1. CORONARY CIRCULATION and CUTANIOUS CIRCULATION
Francis Stanley
Physiology Unit

2. CORONARY CIRCULATION - Learning outcome…………..
1.Describe the functional anatomy of coronary circulation
2.State the normal volume of blood flow in coronary circulation
3.List the important features of coronary blood flow.
4.List and explain the factors regulating the coronary circulation.
5.Describe briefly the neural influence of coronary circulation.
6.Briefly describe the measurment of caronary circulation by electromagnetic flow meter and application of Fick,s principle.
7.Describe the relative role of metabolic & neural influence of caronary
circulation.
8.Describe the physiological mechanism underling coronary artery diseases (CAD), Ischemic heart disese.
9.Signs and symptomes of MI & Angina. Explain the underlying physiological mechanism.

3. CORONARY CIRCULATION
-Blood circulation to the heart muscles is called coronary circulation
-through coronary vessels
I. ARTERIAL SUPPLY
-Two coronary arteries
1. Right Coronary artery and
2. Left Coronary artery
both arteries arise from the root
of ascending aorta

4. CORONARY CIRCULATION 1. Right Coronary artery Areas supplied:
Traverses in the right AV sulcus, gives a marginal branch & runs to the posterior side & continues as posterior interventricular artery
Areas supplied:
-right atrium
-greater part of right ventricle
-small part of left ventricle
-posterior part of inter-ventricular septum
-major portion of conducting system including SA node

5. CORONARY CIRCULATION 2. Left Coronary artery
Divides into two main branches
i. Anterior descending branch or anterior interventricular artery -reaches the apex of the heart. -gives many septal branches
ii. Left circumflex branch -runs in the A-V groove and proceeds as posterior descending branch

6. CORONARY CIRCULATION 2. Left Coronary artery Areas Supplied:
-left atrium
-greater part of left ventricle
-small part of right ventricle
-anterior part of inter-ventricular septum
-part of bundle of His

7. CORONARY CIRCULATION
Normally coronary arteries do not overlap in supply
Still functional anastomosis is present which becomes active in ischemic heart diseases
Two types of anastomosis:
Cardiac anastomosis
coronary arteries & arteries or
coronary arteries & veins.
Extra cardiac anastomosis
anastomosis between coronary arteries and vessels outside the heart (eg: between coronary arteries & pulmonary arteries)

8. CORONARY CIRCULATION II. VENOUS DRAINAGE
Coronary sinus & tributaries
Venous drainage is by three types of veins
1. Coronary sinus -largest vein draining 75% of coronary flow -Great cardiac vein, Middle cardiac vein & Small cardiac vein -opens into right atrium
2. Anterior coronary veins -drain right of heart & open into right atrium
3. Thebesian veins (Venae Cordis Minimae) -drains blood from myocardium into concerned chambers

9. Normal coronary blood flow
200 – 250 ml/minute
forms 4 to 5% of total cardiac output
Measurement of coronary blood flow
Kety Method or Nitrous Oxide Technique -based on Fick’s Principle
Doppler Flow Meter
Coronary Angiography radio nucleotide die is injected
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10. PHASIC CHANGES IN CORONARY BLOOD FLOW
-Effect of cardiac muscle compression
Blood flow through coronary arteries is not constant It decreases during systole & increases during diastole
During systole, arteries are compressed which decreases coronary blood flow During diastole, compression is released which increases blood flow
 aortic pressure causes  coronary blood flow

11. PHASIC CHANGES IN CORONARY BLOOD FLOW
-Effect of cardiac muscle compression
Blood flow in individual ventricles
1. Left Ventricle
During onset of isometric contraction, blood flow sharply declines due to  myocardial pressure &  aortic pressure
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During ejection phase, aortic pressure . Coronary flow remains less
During onset of diastole, blood flow  due to d myocardial pressure

12. PHASIC CHANGES IN CORONARY BLOOD FLOW
-Effect of cardiac muscle compression
Blood flow in individual ventricles
2. Right Ventricle
Some flow occurs as force of contraction is not as severe as in left ventricle

13. REGULATION OF CORONARY BLOOD FLOW
Autoregulation Coronary blood flow is mainly dependent on vascular response
Regulated by the following factors:
1. Oxygen demand - most important factor % of oxygen is absorbed from the blood
2. Metabolic factors - release of metabolic products during hypoxia results in vasodilatation - metabolic products: mainly adenosine (ATP  ADP  Adenosine) K+, H+, CO2 , adenosine phosphate compounds
3. Neural regulation DIRECT EFFECT Coronary vessels have autonomic innervation. Epinephrine or Nor-epinephrine s or s blood flow INDIRECT EFFECT Sympathetic stimulation causes d cardiac activity, causing d metabolic products, resulting in vasodilatation. And vice-versa.

14. Applied Physiology Coronary Occlusion
-obstruction of coronary arteries -due to atherosclerosis -atherosclerosis occurs due to deposition of cholesterol (cholesterol fibrous tissues calcification atherosclerotic plaques) -plaques common nearer to aorta -obstruction of 3/4th of lumen causes myocardial ischemia
Myocardial Infarction -muscle becomes unable to sustain cardiac muscle function due to lack of blood Myocardial infarction can result in cardiac shock
Plaque
Normal artery
Angina Pectoris -the pain felt due to myocardial ischemia -hot pressing, constricting pain -radiates to left arm, shoulder & left neck(referred pain)

15. TREATMENT OF ANGINA PECTORIS
With drugs: -vasodilators during acute pain relieves pain (nitroglycerin, other nitrate drugs) -beta blockers for prolonged treatment -blocks beta receptors, preventing sympathetic enhancement of heart rate
SURGICAL TREATMENT OF CORONARY DISEASES -Aortic-coronary bypass surgery anastomosis between aorta & artery beyond occlusion
-Coronary angioplasty. balloon tipped catheter is introduced & inflated.
-Laser angioplasty laser beams dissolves occlusion

16. Heart disease is an umbrella term for a number of different diseases which affect the heart. The most common heart diseases are:
Coronary artery disease.
Coronary heart disease.
Ischaemic heart disease.
Cardiovascular disease
Pulmonary heart disease.
Hereditary heart disease.
Hypertensive heart disease.
Inflammatory heart disease.
Valvular heart disease.
Pericardial disease
Congenital heart disease
Heart failure

17. Coronary artery disease (CAD), These are diseases of the arteries that supply the heart muscle with blood. CAD is one of the most common forms of heart disease and the leading cause of heart attacks. It generally means that blood flow through the coronary arteries has become obstructed. The most common cause of such obstructions is a condition called atherosclerosis, a largely preventable type of vascular disease. Coronary artery disease can lead to other heart problems, such as chest pain (angina) and heart attack (myocardial infarction).

18. Myocardial Infarction / Heart Attack

19. Angina Pectoris
Hardening of the arteries, and the presence of a thrombus, or clot, in a blood vessel are the most common causes of obstruction. Arteriosclerosis is responsible for most of the deaths resulting from heart attacks. Spasms of the coronary arteries can also result in a heart attack.

20. CUTANIOUS CIRCULATION

21. Cutaneous Circulation:
Learning Outcome……………..
1.Describe the different layers of the human skin
2.List the peculiarities of coetaneous circulation
3.Enumerate the functions of the skin.
4.Describe the regulation of the Coetaneous Circulation.
5.Explain reactive hyperemia, white reaction, triple response and dermographism.

22. 1.Different layers of the skin :

23. 2.Peculiarities of Cutaneous circulation:
There are plenty of arteriovenous anastomosis in some parts.
It has important role in temperature regulation.
Blood flow is in excess to that is required for nutrition of the tissue.
Acts as a reservoir of blood and helps in translocation of blood , when needed.
State of Cutaneous flow reflects nicely on the skin characters, eg. Hot, cold, pale, red, blue, etc.
Amount of flow can vary highly.

24. 3.The skin has several major functions, such as:
Temperature regulation:  When a person is subject to strenuous exercise, or high environmental temperatures, the skin produces sweat from sweat glands.  When the sweat evaporates, it cools the skin, helping to lower the body temperature. 
When the body needs to be kept warm, blood vessels to the skin constrict, and prevents the loss of heat to the outside.  There is the erection of body hair to increase insulation, via the pilomotor reflex.
Protection:  Skin provides a physical barrier that protects underlying tissues from abrasion, bacterial infection, dehydration and UV radiation. 
Sensation:  Skin contains over a thousand nerve endings per square inch, and allows the body  to sense the world around it.  This is important primarily in the case of pain, which signals the brain of potential damage to the body such as touching a very hot object. .

25. Functions of skin cont…………………
Excretion: Eccrine sweat glands, located in the skin all over the body, but primarily the palms, soles of feet, and forehead have sweat that is mostly water and salt, while sweat from apocrine sweat glands contains fatty tissues that are then broken down by bacteria, and cause an odor. 
Immunity:  In addition to providing a physical barrier to foreign bodies, the epidermis contains cells called Langerhan’s cells that are active in immune responses.  Upon infection of an area of skin, Langerhan cells in close proximity will capture, uptake and start processing the antigens

26. Vitamin synthesis: The epidermis can absorb UV rays, through melanin, which begins the production of Vitamin D. First, 7-dehydrocholesterol, a steroid which is found in the deep epidermis, is struck by sunlight. Photolysis of the molecule occurs producing a pre-vitamin D3 .

27. 4.Regulation of Cutaneous circulation:
Neural and chemical factors regulate the blood flow through the skin but here neural regulation plays a more important role.

28. Reactive hyperaemia: :.
If Circulation to a part of the skin is stopped for some time and then the circulation is re-established, blood flow to that part of the skin is increased very much: this is called reactive hyperaemia

29. WHITE REACTION
If a part of the skin is lightly stroked (scratched) by a pointed object, the line of the scratch becomes white within seconds, this is due to vasoconstriction caused by the direct mechanical effect of the stroke and is seen better in fair skin.

30. TRIPLE RESPONSE
If the the skin is firmly stroked by a pointed object, three reactions are seen in succession. All these together are called triple response and the reactions are red, flare and wheal. It was described by Lewis and is also called triple response of Lewis.

31. Dermographism :
In individuals showing a marked triple response, letters can be inscribed on their skin by stroke of a pointed object. This is because, along the scratch made for each letter, prominent wheals occur. This phenomenon is called dermatographism.

32. Do not immagine CVS like this……… see the next pic……………………….

33. It’s a delicious cake only……………………………………………

34. THANK YOU ALL
Dr. Francis Stanley,
PHYSIOLOGY UNIT,
aimst university