Heart anatomy

Dr.Waqas Nawaz
PMAS arid agriculture university rawalpindi

1. Submitted to:
Dr.Zeeshan Akbar
Submitted by:
Waqas Nawaz
11-arid-975

2. Heart Anatomy
Approximately the size of your fist
Wt. = 250-300 grams
Location
In the mediastinum between the lungs
Superior surface of diaphragm
’
⅔
s of it lies to the left of the midsternal line
Anterior to the vertebral column, posterior to the
sternum

3. Heart Anatomy
Figure 18.1

4. Coverings of the Heart
Pericardium – a double-walled sac around the
heart
Composed of:
A superficial fibrous pericardium
A deep two-layer serous pericardium
The parietal layer lines the internal surface of the fibrous
pericardium
The visceral layer or epicardium lines the surface of the heart
They are separated by the fluid-filled pericardial cavity called the
pericardial cavity
Protects and anchors the heart
Prevents overfilling of the heart with blood
Allows for the heart to work in a relatively friction-free
environment

5. Pericardial Layers of the Heart
Figure 18.2

6. Layers of the Heart Wall
Epicardium – visceral
pericardium
Myocardium – cardiac muscle
layer forming the bulk of the
heart
Endocardium – endothelial layer
of the inner myocardial surface

7. Heart Anatomy
External markings
Apex - pointed inferior region
Base - upper region
Coronary sulcus
Indentation that separates atria from ventricles
Anterior and posterior interventricular sulcus
Separates right and left ventricles
Internal divisions
Atria (superior) and ventricles (inferior)
Interventricular and interatrial septa

8. Atria of the Heart
Atria - receiving chambers of the heart
Receive venous blood returning to heart
Separated by an interatrial septum (wall)
Foramen ovale - opening in interatrial septum in fetus
Fossa ovalis - remnant of foramen ovale
Each atrium has a protruding auricle
Pectinate muscles mark atrial walls
Pump blood into ventricles
Blood enters right atria from superior and inferior
venae cavae and coronary sinus
Blood enters left atria from pulmonary veins

9. Gross Anatomy of Heart: Frontal
Section
Figure 18.4e

10. Ventricles of the Heart
Ventricles are the discharging chambers of the
heart
Papillary muscles and trabeculae carneae muscles
mark ventricular walls
Separated by an interventricular septum
Contains components of the conduction system
Right ventricle pumps blood into the pulmonary
trunk
Left ventricle pumps blood into the aorta
Thicker myocardium due to greater work load
Pulmonary circulation supplied by right ventricle is a much low
pressure system requiring less energy output by ventricle
Systemic circulation supplied by left ventricle is a higher pressure
system and thus requires more forceful contractions

11. External Heart: Anterior View
Figure 18.4b

12. Structure of Heart Wall
Left ventricle – three
times thicker than
right
Exerts more pumping
force
Flattens right
ventricle into a
crescent shape
Figure 18.7

13. Heart Valves
Heart valves ensure unidirectional blood flow through the
heart
Composed of an endocardium with a connective tissue core
Two major types
Atrioventricular valves
Semilunar valves
Atrioventricular (AV) valves lie between the atria and the
ventricles
R-AV valve = tricuspid valve
L-AV valve = bicuspid or mitral valve
AV valves prevent backflow of blood into the atria when
ventricles contract
Chordae tendineae anchor AV valves to papillary muscles of
ventricle wall
Prevent prolapse of valve back into atrium

14. Semilunar Heart Valves
Semilunar valves prevent backflow of blood into
the ventricles
Have no chordae tendinae attachments
Aortic semilunar valve lies between the left
ventricle and the aorta
Pulmonary semilunar valve lies between the right
ventricle and pulmonary trunk
Heart sounds (“lub-dup”) due to valves closing
“Lub” - closing of atrioventricular valves
“Dub”- closing of semilunar valves

15. Fibrous Skeleton
Surrounds all four valves
Composed of dense connective tissue
Functions
Anchors valve cusps
Prevents overdilation of valve openings
Main point of insertion for cardiac muscle
Blocks direct spread of electrical impulses

16. Heart Valves

17. Conducting System
Cardiac muscle tissue has intrinsic ability to:
Generate and conduct impulses
Signal these cells to contract rhythmically
Conducting system
A series of specialized cardiac muscle cells
Sinoatrial (SA) node sets the inherent rate of
contraction

18. Conducting System

19. Innervation
Heart rate is altered by
external controls
Nerves to the heart
include:
Visceral sensory fibers
Parasympathetic branches
of the vagus nerve
Sympathetic fibers – from
cervical and upper
thoracic chain ganglia

20. External Heart: Posterior View
Figure 18.4d

21. Major Vessels of the Heart
Vessels returning blood to the heart include:
Superior and inferior venae cavae
Open into the right atrium
Return deoxygenated blood from body cells
Coronary sinus
Opens into the right atrium
Returns deoxygenated blood from heart muscle (coronary veins)
Right and left pulmonary veins
Open into the left atrium
Return oxygenated blood from lungs

22. Major Vessels of the Heart
Vessels conveying blood away from the heart
include:
Pulmonary trunk
Carries deoxygenated blood from right ventricle to lungs
Splits into right and left pulmonary arteries
Ascending aorta
Carries oxygenated blood away from left atrium to body organs
Three major branches
Brachiocephalic
Left common carotid,
Left subclavian artery

23. Blood Flow Through the Heart
Figure 18.6

24. Pathway of Blood Through the Heart and Lungs
Figure 18.5

25. Coronary Circulation
Coronary circulation
The functional blood supply to the heart muscle itself
R and L Coronary arteries are 1st branches off the
ascending aorta
Coronary sinus (vein) empties into R. atrium
Collateral routes ensure blood delivery to heart even
if major vessels are occluded

26. Coronary Circulation - Arteries
Right Coronary Artery
Supplies blood to
Right atrium and posterior surface of both ventricles
Branches into the
Marginal artery - extends across surface of R. ventricle
Posterior interventricular artery
Found in posterior interventricular sulcus
Left Coronary Artery
Supplies blood to
Left atrium and left ventricle
Branches into
Circumflex artery
Anterior interventricular artery
Found in anterior interventricular sulcus
Connected with posterior interventricular artery via arterial
anastomoses

27. Coronary Circulation: Arterial Supply
Figure 18.7a

28. Coronary Circulation - Veins
Coronary sinus -
Vein that empties into right atrium
Receives deoxygenated blood from:
Great cardiac vein - on anterior surface
Posterior cardiac vein
Drains area served by circumflex
Middle cardiac vein
Drains area served by posterior interventricular artery
Small cardiac vein
Drains blood from posterior surfaces of right atrium and ventricle

29. Coronary Circulation: Venous Supply
Figure 18.7b

30. Microscopic Anatomy of Heart
Muscle
Cardiac muscle cells
Short, striated, branched, and interconnected
The connective tissue endomysium acts as both
tendon and insertion
Intercalated discs anchor cardiac cells together
and allow free passage of ions
Heart muscle behaves as a functional syncytium
Many mitochondria (25% of total volume)

31. Microscopic Anatomy of Heart
Muscle
Figure 18.11

32. Disorders of the Heart
Coronary artery disease
Atherosclerosis – fatty deposits
Arteriosclerosis - hardening of the arteries
Angina pectoris – chest pain
Myocardial infarction – blocked coronary artery
Silent ischemia – no pain or warning
Fibrillation - irregular heart beat; may occur in either
atria or ventricles