CVS-anatomy Flashcards
what is the mediastinum?
a space in the thorax, located between the right and left thoracic cavity
what are the 2 portions of the mediastinum?
divided into a superior and inferior portion
what structure lies within the anterior mediastinum?
thymus
what structure lies within the middle mediastinum?
- heart
- pericardium
what structure lies within the posterior mediastinum?
- great vessel
- oesophagus
which structure separates the superior and inferior portion of the mediastinum?
sternal angle-angle of Louis
what vertebral level is the sternal angle?
T4/ T5
what is inferior portion of the mediastinum separated into?
- anterior
- middle
- posterior
where does the left atrium receive oxygenated blood from?
o2- pulmonary veins
what is the texture of the posterior and anterior interior walls of the left atrium?
smooth
what is the texture of the right atrium?
- anterior-rough due to pectinate muscles
- posterior-smooth
which valve does blood pass through from the LA to LV
bicuspid-mitral valve
AV valve
which chamber of the heart has the thickest wall
left ventricle
which valve prevents back flow of blood into the LV form the aorta?
aortic semilunar valve
where does some of the blood in the aorta filter into?
coronary arteries
which 3 structures in the LV help keep the bicuspid/mitral valve shut?
- trabeculae carnae
- chordae tendinae
- papillary muscle
which 3 veins does the RA receive blood from?
- SVC
- IVC
- coronary sinus
which valve allows blood to flow RA–>RV?
tricuspid valve
which structure can been seen in the interatrial septum which is a remnant of the foramen ovale?
fossa ovalis
which 3 structures are present in the RV?
- trabecula carnae
- moderator band/ septomarginal
- chordae tendinae
what are trabeculae carnae?
series of raised cardiac muscle fibres
-prevent suction that would occur with a flat surfaced membrane
what is the role of the moderator band/ septomarginal band in the RV?
acts as a bridge between RV and interventricular septum so that papillary muscles contract before RV walls contract
what is the role of the chordae tendinae in the RV?
responsible for closing tricuspid valve and preventing backflow of blood → papillary muscles can contract and pull chordae tendineae taut
through which valve does blood flow through from the RV?
pulmonary SL valve
-to the pulmonary trunk
what are the 3 layers of the pericardium?
- fibrous pericardium
- serous parietal pericardium
- serous visceral pericardium (epicardium)
what is the visceral serous pericardium also known as?
epicardium
what is the outermost layer of the pericardium?
fibrous
which is the innermost layer of the pericardium which surround the heart?
visceral (epicardium)
what is the name of the space between the visceral and parietal pericardium?
pericardial cavity
what is the pericardial cavity filled with?
pericardial fluid
what is the pericardium?
membrane that surrounds and protects heart, prevents overfilling of heart chambers &
lubricates movement of heart
which 2 ligaments connected to the pericardium allow movement for vigorous and rapid contraction of the heart?
- pericardiophrenic ligament (diaphragm to pericardium-inferior)
- sternopericardial ligament (sternum to pericardium-anterior)
when an AV valve is open where do the cusps project?
atria—>ventricle
when the AV valves (tricuspid/ mitral) are open are the papillary muscles and chordae tendinae relaxed or contracted?
- papillary muscles relaxed
- chordae tendinae-slack
what causes the AV valves to close?
when ventricular pressure exceeds atrial pressure-pushing cusps upwards
what happens to the chordae tendinae and papillary muscles when closing the AV valve?
- chordae tendinae become taut as papillary muscles tense
- chordae tendinae pull down on cusps pulling them into V
how many layers of the heart are there?
3
name the layers of the heart
- epicardium (visceral pericardium)
- myocardium (cardiac muscle)
- endocardium (endothelium)
is cardiac muscle voluntary or involuntary?
involuntary
is cardiac muscle multinucleated or mononucleated?
mononucleated
is cardiac muscle branched or single stranded?
branched
is cardiac muscle striated or smooth?
striated
why can the heart not regenerate itself after damage?
has no stem cells
how is cardiac syncytium achieved?
network of cardiomyocytes are connected by intercalated discs
–>enabling rapid transmission of electrical impulses, allowing the syncytium to act in a coordinated contraction of myocardium
what are intercalated discs?
random transverse thickenings between sarcolemma of adjacent cells
what do intercalated discs contain?
-desmosomes (holding fibres together) with gap junctions inside
describe the role of gap junctions in cardiomyocytes.
- allow for rapid flow of ions between cells-if 1 cardiomyocyte depolarises the rest follow
- allow myocardium of entire chamber of heart to contract as a single coordinated unit
how does the appearance of cardiac muscle differ from skeletal?
-cardiac muscle contains far more mitochondria
name the 2 separated functional syncytiums in the heart
- atrial syncytium
- ventricular syncytium
where do the left and right coronary arteries arise from?
left and right aortic sinuses of aorta
which branches are given off the left coronary artery?
- left anterior descending artery (LAD)
- left marginal artery (LMA)
- left circumflex artery (LCx)
in 20% of individuals which artery does the LCA also contribute to?
posterior interventricular artery (Plv)/ posterior descending—>LEFT CORONARY DOMINANCE
which branches are given off the right coronary artery?
- right marginal artery (RMA)
- posterior interventricular artery/ descending (80% of individuals)
what is right coronary dominance?
right coronary artery (RCA) supplies the posterior portion of the interventricular septum and gives off the posterior descending artery
what is left coronary dominance?
posterior descending artery supplied by LCA
what % of people have left coronary dominance?
20%
name the heart structures supplied by the RCA
- RA
- RV (most)
- LV (diaphragmatic part)
- interventricular septum (posterior 1/3)
- SA node
in what % of people is the SAN is supplied by the RCA?
60%
Which structures of the heart are supplied by the LCA?
- LA
- LV (most)
- RV (partially)
- interventricular septum (anterior 2/3)
- SAN
- AVN
- AV bundle
in what % of people is SAN supplied by LCA?
40%
Which coronary artery supplied the AVN and AV bundle?
LCA
which structure do all coronary veins drain into?
coronary sinus
where does the coronary sinus drain into?
RA
name the 5 tributaries that drain into the coronary sinus
- great cardiac vein
- middle cardiac vein
- small cardiac vein
- left marginal vein
- left posterior ventricular vein
where does the great cardiac vein originate and join to?
originates at apex of heart —>follows anterior interventricular groove—>joins on left
where is the middle cardiac vein situated?
posterior surface—>joins on left
where is the small cardiac vein situated?
anterior surface—>joins on right side
on which surface do the left marginal and left posterior ventricular vein lie?
posterior surface
which layer of tissue associated with the heart is also know as epicardium?
A-fibrous pericardium B-Myocardium C-partietal layer of serous pericardium D-pericardial cavity E-visceral layer of serous pericardium
E
is a depression on the interatrial wall…
Fossa ovalis
receives the umbilical, vitelline and cardinal veins…
sinus venosus
is membranous tissue that grows in a crescentic shape to fuse with the endocardial cushions…
septum primum
shunts blood from the left umbilical vein into the IVC….
ductus venosus
is closed by increased pulmonary blood in the LA…
foramen ovale
what are the 3 layers of blood vessels?
- tunica intima (inner)
- tunica media
- tunica adventitia (outer)
what is the tunica intima made up of?
single layer of flattened, squamous endothelial cells/ basement membrane/ internal elastic lamina
what does the tunica intima allow?
allows diffusion of material to deeper tissue
what does the tunica media layer consist of?
smooth muscle cells and elastic fibres
what does the tunica media allow?
vasoconstriction and dilation
what is the difference in tunica media in arteries compared to veins?
arteries have much thicker tunica media compared to veins
what does the tunica adventitia consist of?
elastic tissue and collagen fibres
what are the 3 types of arteries?
- elastic/ conducting arteries
- muscular/ distributing arteries
- resistance arteries
give examples of elastic/ conducting arteries
- aorta
- aortic branches
- pulmonary arteries
where do conducting arteries transport blood?
from heart to muscular/ distributing arteries
how do elastic/ conducting arteries cope with pressure changes?
-high elastic fibre content in tunica media
what controls the smooth muscles in elastic fibres allowing vasoconstriction/ vasodilation?
ANS
give examples of muscular/ distributing arteries
radial artery
splenic artery
where do muscular/ distributing arteries distribute blood to?
resistance arteries
how does the muscle content of muscular/ distributing arteries differ to elastic/ conducting arteries?
higher muscular content
where are resistance arteries found?
end points of arteries/ arterioles
what is the defining structure of resistance arteries?
- poorly defined adventitia
- little smooth muscle
what can innervation of resistance arteries cause?
vasoconstriction/vasodilation in response to stimuli
which veins contain 70% of blood volume?
reservoir/ capacitance veins
what is the structure of reservoir veins?
-Relatively large tunica adventitia
★ More compliant than arteries – can change according to volume
what structure in veins prevents back flow of blood?
valves
describe the respiratory pump.
during inspiration, intrathoracic pressure is negative and abdominal pressure is positive – this pulls blood towards RA
what are examples of exchange vessels?
capillaries or sinusoids
- often fenestrated
- only tunica intima
what is a great vessel?
term for any large vessel that brings blood to/ from heart
give examples of great vessels.
- ascending aorta
- aortic arch
- descending aorta
- SVC
- IVC
- pulmonary trunk
where does the ascending aorta receive blood from?
LV
which pericardium layer does the ascending aorta lie within?
Lies within fibrous pericardium enclosed in a tube of serous pericardium with the pulmonary trunk
which valve is the ascending aorta attached to?
aortic SL valve
where does the aortic arch pass?
obliquely posterior left
which section of the mediastinum is the aortic arch?
superior
which vessels does the aortic arch give rise to?
- Brachiocephalic trunk
- Left common carotid
- Left subclavian
which section of the mediastinum does the descending aorta lie within?
posterior mediastinum
which vertebral level does the descending aorta begin at?
T4
Where does the descending aorta pass?
- Passes posterior to hilum of lung
- Descends anterior to vertebral bodies and slightly to left
at which vertebral level does the descending aorta pass through the diaphragm at the aortic hiatus?
T12
Which vessel is the most anterior?
pulmonary trunk (but them passes posteriorly to left of aorta)
where does the pulmonary trunk send deoxygenated blood?
RV—>lungs
at which vertebral levels does the pulmonary trunk bifurcate into pulmonary arteries?
T5
where does the SVC receive deoxygenated blood from?
structures above diaphragm
where does the SVC drain into?
RA
how is the SVC formed?
by the junction of left and right brachiocephalic veins
which vertebral spaces does the SVC descend to?
vertically posterior to 1st and 2nd intercostal spaces
where does the IVC receive deoxygenated blood from?
structures below diaphragm
where does the IVC drain blood into?
inferoposterior RA
enters through eustachian valve
which vertebral level does the IVC pass through the diaphragm?
T8
why is the thoracic part of IVC short?
as it passes through pericardium
which system is the heart controlled by?
ANS
-sympathetic (cardiac nerves) and parasympathetic (vagus nerves)
how does the SNS affect the heart?
increases firing rate of SAN → increases heart rate & force of contraction
how does the PNS affect the heart?
decreases firing rate of SAN → decreases heart rate & force of contraction, and constricts coronary arteries
what is the effect of PNS on coronary arteries?
constricts coronary arteries
what does the vagus nerve sense?
changes int BP and chemistry
where does the sympathetic trunk return to?
either cervical or thoracic regions
Which blood vessel layer consists of smooth muscle cells and elastic fibres which allow for vasoconstriction and dilation?
Tunica Media
