Cardiac Anatomy Flashcards
Circumflex Artery
- runs along atrioventricular groove
- 12% cases continues and gives off posterior descending artery
- has branches called obtuse marginal Aa
RCA
- runs in right atrioventricular groove
- 88% of the time it runs around to become posterior descending artery
Part of blood from right ventricle goes _____ but most goes _____
(baby in utero)
- through pulmonary trunk to lungs
- through ductus arteriosus to descending aorta to rest of body and placenta
Heart Apex
- toward left
- listen here for CHF
- medial to midclavicular line at:
- -5th intercostal space in supine
- -6th in standing
- 4th in obese/pregnant
Pericardium
- loose serous sac around heart
- parietal and visceral layers
- lubricates moving parts and holds heart in place
Heart Size
2 clenched fists
Heart Base
- top, central chest
- at rib 3
Heart Location
- 2/3 on left side
- Rotated: left ventricle toward anterior/axilla
pericarditis
- increased amount of fluid in pericardium
- especially after MI
- causes discomfort &/or decreased venous return
Myocardium
- muscle layer of heart
- thickness in proportion of work done
- Left ventricle thickest
Foramen Ovale
- valves between L & R atria
- normally closes at birth
Epicardium
- outside surface of heart
- shiny red
Endocardium
- inner most layer of heart
- shiny and smooth
Prenatal Oxygenation of Blood
-occurs across placenta, not the lungs
At birth, decreased pressure in R atrium and increase pressure in left atrium cause______
- closing of the foramen ovale
- anatomical closure by 2-3 months
Arterial Supply to Heart
-LCA & RCA
branch from base of aorta
Patent foramen ovale
-pathology causing foramen ovale to remain open
-results in R to L shunt
(blood flows from R atrium to L atrium)
Sarcoplasmic Reticulum of Myocardium
less developed so the heart muscle relies on extracellular Ca++
Autorhythmic Cells
- (create their own action potential)
- SA/AV nodes
- Bundle of His
- Purkinje Fibers
Action Potential of Autorhythmic Cells
- slowly depolarizes until threshold met
- due to slow leak of Na+ into cell that then opens long lasting Ca++ gates
Ductus Arteriorsus After Birth
- closes w/n 15-72 hours
- due to increased arterial O2 saturation
- Anatomic closure in 2-3 weeks
Coronary Flow Pattern
when heart muscle gets blood flow
- L & R atria and R ventricle get blood supply to during systole
- L ventricle gets blood during diastole (b/c pressure too high during systole)
Divisions of LCA
- Left Anterior Descending Artery
- Circumflex Artery
Heart Dominance
- Right Dominant=posterior Descending Artery from RCA (80%)
- Left Dominant=Posterior Descending Artery from LCA–Circumflex Artery (5%)
Part of blood from right atria goes to the______ & other 1/2 goes to the _____
(baby in utero)
- right ventricle
- left atrium via foramen ovale
Patent Ductus Arteriosus
-failure of ductus arteriosus to close
-due to hypoxia
-causes L to R shunting
(blood from aorta to pulmonary artery)
LAD
- runs along interventricular groove
- branches into diagonals