1.1.3 Heart Structures Flashcards
What causes the “dub” sound in the cardiac cycle?
Beginning of diastole, the closing of the aortic and pulmonary valves
Ischemic cardiac pain due to inadequate blood flow is carried back to the CNS by afferent nerves that enter the spinal cord where?
C4 to T5
Which layer of the serous pericardium is “on the wall”?
The parietal layer
What is a coronary artery bypass surgery?
An artery is attached to the distal end of the coronary artery, thus bypassing the blockage. This usually requires multiple grafts
What is the purpose of the tricuspid valve?
Allows blood to flow from RA to RV during diastole
What innervates the pericardium?
The phrenic nerve (C3, 4, and 5) - both motor (stimulates contraction of the diaphragm) and carries afferents from the pericardium and diaphragm
In this anterior view of the heart what does each number represent? Numbers 2 and 3 combined make up what?
1 - Fibrous pericardium
2 - Parietal Layer
3 - Visceral Layer
The Parietal and Visceral Layer make up the serous pericardium
In this picture, what do the numbers 1 and 2 represent?
1 - Transverse pericardial sinus
2 - Oblique pericardial sinus
What are the main components of the venous system in the heart?
Return to the venous circulatory system occurs at the RA through either the Coronary sinus or the anterior cardiac veins. Blood reenters the heart at the RA.
What do each of the numbers in this picture of the right atrium mark?
- Sinus Venarum
- Pectinate muscles (righ atrial appendage)
- Crista Terminalis - Superior end marks SA node
- Fossa Ovalis
- Opening of coronary sinus
- Inferior vena cava and valve
- Superior vena cava
- Right AV orifice
SA node lies where?
In the right atrial wall
When does the mitral valve close?
The beginning of systole
What would be the classical presentation of pericarditis in regards to the quality and location of the associated pain?
The pain tends to be substernal and can sometimes go to the back and shoulders. It often becomes worse upon lying down (opposite of heart attack) or when inhaling deeply (pericardial sac is attached to diaphragm)
What would the classic presentation of a cardiac tamponade be in a clinic?
Jugular venous distention (due to elevated venous pressure) , distant heart sounds, and hypotension with dyspnea
What are the two arteries and one vein that tend to be harvested for bypass surgery?
Internal thoracic and radial artery
The great saphenous vein
What are some causes of left ventricular hypertrophy and chamber dilation?
Volume overloading, as a consequence of aortic or mitral valve regurgitation
What is a cardiac tamponade?
It is the compression of the heart due to rapid accumulation of fluid in the pericardial sac, preventing the chambers from fully expanding, and limiting the stroke volume.
What is the pericardial fluid?
It is thought to be produced by the visceral pericardium and thought to be an ultrafiltrate of plasma
What is the pericardial cavity?
It is a space that is normally filled with 15-50ml of lubricating fluid that allows the heart to move freely as it beats in a low friction environment.
What can be a result of a mitral valve prolapse?
It may develop into a mitral valve regurgitation which can lead to pain, arrhythmias and shortness of breathe
What is a mitral valve prolapse?
The mitral valve will evert into the left atrium when the LV contracts
When do the pulmonary valves close?
These are part of S2 beginnign of diastole
What is the base of the heart?
Posterior aspect of the heart formed largely by left atrium along with a narrow portion of the right atrium
What is the obtuse margin (left margin)?
The rounded left side of the heart formed be the left ventricle and to a small extent the left auricle
Where are the most common locations for heart attack pain in males?
Left arm and chest
Shoulder and neck
Sometimes in center of back
What is the role of the SA node?
It initiates heartbeats
Why would a mitral valve prolapse be more common than a tricuspid valve prolapse?
It is more common becasue the left ventricle contracts at higher pressure to pump blood though out the body
What supplies the blood to the pericardium?
Pericardiophrenic artery
Where should you listen for each of the four valves?
Look at the image
Answer
D
What are the two functions a pacemarker can take over?
Replacement of SA node function or AV node function
What can be a result of ruptured papillary muscles?
These muscles can rupture as a result of an MI. This can lead to AV valve dysfunction - as a result regurgitation of blood happens due to valve insufficiency
What is the coronary sulcus?
It separates atria from ventricles
Aortic valve insufficiency causes what?
Blood regurgitation
What causes the “lub” sound in the cardiac cycle?
Closing of the atrioventricular valves (tricuspid and mitral) soon after systole begins
What is the right margin of the heart?
Formed by superior vena cava, RA and inferiour vena cava
What do the numbers on this image represent?
- Pulmonary Veins
- Fossa Ovale
- Left atrial appendage/auricle
What causes increases rate of contraction?
Stimulation by sympathetic cardiac nerves to the SA node
What causes decreased rate of contraction?
Stimulation by parasympathetic nerves to the SA node
What is the diaphragmatic surface?
Formed largely by the left ventricle along with a narrow portion of the RV
Where are the aortic and pulmonic valves in relationship to eachother?
The aorta is slightly posterior and has the posterior cusp
The pulmonary trunk is anterior and has the anterior cusp.
What do each of the numbers represent in this image of the left ventricle?
- Mitral valve cusps
- Trabeculae carneae
- Papillary muscles
- Chordae tendineae
- Aortic valve
Rupture of what can cause mitral valve regurgitation?
Chordae tendineae or papillary muscles
What do each of these numbers represent in the diagram of the heart?
- Right coronary artery
- Sinuatrial nodal branch
- Right marginal branch
- Posterior interventricular (descending)
- Atrioventricular nodal branch
- Left coronary artery
- Anterior interventricular
- Laterial diagonal
- Circumflex
- Left marginal
What is the clinical relevance of the fibrous skeleton in the heart?
If the skeleton becomes stretched then the heart will often fail. Roughly 50% of aortic valve insufficiency is due to aortic root (fibrous skeleton) dilation
What are the 3 most common sites for a coronary artery to become blocked?
- Left anterior descending (most common)
- Base of right coronary artery (2nd most)
- Left circumflex branch
What causes the perceived left arm pain associated with a heart attack?
The convergence of both somatic and visceral afferents onto nerves in the same dorsal horn nerve in the spinal cord.
What is pericarditis?
The inflammation of the pericardial sac lining typically due to viral or bacterial infections
What forms the oblique pericardial sinus?
It is formed by pericardial reflections surrounding pulmonary veins and superior and inferior vena cava
What is the acute margin (inferior border)?
Narrowed inferior border where sternocostal and diaphragmatic surfaces meet and if formed largely by the right ventricle
What is the inferior portion of the pericardium fused to?
The diaphragm
What is ventricular hypertrophy?
Enlarging of the ventricular wall
What is the pericardium?
The sac of connective tissue that encloses the heart and first portion of the great vessels
How would you correct a cardiac tamponade?
Pericardiocentesis - The removal of the excess fluid from the pericardial sac, usually with ultrasound guidance
What is a pericardial friction rub?
This is highly specific for acute pericarditis. It may sound like squeaky leather or a scratchy grating sounds. It is often louder with forced expiration (Forces the pericardial sac against heart as the diaphragm is pushed up against beating heart).
What is the apex of the heart?
The blunt descending projection formed by left ventricle
Where on this image is the pericardial cavity?
Where the arrow is pointing on the left side of the picture
What is the role of the papillary muscles?
Along with the chordae tendineae, attach to the AV valve cusps and restrict valve cusp movement during ventricular systole (contractions) - preventing blood from regurgitating back into the atrial chambers.
What does the term right heart dominant vs left and balanced?
RIght dominant (most common) - posterior interventricular arises from the right coronary artery
Left dominant (10%) - circumflex brancr of left coronary artery gives off the posterior interventricular artery
Balanced - Both right and left coronary arteries supply the posterior interventricular artery
What are some outcomes of a bicuspid aortic valve?
A bicuspid valve is more likely to cause aortic valve stenosis than a normal tricuspid. This is because there is excessive turbulence which can cause ascending aortic aneurysmal
What do each of these numbers in the picture of the right ventricle represent?
- Cusps of the tricuspid valve
- Papillary muscles a - anterior, b - posterior, c - septal
- Chordae tendineae
- Trabeculae carneae
- Septomarginal trabecula (moderator band)
- Conus arteriosus (infundibulum)
- Pulmonary Valve
When is blood flow greatest into the coronary arteries?
During diastole which is opposite of most arteries in the body - optimizes blood flow when cardiac tissue is most capable of reveiving blood.
Damage of the conductive system of the heart will require what?
An artificial cardiac pacemaker to control to electrical output
Which layer of the serous pericardium is on the heart?
Visceral layer
When does the tricuspid valve close?
At the beginning of systole
What are some causes of left ventricular hypertrophy without ventricular dilation?
Chronic hypertension or aortic valve stenosis
What is the sternocostal surface composed of?
It is composed largely of right atrium and right ventricle along with narrow portions of left ventricle
Which pericardial sinus is the most dependent portion of the pericardial sac in a patient lying on one’s back?
The oblique pericardial sinus is the most dependent. Ex. post coronary artery bypass surgery; leaking bypasses might result in excess fluid in the oblique pericardial sinus
