Anatomy and physiologic overview of Human Heart

1. Anatomic and
physiologic overview
of Heart
MRS.ANJU ANN MANI
LECTURER
PUSHPAGIRI COLLEGE OF NURSING

2. Heart
 Heart is a cone shaped, hollow muscular organ located in the mediastinal
space between the lungs and rests on the diaphragm
 Size 12cm long, 8cm width 6cm thickness
 Weight around 300g

3. Layers of the heart
Outermost layer Pericardium- 3 layers
 Fibrous pericardium(outermost layer)
 Parietal pericardium(middle layer)
 Visceral pericardium(Epicardium)
(Pericardial space fluid- 30ml approx.)
Myocardium
Endocardium

4. Heart Chambers and Valves

5. Heart Chambers and Valves

6. Heart valves

7. Coronary circulation
 Left and right coronary arteries and their branches supply arterial blood to
the heart
 These arteries arise from aorta just above the aortic leaflet
 Coronary arteries receive blood during diastole

8. Coronary circulation
 Left coronary artery has 3 branches
 1. Left main coronary artery
 2.Left anterior descending artery(supply anterior wall of heart)
 3. Circumflex artery(supply lateral wall of heart)
 Right coronary artery supplies right side of heart
 1.Posterior descending artery
 2.Marginal arteries

9. Coronary circulation

10.  The cardiac veins, which collect the venous blood returning from the heart itself
consist of numerous venous tributaries and a coronary sinus
 The anterior cardiac veins drain the anterior region of the right ventricle
 The large majority of the cardiac veins drain into the wide coronary sinus about
2 or 3 cm long, lying posterior to the sulcus between the left atrium and the left
ventricle
 The coronary sinus opens into the right ventricle between the orifice of the
inferior vena cava and atrioventricular annulus.

11. Cardiac Conduction System

12. Cardiac Conduction System
 Characteristics of cardiac conduction system
 1.Automaticity –ability to initiate an electrical impulse
 2. Excitability- ability to respond to an electrical impulse
 3.Conductivity-ability to transmit electrical impulse fromone cell to
another

13. Cardiac Conduction System
 SA Node is the primary pacemaker of the heart
 Located at the junction between superior venacava and right atrium
 SA node generates impulse at the rate of 60-100/minute
 Electrical impulse is generated at SA node and transmitted to AV node via
intermodal pathways

14. Cardiac Conduction System
 AV node (atrioventricular node)
 Located in the right atrial wall near tricuspid valve
 AV node coordinates the impulses from SA node
 After a slight delay transmits the impulses to ventricles

15. Cardiac Conduction System
 Bundle of His
 Present in the septum between right and left ventricles
 It conducts the impulses received from AV node to purkinje fibers
 It is divided into right and left bundle branches
 Purkinje fibers
 Terminal part of conduction system
 Myocardial cells are stimulated causing cardiac contraction

16. Cardiac cycle

17. Cardiac cycle
 Cardiac cycle .8 seconds
 Atrial cycle .8
 Atrial diastole .7s and atrial systole .1s
 Ventricular systole .3s and ventricular diastole .5s

18. Cardiac output
Stroke volume – volume of blood pumped from the left ventricle per beat
Normal stroke volume is 70ml
Cardiac output= sroke volume* heart rate
Cardiac output 4-8l/minute

19. Heart sounds
 Normal heart sounds
 S1 first heart sound(Lubb)- closure of AV valves
 S2 second heart sound(Dubb)- closure of semilunar valves
 Abnormal heart sounds
 S3 third heart sound- ventricular gallop. It indicates early ventricular
filling(passive filling)when mitral valve opens. Often associated with heart
failure
 S4 fourth heart sound – Atrial gallop-late ventricular filling

20. Point of Maximum Impulse
 Apex beat
 Auscultated in the midclavicular line in left 5th ICS

21. Factors affecting cardiac output
 Numerous factors affect HR, or SV and thus CO.
 The HR, controlled primarily by autonomic nervous system can reach upto
180/mt for short periods without harmul effects.
 Factors affecting SV are preload, contractility and afterload increases the
workload of the heart muscle, resulting in increased O2 demand.

22. THE ANATOMY OF THE ADULT HEART
 Normal human heart is cone shaped
 Located in the mediastinum, one-third to the right of the
sternum and the remaining two-thirds to the left.
 The top of the heart is referred to as the base and the
pointed lower section as the apex.
 The base of the heart lies in an oblique position behind
the sternum and its apex lies to the left, in the fifth inter
costal space in the mid-clavicular line.

23.  The adult heart is about the size of the person's fist
and varies in weight from 230 to 340 g

24. The pathway of blood through the
heart
 Deoxygenated blood returns to the right side of the heart
from the body via the inferior and superior vena cavae
 The blood enters the right atrium, then passes through the
tricuspid valve to the right ventricle
 From here it passes through the pulmonary artery to the lungs
in the lungs oxygenation occurs and the blood flows back to
the left side of the heart to be pumped around the body
 The circuit to and from the lungs referred to as the
pulmonary circuit.

25.  Oxygenated blood returns to the left side of the heart via
the pulmonary veins into the left atrium
 From there it passes into the left ventricle via the mitral
(bicuspid) valve..
 The oxygenated blood then passes from the left ventricle
to the body via the aorta.
 The circuit supplying blood to the body (other than the
lungs) is referred to as the systemic circuit

26. The chambers and valves of the heart
The atria
 The atria are thin-walled muscular chambers that
form the most anterior aspect of the heart .
 A fibromuscular septum separates the two atria,
forming the distinctive right and left atrium
 This septum features a fairly central fibrous oval
depression known as the fossa ovalis.

27. Atrioventricular (AV) valves
 The tricuspid valve is the largest valvular orifice in the adult
heart and is situated between the right atrium and the right
ventricle
 A ring of collagen and fibrous tissue acts as the base for the
attachments of the three cusps or leaflets (flaps), which make
up this valve
 The three cusps are separated by commissures, which are
tethered by fan-shaped chordae tendinae of varying length
and thickness.
 The chordae tendinae insert into the anterior and septal
papillary muscle

28.  The mitral (bicuspid) valve guards the inlet to the left ventricle
from the left atrium.
 This valve is fixed to an annulus or a ring of fibrocollagenous
tissue.
 The valve itself is formed by two extensive leaflets, which are
joined by commis sures.
 These leaflets are also tethered by chordae tendinae, attached
to papillary muscles emerging from the ventricular walls.

29. The ventricles
 The function of the ventricles is to maintain the circulation via their
pumping action.
 The two chambers are divided by the interventricular septum.
 An intact septum ensures that the two separate but integrated
circulations are maintained
 The right ventricle pumps deoxygenated blood through the
pulmonary circulation, whilst the left ventricle pumps oxygenated
blood through the systemic circulation.
 If the shunt is predominantly from the higher pressure left ventricle
through to the right ventricle, there will be inadequate oxygenation
of the blood

30.  If the septum is damaged, either congenitally or as
the result of an infarct, there is a mixing of the blood
between the two ventricles.

31. The semilunar valves
 The pulmonary valve lies between the right ventricle
and the pulmonary artery.
 This is generally considered as a semilunar valve,
which consists of three cusps that are joined to each
other by commissures.
 The aortic valve guards the left ventricular outflow
tract
 This is also a three-cusp, semilunar valve with a
similar structure to the pulmonary valve

32. THE REGULATION OF THE PUMPING
HEART
 The heart is a highly adaptive organ.
 Its activities are regulated in accordance with the
activities and metabolic needs of the body as a whole
 The two most responsive mechanisms that regulate the
pumping' of the heart are
1. the intrinsic cardiac regulation, which augments the
pumping action of the heart in direct response to
changes in the volume of the blood flowing into the
heart
2. the autonomic nervous system.

33. The intrinsic capacity of the heart to
adapt to change
 The intrinsic capacity of the heart to adapt to changing
volumes of returning blood is referred to as the Frank-Starling
mechanism (Starling's Law of the heart.
 Starling's Law of the heart is based simply on the notion that a
greater stretch of the myocardial fibres during filling will
generate a greater subsequent force of contraction, resulting
in larger volumes of blood being pumped by the ventricles.
 The additional volume of blood returning to the heart causes
the myocardial fibres to stretch to a greater length.

34. Control of the heart function by the
autonomic nervous system
 The effectiveness and efficiency of the pumping action of the
heart are controlled by parts of the sympathetic and
parasympathetic (vagus) nerves, which supply the heart
abundantly.
 Under normal physiological conditions, the sympathetic nerve
fibres to the heart discharge continuously at a slow rate that
maintains cardiac pumping at about 30% above that which
would occur with no sympathetic stimulation

35.  Consequently when the activity of the sympathetic nervous
system is depressed a reduction in the heart rate and force of
ventricular contraction becomes evident.
 This eventually contributes to a significant reduction in
cardiac output
 Conversely, the para- sympathetic (vagal) stimulation can
induce significant bradycardia This may be demonstrated
clinically by any vagal manoeuvre
 This is a purposeful stimulation of the vagus nerve, carotid
sinus massage under the jaw or asking the patient to breathe
out against a closed epiglottis (the Valsalva manoeuvre)

36. ASSESSMENT OF CARDIOVASCULAR
SYSTEM
 Health history- The patient's ability to recognize cardiac
symptoms and to know what to do when they occur is
essential for effective self-care management.
 Major barriers to seeking prompt medical care include lack of
knowledge about the symptoms of heart disease, attributing
symptoms to a benign source, denying symptom significance,
and feeling embarrassed about having symptoms

37. COMMON SYMPTOMS
 Chest pain or discomfort (angina pectoris, dysrhythmias, valvular heart disease)
 Pain or discomfort in other areas of upper body, including one or both arms,
back, neck, jaw, or stomach (ACS)
 Shortness of breath or dyspnea (ACS, cardiogenic shock, valvular heart disease)
 Peripheral edema, weight gain, abdominal distention due to enlarged spleen
and liver or ascites (HF)

38.  Palpitations (tachycardia from a variety of causes, including
ACS, caffeine or other stimulants, electrolyte imbalances,
stress, valvular heart disease, ventricular aneurysms)
 Unusual fatigue, sometimes referred to as vital exhaustion (an
early warning symptom of ACS, HF, or valvular heart disease,
characterized by feeling unusually tired or fatigued irritable,
and dejected)
 Dizziness, syncope, or changes in level of conscioum
(cardiogenic shock, cerebrovascular disorders, dysrhythmias
,hypotension, postural hypotension, vasovagal episode)

39.  Symptoms of ACS can differ between men and women
 Although chest pain or discomfort can occur in both men and
women, it is more likely to be experienced by men.
 On the contrary, women can experience more atypical
symptoms including fatigue, nausea, neck pain, right arm pain,
jaw pain dizziness, and syncope

40. Chest Pain
 Assessing Chest Pain-unstable angina, MI
 Usual distribution of pain with myocardial lschemia- left side radiating to
left arms
 Less common-Epigastrium, Back , jaw,right side,

41.  Angina
 Uncomfortable pressure, squeezing, or fullness In substernal chest area
 Can radiate across chest to the medial aspect of one or both arms and hands,
jaw, shoulders, upper back, or epigastrium
 Radiation to arms and hands, described as numbness, tingling, or aching
 Duration- 5-15 minutes
 precipitating factors- Physical exertion, emotional upset. eating large meal, or
exposure to extremes In temperature


42.  ACS
 Same as angina pectoris
 Pain or discomfort ranges from mild to severe Associated with
shortness of breath, diaphoresis, palpitations, unusual fatigue,
and nausea or vomiting
 ACS: >15 min
 Emotional upset or unusual physical exertion occurring
within 24 hrs of symptom onset
Can occur at rest or while asleep
 Morphine. Reperfusion of coronary artery with thrombolytic
(fibrinolytic) agent or percutaneous coronary intervention

43.  MEDICATIONS
 NUTRITION
 ELIMINATION
 ACTIVITY AND EXERCISE
 SLEEP AND REST