Unit 3: Heart

base of heart

- posterior aspect at T6-T9

- formed mainly by left atrium

- extends from bifurcation of the pulmonary trunk to coronary sulcus inferiorly

- receives pulmonary veins

apex of heart location

- lies in the left 5th intercostal space on the mid-clavicular line

right border of heart

- right atrium

left/superior border of heart

- left ventricle

inferior border / diaphragmatic surface of heart

- right ventricle

anterior surface of heart

- predominately the right ventricle

posterior surface of heart

- primarily the left atrium and left ventricle

aortic arch location

- begins and ends at the sternal angle/2nd costosternal joints

fibrous pericardium

- fibrous CT sac surrounding the heart

- fused to the tunica adventitia on the roots of the great vessels and to the central tendon of the diaphragm

parietal pericardium

- deep to and lines the fibrous pericardium

- continuous with the visceral pericardium on the heart

fibrous skeleton

- CT rings surrounding the orifices of the four heart valves

- support base of cusps and prevent distension of orifices

- provides attachment for muscle fibers of atria and ventricle

- provides electrical insulation between atria and ventricles

right atrioventricular valve

- aka tricuspid

- anterior, posterior, and septal cusps, each with a papillary muscle by the same name

- lies at the level of the 5th costal cartilage on midline

left atrioventricular valve

-aka bicuspid/mitral valve

- anterior and posterior cusps, each with a papillary muscle by the same name

- lies at the level of the 5th costal cartilage to the left of midline

aortic valve

-aka aortic semilunar

- right, left, and posterior cusps

- each has a nodule in the center of the free margin

- lies at the level of the 3rd intercostal space left of the midline

pulmonary valve

-aka pulmonary semilunar

- left , right, and anterior cusps

- each cusp has a nodule in the center of the free margin

- lies posterior to the 3rd sternocostal joint

areas for auscultation

- mitral : 5th left intercostal space at midclavicular line

- tricuspid: para-xiphoid

- aortic: 2nd intercostal, right upper sternal border

- pulmonic: 2nd intercostal, left upper sternal border

coronary arteries

- normally arise as two branches from the aortic sinuses of the ascending aorta

- major branches run in coronary sulcus and interventricular grooves

right coronary artery

- arises from right aortic sinus

- runs around to the right in the right/anterior coronary sulcus

- gives rise to posterior interventricular artery in 90% of people

sinoatrial nodal artery

- comes off right coronary artery

- runs to sinoatrial node

right marginal artery location

- on the right cardiac border

atrioventricular nodal artery location

- found at the junction of the coronary and posterior interventricular sulci

left coronary artery

- normally supplies left ventricle, interventricular septum, and left atrium

- arises from left aortic sinus and divides early

circumflex artery

- runs to the left in the posterior coronary sulcus

- may give off posterior interventricular artery (10%)= L DOM

left marginal artery

- arises from circumflex artery on the left cardiac border

anterior interventricular artery

- lies in interventricular groove

- most commonly occluded coronary artery

- gives extensive blood supply to left ventricle and interventricular septum= blockages quite lethal

coronary anastomoses

- between anterior and posterior interventricular arteries on posterior aspect of apex

- between right coronary and circumflex arteries on posterior surface of heart

- minimally function in a healthy heart

coronary sinus

- returns venous blood of coronary circulation to right atrium

great cardiac vein

- in anterior interventricular groove and coronary sulcus

- runs with anterior interventricular artery

- dumps into coronary sinus

oblique vein

- runs along posterior aspect of the left atrium

- dumps into coronary sinus

small cardiac vein

- runs with the rt marginal artery then inferiorly in the coronary sulcus

- dumps into coronary sinus

middle cardiac vein

- runs with the posterior interventricular artery

- dumps into coronary sinus

sinoatrial node

- lies in the wall of the rt atrium near the opening of the SVC

atrioventricular node location

- lies at the base of the interatrial septum near the opening of the coronary sinus

atrioventricular bundle

- from AV node through fibrous skeleton into membranous interventricular septum

- divides into bundles or bundle branches

Purkinje fibers (aka subendocardial fibers)

• individual fibers (specialized cardiac muscle cells) which make up the bundles

• branch from bundles in the ventricular walls

right bundle branch

- diverges from the left bundle in the upper interventricular septum and branches in the wall of the right ventricle

- some fibers pass through the septomarginal band to the anterior and other papillary muscles

left bundle branch

- diverges from right bundle in the upper interventricular septum and branches in the wall of the left ventricle

fetal circulation

- gas exchange occurs at the placenta, so lungs are bypassed by two right-to-left shunts in prenatal circulation

oxygenated blood from placenta path

1. placenta

2. umbilical vein

3. ductous venosus (liver shunt)

4. IVC

5. RA

6. foramen ovale (direction of IVC ensures most blood
   moves through the opening into the left atrium))

7. LA

8. LV

9. aortic valve

10. aorta

11. head and neck

deoxygenated blood from head and neck path

1. head and neck

2. SVC (direction of SVC ensures most blood moves through the
   right AV valve into the right ventricle)

3. RA

4. R AV valve

5. RV

6. pulmonary trunk

7. ductous arteriosus

8. distal end of aortic arch

9. aorta

10. internal iliac arteries

11. umbilical arteries

12. placenta

pre to postnatal circulation structures

1. foramen ovale -> fossa ovalis

2. ductus venosus -> ligamentum venosum

3. ductus arteriosus -> ligamentum arteriosum

4. umbilical vein -> round ligament of liver

5. umbilical arteries -> medial umbilical ligaments

foramen ovale -> fossa ovalis location

on interatrial septum

ductus venosus -> ligamentum venosum location

from IVC to porta hepatis

ductus arteriosus -> ligamentum arteriosum location

from pulmonary trunk to aortic arch

umbilical vein -> round ligament of liver location

from umbilicus to liver along anterior abdominal wall at midline

umbilical arteries -> medial umbilical ligaments location

lateral on anterior abdominal wall

foramen ovale

- formed by two overlapping membranes with offset openings

-septum prinum, septum secundum

septum primum

• represented by floor of fossa ovalis

• larger

septum secundum

represented by limbus fossae ovalis of right atrium

what happens at birth to the septum primum and septum secundum?

lungs inflate, pressure in left atrium rises above right and septum primum is pushed against septum secundum

atrioventricular valves slam shut…

Lubb

semilunar valve (aortic and pulmonary valves) slam shut..

Dubb

function of chordae tendinae and papillary m

anchor to wall of ventricles so AV valves don’t pop back up into atrium

true or false: blood flows into tricuspid valve first than bicuspid

true

left side of heart pumps harder so we see hypertrophy leading to

hypertension