AP01 Topography of the Heart and Great Vessels Flashcards
Where do the umbilical arteries pass from?
internal iliac arteries
what proportion of the blood from the umbilical vein passes through the liver?
1/2
how does blood from the umbilical vein pass through the liver?
via the portal sinus and ductus venosus
what happens to blood entering the right atrium in the foetus?
bypasses the lungs and enters the left atrium via the foramen ovale.
what happens to the blood from the right ventricle in the foetus?
some goes to the lungs, most goes to the aorta via the ductus arteriosus
what is PDA?
Patent Ductus Arteriosus
what proportion of the blood in the descending aorta goes to the umbilical arteries?
40-50%
what does the right recurrent laryngeal wrap around?
the right subclavian artery
what is the ligamentum arteriosum?
artefact of the ductus arteriosus
formed 3 weeks After birth
what is the function of the fibrous pericardium?
resists overexpansion of the heart
what is the pericardium attached to?
diaphragm
mediastinal pleura laterally
sternum anteirorly
moulds around anterior surface of great vessels posteriorly
what is normally used to measure pericardial pressure?
right atrial pressure
what marks the superior border of the mediastinum?
the sternal angle of louis / trans-thoracic plane
what is the clinical significance of the transverse sinus?
go under the aortic arch and behind the pulmonary trunk to clamp off the vessels
where is the oblique sinus?
gap behind the left atria anterior to the oesophagus
what would happen to heart rate if you damaged the vagus nerve?
inability to decrease heart rate so tachy
what would happen if you damaged sympathetic supply to the heart?
brady
what is the pathway of sympathetic afferents from the heart?
what is their function?
afferents to upper thoracic and lower cervical ganglia
feedback on blood pressure, pain sensation
what is the pathway of sympathetic efferents to the heart?
what is their function?
cardiac nerves from the lower cervical and upper thoracic ganglia
increases heart rate and force of contraction of myocardium
what is the pathway of parasympathetic afferents from the heart?
what is their function?
vagal cardiac nerves
provide feedback on blood pressure
what is the parasympathetic efferent pathway to the heart?
what is its’ function?
vagus nerve
reduces rate and force of contraction, vasoconstricts coronary arteries
where is the superficial cardiac plexus?
below the aortic arch and between the aortic arch and pulmonary trunk
where is the deep cardiac plexus?
between aortic arch and carina
How does parasympathetic innervation negotiate the cardiac plexus?
provided by the Vagus only, preganglionic fibres reach the heart and synapse with ganglia in the cardiac plexus and the walls of the atria
How does sympathetic innervation negotiate the cardiac plexus?
fibres from the sympathetic trunk reach the plexus via cardiac nerves
preganglionic fibres from the upper thoracic spinal chord synapse in the lower cervical and upper thoracic ganglia
What are the 3 main functions of sympathetic innervation of the heart?
increases heart rate
increases contraction force
fight / flight
What are the 4 features of normal heart X-rays?
cardiothoracic ratio < 50%
upper zone of vessels smaller than lower one
lungs are clear
costophrenic angles well defined
How can you tell a CXR is PA?
retracted scapulae and smaller heart appearance
How does an angiogram work?
cathetier through a radial or femoral artery, which is then fed through to the start of the coronary artery, then a contrast media is used
What drains into the right atrium?
superior, IVC
coronary sinus
What are the portions of the right atrium?
sinus venarum (smooth) divided by the crista temrinalis atrium proper (rough)
What is the artefact of the foramen ovale?
fossa ovalis
What are the portions of the right ventricle?
inflow - trabeculae carnae
divided by the supraventricular crest
outflow conus arteriosus
What are the 3 features of trabeculae carnae?
ridges
bridges
pillars
What feature is different about the left ventricle compared to the right?
outflow portion is the aortic vestiblae
What are the muscles of the atria?
pectinate muscle
What is the function of the papillary muscles?
the DO NOT CLOSE AV valves
the pressure in the ventricle does
they prevent the valve from prolapsing
Where do the pulmonary arteries divide?
T5 -T6
What is the only bicuspid valve?
Mitral
What are AV valves supported by?
chordae tendinae, connected papillary muscles (1 per cup)
What are the branches of the Left coronary artery on the anterior surface?
Left Anterior Descending (Diagonal branch off this)
Left Marginal Artery
What is the posterior branch of the left coronary artery?
left circumflex
What are the anterior branches of the right coronary artery?
sinoartrial node branch
right marginal artery
What structure is at the meeting point between circumflex and posterior interventricular arteries?
Coronary Sinus (venous drainage)
What are the tributaries of the coronary sinus?
great cardiac vein left marginal vein left posterior ventricular vein middle cardiac vein small cardiac vein
What proportion of people are right or left dominant for the posterior interventricular artery?
80% right
10% left
10% codominant
Where does the sinoatrial node artery come from?
RCA (60%)
circumflex (40%)
Name the 3 sulci of the heart
coronary sulcus (divides atria from the ventricles) anterior and posterior interventricular sulci
What are the layers of pericardium?
fibrous pericardium
serous pericardium
separated by serous fluid
What innervates the pericardium?
phrenic nerve
What branches off the ascending aorta?
left and right coronary arteries
What branches off the aortic arch?
brachiocephalic trunk
left common carotid
left subclavian
What branches off the thoracic aorta?
bronchial arteries mediastinal arteries oesophageal arteries pericardial arteries superior phrenic arteries intercostal and subcostal arteries
What are the branches and their vertebral levels of the abdominal aorta?
T12 inferior phrenic arteries T12 coeliac artery L1 SMA L1 middle suprarenal L1-L2 renal L2 Gonadal L3 IMA L4 median sacral artery L1-L4 Lumbar arteries (4 pairs)
What are the branches of the common iliac arteries?
external iliac
internal iliac
What are the branches of the internal iliac arteries?
anterior and posterior branches
WHat are the branches of the anterior internal iliac arteries?
umbilical obturator inferior vesicular / vaginal uterine middle rectal inferior pudendal inferior gluteal
What are the branches of the posterior internal iliac arteries?
superior gluteal
lateral sacral