Lecture 11 - Heart and Thorax Flashcards
Thoracic cavity contains:
- organs of the respiratory, cardiovascular, digestive, and lympathic systems
What is the thoracis cavity subdivided into? (3)
- mediastinum
- pleural cavities (right and left)
- pericardial cavity
Mediastinum
central compartment of the thoracic cavity
pleural cavities
surround the lungs
pericardial cavity
surrounds the heart
bounderies of the thoracic cavity
bounded anteriorly and posteriorly by the -> thoracic cage:
- ribs
- sternum
- thoracic spine
- muscles
bounded inferiorly by the diaphram
Where is the heart located?
- located in the middle mediastinum within the pericardial cavity
- directly posterior to the sternum
- between the lungs
- superior to the diaphragm
Apex of the heart points…
anteroinferiorly, and to the left
base of the heart is…
posterior and superior
Overview of the heart
- 4 chambered organ
- heart pumps blood throughout the body within a network of blood vessels
- chambers contract to pump blood
- flow of blood through the heart is controlled via valves
- blood is driven through two circuits
- pulmonary & systemic circuits
pulmonary circulation
- pumps deoxygenated blood from the heart to the lungs to become ocygenated
- pumps oxygenated blood from the lungs back to the heart
systemic circulation
- pumps oxygenated blood from the heart to the rest of the body
- returns deoygenated blood back to the heart
pericardium
- layered, fluid-filled sac that surrounds the heart
- formed by the:
- outer fibrous pericradium
- inner serous pericardium
fibrous pericardium
- outer dense connective tissue layer that surrounds the heart and the roots of the great vessels
- base of the fibrous pericardium is fused with the central tendon of the tendon
Pericardium: central tendon
aponeurosis or flattened tendinois thickening of the diaphragm
fibrous Pericardium: function
- anchors the heart in place
- provides protection
- prevents overextension of the heart
Serious pericradium: layers (2)
- parietal (of the body cavities) pericardium
- visceral ( of the viscera (organs
)) pericardium
parietal pericardium
fused with the fibrous pericardium
visceral pericardium
adhered to the surface of the heart
pericardial cavity/space
- space between the visceral and parietal pericardium layers
- contains small amount of pericardiul fluid
pericardiul fluid
acts as a lubricant, reducing friction between the opposing surfaces of the heart and the pericardium as the heart beats
pericardial cavity: potential space
- adjacent structures are normally pressed together
- opposing layers of the visceral and parietal pericardium are in vlose contact
- can expand unfer pathological conditions (ex: pericardial effusin: accumulation of excess fluid in the pericardial cavity due to infection, injury, etc)
External anatomy of the heart
- 4 chambers
- 2 atria
- 2 venticles
atria
- each atria has an auricle
- forms the base of the heart (posteriorly)
ventricles
- form the apex of the heart
Septa
- seperate chambers of the heart
- interatrial septa seperates right and left atria
- interventricular spetum seperates the right and left ventricles
Grooves
- atrioventricular
- anterior interventricular
posterior interventricular
Great vessels of the heart
large arteries and veins that drain blood into the atria, and pump blood away from the heart via the ventricles;
- superior vena cava
- inferior vena cava
- pulmonary trunk
- pulmonary arteries
- pulmonary veins
- aorta
coronary circulation: arterial supply
right coronary arery (in atrioventricular groove) -> left coronary artery -> left anterior descending artery ( in anterior interventricular groove) -> circumflex artery
coronary circulation: venous drainage
great cardiac vein -> small cardiac vein -> middle cardia vein -> coronary sinus -> draisn into right atrium
superior and inferior vena cava
large veins that drain deoxygenated blood from the body into the right atrium of the heart
inferior vena cava drains…
- lower limbs
- pelvic viscera
- abdominal viscera
superior vena cava drains…
- thorax
- head
- neck
- upper limbs
anatomical features of the right atrium
- pectinate muscles
- fossa ovalis (depression on the interatrial spetum, embryological remnant of the foramen ovale)
fossa ovalis
- foramen ovale: functions during fetal development to allow blood to bypass the fetal lungs
- formane ovale becomes the fossa ovalis after birth when the foramen ovale closes
vessels: right atrium
- SVC
- IVC
- coronary sinus (part of coronary circulation)
valves: right atrium
tricupsid valve
tricupsid valve
- one-way valve between the right atrium and right ventricle
- 3 cusps (tri-cuspid)
anatomical features of the right ventricle
- chordae tendinae (attach to valve cusps)
- papillary muscles (anchor the chordae tendinae)
- trabeculae carnea
- collectively, these structures prevent prolapse of the valve during contraction of the ventricle
vessels: right ventricle
- pulmonary trunk
- pulmonary arteries (2)
pulmonary arteries carry…
deoxygenated blood from the right ventricle of the heart to the lungs
valves: right venticle
- tricupsid valve
- pulmonary valve
which way do the arteries and veins carry blood?
- arteries = away from teh heart
- veins = to the heart
anatomical features of the left atrium
- pectinate muscle
pulmonary veins
- once blood has become ocygenated, it enters the pulmonay veins (carry ocygenated blood from the elungs to the left atrium)
left atrium: valves
- bicuspid/mitral valve
left atrium: vessels
- pulmonary veins
anatomical features of the left ventricle
- chordae tendinae
- papillary muscles
- trabeculae carneae
left ventricle: valves
bicuspid (mitral) valve
- aortic valve
left ventricle: vessels
- aorta
aorta
- large artery that carries ocygenated blood from the heart (left ventricle) to the body
arch of aorta
- vranches supply head, neck, upper limbs
descending aorta
- aupplies blood to the thorax, abdomen, lower limbs
blood flow though the heart (deoxygenated blood from the body to lungs)
deoxygenated blood from the body -> superior or inferior vena cava -> right atrium -> tricuspid valve -> right ventricle -> pulmonary valve -> pulmonary trunk -> pulmonary arteries
blood flow though the heart (oxygenated blood from lungs to the body)
oxygenated blood from lungs -> pulmonary veins -> left atrium -> bicuspid valve -> left ventricle -> aortic valve -> aorta (arch of aorta & descending aorta) -> body
Valve memory aid
- “try before you buy”: tricuspid valve before bicuspid valve
- tRicuspid has an “R” so its on the Right side of the heart
Thoracic cavity: arterial supply
Posterior thoracic wall:
- aorta continues as the descendign thoracci aorta
- gives off the posterior intercostal arteries (supply the posterior thoracic wall)
Anterior thoracic wall:
- subclavian arteries give off the internal thoracic artery (anterior intercostal arteries (upper intercostal spaces))
Thoracic cavity: venous drainage
Anterior and posterior intercostal veins drain into:
- axygous vein (right side)
- hemi-azygous and accessory hemiazygous veins (left side) then to azygous
Innervations
- intercostal nerves
- formed by the ventral rami of thoracic spinal nerves
- motor: innevrates intercostal musclees
- sensory: innervate the overlying skin
