Module 4 - Cardiac system Flashcards
how is the heart held in place in the cavity
its protective covering - the pericardial sac - is joined to the sternum via a line of fat called the mediastinal fat
where is the point of attachment of the pericardium and the heart
at the base of the heart - where the great vessels enter and exit
when viewing the heart anteriorly will the pulmonary trunk lie in front or behind the aorta
in front
which chamber of the heart makes up the apex
left ventricle
which artery lies in the right atrioventricular sulcus
right coronary artery
which artery lies in the left atrioventricular sulcus
the circumflex artery ( a branch of the left coronary artery)
in which groove could you find the anterior interventricular coronary artery
anterior interventricular sulcus
where can you find the great, middle and small cardiac veins
great cardiac vein and small cardiac vein are both on the anterior side (small on the right and is shorter, great on the left and is longer superiorly)
middle cardiac vein is on the posterior aspect of the heart and projects down form the coronary sinus
Which chamber of the heart does the coronary sinus drain into
right atrium
why does the heart need a blood supply instead of getting it from inside the chambers ?
the blood moves too fast for sufficient exchange of nutrients and the walls are much too thick
what is a heart attack and what can be the effect of it on the heart
it is when a coronary artery becomes occluded (blocked)
- this means the muscle cells in the heart aren’t getting oxygen and can be damaged or die
what areas do the superior and inferior vena cava drain blood from
superior - head, neck, upper limbs (arms) and thorax
inferior - abdominopelvic cavity and lower limbs (legs)
what are the 4 functions of the heart
- generating blood pressure
- routing blood (systemic and pulmonary)
- ensuring one way flow
- regulating blood supply to match changing metabolic needs
what is the location of the heart in the body
centrally in the mediastinum but angled to the left
what is in the mediastinum
heart,
trachea,
oesophagus,
thymus,
blood vessels,
nerves
what is the structure of the heart coverings and what are their roles
from outermost to innermost:
* fibrous pericardium (anchoring and protection)
* parietal layer of serous pericardium (adheres to fibrous pericardium)
* pericardial cavity (between serous layers)
* visceral layer of serous pericardium (outer layer of the heart/ epicardium)
what are the 3 layers of the wall of the heart
epicardium (visceral pericardium)
myocardium (muscle for contraction)
endocardium (lines chambers + vessels, simple squamous and extends into blood vessels)
what are the 2 first branches off the ascending aorta
left and right coronary arteries
where on the heart do you find large and small coronary arteries
large arteries travel in sulci on the surface of the heart
small arteries penetrate into the myocardium
describe the fibrous skeleton of the heart (structure and 4 functions)
- dense CT ring around 4 valves
- provides anchorage, structural stability, electrical insulation between atria and ventricles.
what does it mean to “have properties of a functional syncytium” and what is the benefit
- behaves as a single cell mass
- allows very fast electrical conduction from one fibre to another
what is the role of the non-contractile fibres in the heart
- they form the specialised pacemaker and conduction system which regulates heart beat
what are the components of the pacemaker/conduction system
- sinoatrial node - initiates electrical signal to cause contraction
- atrioventricular node - sends conduction + results in spontaneous polarisation
- atrioventricular bundle and purkinje fibres - carry rapid electrical impulse which results in contraction
what must happen to the cardiac muscle before it can contract and relax
it must depolarise before it can contract
and it must repolarise before it can relax
When does atrial repolarization occur
during ventricular depolarisation
when can the next cardiac cycle start
AFTER the ventricles have compeletely repolarised