CVS Flashcards by Abigail Innes

What is the mediastinum?

central compartment of thoracic cavities
located between 2 pleural sacs
contains most of thoracic organs

How well did you know this?

Not at all

Perfectly

superior mediastinum

extends upwards, ending at the superior thoracic aperture

How well did you know this?

Not at all

Perfectly

inferior mediastinum

extends downwards, ending at the diaphragm

further subdivided into anterior, middle and posterior

How well did you know this?

Not at all

Perfectly

anterior mediastinum

smallest subdivision of the mediastinum, lies between body of sternum, and the transverse thoracis muscles anteriorly and the pericardium posteriorly

continuous with superior mediastinum at the sternal angle and is limited inferiorly by the diaphragm

consists of sternopericardial ligaments - fibrous bands that pass from pericardium to sternum , fat, lymphatic vessels, lymph nodes and branches of internal thoracic vessels

in infants, contains inferior part of thymus

How well did you know this?

Not at all

Perfectly

middle mediastinum

coincides with the pericardium, containing the heart, ascending aorta, pulmonary trunk, SVC, arch of azygos vein, and main bronchi

How well did you know this?

Not at all

Perfectly

pericardium

double-walled fibroserous membrane that encloses the heart and the roots of the great vessels, much like the pleura encloses the lungs

How well did you know this?

Not at all

Perfectly

pericardial sac

lies posterior to body of sternum and the 2nd-6th costal cartilages at the level of T5-T8 vetrbrae

its tough external fibrous layer - fibrous pericardium - continues with the central tendon of the diaphragm

How well did you know this?

Not at all

Perfectly

serous membrane of pericardium

parietal layer of serous pericardium -

visceral layer of serous pericardium

How well did you know this?

Not at all

Perfectly

fibrous pericardium

fused with tunica adventitia of the great vessels entering and leaving the heart
attached to the posterior surface of the sternum by sternopericardial ligaments
fused with the central tendon of the diaphragm

protects heart from a sudden overfilling because it’s unyielding and closely related to the great vessels that pierce it superiorly and posteriorly

How well did you know this?

Not at all

Perfectly

pericardial cavity

potential space between the opposing layers of the parietal and visceral layers of serous pericardium

normally contains thin film of serous fluid that enables the heart to move and beat in a frictionless environment

How well did you know this?

Not at all

Perfectly

epicardium

comprised of visceral layer of serous pericardium
thin external layer of heart wall (mesothelium)

reflects from heart and great vessels to become continuous with the parietal layer of serous pericardium

How well did you know this?

Not at all

Perfectly

anterior supply of the pericardium

mainly from pericardiacophrenic artery - branch of internal thoracic artery , which may accompany or parallel the phrenic nerve to the diaphragm

smaller contributions come from musculophrenic artery , terminal branch of internal thoracic artery

How well did you know this?

Not at all

Perfectly

venous drainage of the pericardium

pericardiacophrenic veins , tributaries of the brachiocephalic veins (internal thoracic)
variable tributaries of the azygos venous system

How well did you know this?

Not at all

Perfectly

nerve supply of pericardium

phrenic nerves (C3-C5) a primary source of sensory fibres ; pain sensations conveyed by these nerves are commonly referred to the skin (C3-C5 dermatomes)of ipsilateral shoulder region
vagus nerves (CN X) - function uncertain
sympathetic trunks - vasomotor

How well did you know this?

Not at all

Perfectly

myocardium

thick middle layer composed of cardiac smooth muscle

How well did you know this?

Not at all

Perfectly

endocardium

thin internal layer (endothelium and subendothelial connective tissue) or lining membrane of the heart that also covers its valves

How well did you know this?

Not at all

Perfectly

apex of heart

directed anteriorly and to the left and is formed by the inferolateral part of the left ventricle
located posterior to the left 5th intercostal space in adults , usually 9cm from median plane
where sounds of the mitral valve closure are maximal (apex beat) the apex underlies the site where the heartbeat may be auscultated on the thoracic wall

How well did you know this?

Not at all

Perfectly

base of the heart

heart’s posterior aspect
formed mainly by the LA, with a lesser contribution by the RA
faces posteriorly toward the bodies of the vertebrae T6-T9 and is seperated from them by the pericardium, oblique pericardial sinus, oesophagus and aorta
extends superiorly to bifurcation of pulmonary trunk and inferiorly to coronary sulcus (groove)
receives pulmonary veins on R and L sides of LA and the SVC and IVC at the superior and inferior ends of the RA

How well did you know this?

Not at all

Perfectly

what are the 2 divided parts of the mediastinum

superior and inferior

How well did you know this?

Not at all

Perfectly

explain how the superior mediastinum is bordered

superior - thoracic inlet
inferior - continuous with inferior mediastinum at level of sternal angle
anterior - manubrium of sternum
posterior - vertebral bodies of T1-T4
lateral - pleurae of lungs

How well did you know this?

Not at all

Perfectly

contents of superior mediastinum

neural, vascular and respiratory structures passing from the adjacent regions of neck and abdomen

How well did you know this?

Not at all

Perfectly

what are the 3 main branches of the aortic arch

brachiocephalic artery
left common carotid artery
left subclavian artery

How well did you know this?

Not at all

Perfectly

what does the brachiocephalic artery supply

right side of head and neck and the right upper limb

How well did you know this?

Not at all

Perfectly

what does LCC supply

left side of head and neck

what does left subclavian artery supply

left upper limb

which tributaries of SVC are located in superior mediastinum

brachiocephalic veins left superior intercostal vein supreme intercostal vein azygos vein

what do brachiocephalic veins do

drain blood from upper body

what does left superior intercostal vein do

collects blood from left 2nd and 3rd intercostal vein - drains it into left brachiocephalic vein

what does supreme intercostal vein do

drains vein from first intercostal space directly into the brachiocephalic veins

what does azygos vein do

receives blood from right posterior intercostal veins | left intercostal veins drain first into hemiazygos and accessory hemiazygos veins

what 2 paths does vagus nerve take in superior mediastinum

right vagus nerve | left vagus nerve

what does right vagus nerve do

runs parallel to trachea and passes posteriorly to the SVC and right primary bronchus

what does left vagus nerve do

enters between LCC and Lsubclavian arteries | descends anteriorly to the aortic arch, before travelling posterior to the left bronchus

what are the roots of the phrenic nerve

C3-C5

at what vertebral level is mediastinum divided into superior and inferior

what forms the posterior border of the superior mediastinum

vertebral bodies T1-T4

what is the largest artery in the body

aorta

what does aorta carry

oxygenated blood (pumped by LHS of heart) to the rest of the body

what branches from ascending aorta and where does the ascending aorta lie

lies within the pericardium | coronary arteries branch from it

what do pulmonary arteries carry

deoxygenated blood from RV and deliver to the lungs for gas exchange to take place

what do the arteries begin as and how is it separated from RV

pulmonary trunk | separated by pulmonary valve

at what vertebral level does the pulmonary trunk split into R & L

T5-T6

how many branches do the R & L pulmonary arteries divide into and what do they supply?

divide/bifurcate into 2 | supply each lobe of the lung

what do the pulmonary veins carry

receive oxygenated blood from the lungs, delivering it to LHS side of heart to be pumped back around the body

how many pulmonary veins are there?

4 - one superior and inferior for each lung

where can the oblique pericardial sinus be found

within the pericardium, between right and left veins

where is the inferior left pulmonary vein

hilum of lung

where is right inferior pulmonary vein founf

runs posteriorly to the SVC and the RA

what does the SVC carry

receives deoxygenated blood from the upper body (superior to diaphragm, excluding lungs and heart), delivering it to the RA

how is SVC formed?

merging of brachiocephalic veins, which travel inferiorly through thoracic region until they drain into the superior portion of the RA at rib3

what does IVC carry

receives deoxygenated blood from the lower body (all structures inferior to the diaphragm), delivering it back to the heart

how is IVC formed

in the pelvis by the common iliac veins joining together passes through diaphragm, entering pericardium at the level of T8 drains into inferior portion of RA

what are the 5 surfaces of the heart

``` anterior (sternocostal) - RV posterior (base) - LA inferior (diaphragmatic) - L&RVs right pulmonary - RV left pulmonary - LV ```

what are the 4 borders of the heart

right border - RA inferior border - LV and RV left border - LV and some LA superior border - R&LA and great vessels

what are sulci

grooves on the surface of heart

what is the coronary sulcus (atrioventricular)

runs transversely around the heart - represents the wall dividing the atria from the ventricles contains important vasculatures such as RCoronaryA

what is anterior and posterior interventricular sulci

running vertically on their respective sides of the heart | represent the wall separating the ventricles

what are the pericardial sinuses

oblique pericardial sinus - posterior surface of heart | transverse pericardial sinus - superiorly on heart, can be used in coronary artery bypass grafting

summary of sequence of events during one full contraction of the heart muscle

an excitation signal is created by the sinoatrial node wave of excitation spreads across atria, causing them to contract upon reaching the AV node, signal is delayed then conducted into the bundle of His, down interventricular septum bundle of His and the Purkinje fibres spread the wave impulses along the ventricles, causing them to contract