cardiovascular - part 2

8/14/2019 Cardiovascular - Part 2

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CARDIOVASCULARCARDIOVASCULAR

SYSTEMSYSTEM


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HEART

A hollow muscular organ The heart weighs between 7

and 15 ounces (200 to 425

grams) and is a little largerthan the size of your fist.

heart is located between your

lungs in the middle of yourchest, behind and slightly to the

left of your breastbone

(sternum)


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SURFACES OF THE HEART

1. STERNOCOSTAL SURFACE- Formed mainly by the RA and

RV

2. DIAPHRAGMATIC SURFACE

- Formed by RV and LV

3. BASE OF THE HEART

- Formed by the LA

- Directed posteriorly, superiorly

and to the right


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**APEX OF THE HEART:

Formed by he LV

Lies at the level of the 5th Left

Intercostal space, 3 1/2 inches frommidline.

Directed downward, forward and to

the left.


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BORDERS OF THE HEART:

(INTERNAL BORDERS) Right Border

Formed by RA

Left Border

Formed by Left auricle

Lower Border Formed by LV


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(EXTERNAL BORDERS)

Anterior Surface

Sternum and ribs

Inferior Surface

Part of the heart between apex andright border, diaphragm

Right Border

Right lung

Left Border

Pulmonary border (Left lung, baseto apex)


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PERICARDIUM

Fibroserous sac that encloses theheart the roots of the great vessels.

Lies within the middle mediastinum

FUNCTION:

1. Restrict excessive movement

of the heart as a whole

2. Serves as a lubricated

container in which the different

parts of the heart can contract.


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2 TYPES OF PERICARDIUM

1. FIBROUS PERICARDIUM

- Strong fibrous part of the sac

- Attached to the central tendon of thediaphragm

- Attached in front to the sternum bysternopericardial ligament.

FUNCTIONS:

1. Prevents overstretching of the heart

2. Provides protection

3. Anchors the heart in the

mediastinum


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2. SEROUS PERICARDIUM

2 Layers:

I. Parietal Layer:

- lines the fibrous pericardium

- reflected around the roots of thegreat vessels

II. Visceral Layer:

Closely applied to the heart

A.k.a. EPICARDIUM


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THE HEART WALL:

3 LAYERS:

3. Epicardium external layer

4. Myocardium middle layer

5. Endocardium inner layer


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EPICARDIUM:

Visceral layer of the serouspericardium

The epicardium is the outer layer of thewall of the heart.

The visceral pericardium apparentlyproduces the pericardial fluid, whichlubricates motion between the inner and

outer layers of the pericardium.FUNCTION:

Provides an outer protective layer forthe heart.
http://en.wikipedia.org/wiki/Pericardial_fluidhttp://en.wikipedia.org/wiki/Pericardiumhttp://en.wikipedia.org/wiki/Pericardiumhttp://en.wikipedia.org/wiki/Pericardial_fluid


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ENDOCARDIUM:

The endocardium is the innermost

layer of tissue.

Provides a smooth lining for the

chambers of the heart

Covers the valve of the heart

FUNCTION:

Controls myocardial function Purkinje fibers are located in the

endocardium. They participate in the

contraction of the heart muscle.
http://biology.about.com/library/organs/heart/blpurkinje.htmhttp://biology.about.com/library/organs/heart/blpurkinje.htm


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CHAMBERS OF THE HEART:

1. LEFT ATRIUM

2. RIGHT ATRIUM

3. LEFT VENTRICLES

4. RIGHT VENTRICLES


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ATRIUM:

Upper chambers

VENTRICLES: the lower chambers.

A wall of muscle called the septum

separates the left and right atria and theleft and right ventricles.

The left ventricle is the largest andstrongest chamber in your heart.

The left ventricle's chamber walls are onlyabout a half-inch thick, but they haveenough force to push blood through the

aortic valve and into your body.


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cardiovascular - part 2

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