Mediastinum I Flashcards
what is within the inferior middle mediastinum?
heart
Pericardium
what seperates the inferior and superior mediastinum?
a line between the sternal angle and T-4
what is within the anterior inferior mediastinum?
Lymph nodes, vessels
what is contained within the inferior anterior mediastinum?
Sternum -> pericardium
Fat
Sternopericardial ligaments
Lymphatics
- lymphatic vessels
- Parasternal lymph nodes
Internal thoracic vessels
In children- the inferior thymus
what are the structures that the pericardium attaches to though connective tissue?
Vertebra
Sternum
Xiphoid
Diaphragm
what is the superior pericardial ligaments?
sternopericardial ligaments
what are the inferior pericardial ligaments?
xipho-pericardial
what is the role of the sternopericardial ligaments?
helps retain the heat in its position in the thoracic cavity
where does the thoracic lymphatic system originate?
Lymphatic vessles start from the anterior thoracic wall (the breast)
what is the lymphatic flow in the thorax?
Lymphatic vessels from anterior thoracic wall drain into the parasternal lymph nodes
The parasternal lymph nodes drain into the bronchomediastinal trunks
These drain into the subclavian veins
what are the parasternal lymph nodes associated with?
internal thoracic vessles
where do the internal thoracic arterier originate?
from the left and right subclavian arteries
where do the internal thoracic arteries branch?
to the anterior arteries and veins
what do the internal thoracic arteries supply?
- intercostal muscles
- Diaphragm
- Pericardium
- Thymus
where do the internal thoracic veins run?
Runs with the artery -> brachiocephalic veins
what are the features of the base of the heart?
-Proximal
-Broad, towards the right shoulder
- Left (and right) atria
what are the features of the apex of the heart?
-Distal
- Pointed
-Mid-claviculer line and 5th intercostal space
- left ventricle
what vessel feeds into the right side of the heart?
The superior and inferior vena cava
what vessel flows out of the right side of the heart?
Pulmonary trunk
what feeds into the left side of the heart?
4x pulmonary veins
what are the different sulci of the heart?
Coronary sulcus
Anterior and posterior interventricular sulci
what are the features of the fetal heart that differ from the mature heart?
- Circulation bypasses the lungs
- Foramen ovale
- Ductus arteriosus
(both close after birth (in the first breath))
what is the formen ovale?
In fetal heart
- hole connecting right and left atria
what is the ductus arteriosus?
In fetal heart
- artery connecting pulmonary artery and aorta
what is the fossa ovaslis?
The closed over formen ovale
- it is covered in connective tissue
- Interatrial septum
what is the ligamentum arteriosum?
The ductus arteriosus becomes the ligamentum arteriosum
It connects the aortic arch to the pulmonary trunk
Connective tissue within the superior mediastinum
what are the right side primary cardiac blood vessels?
Coronary
Posterior interventricular
what are the left side primary cardiac blood vessels?
Coronary
Circumflex
Anterior interventricular
Coronary sinus
what is the function of the heart atria?
to collect blood
-On the right side from the superior and inferior vena cavae
- On the left side from the pulomnary veins
what is the role of the atrioventricular valves?
-Close on ventricular contraction to prevent backflow
what is the right atrioventricular valve?
Tricuspid
what is the left atrioventricular valve?
Bicuspid (mitral)
what moves blood from the atria to the ventricles?
Pectinate muscles
what is the role of the ventricles?
Pumps blood out of the heart
- on the right lungs to pulmonary trunk to arterier
- on the left to the rest of the body to the ascending aorta
what are the features of the muscular ventricle walls?
Left is thicker than the right (bigger area to reach)
Trabeculae carnae
Papillary muscles
- AV valves
- Chordae tendinae
what are the semilunar valves?
Right- Pulmonary valves
Left- aortic valve
what are the layers of the heart wall?
- Endocardium
- Myocardium
- Epicardium
- Pericardium
what are the features of the endocardium?
Inner myocardial surface
Lines chamers, valves
Simple squamouse epithelium + areolar tissue
Continuous with endothelium of the great vessels
what are the features of the myocardium?
- Heart muscles
- Striated
- Arranged in spiral bundles
- Have intercalated discs
what are the features of the heart muscles?
-concentric layers
- Blood vessels and nerves
- Thicker on the left side of the heart
what are the heart muscles arranged in spiral bundels?
LInks all parts of the heart together
what is the function of intercalated discs?
Joins muscle fibres end to end
-Contains gap junctions
- Allows rapid spread of excitation
what are the features of the epicardium?
- Outer surface
- Visceral layer of serous pericardium
Areolar tissue (closest to the myocardium)
Mesothelium - closest to the pericardial cavity
- secretes serous fluid
what is the pericardium?
Sac of connective tissue covering the heart
what is in the pericardial cavity?
Serous fluid
- low friction environment
what are the features of the parietal serous pericardium?
Mesothelium (inner)
Areolar tissue (outer)
Continuous with visceral serous layer at the root of the great vessels
what are the features of the parietal fibrous pericardium?
Dense fibrous connective tissue
Cone-shaped “bag”
Base -> diaphragm
Apex continuous with adventitia of great vessels (root)
Sternopericardial ligaments
Limits distention
what is the blood supply to the heart and visceral pericardium?
coronary arteries and veins
what is the blood supply to the parietal and fibrous pericardium?
internal thoracic arteries and veins
what is the nerve supply to the heart and visceral pericardium?
cardiac plexus, vagus nerve, sympathetic trunk
what is the nerve supply to the parietal and fibrous pericardium?
Phrenic nerve
