The cardiovascular system consists of the heart and blood vessels (arteries, capillaries and veins.)

• Supplies oxygen and nutrients to tissues, removes wastes

• Pulmonary circuit carries deoxygenated blood to the lungs to release CO2 and pick up O2

• Systemic circuit sends oxygenated blood to cells of the body and picks up CO2 from cells.

The Cardiovascular System

Deoxygenated blood

Oxygenated blood

Oxygenatedblood pumped toall body tissuesvia aorta

Deoxygenatedblood pumpedto lungs viapulmonary arteries

Deoxygenated blood returnsto heart via venae cavae

Oxygenated blood returnsto heart via pulmonary veins

Left atrium

Left ventricleRight atrium

Right ventricle

The systemic circuit delivers oxygen to allbody cells and carries away wastes.

CO2

CO2CO2

CO2

O2O2

O2

O2

The pulmonary circuit eliminates carbondioxide via the lungs and oxygenates theblood.

CO2

CO2

O2

O2

O2

O2

CO2

CO2

Alveolus

• Pericardium is a dense fibrous connective tissue covering the heart ( sac around the heart)

• 3 distinct layers underneath pericardium– epicardium-contains coronary arteries and vessels

that nourish the heart– myocardium- contains heart muscle tissue– endocardium-contains Purkinge fibers that innervate

the heart

The Heart

Endocardium

Myocardium

Epicardium(visceral pericardium)

Coronaryblood vessel

PericardialcavityParietalpericardium

Fibrouspericardium

Chambers of the Heart

• 4 chambers– 2 thin walled atria that receive blood from the body

• Right atrium receives deoxygenated blood from the body

• Left atrium receives oxygenated blood from the lungs

– 2 thick walled ventricles that pump blood to the body• Right ventricle pumps deoxygenated blood to the

lungs • Left ventricle pumps oxygenated blood to the body

Superiorvena cava

Systemiccapillaries

Tissue cells

Systemiccapillaries

Tissue cells

Pulmonaryartery

Pulmonaryveins

Alveolus

Alveolus

Left atrium

Mitral valve

Aortic valve

Left ventricle

Right atrium

Tricuspid valvePulmonary valve

Inferior vena cava

Right ventricle

Aorta

Alveolarcapillaries

Alveolarcapillaries

O2

CO2

O2

O2

CO2

CO2

O2CO2

Right auricle

Right atrium

Right ventricle

Pericardial cavity

Left ventricle

Heart (covered byvisceral pericardium)

Pulmonary trunk

Left auricle

Cut edge ofparietal pericardium

Cut edge offibrous pericardium

Aorta

Right lung Left lung

Diaphragm

Superiorvena cava

Valves

• Pulmonary Valve -prevents backflow of blood into the right ventricle as blood is pumped to lungs

• Aortic valve -prevents backflow of blood into the left ventricle

• Right Atrioventricular valve (AV) (tricuspid)-prevents backflow of blood into the right atrium from the ventricle

• Left Atrioventricular valve (bicuspid or mitral valve)-prevents backflow of blood into the left atrium from the ventricle

VisibleBody

(a)

Aorta

Pulmonary trunk

Left pulmonary artery

Left pulmonary veins

Left auricleLeft coronary artery

Great cardiac veinAnterior interventricular artery(left anterior descending artery)

Left ventricle

Apex of the heart

Right coronaryartery

Superior vena cava

Right pulmonaryartery

Right auricle

Inferior vena cava

Small cardiac vein

Anterior cardiac vein

Right ventricle

Right pulmonaryveins

Anterior View of Heart

Fig13.09b

Left pulmonaryveins

Left pulmonary artery

Aorta

Left auricle

Circumflex artery

Cardiac vein

Left ventricle

Apex of the heart

Superior vena cava

Right pulmonaryartery

Right pulmonary veins

Left atrium

Right atrium

Inferior vena cava

Coronary sinus

Middle cardiac vein

Posterior interventricularartery

Right ventricle

(b)

Posterior View of Heart

Systole/Diastole

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• Atrial Systole- contracting atria, relaxing ventricles.

• Ventricular systole –contracting ventricles, relaxing atria

• Diastole- when the entire heart is relaxing

12

The Cardiac Cycle

Pulmonaryvalve closed

Tricuspidand mitralvalves open

(a) (b)

Aorticvalve closed

Atrial systoleLA

LV

RV

RA

Ventriculardiastole

Pulmonaryvalve open

Tricuspidand mitralvalves closed

Aorticvalve open

Atrial diastole

Ventricularsystole

Valves and Contractions of the Heart

• Due to vibrations in heart tissues as blood rapidly changes velocity within the heart.

• Heart sounds can be described as a "lubb-dupp" sound.

• First sound (lubb) -ventricles contract and A-V valves are closing

• Second sound (dupp)-ventricles relax and aortic and pulmonary valves are closing.

Heart Sounds

• An electrocardiogram (ECG) is a recording of the electrical changes that occur during a cardiac cycle.

Electrocardiogram

(a)

(b)

0

–.5

.5

1.0

Milliseconds

0 200 400 600

S

Q

PT

R

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Mill

ivol

ts

Electorcardiogram

• Blood pressure -force of blood against inner walls of blood vessels anywhere in the cardiovascular system. – As blood gets further and further from the left ventricle, blood

pressure decreases.

• Pulse-The surge of blood that occurs with ventricular contraction and can be felt at certain points in the body.– Caused by the expansion and contraction of blood vessels

• Systolic pressure- During ventricular contraction, arterial pressure is at its highest.

• Diastolic pressure- When ventricles are relaxing, arterial pressure is at its lowest.

Blood Pressure

Normal blood Pressure= 120/80 or less

Taking Blood Pressure

• Subject is seated and relaxed.• Wrap the fabric cuff around the upper arm• Locate the brachial artery • Place the diaphragm of the stethoscope over the

brachial artery so that you can hear Kortokoff sounds

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• Close the valve and pump air until the pressure reads 180mmHg.

• Open the valve of the bulb slowly until the pressure in the cuff drops at a rate of about 2 or 3 mm Hg per second.

• Listen for the sounds from the brachial artery-1st loud tapping sound=systolic pressure.

• When sounds suddenly are muffled= diastolic pressure.

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Taking Blood Pressure