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1. ANATOMY AND PHYSI OLOGY CL AS S
THE
HEART
CATANDUANES STATE UNIVERSITY

2. Topic Outline
12.1 Functions of the heart
12.2 Size, Form, and Location
of the Heart
12.3 Anatomy of the Heart
12.4 Histology of the Heart
TODAY'S DISCUSSION
12.5 Stimulation of the Heart
12.6 Cardiac Cycle
12.7 Heart Sounds
12.7 Regulation of Heart
Functions

3. 12.1 FUNCTION OF THE
HEART
• People often refer to the heart as the seat of
strong emotions. For example, we may describe a
very determined person as having a lot of heart or
say that a person who has been disappointed.
• Romantically broken hearted.

4. Although it is single structure, the heart is actually two pumps in one. The right side of the heart pumps
blood to the lungs and back to the left side of the heart through vessels of the:
•PULMONARY CIRCULATION
•SYSTEMIC CIRCULATION
THE FUNCTION OF THE HEART ARE:
1.Generating blood pressure - contraction of the heart generate blood pressure, which forces blood through
the blood vessels.
2.Routing blood – separate the pulmonary and systemic circulation, which ensure that the blood flowing to
tissues has adequate levels of 02.
3.Ensuring one- way blood flow- valves of the heart ensure a one way flow of blood through the heart and
blood vessels.
4.Regulating blood supply- changes the rate and force of heart contraction match blood flow to the
changing metabolic needs of the tissues during rest exercise, and changes in body positions.

6. 12.2 SIZE, FORM, AND LOCATION OF THE
HEART
• The adult heart is shaped like a blunt cone and approximately the size of a closed first.
• The heart generally decreases in size after approximately at the age of 65, especially people who are
not physically active.
• APEX- it is the blunt, rounded point of the heart and the larger.
• BASE- flat part at the opposite end of the heart
• The heart are located in the thoracic cavity between the two pleural cavities that surround the lungs.
• The heart, trachea, esophagus and associated structures from the midline partition called the
mediastinum
• The heart is surrounded by its own cavity, the pericardial
• CARDIOPULMONARY RESUSCITATION – is an emergency procedure that maintains blood flow in the
body if a person’s heart stop.

7. The heart lies obliquely in
the mediastinum, with its
base directed posteriorly
and slightly superiorly and
its apex directed
anteriorly and slightly
inferior.

8. 12. 3 ANATOMY OF THE HEART
PERICARDIUM
The heart lies in the pericardial cavity is the form of pericardium, or pericardial which surround the heart and
anchors it within the mediastinum.
THE PERICARDIUM CONSIST TWO LAYERS:
1.THE FIBROUS PERICARDIUM- it is the outer layer of the pericardium and is composed of tough, fibrous
connective tissue.
2.THE SEROUS PERICARDIUM- is the inner layer and consist of flat epithelial cell with a thin layer of
connective tissues.

9. THE SEROUS PERICARDIUM COMPOSED TWO PARTS
• The parietal pericardium lines the fibrous pericardium the visceral pericardium or epicardium covers
the heart surface. Because the two composed parts are continuous with each other where the great
vessel enter or leave the heart.
PERICARDIAL FLUID
• IT CAN PRODUCED BY THE SEROUS PERICARDIUM AND HELPS TO REDUCE FUNCTION AS THE HEART MOVES
WITHIN THE PERICARDIUM.

11. EXTERNAL ANATOMY
• The right and left atria are located at the base of the heart, and the right and left ventricles extend
from the base of the heart toward the apex.
• A groove called the coronary sulcus means it extend around the heart, separating the atria from the
ventricles.
Two additional grooves, or sulci extend inferiorly from coronary sulcus and indicate the division between
the right and left ventricles.
• THE ANTERIOR INTERVENTRICULAR SULCUS- Is on the anterior surface of the heart.
• THE POSTERIOR INTERVENTRICULAR SULCUS- Is on the posterior surface of the heart.

12. • The superior vena cava and inferior vena cava carry blood from the body to the right atrium, and four
pulmonary veins carry blood from the lungs to the left atrium.
• Pulmonary trunk- arising from right ventricle splits into the right and left pulmonary arteries, which
carry blood to the lungs. The aorta arising from left ventricle, carries blood to the rest of the body.

14. HEART CHAMBER AND INTERNAL ANATOMY
The heart is a muscular pump consisting of four chambers:
1. the right atrium
2. left atrium
3. the right ventricle
4. the left ventricles

16. HEART VALVES
• The one way flow blood through the heart chambers is maintained by the heart valves.
There are two types of heart valves:
• Antrioventricular- is located between each atrium and ventricle. Specifically the AV valve
between the right atrium and right ventricle called the tricuspid valve because it is
composed of three cusps or flaps of tissue.
• Papillary muscle these attached by thin, strong, connective tissue string to the free
margin of the cusps of the atrioventricular valves.
• Semilunar valve- located between the left ventricle and its associated great artery.
• Pulmonary semilunar valve- located from the right ventricle and pulmonary trunk.
• Aortic semilunar valve- located between left ventricle and aorta.

18. Cardiac skeleton- fibrous right that
surround the atrioventricular and
semilunar solid support

19. ROUTE OF BLOOD FLOW TO THE HEART

20. BLOOD SUPPLY TO THE HEART
• CORONARY ARTERIES- Supply blood to the wall of the heart.
• LEFT CORONARY ARTERY- originates on the left side of the aorta.
THREE MAJOR BRANCHES:
• Anterior interventricular artery- lies in the anterior sulcus.
• Circumflex artery- extend to coronary sulcus on the surface of heart.
• Left marginal artery- extend inferiorly along the lateral wall of the ventricle.

21. • In a resting person, blood
flowing through the
coronary arteries gives up
approximately 70% of its
02. in comparison blood
flowing through arteries to
skeletal muscle give ups
only about 25% of its 02.
• The percentage of 02
blood release to skeletal
is 70% during exercise.

22. CARDIAC VEINS
• CARDIAC VEINS-, drain blood
from cardiac muscle their
pathways are nearly parallel to
the coronary arteries and
most of them drain blood into
the coronary sinus that large
veins located to posterior
aspect of heart.

23. 12.4 HISTOLOGY
OF THE HEART
HEART WALL – is composed of three layers of tissue:
(1) EPICARDIUM (2) MYOCARDIUM (3) ENDOCARDIUM
• EPICARDIUM- also called the visceral pericardium, is a thin ,
serous membrane forming the smooth outer surface of the
heart.
• MYOCARDIUM- is the thick , middle layer of the heart ,
composed cardiac muscle cells.
• myocardium is responsible for contraction of the heart
Chambers
• ENDOCARDIUM –is the smooth inner surface of the heart ,
which consist of simple squamous epithelium over a layer of
connective tissue.
• allows blood to move easily through the heart.

24. CARDIAC MUCLES CELLS- cells that are elongated, branching cells that contain one, or
occasionally two centrally located nuclei.
TRABECULAE CARNEAE is the surfaces of the interior walls of the ventricles are modified by ridges and columns
of cardiac muscle.
CARDIAC MUSCLE contain actin and myosin myofilaments organized to form sarcomeres , which are joined end-to-
end to form myofibril.
• like skeletal muscle, cardiac muscle relies on Ca²+ and ATP for contraction.
• Cardiac muscle cells have many mitochondria, which produce ATP at a rate of rapid enough to sustain the
normal energy requirements of cardiac muscle.
• Cardiac muscle cells are organized into spiral bundles or sheets.
INTERCALATED DISKS are bound end-to-end and laterally to adjacent cells by specialized cell-to-cell contacts.
GAP JUNCTION allow cytoplasm to flow freely between cells.

26. 12.5 STIMULATION OF THE
HEART
ACTION POTENTIALS IN CARDIAC MUSCLE
– action potential in skeletal muscle and neurons, those in cardiac
muscle exhibit depolarization followed by repolarization.
• Action potentials in skeletal muscle take less than 2milliseconds
(ms) to complete.
• Action potentials in cardiac muscle take approximately 200 to 500
ms to complete.
• Action potentials in cardiac muscle consists of a depolarization
phase.
• A slow repolarization called the plateau phase.
Refractory period allow cardiac muscle to contract and relax almost
completely before another action potentials can be produced.
• Long refractory period prevents tetanic , sustained contraction
from occuring , thus ensuring a rhythm of contraction and relaxation
for cardiac muscle.

27. CONDUCTION SYSTEM OF THE HEART
-Contraction of the atria and ventricles is coordinated by
specialized cardiac muscle cells in the heart wall that form the
conduction system of the heart.
Conduction system can produce spontaneous action potentials.
CONDUCTION OF THE HEART INCLUDES:
1. sinoatrial node
2. atrioventricular node
3. atrioventricular bundle
4. bundle branches
5. purkinje fibers
Sinoatrial (SA) Node- function as the heart’s pacemaker.
SA NODE produce action potentials, faster rate than other areas
of the heart and has a larger number of Ca²+ channels than other
cells in the heart.

28. SA node spontaneously open and close a rhythmic rate. The heart rate can be affected by certain drugs.
• Calcium channels blockers decrease the rate at which Ca²+ moves through Ca²+ channels.
Av bundle , Bundle branches and Purkinje fibers are composed of specialized cardiac muscle fibers that
conduct action potentials more rapidly than do other cardiac muscle fibers.
Ectopic beats may cause very small portions of the heart to contract rapidly and independently of all other
areas.
Fibrillation is a condition that reduces the output of the heart to only a few milliliters of blood per minute
when it occurs in the ventricles.
Defibrillation is use to stop the process of fibrillation, in which they apply a strong electrical shock to the
chest region. The shock causes simultaneously depolarization of all cardiac muscle fibers.

30. ELECTROCARDIOGRAM
– electrodes placed on the body surface and attached to a
recording device can detect the small electrical changes
resulting from action potentials in all of the cardiac muscle.
Normal ECG consists of (1) P wave (2) QRS COMPLEX (3) T
wave
• P wave- results from depolarization of the atrial
myocardium, and the beginning of the P wave precedes
the onset of atrial contraction.
• QRS complex- consists of three individual waves; the Q,
R and S waves .
• the QRS complex- results from depolarization of the
ventricles and the beginning of the QRS complex
precedes ventricular contraction.
• T wave – represent repolarization of the ventricles, and
the beginning of the T wave precedes ventricular
relaxation.

31. • The time between the beginning of the P wave and the beginning of the QRS complex is the PQ
interval , commonly called the PR interval because the Q wave is very small.
• QT interval extends from the beginning of the QRS complex to the end of the T wave and represent the
length of time required for ventricular depolarization and repolarization.
• It is important to note that the ECG is a record of electrical events of the heart and is not a direct
measurements of mechanical events. This means that neither the force of contraction nor the blood
pressure can be determined from an ECG.
• ECG is an extremely valuable tool for diagnosing a number of cardiac abnormalities , particularly
because it is painless, easy to record and nonsurgical.
• Analysis of an ECG can reveal abnormal heart rates or rhythms; problems in conduction pathways, such
as blockages; hypertrophy or atrophy of portion of the heart: and the approximate location of
damaged cardiac muscle

32. Cardiac Cycle – the repetitive pumping process from the beginning of one cardiac
muscle contraction (heartbeat) until the next contraction.
Two Pumps of the Heart
• Primer pump – atrium; complete the filling of the ventricles with blood
• Power pump – ventricle; produce major force that causes blood to flow through
the pulmonary and systemic circulations
Systoles and Diastoles
• Atrial/Ventricular Systole – refers to contraction of the two atria/two ventricles
• Atrial/Ventricular Diastole – refers to relaxation of the two atria/two ventricles
Movement of Blood
-Pressure changes within the heart chambers move blood from areas of higher
pressure to areas of lower pressure.
12.6 CARDIAC CYCLE

34. 12.7 HEART SOUNDS
• Stethoscope – an instrument used to listen to the sounds of the heart
Two Main Heart Sounds
Sounds are produced when heart valves close.
1. “Lubb” – occurs at the beginning of ventricular systole
– produced by the closure of the atrioventricular (AV) valves
2. “Dupp” – occurs at the beginning of ventricular diastole
– produced by the closure of the semilunar valves
• Incompetent valve
– valve that does not close completely
– leaks when it is supposed to be closed and allows blood to flow in reverse direction
Murmur - abnormal heart sounds as a result of faulty valves
• incompetent valve produces a swishing sound immediately AFTER the valve closes
• stenosed (narrowed) valve produces a swishing sound that PRECEDES closure of
the valve

36. 12.8 REGULATON OF HEART
FUNCTION
Various measurements can be taken to assess the heart's function.
• Cardiac output (CO) is the volume of blood pumped by either ventricle of the heart each minute.
• Stroke volume (SV) is the volume of blood pumped per ventricle each time the heart contracts.
• Heart rate (HR) is the number of times the heart contracts each minute. Cardiac output can be calculated by multiplying the
stroke volume times the heart rate:
CO(mL/min) = SV (mL/ beat) x HR (beats/min)
Under normal resting conditions, the heart rate is approximately 72 beats/min, and the stroke volume is approximately 70
mL/beat. Consequently, the cardiac output is slightly more than 5 L/min:
CO = SV X HR
= 70 mL/beat × 72 bpm
= 5040 mL/min (approximately 5 L/min)

37. Intrinsic regulation refers to the mechanisms contained within the heart itself
that control cardiac output.
The mechanisms involved in the regulation are:
Venous return:
• the amount of blood that returns to heart
Preload:
• the degree ventricular walls are stretched at end of diastole
Starlings Law of the Heart:
• relationship between preload and stroke volume
• influences cardiac output
• Example -exercise increases venous return, preload, stroke volume, and
cardiac output
After load:
• pressure against which ventricles must pump blood
INTRINSIC REGULATION OF THE HEART

38. EXTRINSIC REGULATION OF THE HEART
Extrinsic regulation refers to mechanisms external to the heart, such as either nervous or chemical
regulation.
Nervous Regulation: Baroreceptor Reflex
• Nervous system control of the heart occurs through the sympathetic and parasympathetic divisions of the
autonomic nervous system.
• Influences of heart activity are carried through the autonomic nervous system.
• Both sympathetic and parasympathetic nerve fibers innervate the SA node.
• The baroreceptor reflex is a mechanism of the nervous system that plays an important role in regulating
heart function.
Baroreceptors:
• monitor blood pressure in the aorta and carotid arteries
• changes in blood pressure cause changes in frequency of action potentials
• involves the medulla oblongata

40. Chemoreceptor Reflex
The chemoreceptor reflex involves chemical regulation of the heart.
Chemicals can affect heart rate and stroke volume.
Chemical actions:
• epinephrine and norepinephrine from the adrenal medulla can increase heart rate and stroke volume
• excitement, anxiety, and anger can increase cardiac output
• depression can decrease cardiac output
• medulla oblongata has chemoreceptors for changes in pH and CO2
• K+, Ca2+, and Na+ affect cardiac function

42. SUMMARY OF EXTRINSIC REGULATION

43. Coronary Artery Disease
• Coronary artery disease is caused by plaque buildup
in the wall of the arteries that supply blood to the
heart (called coronary arteries).
• due to decrease blood supply to the heart
• coronary arteries are narrowed for some reason
HEART DISEASES

44. Myocardial Infarction (heart attack)
• due to closure of one or more coronary
arteries
• area(s) of cardiac muscle lacking adequate
blood supply die, and scars (infarct)
• cause necrosis

45. Angioplasty:
• is a minimally invasive endovascular
procedure used to widen narrowed or
obstructed arteries or veins, typically
to treat arterial atherosclerosis.
HEART PROCEDURES

46. Stent:
• is a metal or plastic tube inserted into the lumen
of an anatomic vessel or duct to keep the
passageway open, and stenting is the placement
of a stent.