The coronary circulation supplies blood to the heart muscle. Blood flows through the right and left coronary arteries which branch from the aorta. Coronary blood flow increases during cardiac diastole as pressure in the intramural vessels is released, allowing more blood to enter the myocardium. Disruptions to coronary blood flow can cause myocardial ischemia, infarction, and angina pectoris due to insufficient oxygenation of heart tissue. Coronary occlusion from atherosclerosis is a leading cause of restricted blood flow and these downstream effects.

1. CORONARY CIRCULATION
BY- S.APARNA

2. CONTENTS
• INTRODUCTION
• CIRCULATION AND TYPES
• CORONARY CIRCULATION
• COMPONENTS OF CORONARY CIRCULATION
• PHASIC CHANGES
• FACTORS REGULATING C.CIRCULATON
• APPLIED ASPECTS

3. INTRODUCTION:
Cardiovascular system includes heart and blood vessels.Heart
pumps blood into the blood vessels, blood vessels circulate the
blood throughout the body. Blood transports nutrients and
oxygen to the tissues and removes carbon dioxide and waste
product from the tissues.

4. CIRCULATON

5. TYPES OF CIRCULATION
i) Systemic circulation
ii) Pulmonary circulation.

6. Systemic (greater) circulation:
The blood flows from the left ventricle, through various parts of the
body, to the right atrium, i.e. from the left to the right side of the heart
through the arteries and veins which traverse the whole body. This
circulation is responsible for keeping the body tissues alive by
supplying a continuous stream of blood to them.

7. Pulmonary (lesser) circulation:
The blood flows from the right ventricle, through the lungs, to the left
atrium, i.e. from the right to the left side of the heart. This circulation
is responsible for oxygenation of blood. In pulmonary circulation, the
blood passes through the lungs where Carbon dioxide is eliminated
and Oxygen is added to blood. In this way, the pulmonary circulation
makes sure that systemic circulation remains effective.

8. CORONARY CIRCULATION
* Coronary circulation is apart of systemic circulation.
*Coronary circulation is the circulation of blood in the blood vessels
of the heart
*The resting coronary blood flow is about 225 ml/gm ., Which is
about 0.7-0.8 ml/gm of heart muscle or 4-5% of total cardiac output

9. Coronary circulation consists
* Arterial drainage
* venous drainage
*lymphatic drainage

10. ARTERIAL SUPPLY
The cardiac muscles are supplied by the two coronary
arteries ;
i) The right coronary arteries
ii) The left coronary arteries
Both the arteries arises from the sinuses behind the cups of the aortic
valves at the root of aorta

12. VENOUS DRAINAGE
The venous drainage consists
i) coronary sinus
ii) anterior cardiac veins
iii) venae cordis minimae

13. LYMPHATIC DRAINAGE
Lymphatics of the heart accompany the coronary
arteries and form two trunks
The right trunk ends in brachiocephalic nodes and the left trunk into
the tracheobronchial lymph nodes at the bifurcation of the trachea

14. PHASIC CHANGES IN CORONARY BLOOD FLOW
Blood flow through coronary arteries is not cnsatnt it
decreases during systole and increases during diastole
intramural vessels or final arteries supplying myocardium are
perpendicular to cardiac muscles . so, during systole, the
intramural vessels are compressed and blood flow is reduced.
during diastole the compression is released and the blood
vessels are distended .so, the blood flow increases
* Phasic change in left ventricle
* Phasic change in right ventricle

15. PECULIARITIES OF CORONARY CIRCULATION
* Blood flow during systole
* End arteries
* High capillary density
* High oxygen extraction
* Regulation is mainly by metabolites
* Anatomical anastomosis

16. FACTORS REGULATING CORONARY BLOOD
FLOW
* Physical - Aortic blood pressure, Heart rate, Cardiac output
* Chemical -Metabolic factors , Drugs
* Neural - Direct effect, Indirect effect
* Hormonal -Thyroxin , Vasopressin
* Reflex-Anrep's reflex, Gastro-coronary reflex

17. APPLIED ASPECTS

18. • Coronary occlusion
• Myocardial ischemia
• Myocardial infarction
• Angina pectoris

19. Coronary occlusion – Coronary occlusion is the partial or
complete obstruction of coronary artery. coronary occlusion is
caused by atherosclerosis, a condition associated with deposition
of cholesterol on the walls of the artery .
Myocardial ischemia – Myocardial ischemia is the reaction of a
part of myocardium in response to hypoxia. hypoxia
develops when blood flow to part of myocardium
decreases severely due to occlusion of coronary artery

20. CORONARY OCCLUSION
MYOCARDIAL ISCHEMIA

21. Myocardial infarction – Myocardial infarction is the necrosis
of myocardium caused by insufficient blood flow due to
embolus, thrombus, or vascular spasm. It is also called heart
attack. in myocardial infarction, death occurs rapidly due to
ventricular fibrillation.
Angina pectoris- Cardiac pain is the chest pain that is caused
by myocardial ischemia. It is also called angina pectoris. It is
common manifestation of coronary diseases.pain starts beneath
the sternum and radiates to surfaces of left arm and left
shoulder .

22. MYOCARDIAL INFARCTION
ANGINA PECTORIS

23. REFERENCE
• ESSENTIALS OF MEDICAL PHYSIOLOGY
• GUYTON & HALL TEXTBOOK OF MEDICAL
PHYSIOLOGY