Anatomy · Physiology II

Chapter 15, Section 1

The Cardiovascular System

The heart is a remarkable organ

It pumps 7000L (1800 gallons) of blood through our body every day

The heart contracts 2.5 billion times in a lifetime

The heart contains two pumps

The heart is located within the mediastinum

• It is about the size of a

fist (14cm x 9cm)

• 2/3 of the heart is left of

the midline

1/3 2/3

The heart is posterior to the sternum

Base

attachment of major vesselsattachment of major vessels

2nd intercostal space

Apex

Pointed inferior margin

5th intercostal space

A pericardial membrane surrounds the heart.

The fibrous pericardium forms a thick outer layer

of connective tissue.

The parietal pericardium is a serous membrane

attached directly to the fibrous layer.

A visceral pericardium is a serous membrane that

forms the outer layer of the heart wall.

The pericardial cavity contains serous fluid.

The wall of the heart contains 3 layers

The epicardium is also called the visceral pericardium

The myocardium contains a thick layer of cardiac muscle,

with blood vessels and nerves

The endocardium is a smooth layer of squamous

epithelium that lines the heart chambers and valves

The heart has 4 chambers

The left atrium receives

blood from the lungs

The right atrium

receives blood from the

body

The left ventricle pumps

blood towards the body The right ventricle pumps

blood towards the lungs

Interventricular septum

Auricles increase the volume of the atria

Great veins carry blood towards the heart

The superior vena cava

returns blood from the

upper body to the heart

The inferior vena cava

Four pulmonary veins

return blood from the lungs

to the heart

The inferior vena cava

returns blood from the

lower body to the heart

The coronary sinus

returns blood from the

myocardium to the heart

Great arteries carry blood away from the heartGreat arteries carry blood away from the heart

The aorta conveys

oxygenated blood to the

systemic circulation

The pulmonary trunk* conveys

deoxygenated blood to the

pulmonary circulation

* The pulmonary trunk immediately divides

into a left and right pulmonary artery.

AV* valves prevent backflow into the atria. AV* valves prevent backflow into the atria.

The tricuspid valve

guards the right AV

orifice

The bicuspid (mitral)

valve guards the left

AV orifice

*AV = atrioventricular

Chordae tendineae anchor the cusps papillary muscles

Papillary muscles contract to pull the valves tightly shut

AV valves are anchored to the ventricles

Mitral Valve Prolapse – cusp protrudes into atrium.

Symptoms include: chest pain, heart palpitations,

and fatigue.

An Aortic valve (not shown) is

located at the base of the aorta

Semilunar valves prevent backflow into the ventricles

A pulmonary valve is located at A pulmonary valve is located at

the base of the pulmonary trunk

Semilunar valves prevent backflow into the ventricles

Each cusp of a semilunar

valve is shaped like a

crescent moon

Path of blood through the right heart chambers

1. Blood from SVC & IVC enter the

right atrium.

2. It passes through the tricuspid valve

into the right ventricle4

4

3. Blood is pumped from the right

ventricle, through the pulmonary

valve, and into the pulmonary trunk.

4. Blood passes into the pulmonary

arteries towards the lungs

1

2

3

Path of blood through the left heart chambers

5. Oxygenated blood is returned to

the heart through 4 pulmonary veins.

6. Blood enters the left atrium.

7. Blood passes through the bicuspid

valve into the left ventricle. 8

9

99

55

9. Blood enters systemic circulation to

the tissues throughout the body.

68. The left ventricle pumps blood

through the aortic valve into the aorta.

7

PROPERTIES

On passing, 'Finish' button:Goes to Next Slide

On failing, 'Finish' button:Goes to Next Slide

Allow user to leave quiz:After user has completed quiz

User may view slides after quiz:At any time

User may attempt quiz:Unlimited times