortic valve
Fossa ovalis
Left AV (bicuspid) valve
Pectinate muscles
Left ventricle
Right AV
(tricuspid) valve
Papillary muscle
Interventricular septum
Tendinous cords
Endocardium
Trabeculae carneae
Myocardium
Right ventricle
Epicardium
Inferior vena cava
Figure 19.7
19-15

9. B. Internal Anatomy-Heart Chambers
Right and Left Atria
right and left atria
separated by Interatrial Septum
RA and RV separated by
Right AV (Tricuspid) Valve
LA and LV separated by
Left AV (Bicuspid, Mitral) Valve
Right and Left Ventricles
right and left ventricles separated by Interventricular Septum
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Aorta
Right pulmonary
artery
Left pulmonary artery
Superior vena cava
Pulmonary trunk
Right pulmonary
veins
Left pulmonary veins
Pulmonary valve
Interatrial
septum
Left atrium
Right atrium
Aortic valve
Fossa ovalis
Left AV (bicuspid) valve
Pectinate muscles
Left ventricle
Right AV
(tricuspid) valve
Papillary muscle
Tendinous cords
Interventricular septum
Endocardium
Trabeculae carneae
Myocardium
Right ventricle
Epicardium
Inferior vena cava
Figure 19.7
19-11

10. Internal Anatomy - Anterior
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Aorta
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Superior vena cava
Right pulmonary
veins
Left pulmonary veins
Pulmonary valve
Interatrial
septum
Left atrium
Right atrium
Aortic valve
Fossa ovalis
Left AV (bicuspid) valve
Pectinate muscles
Left ventricle
Right AV
(tricuspid) valve
Papillary muscle
Interventricular septum
Tendinous cords
Endocardium
Trabeculae carneae
Myocardium
Right ventricle
Epicardium
Inferior vena cava
Figure 19.7
19-15

11. Heart Valves Valves ensure a one-way flow of blood through the heart
Two Atrioventricular (AV) Valves – control blood flow between atria and ventricles
Right AV Valve
Left AV Valve
Two Semilunar Valves - control flow into great arteries
Pulmonary Semilunar Valve
Aortic Semilunar Valve

12. Heart Valves Atrioventricular (AV) valves
Control blood flow between atria and ventricles
Right AV Valve (Tricuspid Valve)
Has 3 cusps
Separates Right Atrium and Right Ventricle
Allows blood flow from right atrium to right ventricle upon atrial contraction
Prevents blood back flow into right atrium upon ventricular contraction
Left AV Valve (Mitral or Bicuspid Valve)
Has 2 cusps
Separates Left Atrium and and Left Ventricle
Allows blood flow from left atrium to left ventricle upon atrial contraction
Prevents blood back flow into left atrium upon ventricular contraction
19-16

13. Fig. 19.7 Aorta Right pulmonary Left pulmonary artery artery
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Aorta
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Superior vena cava
Right pulmonary
veins
Left pulmonary veins
Interatrial
septum
Left atrium
Right atrium
Left AV (bicuspid) valve
Left ventricle
Right AV
(tricuspid) valve
Interventricular septum
Endocardium
Myocardium
Right ventricle
Epicardium
Inferior vena cava

14. Heart Valves Atrioventricular (AV) valves Chordae Tendineae
Tendinous cords that connect AV valves to papillary muscles on floor of ventricles
Prevent AV valves from flipping inside out or bulging into the atria when the ventricles contract
Papillary Muscles
Small muscle attachments for Chordae Tendineae
On floor of ventricles

15. Fig. 19.7 Aorta Right pulmonary Left pulmonary artery artery
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Aorta
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Superior vena cava
Right pulmonary
veins
Left pulmonary veins
Interatrial
septum
Left atrium
Right atrium
Left AV (bicuspid) valve
Left ventricle
Right AV
(tricuspid) valve
Papillary muscle
Interventricular septum
Tendinous cords
Endocardium
Myocardium
Right ventricle
Epicardium
Inferior vena cava

16. © The McGraw-Hill Companies, Inc.
Heart Valves
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Tendinous
cords
Papillary
muscle
Figure 19.8c
(c)
19-19
© The McGraw-Hill Companies, Inc.

17. Heart Valves Semilunar Valves Pulmonary Semilunar Valve
Control flow into great arteries
Open and close because of blood flow and pressure
Pulmonary Semilunar Valve
In opening between Right Ventricle and Pulmonary Trunk
Allows blood flow out of Right Ventricle into Pulmonary Trunk to lungs
Prevents back flow into the Right Ventricle
Aortic Semilunar Valve
In opening between Left Ventricle and Aorta
Allows blood flow out of left ventricle into Aorta to the body
Prevents back flow into Left Ventricle
19-16

18. Fig. 19.7 Aorta Right pulmonary Left pulmonary artery artery
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Aorta
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Superior vena cava
Right pulmonary
veins
Left pulmonary veins
Pulmonary Semilunar valve
Interatrial
septum
Left atrium
Right atrium
Aortic Semilunar valve
Left AV (bicuspid) valve
Left ventricle
Right AV
(tricuspid) valve
Right ventricle
Inferior vena cava

19. Heart Valves Figure 19.8a Left AV (bicuspid) valve Right AV
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Left AV
(bicuspid) valve
Right AV
(tricuspid) valve
Fibrous
skeleton
Openings to
coronary arteries -
first branch of Aorta
Aortic
valve
Pulmonary
valve
Figure 19.8a
19-17
(a)

20. Endoscopic View of Heart Valve
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Aortic Semilunar
Valve
(b)
© Manfred Kage/Peter Arnold, Inc.
Figure 19.8b
19-18

21. Heart Chambers - Internal
Pectinate Muscles
Internal ridges of myocardium in right atrium and both auricles
Atria not as muscular as ventricles
Trabeculae Carneae
Internal ridges in both ventricles
Left ventricle has a very thick myocardium
19-14

22. Fig. 19.7 Aorta Right pulmonary artery Left pulmonary artery
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Aorta
Right pulmonary
artery
Left pulmonary artery
Pulmonary trunk
Superior vena cava
Right pulmonary
veins
Left pulmonary veins
Pulmonary valve
Interatrial
septum
Left atrium
Right atrium
Aortic valve
Fossa ovalis
Left AV (bicuspid) valve
Pectinate muscles
Left ventricle
Right AV
(tricuspid) valve
Papillary muscle
Interventricular septum
Tendinous cords
Endocardium
Trabeculae carneae
Myocardium
Right ventricle
Epicardium
Inferior vena cava

23. AV Valve Mechanics Stage 1
During Atrial Contraction (Atrial Systole) and Ventricle Relaxation (Ventricular Diastole)
In Atria
Interatrial pressure builds as atria contract
Pressure difference between atria and ventricles force AV valves open
blood flows from atria to ventricle
In Ventricles
Interventricular pressure drops as ventricles relax
semilunar valves close as blood attempts to back up into the ventricles from the vessels
AV valves open
blood flows from atria to ventricle
19-20

24. AV Valve Mechanics Stage 2
During Ventricular Contraction (Ventricular Systole) and Atrial Relaxation (Atrial Diastole)
In Ventricles
Interventricular pressure rises as ventricles contract
AV valves close as blood attempts to back up into the atria
semilunar valves open and blood flows into great vessels (Aorta, Pulmonary Arteries)
In Atria
Interatrial pressure drops as atria relax
AV valves close
Blood from Superior and inferior vena cava/ Left and Right Pulmonary veins refill atria
19-20

25. 1. Blood Flow Through Heart
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Blood enters right atrium from superior
and inferior venae cavae. 2
Blood in right atrium flows through right
AV valve into right ventricle.
Aorta
Left pulmonary
artery 11 3
Contraction of right ventricle forces
pulmonary valve open. 5 5 9 4
Blood flows through pulmonary valve
into pulmonary trunk.
Pulmonary trunk
Superior
vena cava 4
Left pulmonary
veins 6 5
Blood is distributed by right and left
pulmonary arteries to the lungs, where it
unloads CO2 and loads O2.
Right
pulmonary
veins 6
Left atrium 1 6
Aortic valve
Blood returns from lungs via pulmonary
veins to left atrium. 7 3
Left AV
(bicuspid) valve 7
Blood in left atrium flows through left AV
valve into left ventricle.
Right
atrium 8
Left ventricle 2 8
Contraction of left ventricle (simultaneous with
step 3 ) forces aortic valve open.
Right AV
(tricuspid) valve 9
Blood flows through aortic valve into
ascending aorta.
Right
ventricle
Inferior
vena cava 10
Blood in aorta is distributed to every organ in
the body, where it unloads O2 and loads CO2. 11 11
Blood returns to heart via venae cavae.
Figure 19.9
blood pathway travels from the right atrium through the body and back to the starting point
19-21

26. 2. Blood Flow to Heart - Coronary Circulation
5% of blood pumped by heart is pumped to the heart itself through the coronary circulation
250 ml of blood per minute
Needs abundant O2 and nutrients
Coronary Circulation is very variable
Coronary Circulation is supplied by two main Coronary Arteries
Left Coronary Artery (LCA)
Right Coronary Artery (RCA)
19-22

27. 2. Blood Flow to Heart - Coronary Arteries
1. Left Coronary Artery (LCA)
First branch off the ascending aorta
Has two main branches
Anterior Interventricular Branch
Left Anterior Descending (LAD) Branch
supplies blood to both ventricles and anterior two-thirds of the interventricular septum
aka ‘The Widow Maker’
Circumflex Branch
passes around left side of heart in coronary sulcus
gives off left marginal branch and then ends on the posterior side of the heart
supplies left atrium and posterior wall of left ventricle
19-22

28. Coronary Arteries Figure 19.8a Openings to coronary arteries -
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Openings to
coronary arteries -
first branch of Aorta
Left AV
(bicuspid) valve
Right AV
(tricuspid) valve
Circumflex Branch
of LCA continued posteriorly
Left Marginal Branch of Circumflex
Circumflex Branch of LCA
Left Coronary Artery
Anterior Ventricular Branch (LAD)of LCA
Pulmonary
valve
Aortic
valve
Figure 19.8a
19-17
(a)

29. interventricular (LAD) branch of LCA
Fig a
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Left coronary
artery (LCA)
Left auricle
(reflected)
Circumflex
branch
of LCA
Anterior
interventricular (LAD)
branch of LCA
(a) Anterior view

30. Circumflex branch of LCA Left marginal branch of LCA
Fig b
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Circumflex
branch of
LCA
Left marginal
branch of
LCA
(b) Posterior view

31. 2. Blood Flow to Heart - Coronary Arteries
1. Right Coronary Artery (RCA)
First branch off the ascending aorta
Supplies right atrium and sinoatrial node (pacemaker) and Atrioventricular node
Has two main branches
Right Marginal Branch
supplies lateral aspect of right atrium and ventricle
Posterior Interventricular Branch
supplies posterior walls of ventricles
19-22

32. Coronary Arteries Figure 19.8a Openings to coronary arteries -
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Openings to
coronary arteries -
first branch of Aorta
Left AV
(bicuspid) valve
Right AV
(tricuspid) valve
Posterior
Interventricular
branch of RCA
Right Marginal
Branch of RCA
Right Coronary Artery
Pulmonary
valve
Aortic
valve
Figure 19.8a
19-17
(a)

33. Right coronary artery (RCA) Right marginal branch of RCA
Fig a
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Right
coronary
artery
(RCA)
Right
marginal
branch
of RCA
(a) Anterior view

34. Right coronary artery (RCA) Right marginal branch of RCA Posterior
Fig b
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Right coronary
artery (RCA)
Right marginal
branch of RCA
Posterior
interventricular
branch of RCA
Posterior
interventricular
vein
(b) Posterior view

35. Venous Drainage of Heart
Returns coronary blood to pulmonary and systemic circulation
5 -10% drains directly into right atrium and right ventricle by way of the Thebesian Veins
The rest returns to right atrium through veins to the Coronary Sinus
Three major veins empty into the Coronary Sinus
Great Cardiac Vein
Middle Cardiac Vein
Left Marginal Vein
19-27

36. Venous Drainage of Heart
coronary sinus
Large transverse vein in coronary sulcus on posterior side of heart
Collects blood from three veins and empties into right atrium
Venous Drainage
Great Cardiac Vein
travels along side of anterior interventricular artery (LAD) of LCA
collects blood from anterior portion of heart
Middle Cardiac Vein (posterior interventricular)
travels along side of posterior interventricular branch of RCA
collects blood from posterior portion of heart
Left Marginal Vein
Travels along side of left marginal branch of Circumflex branch of LCA
empties into coronary sinus
19-27

37. Left coronary artery (LCA) Left auricle (reflected) Circumflex branch
Fig a
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Left coronary
artery (LCA)
Left auricle
(reflected)
Circumflex
branch
of LCA
Right
coronary
artery
(RCA)
Great cardiac
vein
Right
marginal
branch
of RCA
Anterior
interventricular
branch of LCA
(a) Anterior view

38. (Posterior interventricular vein)
Fig b
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Great cardiac
vein
Circumflex
branch of
LCA
Coronary
sinus
Right coronary
artery (RCA)
Left marginal
branch of
LCA
Right marginal
branch of RCA
Posterior
interventricular
branch of RCA
Left marginal
vein
Middle Cardiac Vein
(Posterior interventricular
vein)
(b) Posterior view

39. Coronary Blood Flow
Blood flow to the heart muscle during ventricular contraction is slowed, unlike the rest of the body
Three Reasons:
contraction of the myocardium compresses the coronary arteries and obstructs blood flow
opening of the aortic valve flap during ventricular systole covers the openings to the coronary arteries blocking blood flow into them
during ventricular diastole, blood in the aorta surges back toward the heart and into the openings of the coronary arteries
blood flow to the myocardium increases during ventricular relaxation

40. Angina and Heart Attack
Angina Pectoris
chest pain from partial obstruction of coronary blood flow
pain caused by ischemia of cardiac muscle
myocardium shifts to anaerobic fermentation producing lactic acid stimulating pain
19-26

41. Angina and Heart Attack
Myocardial Infarction (MI)
Heart Attack
interruption of coronary blood flow from a clot or fatty deposit (atheroma) can cause death of cardiac cells
some protection from MI provided by arterial anastomoses which provides an alternative route of blood flow (collateral circulation) within the myocardium
19-25

42. Angina and Heart Attack
Myocardial Infarction
Sudden death of a patch of myocardium resulting from long-term obstruction of coronary circulation
atheroma (blood clot or fatty deposit) often obstruct coronary arteries
cardiac muscle downstream of the blockage dies
heavy pressure or squeezing pain radiating into the left arm
some painless heart attacks may disrupt electrical conduction pathways, lead to fibrillation and cardiac arrest
19-25

43. Practical Exercise 2 Practical Contents: Pre-Lab(20 points)
Short Answer (10 points)
Matching (10 points)
Small Group Dissection Portion (60 points)
Proctored Q and A (30 points)
Labeling (20 points)
Dissections (5 points)
Participation/ Protocol (5 points)
Post-Lab
Discussion Questions (20 points)

44. How to Prepare for the Practical
Read and Review Chapter 19, images, and the Lecture Slides
Read and Review Chapter 19 Lab Handout and Slides
ID the anatomical structures listed on your lab handout
Review blood flow
Review Resources
Review anatomical models and software in LC
Come prepared for WET LAB
Please see me if you object to conducting dissections