Heart/Mediastinum & Abdomen Flashcards
__ (fraction) of the heart is situated to the right of the midline, and ___ (fraction) is to the left of the midline. Knowing that, we can say that the heart does NOT sit in the ___ plane.
1/3 of heart is to RIGHT of midline, 2/3 is to LEFT of midline. Heart does NOT sit in MEDIAN plane.
Superiorly to inferiorly, the heart extends from the level of ___ to ____.
From level of STERNAL ANGLE to 5th INTERCOSTAL SPACE
At the sternal angle, the heart extends __ inches lateral to the lateral border of the sternum.
1/2 inch lateral to lateral border of sternum at sternal angle
On the left side, the heart protrudes out. In the 5th intercostal space, the ___ of the heart extends __ inches to the left of the sternum.
At the 5th intercostal space, the APEX of the heart extends 3.5 INCHES to the left of the sternum
From an anterior in situ view, what parts of the heart can we see?
Right atrium, right auricle, right ventricle
Part of left ventricle, left auricle
Describe the borders of the heart (chambers, not where it is situated in situ)
Right: Right atrium (mostly)
Inferior: Right ventricle, part of left ventricle
Left: Left ventricle and auricle
The base of the heart faces __ [ant/post/med/lat]. It consists mostly of which chamber? We also see small portions of what other chambers? What exits from the base of the heart?
Base of heart faces POSTERIORLY. Consists mostly of LEFT ATRIUM, with small portions of RIGHT ATRIUM and RIGHT VENTRICLE. 4 PULMONARY VEINS emerge from base of heart
The inferior surface of the heart is AKA the ____ surface. It sits on ___, and consists mostly of ___ and a small part of ___.
Inferior surface = DIAPHRAGMATIC surface. Sits mostly on DIAPHRAGM. Mostly LEFT VENTRICLE and small part of RIGHT VENTRICLE
What are sulci? Describe the 3 sulci of the heart. What do they separate? Where do they run? What, if anything, is in it?
Sulci = grooves in heart where blood vessels run.
Coronary Sulcus (atrioventricular sulcus) = separates atria from ventricles, separates base of heart from diaphragmatic surface. Runs around the top of ventricles, putting boundary of atria above and ventricles below
Anterior Interventricular (longitudinal) sulcus = separates R from L ventricle
Posterior Interventricular (Longitudinal) Sulcus = on posterior side
There are __ (#) coronary arteries: [list name(s)]. They come off of the ____.
2 coronary arteries: RIGHT coronary artery and LEFT coronary artery. They come off of the ascending aorta from the right and left aortic sinuses, respectively.
The right coronary artery comes from the ____. It runs in the ___ between the ___ and ___. It gives off the ___ branch, which supplies the sinoatrial node via the ___ branch. As the RCA reaches the ___ of the heart, it gives off the marginal branch. The RCA continues to the back side of the heart where it gives off the __ in the ___. A smaller branch continues along to the [right/left] side.
The right coronary artery comes from the RIGHT AORTIC SINUS. It runs in the CORONARY SULCUS between the RIGHT ATRIUM and RIGHT VENTRICLE. It gives off the RIGHT ATRIAL branch, which supplies the sinoatrial node via the NODAL branch. As the RCA reaches the ACUTE MARGIN of the heart, it gives off the marginal branch. The RCA continues to the back side of the heart where it gives off the POSTERIOR DESCENDING (INTERVENTRICULAR) BRANCH in the POSTERIOR INTERVENTRICULAR GROOVE. A smaller branch continues along to the LEFT side.
The right coronary artery supplies…
(1) Right atrium
(2) Right ventricle (most of it)
(3) S-A and A-V notes and interarterial septum (conducting system in R atrium)
(4) Posterior part of left ventricle
The left coronary artery comes from the ____. It divides __ [how soon?] into two branches: __ & ___.
The left coronary artery comes from the LEFT AORTIC SINUS. It divides ALMOST IMMEDIATELY (~1/2”) into two branches: LEFT ANTERIOR DESCENDING (INTERVENTRICULAR) A. & LEFT CIRCUMFLEX BRANCH.
The left anterior descending (interventricular) a. comes from the __ and runs in the __ and is the main supplier of the ____. It’s AKA ____.
Comes from the L CORONARY A., and runs in the INTERVENTRICULAR GROOVE, aka WIDOWMAKER (frequently blocked and bypassed)
The left circumflex branch of the ___ runs in the ___ on the [left/right]. It ends and then throws off branches to the ___.
L circumflex branch of L CORONARY A. runs in the CORONARY SULCUS on LEFT. It ends and throws off branches to L VENTRICLE
The left coronary artery supplies…
(1) L Atrium, (2) most of L Ventricle, (3) A-V bundle in interventricular septum (deep in heart)
In general, the cardiac veins mostly parallel ___. They empty into the ___ (in the ___), which empties into the __.
Mostly parallel arteries. They empty into CORONARY SINUS in CORONARY SULCUS. Most of the blood gets collected here. THEN it empties into the R ATRIUM
Right atrium receives venous blood from…
(1) Superior vena cava, (2) Inferior vena cava, (3) Coronary sinus
The posterior wall of the R Atrium is [rough/smooth] between the SVC and IVC.
Posterior wall between SVC and IVC is SMOOTH
Within the R Atrium on the interatrial septum, the impression is called __. Explain what this is.
Impression = fossa ovalis (remnant of foramen ovale). During development, there is a connection between 2 atria. The opening is called the foramen ovale, designed to get blood from the left side of the heart (along with ductus arteriosus) and to keep blood from getting to lung. This foramen closes with the first breath, leaving behind the fossa ovalis.
What is the clinical relevance of the orientation of the SVC to the IVC?
In a bedridden patient (acute care), an umbrella-shaped filter may be put into IVC to catch any blood clots from lower limbs and prevent embolisms. To remove the filter, they take advantage of the fact that IVC and SVC are in a straight line!
Describe the walls of the left atrium
Posterior wall = smooth, pulmonary veins enter here
Anterior wall = pectinate muscles
Compare the muscle thickness in the right vs. left ventricles
Right ventricle is ~1/3 as thick as left ventricle
Describe the features of the right ventricle (including muscles, valves, etc.)
3 Papillary muscles (ant. is largest) protruding from tribeculae carnae.
Chordae tendinae run between papillary muscles and valve leaflets
Moderator band - muscle connects interventricular septum to anterior papillary muscle. Moderator band is a branch of the right conduction bundle branch. It sends impulse directly to the arch
Tricuspid valve between the right atrium and right ventricle.
Pulmonary valve - at exit of pulmonary trunk, 3 semilunar cusps
Describe trabeculae carnae, papillary muscles, and chordae tendinae and their relationship.
Tribeculae carnae: Rough ridges of muscle found in both ventricles. They give rise to papillary muscles, which are 3 nipple-like protrusions of the trabeculae carnae (in RV) and 2 papillary muscles in the LV. The chordae tendonae are tendons that run between papillary muscles and valve leaflets.
Describe the features of the Left Ventricle
Muscle is thicker than in the right.
2 papillary muscles come off of trabeculae carnae, from which chordae tendonae run to AV valve (bicuspid, mitral valve) between atrium and ventricle. No obvious moderator band is present. The aortic valve features 3 semilunar cusps.
Why are the muscles in one ventricle thicker than the other?
In diastole, the atria contract, push blood into ventricles (bottom # of BP; low pressure) [atria = low pressure, thinner walls]
The ventricles then contract to push blood to right side (pulmonary to lungs, and out to body) so they must have stronger, thicker walls to maintain that higher pressure contraction
What’s the purpose of the chordae tendonae?
Without chordae tendonae, the valve leaflets would invert and blood would gush back into atriums (rather than going out pulmonary trunks or into aorta); SO with these muscles, the blood goes into ventricle and when it contracts, the pectinate muscles also contract and hold the valve leaflets down; the blood pushes against them, but b/c of the pectinate muscle contraction, the leaflets stay down (closed) and the blood doesn’t regurgitate; IF the valves flip up and it fails, you hear a swooshing sound and you get prolapse (valve inverts), so then the ventricles have to work harder to get blood to lungs and aorta!
__ forms the skeleton of the heart and acts to do what? It surrounds ____ and separates __ from ___, except at ___.
Fibrous connective tissue acts to LIMIT SPREAD OF IMPULSES. It surrounds the valves and separates the atrium from the ventricle EXCEPT at the A-V bundle
Conducting tissue of the heart is modified muscle tissue called __.
Purkinje cells
Describe the conducting tissue of the heart: __ is the pacemaker of the heart. The impulse spreads over the ___ and arrives at the ___ node. The impulse is then sent down the __(A)_, which runs in the ___. The __(A)__ branches into right and left bundle branches.
SINO-ATRIAL (SA) NODE is the pacemaker of the heart. The impulse spreads over the ATRIA and arrives at the ATRIO-VENTRICULAR (A-V) node. The impulse is then sent down the ATRIO-VENTRICULAR BUNDLE (A-V BUNDLE/ BUNDLE OF HIS), which runs in the INTERVENTRICULAR SEPTUM. The BUNDLE OF HIS branches into right and left bundle branches.
The ___ is a visceral serous layer of the pericardial sac.
EPICARDIUM
The ___ is cardiac muscle (contracting muscle).
MYOCARDIUM
The ___ is the inner layer of chambers, an endothelium. This layer becomes modified to form ___.
ENDOCARDIUM, modified to form the VALVES
There [is/is not] direct contact between blood and myocardium?
There is NO direct contact betwen blood and myocardium. Myocardium is ensheathed by epicardium and endocardium on each sides.
The coronary arteries fill during ___. This is when the cusps are filled with blood, [low/high] pressure. The coronary arteries do NOT fill during __, when the cusps are pressed against the wall, blocking the opening of the coronary arteries.
Coronary arteries fill during DIASTOLE not during SYSTOLE.
During systole, the ___ are open and against the wall of the ascending aorta, blocking the openings of the coronary tissues.
AORTIC VALVE LEAFLETS are open in systole, blocks openings of coronary tissues
During diastole, leaflets fill with blood from the ___, which drops back down at the end of systole
Leaflets fill with blood from ASCENDING AORTA
Blood that falls back down into the ascending aorta at the end of systole fills ____. This filling is [active/passive].
Blood that falls back into ascending aorta at the end of systole is the blood that fills the CORONARY ARTERIES. This means it is completely PASSIVE filling of the coronary arteries.
Name the subdivisions of the mediastinum
Superior, middle, anterior, posterior
Describe the boundaries of the superior mediastinum
(1) Thoracic aperature, (2) plane from angle of sternum to T4, (3) bodies of vertebrae T1-T4, (4) inner surface of manubrium, (5) pleural sac on either side
Describe the boundaries of the middle mediastinum
(1) Anterior portion of pericardial sac, (2) posterior portion of pericardial sac, (3) pleural sac on either side, (4) diaphragm, (5) sternal angle/T4 line
Describe the boundaries of the anterior mediastinum
(1) Anterior portion of pericardial sac, (2) Posterior surface of sternum, (3) Plane from angle of sternum to T4, (4) diaphragm, (5) pleural sac on either side
Describe the contents of the anterior mediastinum
Loose connective tissue, mediastinal branches of internal thoracic artery, lymph nodes, thymus may extend down into it
Describe the boundaries of the posterior mediastinum
(1) Vertebral bodies T4-T12, (2) Posterior portion of pericardial sac, (3) Pleural sacs on either side, (4) plane from angle of sternum to T4, (5) diaphragm (way down at bottom)
The middle mediastinum contains the pericardial sac and its contents, i.e. ___. It also contains the __ nerve and ___ vessels
Heart and roots of great vessels: ascending aorta, pulmonary trunk, superior vena cava, inferior vena cava (plus pulmonary veins and arteries). ALSO contains the phrenic nerve and pericardiacophrenic vessels.
Name the three layers of the pericardial sac
Outer to inner: Fibrous pericardium, Parietal serous pericardium, Visceral serous pericardium (epicardium)
The fibrous pericardium is the __ layer of the pericardial sac. It is in contact with the ___. The ___ nerve and __ vessels are located on either side, [ant./post.] to the root of the lung. This layer is penetrated by what vessels? Finally, the fibrous pericardium is fused to ___.
Fibrous pericardium is the OUTER layer of the pericardial sac and is in contact with the PLEURA. PHRENIC n. and PERICARDIACOPHRENIC vessels located on either side ANTERIOR to the root of the lung. Layer is penetrated by great vessels: aorta, pulmonary artery, pulmonary veins, superior and inferior vena cava. Fused to the central tendon of the diaprhagm
What does the term “serous” mean, e.g parietal serous pericardium?
Serous = epithelium that produces FLUID, thereby reducing friction
The parietal serous pericardium is the ___ lining of the pericardial sac. It’s analogous to the __ pleura and reflects over the roots of the great vessels to form 2 sinuses: [name and give orientation/location]. While this is one continuous layer, once this layer is in contact with the heart, it becomes the __.
Parietal serous pericardium = INNER lining of sac. Analogous to the PARIETAL PLEURA. Forms 2 sinuses: OBLIQUE SINUS [between posterior wall of heart and pericardial sac], TRANSVERSE SINUS [between aorta and pulmonary trunk, in front of SVC and left atrium]. Once in contact with the heart, it becomes the VISCERAL SEROUS PERICARDIUM
The visceral serous pericardium is AKA the ___. It lines the surface of the heart and is continuous with the __.
Epicardium. Continuous with the parietal serous pericardium
The superior mediastinum contains A LOT! List the structures from ANTERIOR to POSTERIOR.
Origin of infrahyoids, Internal thoracic arteries, Thymus gland, Brachiocephalic veins (2), SVC, Left Phrenic N, Right Phrenic N, Arch of Aorta, Left Vagus N., L recurrent Laryngeal N., Right Vagus N., Trachea, Cardiac Plexuses, Esophagus, Thoracic Duct
The thymus gland generates ___. It tends to atrophy in adults, and appears as the ___ of __ (#) lobes.
Generates WHITE BLOOD CELLS. Atrophies in adults, and is the FATTY REMNANT of 2 LOBES
The brachiovephalic veins are formed by the junction of the __ and ___ veins. The left brachiocephalic vein runs [anterior/posterior] to the arch of the aorta.
Junction of the SUBCLAVIAN and INTERNAL JUGULAR VEINS. Left Brachiocephalic v. runs ANTERIOR to arch of aorta.
The superior vena cava is formed by ____ and located to the [right/left] of the aorta.
Formed by 2 BRACHIOCEPHALIC veins and it’s located to the RIGHT of the aorta
The LEFT phrenic nerve runs [ant/post] to anterior scalene, [ant/post] to the left brachiocephalic vein and then [ant/post] to the arch of the aorta. Then, it runs through the middle mediastinum on the ___, [ant/post] to the root of the lung.
Left phrenic nerve runs ANTERIOR to anterior scalene, POSTERIOR to the L brachiocephalic vein, then ANTERIOR to the arch of aorta. Then it runs ANTERIOR to the root of the lung
The RIGHT phrenic nerve runs [ant/post] to the anterior scalene, deep to Right subclavian, and then runs [ant/post/next to] the right brachiocephalic vein. It runs [ant/post] to the Superior vena cava before it runs into the mediastinum along the ___ and [ant/post] to root of the lung.
Right phrenic n. = ANTERIOR to anterior scalene, deep to R subclavian, runs NEXT TO right brachiocephalic vein. Runs POSTERIOR to SVC. Runs along pericardial sac ANTERIOR to root of lung
What runs within [i.e. under the hook of] the aortic arch?
Right pulmonary artery and left bronchus
What are the branches off of the aortic arch?
BCS: Brachiocephalic trunk, Left Common Carotid, Left Subclavian
The ___ attaches to the inferior surface of the arch with the left pulmonary artery. It is the remnant of the ductus arteriosus
Ligamentum arteriosum
At the __ level in the posterior mediastinum, the aorta becomeos vertical, forming the __.
T4, forms descending aorta
The left vagus nerve descends along the ___, anterior to the ___. It gives off the ___ nerve which innervates the __. Then, it passes [ant/post] to the root of the lung to the posterior mediastinum. Finally, it goes to the esophagus where it forms the ___.
L Vagus Nerve: descends along LEFT COMMON CAROTID A. anterior to the ARCH OF THE AORTA. It gives off the RECURRENT LARYNGEAL NERVE which innervates the LARYNX. It passes POSTERIOR to the root of the lung. At esophagus, forms ESOPHAGEAL PLEXUS
The left recurrent laryngeal nerve is a branch of the __. It passes under the ___, [medial/lateral] to what other structure? It ascends between the __ and__ to the larynx.
Left recurrent laryngeal nerve is a branch of the LEFT VAGUS NERVE. Passes under the ARCH OF THE AORTA, LATERAL to the ligamentum arteriosum. It ascends between the ESOPHAGUS and TRACHEA to the larynx.
The right vagus nerve crosses the right bronchus [anteriorly/posteriorly] to go toward the esophagus. It passes [ant/post] to the root of the lung and enters the [ant/post/middle] mediastinum. Note that the right recurrent laryngeal nerve loops under __, [in/not in] the mediastinum.
R Vagus N. crosses right bronchus POSTERIORLY, and passes POSTERIOR to root of lung where it enters the POSTERIOR mediastinum. The right recurrent laryngeal nerve loops under the SUBCLAVIAN A., NOT IN the mediastinum
The trachea biforcates at the ___, spinal level __.
Lower border of superior mediastinum, T4
The cardiac plexuses consist of ___ nerves innervating the __. It has contributions from the ___ nerve (what branches?). It is [parasympathetic/sympathetic] and has a branch from each ___.
Autonomic nerves innervating heart. Has contributions from the VAGUS Nerve (UPPER AND LOWER CERVICAL CARDIAC branches and THORACIC CARDIAC branch). It is SYMPATHETIC with a branch from each CERVICAL SYMPATHETIC GANGLION
The esophagus runs [ant/post] to the trachea in the superior mediastinum. It passes through the __ in the diaphragm and continues into the posterior mediastinum.
Esophagus runs POSTERIOR to (behind) trachea in superior mediastinum. Passes through ESOPHAGEAL HIATUS in diaphragm
The thoracic duct empties at the junction between the ___ and ___ (in the __) on the [right/left]. It is viewed best in the [ant/post/middle/sup] mediastinum. It empties lymph from the ___.
Empties at junction between LEFT SUBVLAVIAN and LEFT JUGULAR veins (in the NECK) on the LEFT. Viewed best in POSTERIOR mediastinum. Empties lymph from lower limb, left, and upper extremity
What do we see in the posterior mediastinum?
Descending aorta, esophagus, vagus nerve, azygos venous system, thoracic duct, sympathetic chain and ganglia
The descending aorta starts at ___ and runs through __ (spinal levels. It runs [in front of/behind] the pericardial sac. It has branches to structures on the way including… Finally, it passes through the ___ to enter the abdomen.
Runs T4-T12. Branches to: BRONCHI, ESOPHAGUS, POSTERIOR INTERCOSTAL ARTERIES, DIAPHRAGM. Passes through AORTIC HIATUS to enter abdomen. This is its own opening!
Explain the embryological significance of the ligamentum arteriosum.
The ligamentum arteriosum was an OPEN vessel embryologically. When the right side of the heart pumped, the lungs produced back pressure on the heart (because the air system wasn’t open), so this open vessel existed between the L pulmonary artery and the arch of the aorta. Most blood leaving the right ventricle was shunted back to the aorta and out to fetus’s body, bypassing the lungs during development. At the first breath, the lungs fill with air, reducing the intralung pressure. The ligamentum arteriosum collapses and closes, turning into a ligament, and the pulmonary arteries open!
The esophagus is a ___ tube. It contracts in a coordinated way to move food bolus down toward stomach. It pierces the diaphragm through the ____. Sits most [ant/post] of all of these organs. The descending aorta is shifted to the [right/left] relative to the esophagus.
Esophagus = MUSCULAR tube. Pierces diaphragm through esophageal hiatus. Sits most POSTERIORLY of these organs. Descending aorta is shifted LEFT relative to esophagus.
In the posterior mediastinum, the vagus nerve branches and forms the ___. Then, __ (#) trunks reform (name them and tell which side they rotated from). Explain the developmental significance of this rotation and naming.
Branches and forms esophageal plexus. Then, 2 trunks reform: ANTERIOR (rotated from the LEFT) and POSTERIOR (rotated from the RIGHT). Naming comes from when stomach was developing external to fetal body: right trunk flips around to be posterior, left becomes anterior as stomach squishes to right side
The azygos venous system drains blood from ___. “Azygos” means ___. The azygos vein on the right is [larger/smaller]. On the left, the ___ [inf/sup] and ____ [inf/sup] run interconnected with each other and train by connecting veins into the azygos. The azygos extends up to spinal level __ and loops [over/under] root of lung and empties into __.
Azygos venous system drains blood from BODY WALL. Azygos means UNPAIRED. Vein on right is LARGER. On left, the HEMIAZYGOS (inferior) and ACCESSORY HEMIAZYGOS (superior) run interconnected. Azygos extends to T4 and loops OVER root of lung before emptying into SUPERIOR VENA CAVA
The thoracic duct ascends from the abdomen via the ___. It takes care of lymphatic drainage from ___. It ascends [ant/post] to the esophagus between the __ and___. It turns __ and __ before it enters the ___.
Acends from abdomen through AORTIC HIATUS. It drains lymph from BELOW DIAPHRAGM. Ascends POSTERIOR to esophagus between AZYGOS V. and AORTA. Turns LATERAL and ANTERIOR then enters the SUPERIOR MEDIASTINUM.
The sympathetic chain and ganglia are covered by ___ superiorly. It consists of ___ for each spinal nerve and and __ or __ (#) ganglia. It is responsible for the ___ response of the autonomic nervous system.
Covered by PLEURA superiorly. Consists of GREY AND WHITE COMMUNICANTES for each spinal nerve and 11 or 12 ganglia. “Fight or Flight” response of ANS.
In the sympathetic chain and ganglia, cell BODIES of neurons only exist between the spinal bodies of __ and __ of the spinal cord. The chain then acts as a highway for sympathetic neurons to exit the spinal cord and travel where they need to go!
Cell bodies exist between spinal bodies of T1 and L2
The splanchnic nerves are [preganglionic/postganglionic] [sympathetic/parasympathetic] fibers. There are __ (#) splanchnic nerves. Name them and describe their spinal level origins.
Preganglionic sympathetic fibers. 3 splanchnic nerves:
(1) Greater - T5- T9 to celiac ganglion
(2) Lesser - T10 and T11 to aortico-renal ganglion
(3) Lowest (or least) - last thoracic ganglion to renal ganglia
The pattern for splanchnic nerves is that the pass through the ___ [without synapsing/where they synapse] and then pierce the diaphragm to enter abdomen. There they synapse in ___ that are located near __. The postganglionic axons then travel from the blood vessels to the organs they are going to innervate.
The pattern for splanchnic nerves is that the pass through the SYMPATHETIC CHAIN GANGLIA WITHOUT synapsing and then pierce the diaphragm to enter abdomen. There they synapse in GANGLIA that are located near MAJOR BLOOD VESSELS. The postganglionic axons then travel from the blood vessels to the organs they are going to innervate.
The vagus nerve is all [sympathetic/parasympathetic]
Vagus = Parasympathetic
True or false: there is no parasympathetic innervation of the limbs (periphery).
TRUE: there is NO parasympathetic innervation of the limbs.
The abdominal cavity is lined by ___ creating the ___ cavity. This cavity is filled with __ which acts to ___.
Lined with PERITONEUM creating the PERITONEAL cavity. Fluid-filled, allows organs to move without pain/friction
