[USMLE] Pericardium and Heart Flashcards
Is a fibroserous sac that encloses the heart and the roots of the great vessels and occupies the middle mediastinum
Pericardium
Pericardium is composed of the
fibrous pericardium and serous pericardium
pericardium receives blood from the
pericardiophrenic, bronchial, and esophageal arteries
pericardium is innervated by
vasomotor and sensory fibers from the phrenic and vagus nerves and the sympathetic trunks
Is a strong, dense, fibrous layer that blends with the adventitia of the roots of the great vessels and the central tendon of the diaphragm.
fibrous pericardium
consists of the parietal layer and the visceral layer
serous pericardium
lines the inner surface of the fibrous pericardium
parietal layer
forms the outer layer (epicardium) of the heart wall and the roots of the great vessels
visceral layer
is an inflammation of the pericardium (has symptoms of dysphagia, dyspnea and cough, inspiratory chest pain, and paradoxic pulse)
pericarditis
pericarditis also causes the
pericardial murmur or pericardial friction rub
Is a potential space between the visceral layer of the serous pericardium (epicardium) and the parietal layer of the serous pericardium lining the inner surfaces of the fibrous pericardium
pericardial cavity
Is a subdivision of the pericardial sac
transverse sinus
transverse sinus boundaries
lying posterior to the ascending aorta and pulmonary trunk, anterior to the SVC, and superior to the left atrium and the pulmonary veins
transverse sinus is of great importance to the cardiac surgeon because
while performing surgery on the aorta or pulmonary artery, a surgeon can pass a finger and make a ligature through the sinus between the arteries and veins, thus stopping the blood circulation with the ligature
Is a subdivision of the pericardial sac behind the heart
oblique sinus
oblique sinus is surrounded by the
reflection of the serous pericardium around the right and left pulmonary veins and the inferior vena cava (IVC)
is an acute compression of the heart caused by a rapid accumulation of fluid or blood in the pericardial cavity from wounds to the heart or pericardial effusion (passage of fluid from the pericardial capillaries into the pericardial sac)
Cardiac tamponade:
tamponade can be treated by
pericardiocentesis
is an accumulation of fluid in the pericardial space resulting from inflammation caused by acute pericarditis, and the accumulated fluid compresses the heart, inhibiting cardiac filling.
Pericardial effusion
is a surgical puncture of the pericardial cavity for the aspiration of fluid, which
is necessary to relieve the pressure of accumulated fluid on the heart
pericardiocentesis
in pericardiocentesis, a needle is inserted into pericardial cavity through the
fifth intercostal space left to the sternum
Because of the cardiac notch, the needle misses the pleura and lungs, but it penetrates the pericardium.
apex of the heart location
is the blunt rounded extremity of the heart formed by the left ventricle and lies in the left fifth intercostal space slightly medial to the midclavicular (or nipple) line, about 9 cm from the midline
the apex of the heart location is useful clinically for determining the
left border of the heart and for auscultating the mitral valve
the base of the heart is formed by
primarily by the left atrium and only partly by the posterior right atrium
the right (acute) border of the heart is formed by the
SVC, right atrium, and IVC, and its left (obtuse) border is
formed by the left ventricle
in radiology, the left border of the heart consists of the
aortic arch, pulmonary trunk, left auricle, and left ventricle
the heart wall consists of three layers:
inner endocardium , middle myocardium , and outer
epicardium
a groove on the external surface of the right atrium
sulcus terminalis
sulcus terminalis marks the junction of the
primitive sinus venosus with the atrium in the embryo and corresponds to a ridge on the internal heart surface
a ridge on the internal heart surface
crista terminalis
a groove on the external surface of the heart
coronary sulcus
coronary sulcus marks the division between the
atria and the ventricles
is the point at which the interventricular and interatrial sulci cross the coronary sulcus
crux
The cardiovascular silhouette, or cardiac shadow, is the contour of the heart and great vessels seen on
posterior-inferior chest radiographs
the right border of the cardiovascular silhouette is formed by the
SVC, the right atrium, and the IVC
the left border of the cardiovascular silhouette is formed by the
aortic arch (which produces the aortic knob ), the pulmonary trunk, the left auricle, and the left ventricle
the inferior border of the cardiovascular silhouette is formed by the
right ventricle, and the left atrium shows no border
Has an anteriorly situated rough-walled atrium proper and the auricle lined with pectinate muscles and a posteriorly situated smooth-walled sinus venarum , into which the two venae cavae open
right atrium
right vs left atrium (size)
the right atrium is larger than the left atrium but has a thinner wall
the sinus venarum between two venae cavae is separated from the atrium proper by the
crista terminalis
right vs left atrium (pressure)
right atrium has a right atrial pressure that is normally slightly lower than left atrial pressure
right atrium contains the
valve of the IVC and the valve of the coronary sinus
valve of the IVC
eustacian
valve of the coronary sinus
thebesian
Is the conical muscular pouch of the upper anterior portion of the right atrium, which covers the first part of the right coronary artery
Right auricle
Is a posteriorly situated, smooth-walled area that is separated from the more muscular atrium proper by the crista terminalis
Sinus venarum (sinus venarum cavarum)
sinus venarum develops from the _____ and receives the SVC, IVC, coronary sinus, and anterior cardiac veins
embryonic sinus venosus
Are prominent ridges of atrial myocardium located in the interior of both auricles and the right atrium
Pectinate muscles
Crista terminalis is a vertical muscular ridge running
anteriorly along the right atrial wall from the opening of
the SVC to the opening of the IVC
crista terminalis provides the
origin of the pectinate muscles
crista terminalis represents the junction between the
primitive sinus venarum (a smooth-walled region) and the right atrium proper
crista terminalis is indicated externally by the
sulcus terminalis
Are the smallest cardiac veins
Venae cordis minimae
Venae cordis minimae begins
in the substance of the heart (endocardium and
innermost layer of the myocardium)
Venae cordis minimae ends
in the atria at the foramina venarum
minimarum cordis
Is an oval-shaped depression in the interatrial septum
fossa ovalis
fossa ovalis represents the site of the
foramen ovale
in the foramen ovale, blood runs from the
right atrium to the left atrium before birth
upper rounded margin of the fossa is called the
limbus fossa ovale
the walls of the left atrium are smooth except fot a few
pectinate muscles in the auricle
left atrium boundaries
is the most posterior of the four chambers lying posterior to the right atrium but anterior to the esophagus and shows no structural borders on a posteroanterior radiograph
left atrium receives oxygenated blood through
four pulmonary veins
Makes up the major portion of the anterior (sternocostal) surface of the heart
right ventricle
the right ventricle contains
Trabeculae carneae cordis, Papillary muscles, Chordae tendineae, Conus arteriosus (infundibulum), Septomarginal trabecula (moderator band), IV septum
Are anastomosing muscular ridges of myocardium in the ventricles
Trabeculae carneae cordis
Are cone-shaped muscles enveloped by endocardium
Papillary muscles
papillary muscles extend from the anterior and posterior ventricular walls and the septum, and their apices are
attached to the
chordae tendineae
why papillary muscles contract?
to tighten the chordae tendineae, preventing the cusps of the tricuspid valve from being everted into the atrium by the pressure developed by the pumping action of the heart. This prevents regurgitation of ventricular blood into the right atrium
Extend from one papillary muscle to more than one cusp of the tricuspid valve
chordae tendinae
chordae tendinae prevent eversion of the valve cusps into the atrium during
ventricular contractions
Is the upper smooth-walled portion of the right ventricle, which leads to the pulmonary trunk.
Conus arteriosus (infundibulum)
Is an isolated band of trabeculae carneae
Septomarginal trabecula (moderator band)
Septomarginal trabecula (moderator band) forms a bridge between the
intraventricular (IV) septum and the base of the anterior papillary muscle of the anterior wall of the right ventricle.
septomarginal trabercula is called the moderator band for its ability to
prevent overdistention of the ventricle and carries
the right limb (Purkinje fibers) of the atrioventricular (AV) bundle from the septum to the sternocostal wall of the ventricle
Is the place of origin of the septal papillary muscle.
IV septum
IV septum is mostly muscular but has a small membranous upper part, which is a common site of
ventricular septal defects
left ventricle lies
at the back of the heart
the apex of the left ventricle is directed
downward, forward and to the left
left ventricle is divided into the
left ventricle proper and the aortic vestibule
the upper anterior part of the left ventricle and leads into the aorta
aortic vestibule
left ventricle contains
two papillary muscles (anterior and posterior) with their chordae tendineae and a meshwork of muscular ridges, the trabeculae carneae cordis
left vs right ventricle (function, thickness, size, shape)
the left ventricle performs harder work , has a thicker (two to three times as thick) wall, and is longer, narrower, and more conical-shaped than the right ventricle
is a necrosis of the myocardium because of local ischemia resulting from vasospasm or obstruction of the blood supply
Myocardial infarction
symptoms of myocardial infarction
severe chest pain or pressure for a prolonged period (more than 30 minutes), congestive heart failure, and murmur of mitral regurgitation
Myocardial infarction can be treated with
nitroglycerin, morphine, lidocaine or atropine
prevents coronary spasm and reduces myocardial oxygen demand
nitroglycerin
relieves pain and anxiety
morphine
reduces ventricular arrhythmias
lidocaine
restores conduction and increases heart rate
atropine
is characterized by attacks of chest pain originating in the heart and felt beneath the sternum, in many cases radiating to the left shoulder and down the arm
angina pectoris
angina pectoris is caused by an
insufficient supply of oxygen to the heart muscle because of coronary artery disease or exertion
(e.g., exercise, excitement) or emotion (e.g., stress, anger, frustration)
angina pectoris symptoms
severe chest pain or pressure for a prolonged period (more than 30 minutes), congestive heart failure, and murmur of mitral valve regurgitation
angina pectoris can be treated with
nitroglycerin, beta-adrenergic blockers, morphine,
lidocaine, or atropine
is a variant form of angina pectoris caused by transient coronary artery spasm.
Prinzmetal’s angina
The vasospasm typically occurs at
rest
is a restoration of cardiac output and pulmonary ventilation following cardiac arrest and apnea (cessation of breathing) by external cardiac massage
Cardiopulmonary resuscitation (CPR)
CPR is performed by applying firm pressure to the chest vertically downward over the
inferior part of the sternum to move it posteriorly, forcing blood out of the heart and into the great vessels
pulmonary valve lies behind the
medial end of the left third costal cartilage and adjoining part of the sternum
pulmonary valve is most audible over the
left second intercostal space just lateral to the sternum
pulmonary valve is opened by the
ventricular systole
pulmonary valve is shut slightly after
closure of the aortic valve
aortic valve lies behind the
left half of the sternum opposite the third intercostal space
aortic valve is closed during the
ventricular diastole
closure of the aortic valve at the beginning of ventricular diastole causes the
second heart sound
the aortic valve is most audible over the
right second intercostal space just lateral to the sternum
tricuspid valve aka
right AV
tricuspid valve lies between the
right atrium and ventricle, behind the right half of the sternum opposite the fourth intercostal space
tricuspid valve is covered by
endocardium
the tricuspid valve is most audible over the
right lower part of the body of the sternum
tricuspid valve has
anterior, posterior, and septal cusps
anterior, posterior, and septal cusps are attached by the
chordae tendineae to three papillary muscles that keep the valve closed against the pressure developed by the pumping action of the heart.
tricuspid valve is closed during
ventricular systole (contraction)
its closure contributes to the
first heart sound
bicuspid valve (left AV) is aka
mitral valve
why is it called mitral valve?
it is shaped like a bishops miter
bicuspid valve lies between the
left atrium and ventricle, behind the left half of the sternum at the fourth costal cartilage
bicuspid valve has how many cusps?
two; larger anterior and smaller posterior
bicuspid valve is closed slightly before the tricuspid valve by the
ventricular contraction (systole)
the closure at the onset of ventricular systole causes the
first heart sound
the bicuspid valve is most audible over the
apical region of the heart in the left fifth intercostal space at the midclavicular line
is a condition in which the valve everts into the left atrium and thus fails to close properly when the left ventricle contracts
Mitral valve prolapse
mitral valve prolapse may cause
chest pain, shortness of breath,
palpitations, and cardiac arrhythmia
s a characteristic sound generated by turbulence of blood flow through an orifice of the heart
Cardiac murmur
first heart sound is caused by
the closure of the tricuspid and mitral valves at the onset of ventricular systole
second heart sound is caused by
the closure of the aortic and pulmonary valves (and vibration of walls of the heart and major vessels) at the onset of ventricular diastole
Is composed of modified, specialized cardiac muscle cells that lie immediately beneath the endocardium
and carry impulses throughout the cardiac muscle, signaling the heart chambers to contract in the proper
sequence
Conducting system of the heart
aka pacemaker of the heart and initiates the heartbeat
Sinoatrial (SA) node
SA node is a small mass of specialized cardiac muscle fibers that lies in the myocardium at the
upper end of the crista terminalis near the opening of the SVC in the right atrium
SA node is supplied by the
sinus node artery
sinus node artery is a branch of the
right coronary artery
AV node lies in the
interatrial septum, superior and medial to the opening of the coronary sinus in the right atrium
AV node receives the impulse from the ____ and passes it to the _____
SA node and passes it to the AV bundle
AV node is supplied by the
AV nodal artery
AV nodal artery arises from the
right coronary artery opposite the origin of the posterior interventricular artery
AV node is innervated by the
autonomic nerve fibers, although the cardiac muscle fibers lack motor endings
Splits into right and left branches, which descend into the muscular part of the interventricular septum, and breaks up into terminal conducting fibers (Purkinje fibers) to spread out into the ventricular walls.
AV bundle (bundle of His)
AV bundle (bundle of His) begins and runs along where
at the AV node and runs along the membranous part of the interventricular septum
damage to the conducting system causes
heart block
coronary arteries arise from the
ascending aorta
coronary arteries are filled with blood during the
ventricular diastole
coronary arteries have maximale blood flow during
diastole
coronary arteries have minimal blood flow during
systole because of compression
of the arterial branches in the myocardium during systol
right coronary artery arises from the
anterior (right) aortic sinus of the ascending aorta,
right coronary artery pathway
runs between the root of the pulmonary trunk and the right auricle
right coronary artery descends in the
right coronary sulcus
right coronary artery generally supplies the
right atrium and ventricle
Passes between the right atrium and the root of the ascending aorta, encircles the base of the SVC
Sinuatrial nodal artery
Sinuatrial nodal artery supplies the
SA node and the right atrium
marginal artery pathway
Runs along the inferior border toward the apex
Runs along the inferior border toward the apex supplies the
inferior margin of the right ventricle
Is a larger terminal branch
Posterior IV (posterior descending) artery
Posterior IV (posterior descending) artery supplies
a part of the IV septum and left ventricle and the AV node
AV nodal artery arises
opposite the origin of its posterior IV artery
AV nodal artery supplies the
AV node
is characterized by the presence of sclerotic plaques containing cholesterol and lipoid material that impair myocardial blood flow, leading to ischemia and myocardial infarction
Coronary atherosclerosis:
is an angiographic reconstruction (radiographic view of vessels after the injection of a radiopaque material) of a blood vessel made by enlarging a narrowed coronary arterial lumen
Coronary angioplasty
involves a connection of a section of vein (usually the saphenous vein) or of the internal thoracic artery or other conduit between the aorta and a coronary artery distal to an obstruction in the coronary artery, shutting blood from the aorta to the coronary arteries
coronary bypass
the thoracic artery is connected to the
coronary artery distal to the obstructive lesion
left coronary artery arises from the
left aortic sinus of the ascending aorta just above the aortic semilunar valve
left coronary artery is usually distributed to more of the
myocardium
left vs right coronary artery (length)
left coronary artery is shorter than the right coronary artery
is the chief source of blood to the IV septum and the apex
Anterior IV (left anterior descending) artery
Anterior IV (left anterior descending) artery generally supplies the
anterior aspects of the right and left ventricles
circumflex artery runs in the
coronary sulcus
Circumflex artery gives off the
left marginal artery
Circumflex artery supplies the
left atrium and left
ventricle
Circumflex artery anastomoses with
terminal branch of the right coronary artery
Is the largest vein draining the heart and lies in the coronary sulcus , which separates the atria from
the ventricles.
coronary sinus
coronary sinus opens into the
right atrium between the opening of the IVC and the AV opening
coronary sinus has how many cusp
one-cusp valve at the right margin of its aperture
coronary sinus receives the
great, middle, and small cardiac veins; the oblique vein of the left atrium; and the posterior vein of the left ventricle
great cardiac vein begins
at the apex of the heart
great cardiac vein ascends along with the
IV branch of the left coronary artery
great cardiac vein turn to the left to lie in the coronary sulcus and continues as the
coronary sinus
Middle cardiac vein begins at
the apex of the heart
Middle cardiac vein ascends in the
posterior IV groove accompanying the poterior branch of the right coronary artery
Middle cardiac vein drains
into the right end of the coronary sinus
Small cardiac vein runs along the
right margin of the heart in company with the marginal artery and then posteriorly in the coronary sulcus to end in the right end of the coronary sinus
Oblique vein of the left atrium descends to empty into the
coronary sinus, near its left end
Anterior cardiac vein drains the
anterior right ventricle
Anterior cardiac vein crosses the
coronary groove
anterior cardiac vein ends directly in the
right atrium
Smallest cardiac veins (venae cordis minimae) begin
in the wall of the heart
Smallest cardiac veins (venae cordis minimae) empty
directly into its chambers
Lymphatic vessels of the heart receive lymph from the
myocardium and epicardium
Lymphatic vessels of the heart follow the right coronary artery to empty into the
anterior mediastinal nodes
Lymphatic vessels of the heart follow the left coronary artery to empty into the
tracheobronchial node
Cardiac plexus receives the superior, middle, and inferior cervical and thoracic cardiac nerves from the
sympathetic trunks and vagus nerves
lies beneath the arch of the aorta in front of the
pulmonary artery
superficial cardiac plexus
lies posterior to the arch of the aorta in front of
the bifurcation of the trachea
deep cardiac plexus
cardiac plexus richly innervates the
conducting system of the heart
right sympathetic and parasympathetic branches terminate chiefly in the region of the
SA node
left branches end chiefly in the region of the
AV node
are devoid of motor endings and are activated by the
conducting system
cardiac muscle fibers
cardiac plexus supplies the heart with
sympathetic fibers
sympathetic fibers _____ the heart rate and the force of the heartbeat
increase
sympathetic fibers cause _____ of the coronary arteries
dilation
parasympathetic fibers _____ heart rate
decrease
parasympathetic fibers _____ the coronary arteries
the coronary arteries
Ascending aorta origin
from the left ventricle within the pericardial sac
Ascending aorta ascends behind the
sternum to end at the level of the sternal angle
ascending aorta lies in the
middle mediastinum
ascending aorta has how many aortic sinuses
three
location of the three aortic sinuses
immediately above the cusps of the aortic valve
ascending aorta gives off the
right and left coronary artery
arch of aorta is found within the
superior meiastinum
arch of aorta pathway
begins as a continuation of the ascending aorta, and arches over the right pulmonary artery and the left main bronchus
arch of aorta forms a prominence that is visible on the radiograph as the
aortic knob
arch of aorta gives rise to the
brachiocephalic, left common carotid, and left subclavian arteries
is a sac formed by dilation of the aortic arch that compresses the left recurrent laryngeal nerve, leading to coughing, hoarseness, and paralys is of the ipsilateral vocal cord
Aneurysm of the aortic arch:
dysphagia
difficulty in swallowing; resulting from pressure on the esophagus
dyspnea
difficulty in breathing; esulting from pressure on the trachea, root of the lung, or phrenic
nerve
is an inheritable disorder of connective tissue that affects the skeleton, skin, eyes, heart, and blood vessels.
Marfan’s syndrome:
Is formed by the union of the right and left brachiocephalic veins and returns blood from all structures superior to the diaphragm, except the lungs and heart
superior vena cava
superior vena cava pathway
Descends on the right side of the ascending aorta, receives the azygos vein , and enters the right
atrium
upper half of the SVC
superior mediastinum
lower half of the SVC
middle mediastinum
pulmonary trunk pathway
Arises from the conus arteriosus of the right ventricle, passes obliquely upward and backward across the
origin and on the left side of the ascending aorta within the fibrous pericardium, and bifurcates into the
right and left pulmonary arteries in the concavity of the aortic arch
Development of the Heart begins to form angiogenic cell clusters formed in the
splanchnic mesoderm
Development of the Heart involves fusion of two endocardial tubes into a
single primitive heart tube
primitive heart tube develops into the
endocardium
the splanchnic mesoderm surrounding the tube develops into
myocardium and epicardium
Primitive heart tube forms how many dilations
five (truncus arteriosus, bulbus cordis, primitive ventricle, primitive atrium, and sinus venosus)
Primitive heart tube undergoes a folding into a
U-shape
Primitive heart tube brings the arterial and venous ends of the heart together and moving the ventricle ____ and the atrium _____.
caudally; cranially
forms aorta and pulmonary trunk by formation of the
aorticopulmonary (AP) septum.
Truncus arteriosus (ventral aorta)
forms conus arteriosus (smooth part of right ventricle) and aortic vestibule (left ventricle
Bulbus cordis
forms trabeculated part of right and left ventricles
Primitive ventricle
forms trabeculated part of right and left atrium
Primitive atrium
forms sinus venarum (smooth part of right atrium), coronary sinus, and oblique vein of left atrium
Sinus venosus
heart divides into how many chambers?
four
by formation of its
septum and valves
Four main septa involved in dividing the heart include the
AP septum, the atrial septum, the AV septum,
and the IV septum
grow in a spiral fashion and fuse to form the AP septum
The truncal ridges and the bulbar ridges derived from neural crest mesenchyme
The AP septum divides the truncus arteriosus into the
aorta and pulmonary trunk
grows toward the AV endocardial cushions from the roof of the primitive atrium
Septum primum
forms to the right of the septum primum and fuses with the septum primum to form the atrial septum
Septum secundum
separates the right and left atria
atrial septum
forms between the free edge of the septum primum
Foramen primum
allowing a passage between the right and left atria
AV septum
foramen primum is closed by growth of the
septum primum
forms in the center of the septum primum
Foramen secundum
an oval opening in the septum secundum that provides a communication between the atria
Foramen ovale
The dorsal and ventral AV endocardial cushions fuse to form the
AV septum
AV septum partitions the AV canal into the
right and left AV canals
develops as outgrowth of muscular wall in the floor of the primitive ventricle and grows toward the AV septum but stops to create the IV foramen, leaving the septum incomplete
Muscular IV septum
Membranous IV septum forms by fusion of the
bulbar ridges with the endocardial cushion, the AP
septum, and the muscular part of the IV septum
The membranous IV septum closes the _____,
completing partition of the ventricles
IV foramen
It is characterized by right-to-left shunting of blood and cyanosis.
Tetralogy of Fallot
occurs when the AP septum fails to align properly with the AV septum, resulting in pulmonary stenosis (obstruction to right ventricular outflow), overriding aorta (dextroposition of aorta), interventricular septal defect , and hypertrophy of the right ventricle.
Tetralogy of Fallot
occurs when the AP septum fails to develop in a spiral fashion, causing the aorta to open into the right ventricle and the pulmonary trunk to open into the left ventricle.
It results in right-to-left shunting of blood and cyanosis
Transposition of the great vessels
is caused by abnormal development of the septum primum or secundum, resulting in a patent foramen ovale
Atrial septal defect (ASD)
A blood clot , which usually forms in the deep veins of the thigh or the leg, travels
to the right atrium, the left atrium through the atrial septal
defect, the left ventricle, the systemic circulation, and eventually to the brain, causing a stroke
occurs commonly in the membranous part of the IV septum because of failure of the membranous IV septum to develop, resulting in left-to-right shunting of blood through the IV foramen, which increases blood flow to the lungs and causes pulmonary hypertension
Ventricular septal defect (VSD)
The arterial system develops from the
aortic arches and branches of the dorsal aorta
Aortic arch 1 has no derivative because
it disappears soon after development
Aortic arch 2 has no derivative because
it persists only during the early development
Aortic arch 3 forms the
common carotid arteries and the proximal part of the internal carotid arteries
Aortic arch 4 forms the _____ on the left and _____ on the right
aortic arch on the left;
and the brachiocephalic artery and the proximal subclavian artery on the right
Aortic arch 6 forms the
proximal pulmonary arteries and ductus arteriosus
Form the intercostal, lumbar, vertebral, cervical, internal thoracic, and epigastric arteries, and arteries to
upper and lower limbs.
Posterolateral branches
Form the renal, suprarenal, and gonadal arteries.
Lateral branches
form the celiac (foregut), superior mesenteric (midgut), and inferior mesenteric (hindgut) arteries
Vitelline arteries
form a part of the internal iliac and superior vesical arteries
Umbilical arteries
The venous system develops from the
vitelline, umbilical, and cardinal veins
The venous system drain into the
venosus
Return poorly oxygenated blood from the yolk sac
Vitelline veins
Right (vitelline) vein forms the
hepatic veins and sinusoids, ductus venosus, hepatic portal, superior mesenteric, inferior mesenteric, and splenic veins and part of the IVC
Left (vitelline) vein forms the
hepatic veins and sinusoids and ductus venosus
Carry well-oxygenated blood from the placenta.
Umbilical veins
Right (umbilical) vein degenerates during
early development
Left (umbilical) vein forms the
ligamentum teres hepatis
Return poorly oxygenated blood from the body of the embryo
cardinal veins
Anterior cardinal vein forms the
internal jugular veins and SVC
Posterior cardinal vein forms
a part of the IVC and common iliac veins
Subcardinal vein forms
a part of the IVC, renal veins, and gonadal veins
Supracardinal vein forms
a part of the IVC, intercostal, azygos, and hemiazygos veins
the fetus has blood that is oxygenated in the
placenta rather than in the lungs
the fetus has_____ shunts that partially bypass the lungs and liver
three
Is an opening in the septum secundum.
Foramen ovale
Foramen ovale usually closes functionally at
birth, but with anatomic closure occurring later.
Foramen ovale shunts blood from the
right atrium to the left atrium, partially bypassing the lungs (pulmonary circulation).
Ductus arteriosus is derived from the ______ connects the bifurcation of the pulmonary trunk
sixth aortic arch
Closes functionally soon after birth, with anatomic closure requiring several weeks
Ductus arteriosus
Ductus arteriosus becomes the
ligamentum arteriosum
connects the left pulmonary artery (at its origin from the
pulmonary trunk) to the concavity of the arch of the aorta
ligamentum arteriosum
Ductus arteriosus shunts blood from the
pulmonary trunk to the aorta, partially bypassing the lungs (pulmonary circulation).
results from failure of the ductus arteriosus to close after birth. It is common in premature infants
Patent ductus arteriosus
Shunts oxygenated blood from the umbilical vein (returning from the placenta) to the IVC, partially
bypassing the liver (portal circulation).
Ductus venosus
Ductus venosus joins the left branch of the portal vein to the IVC and is obliterated to become the
ligamentum venosum after birth
Carry blood to the placenta for reoxygenation before birth.
Umbilical arteries
Umbilical arteries become what after birth
medial umbilical ligaments after birth, after their distal parts have atrophied
Carry highly oxygenated blood from the placenta to the fetus
Umbilical veins
Umbilical veins consists of the right vein, which is obliterated during the
embryonic period
Umbilical veins consists of the left vein, which is obliterated to form the
ligamentum teres hepatis after birth
Is a muscular tube that is continuous with the pharynx in the neck and enters the thorax behind the trachea
esophagus
length of esophagus
about 10 inches long
the 3 constrictions of the esophagus
one at the level of the sixth cervical vertebra, where it begins;
one at the crossing of the left main stem bronchus;
and one at the tenth thoracic vertebra, where it pierces the diaphragm.
The left atrium also presses against the
anterior surface of the esophagus
the esophagus has a physiologic sphincter, which is the circular layer of smooth muscle at the gastroesophageal junction aka ____ by clinicians
inferior esophageal sphincter
esophagus receives blood from
three branches of the aorta (the inferior thyroid, bronchial, and esophageal arteries)
and from the left gastric and inferior phrenic arteries
is a condition of impaired esophageal contractions because of failure of relaxation of the inferior esophageal sphincter, resulting from degeneration of myenteric (Auerbach’s) plexus in the esophagus
Achalasia of esophagus
is a systemic collagen vascular disease and has clinical features
of dysphagia for solids and liquids, severe heartburn, and esophageal stricture
Systemic sclerosis (scleroderma)
thoracic aorta begins
at the level of the fourth thoracic vertebra
thoracic aorta pathway
Descends on the left side of the vertebral column and then approaches the median plane to end in front
of the vertebral column by passing through the aortic hiatus of the diaphragm
thoracic aorta gives rise to
nine pairs of posterior intercostal arteries and one pair of subcostal arteries
The first two intercostal arteries arise from the
highest intercostal arteries of the costocervical trunk
The posterior intercostal artery gives rise to
a collateral branch, which runs along the upper border of the rib below the space
thoracic aorta also gives rise to
pericardial, bronchial (one right and two left), esophageal, mediastinal, and superior phrenic branches
occurs when the aorta is abnormally constricted just inferior to
the ductus arteriosus
Coarctation of the aorta
Is formed by the union of the right ascending lumbar and right subcostal veins. Its lower end is connected to the IVC.
Azygos (unpaired) vein
Azygos (unpaired) vein enters the thorax through the
aortic opening of the diaphragm
Azygos (unpaired) vein receives the
right intercostal veins, the right superior intercostal vein , and the hemiazygos and accessory hemiazygos veins.
Azygos (unpaired) vein arches over the root of the
right lung
Azygos (unpaired) vein empties into the
SVC, of which it is the first tributary
Is formed by the union of the left subcostal and ascending lumbar veins. Its lower end is connected to the left renal vein.
Hemiazygos vein
Hemiazygos vein ascends on the left side of the vertebral bodies behind the
thoracic aorta, receiving the ninth, tenth, and
eleventh posterior intercostal veins
Accessory hemiazygos vein pathway
Begins at the fourth or fifth intercostal space;
descends, receiving the fourth or fifth to eighth intercostal veins;
turns to the right; passes behind the aorta;
and terminates in the azygos vein
Is formed by a union of the second, third, and fourth posterior intercostal veins
Superior intercostal vein
Superior intercostal vein drains into the
azygos vein on the right and the brachiocephalic vein on the left
The first posterior intercostal vein on each side drains into the
corresponding brachiocephalic vein
The second, third, and often the fourth posterior intercostal vein joins to form the
superior intercostal vein
The rest of the veins drain into the
azygos vein on the right and into the hemiazygos or accessory hemiazygos veins on the left
Thoracic duct begins in the
abdomen at the cisterna chyli
is the dilated junction of the intestinal, lumbar, and
descending intercostal trunks
cisterna chyli
Thoracic duct drains the
lower limbs, pelvis, abdomen, left thorax, left upper limb, and left side of the head and neck
Thoracic duct passes through the
aortic opening of the diaphragm
Thoracic duct ascends through the
posterior mediastinum between the aorta and the azygos vein
Thoracic duct arches laterally over the
apex of the left pleura and between the left carotid sheath in front and the
vertebral artery behind
Thoracic duct runs behind the
left internal jugular vein
Thoracic duct empties into
the junction of the left internal jugular and subclavian veins.
Right lymphatic duct drains the
right sides of the thorax, upper limb, head, and neck
Right lymphatic duct empties into the
junction of the right internal jugular and subclavian veins
Is composed of motor, or efferent, nerves through which cardiac muscle, smooth muscle , and glands
are innervated
Autonomic Nervous System in the Thorax
thoracolumbar outflow
sympathetic
craniosacral outflow
parasympathetic
cholinergic fibers use ____ as neurotransmitter
acetylcholine
adrenergic fibers use _____ as the neurotransmitter
norepinephrine
fight-or-flight division; Enables the body to cope with crises or emergencies
Sympathetic nervous system
Sympathetic nervous system contains preganglionic cell bodies that are located in the lateral horn or intermediolateral cell column of the spinal cord segments between
T1 and L2
Sympathetic nervous system has _____ that pass through the white rami communicantes and enter the sympathetic chain ganglion, where they synapse
preganglionic fibers
Sympathetic nervous system has _____ that join each spinal nerve by way of the gray rami communicantes and supply the blood vessels, hair follicles (arrector pili muscles), and sweat glands.
postganglionic fibers
Sympathetic nervous system increases the
heart rate
Sympathetic nervous system dilates the
bronchial lumen and the coronary arteries
Is composed primarily of ascending and descending preganglionic sympathetic fibers and visceral
afferent fibers, and contains the cell bodies of the postganglionic sympathetic (GVE) fibers.
Sympathetic trunk
Sympathetic trunk descends in
front of the neck of the ribs and the posterior intercostal vessels
Sympathetic trunk contains the
cervicothoracic (or stellate) ganglion
cervicothoracic (or stellate) ganglion is formed by
fusion of the inferior cervical ganglion with the first thoracic ganglion
sympathetic trunk enters the abdomen through the
crus of the diaphragm or behind the medial lumbocostal arch
sympathetic trunk gives rise to
cardiac, pulmonary, mediastinal, and splanchnic branches
sympathetic trunk is connected to the thoracic spinal nerves by
gray and white rami communicantes
is an injection of local anesthetic near the stellate ganglion by placing the tip of the needle near the neck of the first rib. It produces a temporary interruption of sympathetic function such as in a patient with excess vasoconstriction in the upper limb.
Stellate block
Contain preganglionic sympathetic GVE (myelinated) fibers with cell bodies located in the lateral horn (intermediolateral cell column) of the spinal cord and GVA fibers with cell bodies located in the dorsal root ganglia.
White rami communicantes
Contain postganglionic sympathetic GVE (unmyelinated) fibers that supply the blood vessels, sweat glands, and arrector pili muscles of hair follicles
Gray rami communicantes
Gray rami communicantes are connected to every spinal nerve and contain fibers with cell bodies located in the
sympathetic trunk
Contain sympathetic preganglionic GVE fibers with cell bodies located in the lateral horn (intermediolateral cell column) of the spinal cord and GVA fibers with cell bodies located in the dorsal root ganglia
Thoracic splanchnic nerves
Arises usually from the fifth through ninth thoracic sympathetic ganglia, perforates the crus of the
diaphragm or occasionally passes through the aortic hiatus, and ends in the celiac ganglion
Greater splanchnic nerve
Is derived usually from the tenth and eleventh thoracic ganglia, pierces the crus of the diaphragm,
and ends in the aorticorenal ganglion.
Lesser splanchnic nerve
Is derived usually from the twelfth thoracic ganglion, pierces the crus of the diaphragm, and ends in
the ganglia of the renal plexus.
Least splanchnic nerve
Parasympathetic nervous system decreases the
heart rate
Parasympathetic nervous system constricts the
bronchial lumen
Parasympathetic nervous system causes
vasoconstriction of the arteries
Right vagus nerve gives rise to the
right recurrent laryngeal nerve
right recurrent laryngeal nerve hooks around the right subclavian artery and ascends into the neck between the
trachea and the esophagus
right vagus nerve pathway
Crosses anterior to the right subclavian artery, runs posterior to the SVC, and descends at the right
surface of the trachea and then posterior to the right main bronchus.
right vagus nerve forms the posterior vagal trunk (or gastric nerves) at the
lower part of the esophagus
right vagus nerve enters the abdomen through
the esophageal hiatus
left vagus nerve enters the thorax between the _____ and _____ and behind the _____
left common carotid and subclavian arteries;
left brachiocephalic vein
left vagus nerve descends on the
arch of the aorta
Left vagus nerve gives rise to the
left recurrent laryngeal nerve
hooks around the arch of the aorta to the left of
the ligamentum arteriosum
left recurrent laryngeal nerve
Left vagus nerve ascends through the superior mediastinum and the neck in a
groove between the trachea and esophagus
Left vagus nerve gives off the
thoracic cardiac branches
Left vagus nerve breaks up into the
pulmonary plexuses
Left vagus nerve continues into the
esophageal plexus
Left vagus nerve forms the
anterior vagal trunk
caused by a bronchogenic or esophageal carcinoma,
enlargement of mediastinal lymph nodes, or an aneurysm of the aortic arch, causing respiratory
obstruction, hoarseness, and an inability to speak because of paralysis of the vocal cord
Injury to the recurrent laryngeal nerve
is transection of the vagus nerves at the lower portion of the esophagus in an attempt to reduce gastric secretion in the treatment of peptic ulcer
vagotomy
increases heart rate, dilates coronary arteries, and thus increases blood flow through the vessels, supplying more oxygen and nutrients to the myocardium.
Sympathetic stimulation
Sympathetic nerve also produces
bronchodilation and vasoconstriction of pulmonary vessels
slows the heart rate, constricts the coronary arteries, produces bronchoconstriction (motor to smooth muscle) and vasodilation of the pulmonary vessels, and increases
glandular secretion of the bronchial tree (secretomotor).
Parasympathetic stimulation