copyright © 2010 pearson education, inc. heart anatomy approximately the size of a fist location ...

Copyright © 2010 Pearson Education, Inc.

Heart Anatomy

• Approximately the size of a fist

• Location

In the mediastinum between second rib and fifth intercostal space

Directly on top of the diaphragm

Two-thirds to the left of the midsternal line

In front of the vertebral column, behind the sternum

Copyright © 2010 Pearson Education, Inc. Figure 18.1a

Point ofmaximalintensity(PMI)

Diaphragm

(a)

Sternum

2nd rib

Midsternal line

• Enclosed in pericardium, a double-walled sac


Pericardium

• Outer layer is a tough, dense fibrous layer

Protects, anchors, and prevents overfilling


PericardiumDouble-walled sac that encloses the heart

Inner Layer:

Parietal layer lines the internal surface of the fibrous pericardium

Visceral layer (epicardium) on external surface of the heart

Separated by fluid-filled pericardial cavity (decreases friction)


The pericardium….

…you’ve got it in the bag!


Pericarditis – Inflammation of the pericardium• Roughens the serous membrane surfaces

• Causes the beating heart to rub against pericardial sac

• Creates a pericardial friction rub heard with a stethoscope

• Can cause sever pain and inflammatory build up of fluid putting pressure on the heart causing a condition known as cardiac tamponade

Treated by inserting a needle into the pericardial cavity and draining off excess fluid


Pericarditits


Layers of the Heart Wall

1. Epicardium— Outer, visceral layer of the serous pericardium

2. Myocardium – Middle muscular layer

• Forms the bulk of the heart

3. Endocardium - Lines the chambers of the heart

Copyright © 2010 Pearson Education, Inc. Figure 18.2

Fibrous pericardium

Parietal layer ofserous pericardiumPericardial cavity

Epicardium(visceral layerof serouspericardium)Myocardium

Endocardium

Pulmonarytrunk

Heart chamber

Heartwall

Pericardium

Myocardium


Cardiacmusclebundles


4 Chambers of the Heart

• 2 Atria superiorily

• 2 Ventricles inferiorily


Chambers

The Atria

Separated internally by the interatrial septum

Coronary sulcus (atrioventricular groove) encircles the junction of the atria and ventricles

Auricles increase atrial volume


Chambers

The ventricles

Separated by the interventricular septum

Anterior and posterior interventricular sulci mark the position of the septum externally

Copyright © 2010 Pearson Education, Inc. Figure 18.4b

(b) Anterior view

Brachiocephalic trunk

Superior vena cava

Right pulmonaryarteryAscending aortaPulmonary trunk

Right pulmonaryveins

Right atrium

Right coronary artery(in coronary sulcus)Anterior cardiac vein

Right ventricle

Right marginal artery

Small cardiac vein

Inferior vena cava

Left common carotidarteryLeft subclavian artery

Ligamentum arteriosum

Left pulmonary artery

Left pulmonary veins

Circumflex artery

Left coronary artery(in coronary sulcus)

Left ventricle

Great cardiac vein

Anterior interventricularartery (in anteriorinterventricular sulcus)

Apex

Aortic arch

Auricle ofleft atrium


Atria: The Receiving Chambers

•Walls are ridged by pectinate muscles

• Vessels entering right atrium

Superior vena cava

Inferior vena cava

Coronary sinus

• Vessels entering left atrium

Right and left pulmonary veins


Ventricles: The Discharging Chambers•Walls are ridged by trabeculae carneae

• Papillary muscles project into the ventricular cavities

• Vessel leaving the right ventricle

• Pulmonary trunk

• Vessel leaving the left ventricle

• Aorta

Copyright © 2010 Pearson Education, Inc. Figure 18.4e

Aorta

Left pulmonaryarteryLeft atriumLeft pulmonaryveins

Mitral (bicuspid)valve

Aortic valve

Pulmonary valveLeft ventricle

Papillary muscleInterventricularseptumEpicardiumMyocardiumEndocardium

(e) Frontal section

Superior vena cava

Right pulmonaryarteryPulmonary trunk

Right atrium

Right pulmonaryveinsFossa ovalisPectinate muscles

Tricuspid valveRight ventricle

Chordae tendineae

Trabeculae carneae

Inferior vena cava


Heart Valves

• Ensure unidirectional blood flow through the heart

• Atrioventricular (AV) valves

• Prevent backflow into the atria when ventricles contract

• Tricuspid valve (right)

• Mitral valve (left)

• Chordae tendineae anchor AV valve cusps to papillary muscles


Heart Valves

• Semilunar (SL) valves

• Prevent backflow into the ventricles when ventricles relax

• Aortic semilunar valve

• Pulmonary semilunar valve


Pulmonary valveAortic valveArea of cutaway

Mitral valveTricuspid valve

Myocardium

Tricuspid(right atrioventricular)valveMitral(left atrioventricular)valveAorticvalve

Pulmonaryvalve

(b)



Myocardium

Tricuspid(right atrioventricular)valve

(a)

Mitral(left atrioventricular)valveAortic valve

Pulmonaryvalve

Fibrousskeleton

Anterior




Myocardium

Tricuspid(right atrioventricular)valveMitral(left atrioventricular)valveAorticvalve

Pulmonaryvalve

(b)

Copyright © 2010 Pearson Education, Inc. Figure 18.8c

Pulmonaryvalve

AorticvalveArea ofcutawayMitralvalve

Tricuspidvalve

Chordae tendineaeattached to tricuspid valve flap

Papillarymuscle

(c)

Copyright © 2010 Pearson Education, Inc. Figure 18.8d

PulmonaryvalveAortic valveArea of cutawayMitral valveTricuspidvalve

Mitral valve

Chordaetendineae

Interventricularseptum

Myocardiumof left ventricle

Opening of inferiorvena cava

Tricuspid valve

Papillarymuscles

Myocardiumof rightventricle

(d)


1 Blood returning to theheart fills atria, puttingpressure againstatrioventricular valves;atrioventricular valves areforced open.

1 Ventricles contract, forcingblood against atrioventricularvalve cusps.

2 As ventricles fill,atrioventricular valve flapshang limply into ventricles.

2 Atrioventricular valvesclose.

3 Atria contract, forcingadditional blood into ventricles.

3 Papillary musclescontract and chordaetendineae tighten,preventing valve flapsfrom everting into atria.

(a) AV valves open; atrial pressure greater than ventricular pressure

(b) AV valves closed; atrial pressure less than ventricular pressure

Direction ofblood flow

Atrium

Ventricle

Cusp ofatrioventricularvalve (open)

Chordaetendineae

Papillarymuscle

Atrium

Blood inventricle

Cusps ofatrioventricularvalve (closed)


As ventriclescontract andintraventricularpressure rises,blood is pushed upagainst semilunarvalves, forcing themopen.

As ventricles relaxand intraventricularpressure falls, bloodflows back fromarteries, filling thecusps of semilunarvalves and forcingthem to close.

(a) Semilunar valves open

(b) Semilunar valves closed

Aorta

Pulmonarytrunk


Pathway of Blood Through the Heart

The heart is actually two side-by-side pumps

• Right side is the pump for the pulmonary circuit

Vessels that carry blood to and from the lungs

• Left side is the pump for the systemic circuit

Vessels that carry the blood to and from all body tissues


Oxygen-rich,CO2-poor bloodOxygen-poor,CO2-rich blood

Capillary bedsof lungs wheregas exchangeoccurs

Capillary beds of allbody tissues wheregas exchange occurs

Pulmonary veinsPulmonary arteries

PulmonaryCircuit

SystemicCircuit

Aorta and branches

Left atrium

Heart

Left ventricleRight atrium

Right ventricle

Venae cavae



• Right atrium tricuspid valve right ventricle

• Right ventricle pulmonary semilunar valve pulmonary trunk pulmonary arteries lungs



• Lungs pulmonary veins left atrium

• Left atrium bicuspid valve left ventricle

• Left ventricle aortic semilunar valve aorta

• Aorta systemic circulation


Hmmm….

Notice Something Funny?

What do arteries usually carry?

What do veins usually carry?

What’s going on in the heart?



• Equal volumes of blood are pumped to the pulmonary and systemic circuits

• Pulmonary circuit is a short, low-pressure circulation

• Systemic circuit blood encounters much resistance in the long pathways

• Anatomy of the ventricles reflects these differences


Rightventricle

Leftventricle

Interventricularseptum


Coronary Circulation

• The functional blood supply to the heart muscle itself

• Arterial supply varies considerably and contains many anastomoses (junctions) among branches

• Collateral routes provide additional routes for blood delivery


Coronary Circulation

• Arteries

• Right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries

• Veins

• Small cardiac, anterior cardiac, and great cardiac veins


Rightventricle

Rightcoronaryartery

Rightatrium

Rightmarginalartery

Posteriorinterventricularartery

Anteriorinterventricularartery

Circumflexartery

Leftcoronaryartery

Aorta

Anastomosis(junction ofvessels)

Leftventricle

Superiorvena cava

(a) The major coronary arteries

Left atrium

Pulmonarytrunk


Superiorvena cava

Anteriorcardiacveins

Small cardiac vein

Middle cardiac vein

Greatcardiacvein

Coronarysinus

(b) The major cardiac veins

Copyright © 2010 Pearson Education, Inc. Figure 18.4d

(d) Posterior surface view

Aorta

Left pulmonaryartery

Left pulmonaryveinsAuricle of leftatriumLeft atrium

Great cardiacvein

Posterior veinof left ventricle

Left ventricle

Apex

Superior vena cava

Right pulmonary artery

Right pulmonary veins

Right atrium

Inferior vena cava

Right coronary artery(in coronary sulcus)

Coronary sinus

Posteriorinterventricularartery (in posteriorinterventricular sulcus)Middle cardiac veinRight ventricle


Homeostatic Imbalances

• Angina pectoris

• Thoracic pain caused by a fleeting deficiency in blood delivery to the myocardium

• Cells are weakened

• Myocardial infarction (heart attack)

• Prolonged coronary blockage

• Areas of cell death are repaired with noncontractile scar tissue

copyright © 2010 pearson education, inc. heart anatomy approximately the size of a fist location ...

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