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Chapter 18 The Heart

Do you love me with all your heart?

My heart doesnt love you at all. Its a chunk of muscle that

pumps blood

What do we already know?

What is the heart?

If you had only one word to describe the heart? Pump

Two words? Pumping Muscle

Three words? Chambered Pumping Muscle

Big Idea: Function

Why does your heart pump?? Transport! Nutrients O2, CO2 Waste Heat Hormones Immune Cells

But more on that LATER

BI: Size & Shape (Gross Anatomy) Size:

Double fist (adult) , fist (child) Mass:

250-350 grams (

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Location Medial anterior portion of chest 5 in long Between 2nd-5th ribs Behind the sternum Between the lungs Base R shoulder Apex L Hip Sits on diaphragm Point of Maximal Intensity

Apex contacts chest wall Can best feel heartbeat Around left nipple

Location Medial anterior portion of chest 5 in long Between 2nd-5th ribs Behind the sternum Between the lungs Base R shoulder Apex L Hip Sits on diaphragm Point of Maximal Intensity

Apex contacts chest wall Can best feel heartbeat Around left nipple

Location Mediastinum Cavity

BI: Coverings (Gross Anatomy) Pericardium Think back!!

Peri= Cardi =

Double-walled sac Keeps things

friction-free

Coverings

Peri = around Cardi = heart

Pericardium Double-walled sac Keeps things friction -free

Fibrous Pericardium attaches & anchors

Serous Pericardium slippery liner

Parietal Layer (Serous) lines fibrous pericardium

Pericardial Cavity serous fluid

Visceral Layer (Serous) lines outside of heart = pericardium

Coverings

Pericardium Double-walled sac Keeps things friction -free

Fibrous Pericardium attaches & anchors

Serous Pericardium slippery liner

Parietal Layer (Serous) lines fibrous pericardium

Pericardial Cavity serous fluid

Visceral Layer (Serous) lines outside of heart

= pericardium

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BI: Heart Wall (Gross Anatomy) Epicardium

= visceral pericardium!

Myocardium What kind of muscle?? Bulk of heart Bundles of muscle are

arranged in spiral and circular patterns

Epi = upon; Cardi = heart

Myo = muscle

Endocardium Squamous Epithelial & Connective Tissue Lines

All heart chambers Continuous with lining of all veins/arteries coming

in and out of the heart

Endo = inside

Review / Draw It Pericardium Fibrous Pericardium

Serous Pericardium Parietal Layer Pericardial Cavity Visceral Layer

Heart Wall Epicardium Myocardium Endocardium

Review

What cavity is the heart located in? Mediastinum

What is the covering of the heart called? Pericardium

What are the three layers/components of the visceral serous pericardium? Parietal Layer, Pericardial Cavity, Visceral

Layer

Review

What layer of the pericardium functions to attach and anchor? Fibrous Pericardium

What is the point of maximal intensity and where is it located?

What is the heart? A blood-pumping muscle

How does a garden waterfall work? A pump creates pressure to move the

water How does a hair spray can work?

Fluids move from high pressure to low pressure

The Heart

The heart creates and maintains a pressure gradient High hydrostatic pressure to move blood out

of the heart Low hydrostatic pressure to allow blood into

the heart

Chambers, valves, veins and arteries all work together to create and maintain the pressure gradient

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Big Idea: Internal Heart Structure

Divided into 2 parts by an inner septum

4 chambers Atrium = top 2

Low pressure Thin walls Receiving chambers

Ventricle = bottom 2 High pressure Thick walls Discharging chambers

Internal Heart Structure Heart chambers are

separated by 4 valves Mitral (bicuspid)

L At / L Vt Tricuspid

R At / R Vt Pulmonary Semilunar

R Vt / Pulmonary Artery Aortic semilunar

L Vt / Aorta

Valves Allow blood to enter but not exit chambers

Atrioventricular Valves Mitral & Tricusupid

Semilunar Valves Pulmonary & Aortic

Atrioventricular Valves Tricuspid Valve

Right side Three cusps

Mitral (Bicuspid) Valve Left side Two cusps

Cusp Flaps of endocardium

reinforced by connective tissue

Chordae Tendineae heart strings Anchor cusps to the papillary

muscles

Semilunar Valves Aortic Semilunar & Pulmonary Semilunar

Guard bases of the aorta and pulmonary trunk Prevent backflow Three cusps that look like crescent moons

Valves Lub = closure of mitral & tricuspid valves Dub = closure of aortic & pulmonary

semilunar valves

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Valves: All About the Pressure Lub = closure of mitral & tricuspid valves

Close to build up pressure when ventricles contract to pump blood out of the heart

Systole = high pressure caused by ventricle contraction

Valves: All About the Pressure Dub = closure of aortic & pulmonary semilunar

valves Close at the start of diastole Diastole = ventricles relaxing to receive next gush

of blood from the L & R atria

Valves Note

No valves guard entrances from vena cava or pulmonary veins

Which brings us to

The Internal Heart

Internal Heart Structure: Details Interatrial Septum

Fossa Ovalis - Location of fetal heart foramen ovale

Right Atrium Pectinate Muscles

Found on anterior wall

Posterior wall is smooth

No distinguishing features in L At

Pectin = comb

Internal Heart Structure: Details Ventricles

Trabeculae Carneae: Irregular ridges of muscle Papillary Muscles: Valve function, attach to chordae tendineae Massive Myocardium

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Big Idea: Blood Movement 1. Right Ventricle 2. Pulmonary Semilunar

Valve 3. Pulmonary Trunk 4. R/L Pulmonary Arteries* 5. R/L Lungs 6. Lung Capillaries 7. Pulmonary Veins* 8. Left Atrium

(creates pressure)

9. Mitral Valve 10. Left Ventricle

(lower pressure)

*Pulmonary arteries are the only place you will find deoxygenated blood in an artery *Pulmonary veins are the only place you will find oxygenated blood in a vein

Pulmonary Circuit 1. Right Ventricle 2. Pulmonary Semilunar Valve 3. Pulmonary Trunk 4. R/L Pulmonary Arteries* 5. R/L Lungs 6. Lung Capillaries 7. Pulmonary Veins* 8. Left Atrium

(creates pressure)

9. Mitral Valve 10. Left Ventricle

(lower pressure)

Right side of heart is the pump

Carbaminohemoglobin becomes oxyhemoglobin Removes CO2 from the

blood and replenishes O2

O2 needs to get where?

Blood Movement: Systemic Circuit 1. Left Ventricle

(creates pressure)

2. Aortic Semilunar Valve 3. Aorta* 4. Arteries 5. Capillaries 6. Veins 7. Vena Cava

Superior & Inferior

8. Right Atrium (creates pressure)

9. Tricuspid Valve 10.Right Ventricle

*Aorta is about the size of a garden hose! Largest artery in the body

1. Left Ventricle (creates pressure)

2. Aortic Semilunar Valve 3. Aorta* 4. Arteries 5. Capillaries 6. Veins 7. Vena Cava

Superior & Inferior

8. Right Atrium (creates pressure)

9. Tricuspid Valve 10. Right Ventricle

Systemic Circuit Left side of heart is the

pump High pressure circulation 5x more friction/resistance

to blood flow than pulmonary circuit

Left ventricle wall 3x thicker than right and has larger chamber

Systemic & Pulmonary Circuits Blood Movement: Details Right atrium receives

blood from three veins: 1. Superior vena cava 2. Inferior vena cava 3. Coronary Sinus

Left atrium receives blood from four pulmonary arteries

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1. Left Ventricle 2. Aortic Semilunar Valve 3. Aorta*

Congestive Heart Failure LV cant pump blood

out to body It backs up and leaks

into the lungs Eventually backs up

into the lungs Lungs are congested

BUT WAIT

Where does the heart get blood??

Big Idea: Coronary Circulation

Myocardium is too thick for blood diffusion Coronary Arteries Cardiac Veins

Coronary Arteries

Right and left coronary arteries Come from the base of the aorta Encircle heart Lie in coronary sulcus

Cardiac Veins

Cardiac Veins Join together at coronary sinus Empty into right atrium

Which brings us to

The External Heart

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Big Idea: External Anatomy R/L Atria R/L Ventricles R/L Coronary Sulcus R/L Coronary Arteries Coronary Sinus posterior Pulmonary Trunk R/L Pulmonary Arteries Aortic Arch

Brachiocephalic Left common carotid Left subclavian

Pulmonary Arteries Sup/Inf Vena Cava

External Anatomy R/L Atria R/L Ventricles R/L Coronary Sulcus R/L Coronary Arteries Coronary Sinus posterior Pulmonary Trunk R/L Pulmonary Arteries Aortic Arch

Brachiocephalic Left common carotid Left subclavian

Pulmonary Arteries Sup/Inf Vena Cava

Coronary Sinus R/L Atria R/L Ventricles R/L Coronary Sulcus R/L Coronary Arteries Coronary Sinus posterior Pulmonary Trunk R/L Pulmonary Arteries Aortic Arch

Brachiocephalic Left common carotid Left subclavian

Pulmonary Arteries Sup/Inf Vena Cava

External Anatomy Auricles Little Ears

Small appendages that slightly increase atrial volume

That was all gross anatomy. Now we move on to

Microscopic Anatomy

Think CELLULAR!