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The Heart

Mr.Sohan A Patel, Assistant Professor

Cardiovascular SystemCardiovascular System• CVS closed circulatory system.

• The Principle function of the blood flow in the cvs is - provide oxygen and nutrients to the tissues of the body and - remove carbon dioxide and waste products.

Main part of CVS is

Heart.

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HEART

• The heart is a complex muscular pump that maintains blood pressure and flow through the lungs and the rest of the body.

• The heart pumps about 100,000 times and moves 7200 liters (1900 gallons) of blood every day.

The Heart

Left Ventricle

Left AtriumRight Atrium

Right Ventricle

valve

Vein from Lungs

Artery to Head and BodyArtery to Lungs

Vein from Head and Body

valve

HODS - November 2006

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HEART

HODS - November 2006

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HEART ANATOMY • Hollow, muscular organ• 300 grams (size of a fist)• 4 chambers• found in chest between lungs • surrounded by membrane called Pericardium• Pericardial space is fluid-filled to nourish and

protect the heart.

1. Location of heart 2. Structure of the heart 3. Layers 4. Coverings Chambers 5. Structure and function of myocardial

6. valves

Different Parts of Heart

Location of the Heart

• The heart is located between the lungs behind the sternum and above the diaphragm.

• It is surrounded by the pericardium.• Its size is about that of a fist, and its weight is

about 250-300 g.• Its center is located about 1.5 cm to the left of

the midsagittal plane.

Location of the heart

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Heart’s position in thorax

Coverings of the heartCoverings of the heart

• Pericardium -loose fitting, double layered sac• Visceral pericardium -serous membrane that is on the surface

of the heart muscle• Parietal pericardium- inner layer of sac; secretes pericardial

fluid• Pericardial fluid- (Serous fluid)-fluid that is between the

parietal and visceral pericardium which prevents friction as the heart beats.

Pericardial Sac

Layers of heart tissueLayers of heart tissue

• Epicardium• Myocardium• Endocardium

Serous membrane

Continuous withblood vessels

Epicardium

• Protective, outer layer of the heart wall same as the visceral pericardium

• The coronary blood vessels that nourish the heart wall are located here

Myocardium= Middle layer made of cardiac muscle

= Forms the bulk of the heart wall

= Contains the septum- a thick muscular wall that

completely separates the blood in the right side of

the heart from the blood in the left side.

• The walls of the heart are composed of cardiac muscle, called myocardium.

• It consists of four compartments:– the right and left atria

and ventricles

Endocardium

• Inner lining

• Smooth surface that permits blood to move easily

through the heart without agglutination.

• Continuous with lining of blood vessels

• Epicardium – Outer, serous layer of heart

• Myocardium – Strong, muscular layer of heart• Endocardium – lines the heart chambers

Serous membrane

Continuous withblood vessels

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HEART chambers

The heart has four chambers.

Two atria act as collecting reservoirs.

Two ventricles act as pumps.

The heart has four valves for: Pumping action of the

heart. Maintaining

unidirectional blood flow.

Chambers Right Atrium• Thinner wall than ventricles• Receives deoxygenated blood from vena cava• Passes blood through tricuspid valve into right

Ventricle Chambers• Right Ventricle• Thicker wall than atria• Comprises most of anterior surface of heart• Circulates deoxygenated blood to lungs through the pulmonic valve into pulmonary trunk

Chambers Left Atrium• Receives freshly oxygenated blood from pulmonary

vein• Passes blood to left ventricle through mitral valve

Chambers Left Ventricle• Receives blood from left atrium• Thickest myocardial wall• Forms apex of heart• Sends blood to systemic circulation via aorta

Chambers of the heart; valves

Septa• Interatrial septum• Muscular division b/w atria• Interventricular septum• Thick muscular wall• Seperates ventricles

Heart Valves• Function- prevent blood from flowing

backwards• Responds to changes in pressureTwo types of valves in heart• Atrioventricular valves (AV)• Semi-lunar valves

Semilunar valves• Located at exit of ventricles, originiate from

endothelial lining of veinsHeart contains two semilunar valves• Pulmonic• Aortic

Atrioventricular ValvesLeft AV valve (Mitral, bicuspid)• Contains 2 cusps• Subject to abuse Right AV valve (Tricuspid)• Contains 3 cusps• Not subjected to great abuses

Atrioventricular Valves• Valve cusps are connected to papillary

muscles

The Heart Valves • The tricuspid valve regulates blood

flow between the right atrium and right ventricle.

• The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries

• The mitral valve lets oxygen-rich blood from your lungs pass from the left atrium into the left ventricle.

• The aortic valve lets oxygen-rich blood pass from the left ventricle into the aorta, then to the body

S. MORRIS 2006

The circulatory system carries blood and dissolved substances to and from different places in the body.

The Heart has the job of pumping these things around the body.

The Heart pumps blood and substances around the body in tubes called blood vessels.

The Heart and blood vessels together make up the

Circulatory System.

The circulatory system

lungs

head & arms

liver

digestive system

kidneys

legs

pulmonary artery

aorta

pulmonary vein

main vein

Left Right

How does this system work?

Circulatory System

Lungs

Body cells

Our circulatory system is a double circulatory system. This means it has two parts parts.

the right side of the system

deals with deoxygenated

blood.

the left side of the system

deals with oxygenated

blood.

The Heart

These are arteries. They carry blood away from the heart.

This is a vein. It brings blood from the body, except the lungs.

Coronary arteries, the hearts own blood supply

The heart has four chambers

2 atria

2 ventricles

now lets look inside the heart

The Heart

Left Ventricle

Left AtriumRight Atrium

Right Ventricle

valve

Vein from Lungs

Artery to Head and BodyArtery to Lungs

Vein from Head and Body

valve

How does the Heart work?

blood from the body

blood from the lungs

The heart beat begins when the

heart muscles relax and blood

flows into the atria.

STEP ONE

The atria then contract and

the valves open to allow blood

into the ventricles.

How does the Heart work?

STEP TWO

How does the Heart work?

The valves close to stop blood

flowing backwards.

The ventricles contract forcing

the blood to leave the heart.

At the same time, the atria are

relaxing and once again filling with

blood.

The cycle then repeats itself.

STEP THREE

3 Kinds of Circulation:

• Pulmonary circulation• Coronary circulation• Systemic circulation

Pulmonary Circulation

Movement of blood from the heart, to the lungs, and back to the heart again

sln.fi.edu/biosci/systems/ pulmonary.html

Coronary Circulation

Movement of blood through the tissues of the heart

http://sln.fi.edu/biosci2/systems/

Systemic Circulation

Supplies nourishment to all of the tissue located throughout the body , except for

the heart and lungs

http://sln.fi.edu/biosci/systems/systemic.html

Hollow tubes that circulate your blood

There are 3 types of blood vessels

a. ARTERY

b. VEIN

c. CAPILLARY

Blood Vessels

Arteries

• Carry blood AWAY from the heart• Heart pumps blood • Main artery called the aorta • Aorta divides and branches • Many smaller arteries • Each region of your body has system of arteries

supplying it with fresh, oxygen-rich blood.

The ARTERY

thick muscle and elastic fibres

Arteries carry blood away from the heart.

the elastic fibres allow the artery to stretch under pressure

the thick muscle can contract to push the blood along.

Aortic arch

Arteries

Pulmonary artery (trunk)

Coronary arteries

Arteries circulation

Veins

• Carry blood to the heart• Receive blood from the capillaries• Transport waste-rich/ oxygen-poor blood back to

the heart • Allow blood to move in one direction

The VEINVeins carry blood towards from the heart.

thin muscle and elastic fibres

veins have valves which act to stop the blood from going in the wrong direction.

body muscles surround the veins so that when they contract to move the body, they also squeeze the veins and push the blood along the vessel.

Capillaries

• Very thin• Only one cell thick• Connect arteries & veins

Capillaries

• Food and oxygen released to the body cells

• Carbon dioxide and other waste products returned to the bloodstream

The CAPILLARYCapillaries link Arteries with Veins

the wall of a capillaryis only one cell thick

they exchange materials between the blood and other body cells.

The exchange of materials between the blood and the body can only occur through capillaries.

artery vein

capillariesbody cell

The CAPILLARYA collection of capillaries is known as a capillary bedcapillary bed.

http://users.tpg.com.au/users/amcgann/body/circulatory.html

www.biosbcc.net/doohan/ sample/htm/heart.htm

Heart Circulation

Heart Circulation

Veins circulation

Physiology Of heart

Properties of Cardiac muscle:-

1.Excitability or irritability

2.Contractility

3.Automaticity

4.Rhythmicity

5.All or none phenomenon

6.Refractory period

7.Tonicity

Coordination of chamber contraction, relaxation

I. Excitability (Irritability):

= the ability of cardiac muscle to respond to adequate stimuli by generating an action potential followed by a mechanical contraction.

Electrophysiology of the cardiac muscle cell

The Conduction System

• Electrical signal begins in the sinoatrial (SA) node: "natural pacemaker." – causes the atria to contract.

• The signal then passes through the atrioventricular (AV) node. – sends the signal to the ventricles via the “bundle of

His” – causes the ventricles to contract.

The Conduction System

The normal electrocardiogram

Abnormalities of Heart:-

1.Hypertension

2.CHF (Conjunctive heart failure)

3.Hyperlipidemic

4.Arraythmias

5.Angina pectories