Cardiovascular I Flashcards
Describe the flow of blood through the heart, including chambers and valves
DE-OX blood IN the RA via vena cavae Tricuspid AV valve RV SL pulmonary valve **De-ox blood goes thru pulmonary artery to LUNGS OX blood in LA via pulmonary veins Mitral/Bicuspid AV valve LV SL aortic valve aortic arch
Tricuspid valve
AV valve
Between RA and RV
Bicuspid valve (Mitral valve)
AV valve
Between LA and LV
Name the 3 openings of the RA
1) SVC
2) IVC
3) coronary sinus
Pulmonary valve
semilunar valve
RV to lungs
Aortic valve
semilunar valve
LV to aorta
What is the most muscular chamber of heart?
LV
What are the roles of the pericardium
fibrous fluid filled sac…
- prevents overfilling of blood
- anchors heart
- protects heart
What is the outer layer of pericardium
fibrous pericardium
dense CT
Pericardial cavity
inner serous part of pericardium
in between PARIETAL and VISCERAL
**CONTAINS A THIN FILM OF FLUID SO HEART CAN MOVE AND BEAT IN FRICTIONLESS ENVIRONMENT
Cardiac tapenade
when blood leaks into pericardial cavity and compresses the heart
Blood supply to pericardium
pericardiacophrenic arteries
musculophrenic arteries
thoracic aorta (brachial, eso, superior phrenic)
coronary arteries (to visceral only)
Innervation: pericardium: somatic sensory
fibrous and parietal
via PHRENIC nerves C3-C5
Innervation: pericardium: visceral sensory
epicardium (insensitive to pain)
via CARDIAC PLEXUSES
Label the external anatomy of heart
label
If stabbed in left 2nd intercostal space, what part of heart is affected?
pulmonary valve
if stabbed in left 4th intercostal space, what part of heart is affected?
RV
if stabbed in left 5th intercostal space, what part of heart is affected?
apex, mitral valve
Layers of heart from external to internal
fibrous pericardium parietal pericardial cavity epicardium (visceral) myocardium endocardium
Right Atrium what are the 2 parts
1) sinus venarum
=recieves vena cave and coronary sinus
2) pectinate muscles
= divided by crista terminalis
what is the interatrial septum
divides RA and LA
fossa ovalis is here (remains of foramen ovale)
How does RV receive its blood
receives blood from RA via R AV orifice
what is the RV guarded by
tricuspid valve
where does the blood in RV go
through pulmonary valve to lungs in a U-shaped path 140 degrees
Features of ventricles
trabeculae carnae = rounded or irregular muscular columns which project from the inner surface of the right and left ventricle of the heart.
***These are different from the pectinate muscles, which are present in the atria of the heart.
-finer and more numerous in LV than RV
how does LV receive its blood
from LA via L AV orifice
what is LV guarded by
bicuspid/mitral valve
Is the RV or LV thicker?
LV (2x thicker than RV)
Features of LV
aortic vestibule = leads to aorta
aortic valve = guards ascending aorta
where does blood from LV go
thru LV, 2 right turns, 180 change in direction to aorta via aortic valve
Right AV valve: structure and function
Structure:
- tricuspid = 3 cusps (ant, post, septal)
- papillary muscles (ant, post, septal)
- chordinae tendinae
Function of VALVE = PREVENTS BACKFLOW INTO ATRIA DURING VENTRICULAR CONTRACTION (SYSTOLE)
Function of papillary and chordae = prevent cusps from prolapsing into the aorta
function of chordae tendineae is to anchor the AV valves to ventricular papillary muscles and keep the AV valves in a closed position during ventricular systole to prevent the backflow of blood into the atria
during systole taut & contract (holds in closed position)
During systole, describe valves and papillary, chordae tendinae
AV closed
SL open
chordinae taut
papillary contract
During diastole, describe valves and papillary, chordae tendinae
AV open
SL closed
chordinae slack
papillary relax
Left AV valve
mitral/bicuspid = 2 cusps (ant, post)
most commonly diseased valve
papillary muscles (ant, post) chordinae tendinae
Function chordinae tendinae
function of chordae tendineae is to anchor the AV valves to ventricular papillary muscles and keep the AV valves in a closed position (by being taut) during ventricular systole to prevent the backflow of blood into the atria
What does prolapse of Left AV valve cause
errodes endothelial surfaces of valve, predisposed to endocardial infections
RESULTS IN ENLARGED LA because blood leaks back into LA
Formation of interatrial septum
1) septum primum
2) foramen/ostium primum before septum premum fuses
3) foramen ovale (septum and foramen secundum)
4) flap valve
5) blood RA –> LA (bypass lungs)
* in fetus the lungs are not inflated, baby receives oxygenated blood from mom via umbilical vein
Foramen ovale
shunts blood RA to LA to bypass lungs in fetus
Atrial Septal Defects
25% of individuals
if large, OX blood shunted into RA, overloads pulmonary system and ENLARGES RA, RV, and pulm trunk
Ventricular Septal Defects
25% of all congenital heart defects
most are in muscular portion (these spontaneously close)
membranous defects corrected surgically
Function of semilunar valves
prevent back flow into ventricles during ventricular relaxation (diastole)
- aortic valve
- pulmonary valve
3 cup-like cusps
AV open
SL closed
Function of AV valves
prevent back flow into atria during contraction (systole)
AV closed
SL open
Conducting system of heart
1) SAN = initiates cardiac m. contraction, HR
2) AVN = delays impulse
3) Bundle of His
4) RBB, LBB
5) Purkinje fibers
Can the heart contract without any innervation?
Yes, that is why we can do heart transplants
Sympathetic Cardiac Innervation
increase HR, increase force of contraction
Blood flow –> CA
Pre-ganglionic sympathetic
lateral horns of SC
T1-T5
post-ganglionic sympathetic
cervical and superior thoracic paravertebral ganglia
post-synaptic fibers sympathetic
carried in thoracic (cardiopulmonary) splanchnic nerves
contributes to cardiac plexus
ends in SAN and AVN
Parasympathetic Cardiac Innervation
decrease HR, decrease force of contraction
constricts CA
pre-ganglionic parasympathetic
VAGUS Nerve
pre-synaptic fibers parasympathetic
contributes to cardiac plexuses
post-ganglionic parasympathetic
cardiac tissue
atrial wall, IV septum near SAN, AVN
Visceral afferent cardiac innervation
follow path of sympathetics backward
reflex actions
=lower BP, lower HR = vagus nerve
vagus nerve
doesn’t transmit any visceral pain fibers originating in heart
small cardiac vein pairs with the
right marginal artery
middle cardiac vein pairs with the
posterior IV artery
great cardiac vein pairs with the
anterior IV artery
coronary sinus pairs with the
circumflex artery
