The Pericardium, Heart Surface and Coronary Arteries Flashcards
what circulation does the right pump give
pulmonary circulation
what type of circulation does the left pump do
systemic and coronary circulation
pericardium function
Shock absorber (cardiac seatbelt), prevents over expansion when blood increases and limits heart movements
describe fibrous layer of pericardium
- Outermost layer
- Irregular dense CT with much collagen
- Serves to anchor heart to diaphragm, sternum and the great vessels
two layers of pericardium
- fibrous
- serous
describe two layers of serous pericardium
- Parietal layer attached to fibrous pericardium
- Visceral layer attached to surface of the heart and aorta, pulmonary trunk, vena cavae (epicardium)
what is the pericardial cavity
- cavity between two layers of pericardium
- filled with serous pericardial fluid
pericarial cavity function
lubrication prevents friction as the heart beats
what is pericarditis
inflammation of the pericardium
where is the transverse pericardial sinus
- Anterior to the superior vena cava and posterior to the ascending aorta and pulmonary trunk
- Therefore it separates the arterial vessels (Aorta, Pulmonary Trunk) and the venous vessels (Superior Vena Cava, Pulmonary Veins)
where is the oblique pericardial sinus
Bounded by the lines of reflection of the serous pericardium onto the
inferior vena cava and the left and right pulmonary veins
where is the oblique pericardial sinus
Bounded by the lines of reflection of the serous pericardium onto the
inferior vena cava and the left and right pulmonary veins
what is cardiac tamponade
- The relatively inextensible fibrous pericardium can cause pericardial effusion (increased fluid) in the pericardial cavity
- There is an increase in pressure.
- The chambers can become compressed, thus compromising cardiac output.
- Can lead to Haemopericardium (blood in the pericardium) and pericarditis
causes of pericarditis
- acute
- chronic
- cardiac tamponade
arterial supply of pericardium
- Internal thoracic – gives off musculophrenic and pericardiophrenic branches
- Descending thoracic aorta - gives off bronchial, oesophageal and superior phrenic arteries
venous drainage of pericardium
Venous drainage to azygous system
nervous supply of pericardium
- Phrenic nerve to fibrous and serous pericardium
- Vagus and sympathetic trunks to visceral pericardium (insensitive to pain)
nervous supply of pericardium
- Phrenic nerve to fibrous and serous pericardium
- Vagus and sympathetic trunks to visceral pericardium (insensitive to pain)
layers of the heart wall
- epicardium
- myocardium
- endocardium
epicardium
- Visceral layer of pericardium
- Adipose and fibroelastic tissues
myocardium
- Muscle
- Double helical orientation of the cardiac muscle fibres
endocardium
- Endothelial cells
- Smooth lining also covering valves
myocarditis
- Infection of myocardium often caused by viral infection
- Need for biopsy
- Mild disease, chest pain to heart failure, or sudden death
infective endocarditis
- Bacterial infection
- Affects valves, septum, chordae tendinae
- Most common cardiovascular infection worldwide
what is the fibrous skeleton
Framework of dense collagen forming four fibrous rings (annuli fibrosi) that surround the orifices of the valves 2 rings and 2 cononets
three functions of the fibrous skeleton
- Prevent over distension of valves
- Serve as attachments of leaflets and cusps
- Provide electrical insulation from atria and ventricles
sulci
Grooves on surface of heart containing coronary blood vessels and fat
coronary sulcus
Encircles heart and marks the boundary between the atria and the ventricle
anterior interventricular sulcus
Marks the boundary between the ventricles anteriorly
posterior interventricular sulcus
Marks the boundary between the ventricles posteriorly
how is dominance of the coronary arterial system defined
by which artery gives rise to the posterior interventricular (IV) branch (posterior descending artery)
where do the coronary arteries branch off the aorta
above aortic semilunar valve
path of LCA
arises from left posterior aortic sinus and passes forward between the left auricle (anterior surface of atrium, purpose to increase volume when needed) and infundibulum (aka conus arteriosus, the pulmonary trunk arises here)
where does the LCA arise in 40% of people
the Sinoatrial (SA) nodal artery
where is the circumflex branch of LCA
in coronary sulcus, supplies left atrium and left ventricle – sometimes AV node (left dominant)
where is the anterior descending interventricular artery
interventricular groove
what branches does the LCA give off
conus branch and diagonal branch
what does the LCA supply
anterior 2/3 of interventricular septum (bundle of His), most of the left ventricle, and part of the right ventricle before anastomosing with right coronary
where does the RCA arise in 40% of people
the SA nodal artery
RCA path
located in ant aortic sinus travels between infundibulum of the right ventricle and the right auricle to Atrioventricular groove
what branches does the RCA give off
- the right marginal branch in coronary sulcus, supplies right ventricle
- posterior descending interventricular artery (in ~ 70%)
what does the RCA sipply
most of the right ventricle, the diaphragmatic surface of the left ventricle, interventricular septum and AV node - typically right dominant
what is right coronary artery dominance associated with
severity of Coronary Artery Disease
coronary veins
- Posterior vein, oblique vein, middle and small cardiac veins drain to
great cardiac vein which drains into coronary sinus on posterior
surface of heart - continuation of great vein. - Coronary sinus empties into right atrium
- Anterior vein drains directly into heart chambers
describe right atrium
- Posterior wall is smooth
- Rest of wall is ridged by pectinate muscles
- Small out pouching extension called the auricle
- Receives blood from the superior and inferior vena cava and the coronary sinus
- Fossa ovalis is a remnant of the embryonic inter-atrial circulation
- Opens into the right ventricle - regulated by the tricuspid valve
describe right ventricle
- Separated from atrium by tricuspid valve
- Inflow tract is rugged - Trabeculae carnae
- Outflow tract is smooth
- Outflow to pulmonary trunk is controlled by pulmonary valve
- Pulmonary trunk splits into left and right pulmonary arteries (only arteries containing de-oxygenated blood)
decribe tricuspid valve
- Three cusps of connective tissue
- Opened by contraction of papillary muscles pulling on chordae tendinae
- Anterior, posterior and septal cusps
- Attached to fibrous AV ring
sulcus terminalis
between the superior vena cava and the auricle - produced by the crista terminalis on the lateral wall
tendon of todaro
a tendinous structure connecting the valve of the inferior vena cava ostium to the central fibrous body
what side of the heart is the triangle of koch
right
components of triangle of koch
- Ostium of coronary sinus posteriorly
- Anterior septal leaflet commissure
- Tendon of Todaro
components of triangle of koch
- Ostium of coronary sinus posteriorly
- Anterior septal leaflet commissure
- Tendon of Todaro
apex of triangle of koch
AV node
describe left atrium
- Posterior wall is smooth
- Anterior wall is also smooth
- Small out pouching extension - auricle which has pectinate muscles
- Receives blood from the four pulmonary veins
- Opens into left ventricle - controlled by bicuspid valve
describe pulmonary veins
- four
- Two from each lung
- Only veins carrying oxygenated blood
describe left ventricle
- Separated from atrium by the bicuspid valve
- Inflow tract is rugged - trabeculae carnae
- Outflow tract is smooth
- Wall of left ventricle is the thickest part of the heart
- Outflow to the aorta is controlled by the aortic valve
- Coronary arteries branch off the ascending aorta
describe bicuspid valve
- Two cusps of connective tissue
- Mitral valve
- Anterior and posterior cusps
- Attached to fibrous AV ring
- Opened by contraction of papillary muscles pulling on chorda tendinae
sympathetic innervation of the heart
- Sympathetic system enhances activity – sympathetic trunk
- Acts via release of norepinephrine and epinephrine
parasympathetic innervation of the heart
- The parasympathetic system inhibits activity - vagus nerve
- Acts via acetlycholine
parasympathetic innervation of the heart
- The parasympathetic system inhibits activity - vagus nerve
- Acts via acetlycholine
what is the cardiac plexus
collection of parasympathetic and sympathetic nerve fibres (inferior aortic arch)
sensory cardiac nerves
- Afferent (sensory nerve fibres) accompany sympathetic nerves
- Transmit visceral information to the CNS
diastole
relaxation period - ventricles are relaxed and blood flows from atria to ventricles
atrial systole
atria contract to fill ventricles
atrial systole
atria contract to fill ventricles
venticular systole
ventricles contract to push blood out of the heart
how do signals travel through heart
- SA node generated action potential which spreads through the atria, synchronising their contraction
- SA node signal to the AV node is delayed ensuring time for the atria to drain into ventricles
- AV node signal spreads through the ventricles via bundle of His and Purkinje fibres, ventricles then contract to expel blood
- Nodes are autorhythmic - generate their own action potential
how do signals travel through heart
- SA node generated action potential which spreads through the atria, synchronising their contraction
- SA node signal to the AV node is delayed ensuring time for the atria to drain into ventricles
- AV node signal spreads through the ventricles via bundle of His and Purkinje fibres, ventricles then contract to expel blood
- Nodes are autorhythmic - generate their own action potential
valve disorders
- genetic, bacterial infection
- Incompetent valve - failure to completely close
- Stenotic - narrowed opening
valve disorders
- genetic, bacterial infection
- Incompetent valve - failure to completely close
- Stenotic - narrowed opening
heart disorders
- Coronary artery disease (blockage of coronary arteries)
- Angina pectoris
- Myocardial infarction
- Heart failure - weakening of heart muscle
- Fibrillations - atrial and ventricular
- Transposition of the great vessels
- Septal defects
bradycardia
when heart rate is too slow - less than 60bpm
tachycardia
when heart rate is too fast - more than 100bpm
1
ascending aorta
2
superior vena cava
3
right auricle
4
right atrium
5
inferior vena cava
6
right coronary artery
7
marginal artery
8
right ventricle
9
apex
10
left ventricle
11
anterior interventricular artery
12
left auricle
13
infundibulum
14
pulmonary trunk
15
ligmentum arteriosum
16
arch of aorta
1
right atrium
2
inferior vena cava
3
left atrium
4
coronary sinus
5
circumflex artery
6
posterior interventricular artery and middle cardiac vein
7
left ventricle
8
right ventricle
9
right coronary artery
1
pulmonary trunk
2
left auricle
3
left ventricle
4
coronary sinus
5
left atrium (oblique sinus)
6
inferior vena cava
7
right atrium
8
transverse sinus
9
superior vena cava
10
ascending aorta
