Heart and great vessels

pericardium

fibrous sac that encloses the heart

3 portions of pericardium

-Fibrous pericardium

-Serous pericardium: parietal layer and visceral layer -pericardial cavity

Fibrous pericardium

outermost layer

function: protection

Serious pericardium: parietal layer

contacts fibrous pericardiu

Serious pericardium: Visceral layer

contacts epicardium (surface of heart)

pericardial cavity

space between visceral and parietal layer (of serous pericardium)

filled with serous fluid (5-30mL)

Inner to outer layers of heart to pericardium

heart epicardium

visceral pericardium (serous pericardium)

pericardial cavity with serous fluid

parietal pericardium (serous pericardium)

Fibrous pericardium

Heart anatomical location

1. intercostal spaces

- right: 2-5

-left: 2-6

right of midline= 1/3 mass

left of midline= 2/3 mass

4 heart borders

1. right

2. left

3.superior

4. inferior

Left heart margin

right heart margin

inferior heart margin

Apex of heart

inferior

base of the heart

superior (this is where vessels reside)

Auricles of the heart

Flaps that cover the atria

Function: unknown but thought to be evolution remnants

3 layers of the heart wall

Epicardium

myocardium

endocardium

epicardium

composed of mesothelial cells and connective tissue (fat)

contains: fat, vessels, nerves

myocardium

muscle layer (contractile myocytes)

endocardium

lines inner cavities of the heart

comprised of smooth muscle and connective tissue

deep layer of connective tissue contains conduction system

-AKA: subendocardial layer

pericardium and heart wall layers from outside to insude

pericardial sac (fibrous layer then serous layer)

epicardium

myocardium

endocardium

skeleton of the heart

fibrous rings that hold the heart open and provide a substrate for cardiac muscle contraction

rings surround valves and pulmonary orifices (openings)

Electrical conduction system

sinoatrial node

atrioventricular node

AV bundles

Left and right bundle branches

purkinje (plexus) fibers

sinoatrical node

pacemaker (in right atrium)

Atrioventricular node

ectopic pacemaker (backup)

in interatrial septum

AV bundles

(bundle of His)

top (superior) of interventricular septum

Left and right bundle branches

run inferiorly along right and left sides of interventricular spetum

purkinje (plexus) fibers

lateral walls of ventricles

Atrioventricular valves

1. tricuspid (right AV valve)

2. bicuspid (left AV valve) (also called mitral valve)

have chordae tendinae attached

what do chordae tendinae do for AV valves

prevent backflow of blood (from ventricle into atrium)

the papillary muscles contract and that generates tension on the chordae tendinae which hold the AV valves closed

Semilunar valves

pulmonary and aortic

have sinuses

what do sinuses do for semilunar valves

full with blood to prevent backflow (of blood from aorta or pulmonary trunk back into left and right ventricles respectively)

All heart valves lie

in one plane

Right atrium

sulcus terminalis (external)- cavity and auricle

crista terminalis- internal ridge

**pectinate muscles- internal ridges

4 major openings of right atrium

Superior vena cava

inferior vena cava

coronary sinus- drains deoxygenated blood from heart into right atrium

right AV orifice - guarded by tricuspid valve

Right atrium: SA node

firing mediated by SNS and PSNS (ANS)

vagal tone (PSNS): heart rate (depolarizations) decreased by vagus nerve

usually depolarize 80-100 times per minute by with vagus nerve, 60-80 time per minute

Right atrium: AV node

regulates impulse conduction from atria to ventricles

Right atrium: interatrial septum

fossa ovalis- depression that is closed

in the fetus it is called foramen ovale (hole)

-connects left and right atrium

-closes within 24 hours of birth

Clinical application of interatrial septum

open back up in post menopausal females

the symptom= feelings bubbles/butterflies

can cause strokes in the post menopausal age (58ish)

Right ventricle communicates with

right atrium via Atrioventricular orifice

Right ventricle characterisitics

-additional openings: pulmonary orifice

-guarded by pulmonary semilunar valve

-thicker walls than right atrium- contain projecting ridges called trabeculae carnae

2 types of projecting ridges in right ventricle

1. papillary muscles

2. trabeculae carnae (in right ventricle there is a specific special one)

Special trabeculae carnae in right ventricle

septomarginal trabecule (moderator band)

-used during fetal ultrasound to find fetus heart rate...helps orient yourself to heart because you know it is the right ventricle (can find what is what after this)

septomarginal trabecule (moderator band)

-prevent overdistension of ventricle

-spans base anterior papillary muscle to ventriclular septum

-carries part of right branch of AV bundle to anterior papillary muscle (helps with electrical conduction system pathway)

Left atrium

cavity and auricle

AV orifice guarded by mitral valve

4 pulmonary orifices-represent 4 pulmonary veins (number can vary)

Left ventricle communicates with

left atrium via AV orifice guarded by mitral valve

Left ventricle characteristics

additional opening= aortic orifice

walls 3-5 times thicker than right ventricle because more pressure on the left side

Aortic SL valve

Aortic SL valve

behind each cusp are bulges

-anterior and posterior aortic sinuses that give rise to right and left coronary arteries (feed oxygen rich blood to heart muscle)

ostium

opening of the right and left coronary artery (in aorta)

Blood flow through the heart

Superior/ Inferior vena cava

Right atrium

tricuspid valve

right ventricle

pulmonary semilunar valve

pulmonary trunk (artery)

lungs

The blood picks up oxygen in the lungs, and then flows from the lungs:

pulmonary veins

left atrium

Bicuspid valve

left ventricle

aortic semilunar valve

aorta

to the body

When is blood deoxygenated in that path

from superior vena cava to the lungs

-notice that the pulmonary artery holds deoxygenated blood

When is blood oxygenated in that path

From lungs to aorta

notice that the pulmonary veins have oxygenated blood

Heart arterial supply

variation!!!

right coronary artery ad left coronary artery

Right coronary artery supplies

right atrium, most right ventricle, part of left ventricle, SA and AV nodes

Right coronary branches

right marginal artery

nodal artery (SA node=60%) and (AV node=80%)

posterior interventricular artery (most commonly)

Left coronary artery supplies

left atrium, most left ventricle, part of right ventricle, SA node= 40% and AV node=20%

Branches of left coronary artery

circumflex artery

left anterior interventricular artery (AKA: left anterior descending artery...LAD)

Coronary artery dominance

which coronary artery gives rise to the posterior interventricular artery

most common= RCA (67%)

right and left coronary artery

right anterior ventricular artery

right coronary artery branch

right marginal artery

right coronary artery branch

right atrial artery

right coronary artery branch

right conus artery

right coronary artery branch

left marginal artery

left coronary artery branch

left interventricular artery

left coronary artery branch

left anterior ventricular artery

left coronary artery branch

venous drainage of the heart

primarily via coronary sinus

coronary sinus is a continuation of

great cardiac vein

tributaries of coronary sinus

small and middle cardiac veins

AKA: coronary veins (coronary is usually just used for arteries)

right anterior coronary vein branches

right atrial vein

small cardiac vein

right anterior ventricular vein

right marginal vein

right atrial vein

small cardiac vein

right anterior ventricular vein

right marginal vein

left anterior coronary vein branches

great cardiac vein

left marginal vein

left anterior ventricular vein

great cardiac vein

left marginal vein

left anterior ventricular vein

coronary/cardiac veins

small cardiac vein, great cardiac vein, middle cardiac vein all drain into coronary sinus

rate of contraction set by

SA node but you can control with NS

innervation of heart sympathetic

1. cervical sympathetic trunks

2. upper thoracic sympathetic trunks

3. effect on rate= increase heart rate

innervation of heart parasympathetic

1. vagus nerve

2. effect on rate= decrease heart rate (vagal tone)

great vessels of the heart

aorta

pulmonary trunk

superior and inferior vena cavae

aorta

ascending

aortic arch

descending

branches of ascending aorta

right and left coronary arteries

branches of aortic arch

brachiocephalic artery, left common carotid artery, left subclavian artery

pulmonary trunk composed of

right and left pulmonary arteries

ligamentum arteriosum

location: pulmonary trunk and aorta- closed

fetus-ductus arteriosus (open) (fetal lungs do not work so used to bypass the lungs to aorta)

takes 1 week from birth to close

superior and inferior vena cavae

superior vena cava joined by azygous vein before entering heart

azygous drains thoracic body wall

layers of arteries and veins

tunics externa, tunica media, and tunica intima

arteries vs vein

arteries have thicker tunica media

veins have valves

veins collapse because there is not much muscle to keep up

veins have larger lumen

capillary

1 cell thick and has pores for diffusion (filtration)