THE CARDIOVASCULAR

SYSTEM

CONTENTS

Introduction Circulatory system Diseases related to circulatory system Lymphatic system Diseases related to Lymphatic system Summary References

Introduction

The cardiovascular system is divided for descriptive purposes into two main parts.

• The circulatory system.• The lymphatic system.

The circulatory system consist of the heart, which acts as a pump, the blood vessels and the blood.

The lymphatic system consist of lymph nodes the lymph vessels and the lymph.

The two systems communicate with one another and are intimately associated.

The circulatory system

The heart pumps blood into two anatomically separate systems of blood vessels.

• The pulmonary circulation.• The systemic circulation.

The right side of the heart pumps blood to the lungs(the pulmonary circulation) where gas exchange occurs.

The left side of the heart supplies the blood into the systemic circulation, which supplies blood to the rest of the body.

The blood vessels:

The heart pumps the blood into vessels that vary in structure, size and function and there are several types: Arteries, arterioles, capillaries, venules and veins

The walls of the blood vessel are made up of three layers of tissue:

•Tunica adventitia•Tunica media •Tunica intima

Control of blood vessel diameter

When nervous activity is increased the smooth muscle of tunica media contracts and thickens; this process is called vasoconstriction.

Decreased nerves stimulation relaxes the smooth muscle thinning the vessel wall and enlarging the lumen . This process is called Vasodilatation.

The Heart:

Courtesy

The heart is roughly cone-shaped hollow muscular organ.

The heart lies in the thoracic cavity in the mediastinum (the space between the lungs).

The heart is composed of three layers of tissue;

• Pericardium: is made up of two sacs the outer sac consist of fibrous tissueand inner of a continuous double layer of serous membrane.

• myocardium : is composed of specialized cardiac muscle found only in heart.

• endocardium: This lines the chamber and valves of the heart. It is a thin smooth glistening membrane that permits smooth flow of the blood inside the heart.

The heart is supplied with arterial blood by the right and left coronary arteries, the arteries receive about 5% of blood pumped from heart.

Interior of the heart

The heart is divided into right and left side by the septum.

Each side is divided by an atrioventricular valve into an upper chamber, The atrium and a lower chamber, The ventricle.

The right atrioventricular valve is tricuspid valve and the left atrioventricular valve is mitral valve.

The valves between the atria and ventricles open and close passively according to changes in pressure in chambers.

The opening of the pulmonary artery is guarded by the pulmonary valve and the opening of aorta is guarded by the aortic valve.

Conducting system of the heart

Small group of specialized neuromuscular cells in the myocardium initiate and conduct impulses, causing coordinated and synchronized contraction of the heart muscle .

Sinoatrial node (SA node) • Mass of specialized cells• Lies in the wall of right atrium• Is the pacemaker of heart • Firing of SA node causes atrial

contraction.

Atrioventricular node (AV node)• situated in the wall of atrial septum near the

atrioventricularvalve

• conducts the impulse that arrive from SA node, passes it through AV bundle and purkinje fibres which in turn convey the impulse to the ventricle.

Pulmonary circulation and systemic circulation :

In the pulmonary circulation the blood circulates from the right ventricle of the heart to the lungs and back to the left atrium.

In lungs, carbon dioxide is excreted and oxygen is absorbed.

The pulmonary artery carries deoxygenated blood to the lungs.

Two pulmonary veins leave each lung returning oxygenated blood to left atrium.

During the ventricular systole the blood is forced into aorta, the first artery of general circulation which carries it to different organs of the body and returns to right atrium by superior and inferior vena cavae.

Fetal circulation:

DISORDERS OF THE CIRCULATORY

SYSTEM

Diseases of the blood vessels

Atheroma : Atheromatous plaques are patchy changes that develop in tunica intima of arteries.

Arteriosclerosis: progressive degeneration of arterial walls, associated with ageing.

Varicose Veins: Veins bulge with pools of blood when they fail to circulate the blood properly. These visible and bulging veins, called varicose veins.

Atheroma Arteriosclerosis

Varicose vein and spider vein

Diseases of heart

Myocardial infarction

Commonly known as a heart attack, is the interruption of blood supply to a part of the heart, causing heart cells to die.

This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, in the wall of an artery.The resulting ischemia(restriction in blood supply) and oxygen shortage, if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium)

Symptomschest anxiety pain, shortness of breath nausea, vomiting, palpitations, sweating

Risk factorsDiabetes , Tobacco smoking, Hypercholesterolemia ,Low HDLHigh Triglycerides, High blood pressure, Family history of ischaemic heart disease ,Obesity, age, Stress and Alcohol

Diagnostic Test

ECG (Electrocardiogram)An ECG is a simple test that detects and records the heart's electrical activity. The test shows how fast the heart is beating and its rhythm (steady or irregular). An ECG also records the strength and timing of electrical signals as they pass through each part of the heart.Blood TestsCommonly used blood tests include troponin tests, CK or CK–MB tests, and serum myoglobin tests. Coronary AngiographyCoronary angiography is a test that uses dye and special x rays to show the insides of your coronary arteries. This test often is done during a heart attack to help find blockages in the coronary arteries.

Treatment

Certain treatments usually are started right away if a heart attack is suspected, even before the diagnosis is confirmed. These include:•Oxygen therapy•Aspirin to thin the blood and prevent further blood clotting•Nitroglycerin to reduce heart's workload and improve blood flow through the coronary arteries•Treatment for chest pain.

Once the diagnosis of a heart attack is confirmed or strongly suspected, doctors start treatments to try to promptly restore blood flow to the heart. The two main treatments are "clot-busting" medicines and angioplasty, a procedure used to open blocked coronary arteries

Beta blockers. Beta blockers decrease heart's workload.

ACE( angiotensin converting enzyme) inhibitors.• ACE inhibitors lower blood pressure and reduce strain on heart. • They also help slow down further weakening of the heart muscle.

Anticoagulants. Anticoagulants, or "blood thinners," prevent blood clots from forming in arteries. These medicines also keep existing clots from getting larger.

Anti clotting medicines. Anti clotting medicines stop platelets from clumping together and forming unwanted blood clots. Examples of anti clotting medicines include aspirin and clopidogrel. 

Medicines

Angioplasty•Angioplasty is a nonsurgical procedure that opens blocked or narrowed coronary arteries. •A thin, flexible tube with a balloon or other device on the end is threaded through a blood vessel to the narrowed or blocked coronary artery.•Once in place, the balloon is inflated to compress the plaque against the wall of the artery. This restores blood flow through the artery.•During the procedure, a small mesh tube called a stent is put in the artery. The stent helps prevent blockages in the artery in the months or years after angioplasty.

Coronary artery bypass grafting (CABG) • May be used to treat a heart attack. During CABG, a surgeon removes a healthy artery or vein from body. •The artery or vein is then connected, or grafted, to the blocked coronary artery.•The grafted artery or vein bypasses (that is, goes around) the blocked portion of the coronary artery. •This provides a new route for blood to flow to the heart muscle

Angina Pectoris

Is chest pain or discomfort that occurs if an area of heart muscle doesn't get enough oxygen-rich blood.

Angina may feel like pressure or squeezing in chest. The pain also can occur in shoulders, arms, neck, jaw, or back.

Angina pain may even feel like indigestion.

Angina isn't a disease; it's a symptom of an underlying heart problem. Angina usually is a symptom of coronary heart disease (CHD )

Types of Angina: stable, unstable, variant (Prinzmetal's), and microvascular.

Stable Angina• It occurs when the heart is working harder than usual.• Stable angina has a regular patternUnstable Angina•Unstable angina doesn't follow a pattern•Unstable angina also can occur with or without physical exertion, and rest or medicine may not relieve the pain.Variant (Prinzmetal's) Angina•Variant angina is rare.• A spasm in a coronary artery causes this type of angina. •Variant angina usually occurs while at rest, and the pain can be severe.• It usually happens between midnight and early morning. Microvascular Angina•Microvascular angina can be more severe and last longer than other types of angina.• Medicine may not relieve this type of angina

Diagnostic Tests

EKG (Electrocardiogram)Stress TestingChest X RayCoronary Angiography and Cardiac CatheterizationBlood Tests

Treatment

Nitrates :For aborting or terminating angina attack , sublingual GTN (glyceryl trinitrate) tablet or spray is taken.

The major action of nitrate is direct nonspecific smooth muscle relaxation.

Hence when there is an angina attack due to narrowing of coronary artery, nitrates help the vascular smooth muscle to relax thereby dilating the vessel and increasing the blood flow to that particular area.

The GTN tablet may be crushed under teeth and spread over buccal mucosa

It acts within 1-2 min because of direct absorption in the systemic circulation bypassing the liver.

β Blockers:Certain hormones such as epinephrine (adrenaline) non epinephrine and other such hormones act on the β receptors of various body tissue and produce stimulative effect.

The effect of these hormones on the heart is more forceful contraction of the heart muscle.

β blockers are the agents that block the action of these hormones on the receptors of the body tissue.

Thus leading to decrease heart rate, decrease force of contraction and decrease cardiac output .

Examples of β blockers are metoprolol, propranolol etc.

Congestive Cardiac Failure

Is a condition in which the heart can’t pump enough blood to meet the body’s needs

In some cases, the heart can’t fill with enough blood. In other cases, the heart can’t pump blood to the rest of the body with enough force

Right-side heart failure occurs if the heart can’t pump enoughblood to the lungs to pick up oxygen. Left-side heart failure occurs if the heart can’t pump enough oxygen-rich blood to the rest of the body.

Right sided (congestive) failure:•The right ventricle fails when the pressure developed within it is less than the force needed to push blood through the lungs.•When the ventricles is not emptying completely the right atrium and vena cavae become congested with blood.•The organs affected are liver, spleen kidney. Oedema of limbs usually follows.

Left sided( left ventricular ) failure:•This occurs when the pressure developed in the left ventricle by the contracting myocardium is less than the pressure in the aorta and the ventricle cannot pump out all the blood it receives.•This leads to dilatation atrium increase in pulmonary blood pressure and eventually to congestion in lungs leading to pulmonary oedema.

Causes of Congestive Heart Failure

Coronary artery diseaseHigh blood pressure (hypertension) Longstanding alcohol abuseDisorders of the heart valvesUnknown (idiopathic) causes, such as after recovery from myocarditisLess common causes include viral infections of the stiffening of the heart muscle, thyroid disorders, disorders of the heart rhythm, and many others.

Treatment

Digoxin:

These are glycosidic drugs having cardiac inotropic property i.e. they increase the force of contraction of the myocardial muscle.

They increase the myocardial contractibility in failing heart without proportionate increase in the oxygen consumption .

Since they increase the force of contraction there is more complete emptying of the failing , dilated ventricles thereby increasing the efficiency of the heart.

Diuretics:

Diuretics help in treating the symptoms of the CHF.

They help to keep the fluid from building up in lungs and other tissues by promoting the flow of fluid through kidney thus preventing the pulmonary oedema and oedema in any other parts of the body.

Examples of diuretics are furosemide(lasix),bumetamide(bumex) etc.

Vasodilators __ ACE inhibitors, nitrates

β blockers ___ metorolol etc.

Following devices may be recommended for certain patients with heart failure:•A pacemaker to help treat slow heart rate or other signaling problem.•A biventricular pacemaker to help both side of heart contract at same time.

Surgery and medication can repair underlying causes of heart failure, however once the heart’s ability to pump blood is severely, permanently impaired no surgery can repair the damage, the only alternative remain is a heart transplant

Mitral valve stenosis Rheumatic heart disease Infective endocarditis Cardiac arrhythmias Congenital abnormalities

Other disorders related to heart includes

Diseases related to blood pressure

Hypertension or high blood pressure is a condition in which the blood pressure in the arteries is chronically elevated. Blood pressure is the force of blood that is pushing up against the walls of the blood vessels.

If the pressure is too high, the heart has to work harder to pump, and this could lead to organ damage and several illnesses such as heart attack, stroke, heart failure, aneurysm, or renal failure.

The normal level for blood pressure is below 120/80, where 120 represents the systolic measurement (peak pressure in the arteries) and 80 represents the diastolic measurement (minimum pressure in the arteries).

Blood pressure between 120/80 and 139/89 is called prehypertension (to denote increased risk of hypertension), and a blood pressure of 140/90 or above is considered hypertension. Hypertension may be classified as essential or secondary. •Essential hypertension is the term for high blood pressure with unknown cause. It accounts for about 95% of cases.•Secondary hypertension is the term for high blood pressure with a known direct cause, such as kidney disease, tumors, or birth control pills.

Though the exact causes of hypertension are usually unknown, there are several factors that have been highly associated with the condition. These include:•Smoking•Obesity or being overweight•Diabetes•Sedentary lifestyle•Lack of physical activity•High levels of salt intake (sodium sensitivity)•Insufficient calcium, potassium, and magnesium consumption•Vitamin D deficiency•High levels of alcohol consumption•Stress•Aging•Medicines such as birth control pills•Genetics and a family history of hypertension•Chronic kidney disease•Adrenal and thyroid problems or tumors

What causes hypertension?

Treatment

ACE inhibitors- Captopril, enalapril. Ramipril.

Diuretics--- furosemide, amiloride.

Beta blockers– Metoprolol, propranolol

Vasodilators — Hydralazine

Calcium channel blockers--- Verapamil, Lacidipine

Clinical trial

Sponsor French Cardiology Society

Collaborator:Institute National de la Santé Et de la Recherche Médicale, France

Information provided by: French Cardiology Society

ClinicalTrials.gov Identifier: NCT01186445

Purpose

The purpose of this study is to determine whether intracoronary injection of morphine chlorhydrate is effective to limit ischemia-reperfusion lesion during percutaneous coronary angioplasty in patients with acute myocardial infarction (AMI).

Morphine In Acute Myocardial Infarction (MIAMI)This study is currently recruiting participants.Verified on January 2010 by French Cardiology Society First Received on August 20, 2010. Last Updated on June 21, 2011

Study Type: Interventional

Study Design:

Allocation: RandomizedEndpoint Classification: Efficacy Study

Intervention Model: Parallel AssignmentMasking: Double Blind (Subject, Caregiver,

Investigator, Outcomes Assessor)Primary Purpose: Treatment

Official Title:

Evaluation of the Cardioprotective Effect of Intracoronary Injection of Morphine

During Reperfusion in Acute Myocardial Infarction

Condition Acute Myocardial Infarction

intervention Drug: morphine chlorhydrateDrug: saline solution

Phase Phase III

Components of lymphatic system Lymph fluid

• Intermediary between blood in capillary and tissues

Lymphatic organs• Lymph nodes• Tonsils • Spleen• Thymus

Lymph vessels

The Lymphatic System

Returns excess interstitial fluid to circulatory system

Absorption of fat and fat soluble vitamins from GI system

Defense against invading pathogens and disease

Functions of lymphatic system

90% of fluid that leaves capillaries is returned the 10% that does not return becomes part of the interstitial fluid.

Similar in composition to plasma• Without erythrocytes and large protein molecules• Contains lymphocytes, granulocytes, water,

respiratory gases, nutrients, hormones, ions, urea

Lymph

Lymphatic Vessels

Not found in nails, hair.

Form an extensive system that flows one way toward the heart

Several types of lymphatic vessels• Lymphatic capillaries• Lymphatic collecting vessels•Lymphatic trunks• Lymphatic ducts

There is no “pump” like in circulatory system

Very low pressure

Flow accomplished because of three factors– Skeletal muscle pump– Respiratory pump– Valves prevent backflow

Failure to move lymph results in accumulation of interstitial fluid (edema)

Movement of Lymph

Situated in between two lymphatic collecting vessels are lymph nodes

Nodes serve as filters to capture foreign material or abnormal cells (cancer) Site of lymphocyte production

Can become inflamed/ engorged with infectious material

Can be found in large clusters in inguinal, cervical, and axillae

Lymph Nodes

Largest lymphoid organ

Primary purpose is to remove aged RBCs

Provides a place to screen for pathogenic agents

Stores large amount of RBCs that can be accessed during periods of stress

Lymphoid Organ: Spleen

Found in superior mediastinum

Produces lymphocytes

Does not directly fight antigens

Can be considered an endocrine organ because it produces the hormone thymosin.Thymosin stimulates production of lymphoid cells

Largest in infancy and early childhood

Atrophys as we age

Thymus

DISORDER OF LYMPHATIC SYSTEM

Lymphadentis: An inflammatory condition of the lymph nodes, usually the result of systemic neoplastic disease, bacterial infection, or other inflammatory condition. The nodes may be enlarged, hard, smooth or irregular, red, and may feel hot. Lymphangitis : An inflammation of one or more lymphatic vessels, usually resulting from an acute streptococcal infection of one of the extremities. It is characterized by fine red streaks extending from the infected area to the axilla or groin, and by fever, chills, headache, and myalgia. The infection may spread to the bloodstream. Lymphedema: A primary or secondary disorder characterized by the accumulation of lymph in soft tissue and swelling, caused by inflammation, obstruction, or removal of lymph channelsSplenomegaly: This is enlargement of the spleen usually due to infection, circulatory disorders, blood disease etc.

Summary

Cardiovascular systemCirculatory system

Lymphatic system

Circulatory systemThe heart

The blood vessels

The blood

Lymphatic system

The lymph

The lymphatic vessels

The lymphoid organs

Disorders of circulatory system

Related to blood vessel

Related to heart

Related to blood pressure

Atheroma , arteriosclerosis, varicose vein

Myocardial infarction, angina pectoris, congestive heart failure, mitral valve stenosis, etc

Hypertension and hypotension

Disorders of the lymphatic system

Lymphadentis Lymphangitis Lymphedema

Splenomegaly

References

•Anne waugh, allison grant “Anatomy and physiology in health and illness”10th edition .•http://www.nlm.nih.gov/medlineplus/heartdiseases.html•http://www.dherbs.com/articles/lymphatic-system-disorders•http://en.wikipedia.org/wiki/Circulatory_system•http://www.healthcare-online.org/Cardiovascular_Diseases.htm•http://www.mayoclinic.com/health/heart-disease• KD Tripathi “ essentials of medical pharmacology” 5th edition.