Exam 1 Flashcards
fibrous pericardium
- most superficial layer of the pericardial sac
- made of strong fibrous CT
what is tamponade? how does it occur and what are the clinical manifestations/symptoms? when is one at risk?
pressure on the heart muscle
fibrous pericardial sac is non-distensible so effusion of fluid into the pericardial cavity results in tamponade
decreases venous return and cardiac output
manifests as Kussmaul’s sign (distension of neck veins during inspiration)
at risk 24-48 hrs after heart surgery from clots in chest tubes draining blood
can be treated by pericardiocentesis
parietal pericardium
- layer of serous pericaridal sac adherent to fibrous pericardium
visceral pericardium
- inner layer of the serous pericardial sac
epicardium
- visceral pericardium that touches the heart
- produces pericardial fluid
where are visceral and parietal pericardium continuous?
pulmonary veins, SVC, IVC, and great arteries
what are the two pericardial sinuses and where are they?
recesses of the pericardial cavity situated between vessels of the heart
- transverse pericardial sinus- posterior to ascending aorta and pulmonary trunk and anterior to SVC
- oblique sinus- inferior to pulmonary veins and left of the IVC (posterior to heart)
- neither are continuous
where does the right coronary artery course, what does it branch into, and what does it supply?
courses in the coronary sulcus and supplies the right atrium, right ventricle, and part of LBBB
branches into the nodal branch, marginal branch, and if dominant the posterior interventricular artery
coronary sulcus
divides the atria and ventricles
nodal branches of R coronary artery supplies?
SA and AV nodes
marginal branch of R coronary artery supplies?
Right ventricle
posterior interventricular artery/posterior descending (PDA) courses where and supplies what?
courses in the posterior interventricular sulcus and supplies the L and R ventricles, 1/3 of the posterior interventricular septum, and a branch to the AV node
where does the left coronary artery originate, what does it branch into and what does it supply?
it is a short artery that branches within 1 cm of its origin at the left aortic sinus
branches into the anterior interventricular artery/left anterior decending (LAD) and circumflex (LCX)
supplies L and R ventricles, 2/3 of interventricular septum (including AV bundle), L atrium, RBB and part of LBB
where does the LAD course and what does it supply?
courses in the anterior interventricular sulcus
supplies the R and L ventricles and 2/3 of the interventricular septum, including the AV bundle
where does the circumflex artery course and what does it supply?
courses in the coronary sulcus
supplies the L atrium and L ventricle
branches into the obtuse marginal artery
where do coronary artery anastomoses occur?
a. RCA anatomoses with circumflex of LCA after RCA gives rise to posterior interventricular artery
b. LAD hooks around apex to anastomose with posterior interventricular artery
where are common sites of coronary occulsion?
- proximal part of LAD
- RCA (proximal)
- circumflex branch of LCA
- Left main
where is pain referred to from the heart and how?
afferent pain fibers in heart enter at T1-T4 or T5 on the left side resulting in angina pectoris pain on the left side of the best and medial aspect of the upper arm and forearm (T1 dermatome)
which vessels enter the right atrium?
SVC and IVC as well as ostium of coronary sinus and openings of anterior cardiac veins
sinus venarum
smooth walled part of the R atrium which is remnant of sinus venosus
makes up the SA node and coronary sinus
crista terminalis
separates sinus venarum from part with pectinate muscles
looks like a thick portion of heart muscle in a crescent shape at the opening into the right auricle
origin of the pectinate muscles
pectinate muscles
parallel ridges in the rough-walled part of the atria of the heart (anterior wall and auricle)
fossa ovalis
in the interatrial septum of R atrium
remnant of foramen ovale
foramen ovale
in fetal life it permits oxygenated blood to bypass lungs by shunting blood from right to left atrium
tricuspid valve
separates the R atrium from the R ventricle in the right AV orifice
three leaflets (anterior, posterior, septal with anterior facing closest to you)
trabeculae carneae
rounded or irregular muscular columns which project from the inner surface of the right and left ventricles of the heart (rough-walled part)
conus arteriosis/infundibulum
conical pouch representing entrance from the right ventricle into the pulmonary artery and pulmonary trunk.
wall of the infundibulum is smooth
right papillary muscles
anterior/great, posterior, septal
when contracted prevents prolapse of tricuspid valve
septomarginal trabecula or moderator band
extends base of anterior papillary in R ventricle to interventricular septum and contains RBB of AV bundle
which valve separates the RV from the pulmonary trunk?
pulmonic semilunar valves
which part of the left atrium has pectinate muscles?
auricle (rough-walled)
which vessels empty into the left atrium?
the 4 pulmonary veins (2 to each lung)
mitral valve/bicuspid valve
closed by anteriomedial and posteriolateral leaflets
separate the L atrium and L ventricle
mitral valve stenosis
a. where can the heart sound be best heard
b. what heart changes occur
c. what happens in the lungs
d. what is a common complication
a. can be heart at left 5th intercostal space slightly medial to mid-clavicular line
b. as result the the left ventricle regurgitates into the left atrium causing its enlargement
c. if further progressive narrowing of the orifice occurs, blood builds up in left atrium causing pulmonary congestion in the lungs (pulmonary hypertension) and strain on the right side of the heart–>R ventricle hypertrophies
d. blood clots are common complication and if dislodged from the LV can enter systemic circulation–>carotid arteries–>brain–>stroke
aortic vestibule
smooth walled part of L ventricle to ascending aorta through aortic semilunar valve
aortic semilunar valve
right, left and posterior cusps
left papillary muscles
two: anterior and posterior with chordae tendineae attached to leaflets of mitral valve which contract during ventricular contraction
SA node
pacemaker (70 bpm)
in sinus venarum of right atrium near entrance of SVC
initiates wave of depolarization–>atria contract
AV node
in interatrial septum near right AV orifice
stimulated by depolarization of atria muscles
delays waveof depolarization from passing to ventricles until atria fully contract
rate of 50-60 bpm
AV bundle of His
passes into interventricular septum
divides into RBB and LBB
causes paillary muscles to contract
Purkinje fibers
spread depolarization to R and L ventricles
(the septomarginal trabecula/moderator band carries purkinje fibers from RBB to base of anterior papillary muscle)
what occurs with an AV block?
conduction is slowed through the AV node or is not transmitted
complete AV block: contraction of atria and ventricles dissociated and chambers beat independently
atria may continue to contract about 70 bpm and pacemaker may develop in the AV bundle distal to site of block so that contraction of ventrcles occurs at rate of 30-40 bpm
coronary sinus
largest venous channel of the heart
located in the coronary sulcus and passes to the posterior surface of the heart, just below IVC
the major veins of the heart empty into the coronary sinus which inturn empties directly into the right atrium
great cardiac vein
runs from apex superiorly along anterior interventricular sulcus and veers left to empty into coronary sinus
middle cardiac vein
travels with the posterior interventricular artery in the posterior interventricular sulcus
small cardiac vein
drains blood from posterior and lateral R ventricle
runs along the margin of the heart (coronary sulcus) with the marginal branch of the right coronary artery
will meet up posteriorly with great cardiac vein to coronary sinus
anterior cardiac veins
drain blood directly from anterior R ventricle to R atrium
where does the heart get its parasympathetic innervation?
preganglionic parasympathetic axons from vagus nerve synpase in terminal ganglia
then postganglionic parasympathetic axons from terminal ganglia in cardiac plexus synpase in SA node, AV node, and walls of coronary arteries
where does the heart get its sympathetic innervation?
postganglionic sympathetic axons from cervical and upper thoracic splanchnic nerves (which have cell bodies in superior, middle, and infervior cervical paravertebral ganglia and in the T1-T5 paravertebral ganglia) synpase in SA and AV nodes and walls of coronary arteries
how are the cardiac plexus sensory fibers carried back to the CNS?
a. sensory fibers innervate varoreceptors and chemoreceptors in the heart and aortic arch which course back to CNS with vagus nerve
b. pain sensations are carried back with synpathetic nerves and enter CNS from T1-T5 (which is why pain is reffered to T1-T5 dermatomes ex. angina pectoris)
what are the heart sounds and what do they correspond to?
cuased by acceleration/deceleration of blood flowing through valve
S1: closing of mitral/tricuspid valve (beginning of systole)
S2: closing of aortic/pulmonary valve (end of systold and beginning of diastole)
where do you put the stethoscope to best hear the heart sounds?
- Aortic region (between the 2nd and 3rd intercostal spaces at the right sternal border) (RUSB – right upper sternal border)
- Pulmonic region (between the 2nd and 3rd intercostal spaces at the left sternal border) (LUSB – left upper sternal border)
- Tricuspid region (between the 3rd, 4th, 5th, and 6th intercostal spaces at the left sternal border) (LLSB – left lower sternal border)
- Mitral region (near the apex of the heard between the 5th and 6th intercostal spaces in the mid-clavicular line) (apex of the heart)
what are the structures of the foregut?
lower esophagus, spleen (mesodermal derivative), liver, gallbladder, biliary ducts, stomach, pancreas, prox 1/2 of duodenum
which artery supplies the foregut?
celiac artery
where does the celiac artery originate from and branch into?
branches from abdominal aorta just inferior to aortic hiatus of diaphragm
in 1 cm it divides into the
a. splenic artery
b. left gastric artery
c. common hepatic artery
what does the splenic artery supply? (include branches)
- spleen
- neck, body, tail of pandreas
- left side of greater curvature of stomach (by left gastroepipolic/omental artery)
- fundus of stomach (by short gastric arteries)
what does the left gastric artery supply?
- most of lesser curvature of stomach
- abdominal part of esophagus
which artery is subject to erosion by ulcer in the lesser curvature of the stomach?
left gastric artery
what does the common hepatic artery branch into?
- proper hepatic artery
- gastroduodenal artery
what does the proper hepatic artery supply? (include branches)
- lesser curvature of stomach (R gastric artery)
- liver (R and L hepatic arteries)
- gallbladder (cystic artery, off of the R hepatic artery)
what does the gastroduodenal artery supply? (include branches)
- foregut part of duodenum
- superior head of pandreas (by anterior and posterior superior pancreaticoduodenal arteries)
- right side of greater curvative (R gastroepiploic/omental artery)
which artery is subject to erosion by ulcer of duodenum?
gastroduodenal artery from the common hepatic
peritoneal
generally mobile, suspended by mesentery
which structures are peritoneal?
stomach, first 1/3 of duodenum (1st part), jejunum, ileum, cecum, appendix, transverse colon, sigmoid colon, superior rectum, liver, spleen, tail of pancreas
secondarily retroperitoneal
in fetal life suspended by mesentery, but lost in development
which structures are secondarily retroperitoneal?
distal duodenum inferior to entrance of bile duct (2nd-4th parts), ascending colon, descending colon, head/neck/body of pancreas
“PADD” (pancreas, ascending, descending, duodenum)
primarily retroperitoneal
were never suspended by mesentary
which structures are primarily retroperitoneal?
kidneys, adrenal glands, ureter, bladder, aorta, IVC, esophagus (thoracic) and rectum
which structures are retroperitoneal?
SAD PUCKER
supradrenal glands, aorta/IVC, duodenum (second and third segments), pandreas (except tail), ureters, colon (only ascending and descending), kidneys, esophagus, rectum
which ligaments suspend the spleen?
gastrosplenic and splenorenal ligaments
which arteries and veins supply/drain blood from spleen?
Splenic artery reaches spleen by coursing posterior to stomach and superior to pancreas (very kinked)
Drained by splenic vein which is posterior to body and tail of pancreas
what are the functions of the liver?
exocrine gland: produces and secretes bile into the biliary duct system
endocrine gland: plasma proteins, release of glucose/lipoproteins
processes nutrients, regulates glucose, detoxifies drugs/toxins, stores triglycerides and vitamin A
which ligaments suspend the liver?
falciform ligament (ends inferiorly at umbilicus), coronary ligament, and lesser omentum (lesser curvature of stomach to liver)
round ligament of uterus/ligamentum teres hepatis
at inferior end of falciform ligament
remnant of fetal umbilical vein
what are the four anatomic lobes of the liver and what separetes?
- left 2. right 3. quadrate 4. caudate
falciform ligament and ligamentum venosum (remnant of fetal ductus venosus) separate anatomic left and right
what are the two functional lobes of the liver and what do they include?
- func left: left lobe, quadrate, and caudate
- func right: right and part of caudate
contain separate arterial blood, venous drainage, and biliary drainage
separated by interconnecting gallbladder and IVC
what is contained in the porta hepatis and where is it located?
portal triad= hepatic ducts, portain vein (70% of blood) and proper heptic (30%)
in the hepatoduodenal ligament
what drains the liver and into what?
hepatic veins into IVC
what is the function of the gallbladder?
stores and releases bile produced by the liver in response to CCK in presence of fats
what artery supplies the gallbladdeR?
cystic artery (branch of R hepatic artery)
what is the path of bile from the liver?
R and L common hepatic ducts–>common hepatic duct+cystic duct–>bile duct–>posterior to duodenum and through head of pancreas–>joins with main pancreatic duct–>hepatopancreatic ampulla–>enters second part of duodenal papilla
what suspends the stomach?
greater and lesser omentum
which ligaments are associated with the lesser omentum?
extends from lesser curvature to liver
hepatoduodenal ligament and hepatogastric ligament
omental bursa/lesser peritoneal cavity
posterior to lesser omentum and stomach
epiploic foramen
bounded anteriorly by hepatoduodenal ligament, posteriorly by IVC, superiorly by caudate lobe of liver, inferiorly by duodenum
communicates lesser and greater peritoneal cavity
which ligaments are assocaited with greater omentum?
extends from greater curvature to encircle the spleen and reflect back to dorsal wall
gastrocolic ligament extends from greater curvature to transvere colon
splenorenal ligament extends from spleen to dorsal body wall
what are the functions of the pancreas?
endocrine: glucagon, insulin, somatostatin, pancreatic polypeptides
what suspends the pancreas?
only tail is peritoneal, located in splenorenal ligament
what supplies/drains the pancreas?
head has uncinate process which is enclosed by the duodenum and supplied by pancreatoduodenal branches of the gastroduodenal and SMA
splenic vein and SMV join to form portal vein posterior to neck
SMV and SMA pass porterior to neck and anterior to uncinate process
Innervations of the foregut
- parasympathetic: vagus nerves, in terminal ganglia
- sympathetic: pregangiolic sympathetic axons in lower thoracic splanchnic nerves (greater splanchnic nerves)from T5-T9 and celiac ganglia
- visceral pain fibers back in greater splanchnic nerves
- sensations that are not pain carried back in vagus nerves
what structures are contained in the midgut?
distal duodenum inferior to entrance of bile duct, jejunum, ileum, cecum , appendix, ascending colon, prox 2/3 of transverse colon
what main artery supplies the midgut?
superior mesenteric artery
leaves aorta 1 inch below celiac artery (can trace middle colic supplying the transverse back to SMA)
what are the branches of the SMA and what do they supply?
- anterior and posterior inferior pancreaticoduodenal branches–>midgut part of duodenum and inferior head and uncinate process of pancreas
- intestinal branches–>jejunum and ileum (arcades and vasa rectas)
- ileocolic–>distal ileum, appendix (appendicular artery), cecum, prox ascending colon
R colic–>ascending colon
Middle colic–>prox 2/3 of transverse colon
what are the parts of the duodenum? which parts are peritoneal/retroperitoneal? which part are supplied by which arteries?
- from pylorus to superior duodenal flexure (only part that is peritoneal): foregut, supplied by the celiac trunk
- descending part: inferiorly to L3
- horizontal part: R to L anteror to body of L3 and corssed anteriorly by SMA and SMV
- ascending part: superiorly left of L3 to left of L2 (at duodenojejunal junction)
parts 2-4 are midgut, supplied by SMA, and enclose head of pancreas
where does the pancreatic duct enter the duodenum?
through the major duodenal papilla (known as Ampulla of Vater) at second part of duodenum
represents junction between the embryological foregut and midgut lies just below the major duodenal papilla
ligament of Treitz
suspensatory ligament at duodenojejunal junction (contains muscle from R cruz of diaphragm)
jejunum begins left of L2
how can you tell the difference between the jejunum and ileum?
jejunum has simple arcades and long vasa recta, also thicker walls, larger luminal diameter, more prominent plica circulares, greater vascularity
ileum has complex/branched arcades and short vasa cecta, also more fat in mesentary and contains Peyer’s patches in wall
which parts of the colon are in the midgut?
cecum, ascending colon, proximal 2/3 of transverse colon
what are characteristics of the colon?
- larger luminal diameter than SI
- taeniae coli
- haustrations or sacculations
- omental appendices
teniae coli
3 independent longitudinal bands of smooth muscle from appendiz to sigmoid colon/rectal junction
haustrations/sacculations
form because teniae coli are shorter than total length of colon
omental appendices
globules of fat covered by peritoneum suspended from teniae coli
where is the appendix located? what suspends the appendix? what supplies the appendix?
inferior to iliocecal opening
peritomeal, suspended by mesoappendix
supplied by appendicular artery (branch of ileocolic)
what is appendicitis and how/where does it present?
result of obstruction by stool–>fecalith (adults) or hyperplasia of lymphatic tissue (children)
pain is referred by the lower splanchnic to umbilical
McBurney’s point: 1/3 distance from ASIS to umbilicus in the lower right quad
where is the ascenidng colon? what is it fused to? what supplies it?
extends to R colic/hepatic flexure to the transverse colon
it is fused to the R posterior abdominal wall
supplied by R colic artery and middle colic artery
what suspends the transverse colon? what supplies the transverse colon of the mid-gut?
posterior greater omentum
middle colic artery
where does the mid-gut get its parasympathetic innervation?
from preganglionic presympathetic axons in the vagus and neurons in the terminal ganglia
where does the mid-gut get its sympathetic innervation from?
lower thoracic splanchnic nerves (greater, lesser, and least) from T5-T 12 and neurons in celiac and superior mesentery ganglia
where is pain in the mid-gut referred (SI versus colon) and how (aka through which spinal nerves)?
visceral pain fibers go through the lower splanchnic back to the CNS
from from SI is referred through T5 to 10 dermatomes in the epigastric and umbilical region
from cecum, appendix, AC, 2/3 of TC referred through T10-T12 to umbilical, hypogastric, and lumbar region
how do visceral sensations other than pain get back to CNs from the mid-gut?
vagus nerves
what are the structures of the hind-gut?
distal 1/3 of transverse colon, descending colon, sigmoid colon, rectum, anal canal
which structures of the hind-gut are peritoneal or retroperitoneal?
sigmoid and distal 1/3 of transverse colon are peritoneal, descending colon and upper rectum are secondarily retroperitoneal, lower rectum and anal canal are primarily retroperitoneal
what artery supplies the hind-gut and where does it originate?
inferior mesenteric artery , which leaves aorta 4 cm above bifurcation into the common iliac arteries
why is the splenic flexure a common site for ischemic bowel infarction?
distal parts of the vascular beds of the middle colic branches of the SMA and the left colic branches of the IMA anastomose here
what are the branches of the IMA and what do they supply?
- left colic artery–>descending colon and dital 1/3 of transvere colon
- sigmoid arteries–>sigmoid colon
- superior rectal artery–>rectum and anal canal to pectinate line
(middle rectal artery of internal iliac–>rectum and anal canal above pectinate line)
where is the descending colon located?
from transverse colon at splenic flexure to the left iliac fossa
where is the sigmoid colon located and what suspends it?
iliac fossa to rectum at S3 vertebra
suspended by sigmoid mesocolon
what is different about rectum from the rest of the colon?
end of teniae coli, haustrations, omental appendices
ampulla of rectum
inferior aspect of rectum is dilated to store feces
where does the hind-gut get its parasympathetic innervation from?
pregangionic axons in pelvic splanchnic nerves from sacral spinal (S2-S4) and terminal ganglia
where does the hind-gut get its sympathetic innervations from?
lower thoracic and lumbar splanchnic from T11-L2 and neurons in the inferior mesenteric ganglia
how do pain sensations from the hind-gut reach the CNS and where are they referred to, and how?
visceral pain to the lower thoracic and lumbar splanchnic from T11-L2 and referred to hypogastric and iliac regions
how do sensations other than visceral pain get to CNS from hind-gut?
pelvic splanchnic nerves
Which nerves are sympathetic, post-ganglionic splanchnics and what is their path of innervation?
cardiopulmonary splanchnics
presynaptic fibers from upper thoracic vertebral levels–>sympathetic paravertebral ganglia via white rami–>synapse in upper thoracic and lower cervical ganglia–>immediately exit both ganglia and sympathetic chain directy to thoracic viscera
do not re-enter spinal nerve (no grey rami) and don’t travel up and down sympathetic chain
Which nerves are sympathetic, preganglionic splanchnics and what is their path of innervation?
greater, lesser, and least thoracic splanchnic nerves, lumbar splanchnic nerves, sacral splanchnic nerves
fibers originally enter sympathetic chain via white rami but don’t synpase in paravertebral ganglia–>prevertebral ganglia in the abdomen or pelvis where they will synapse
what does the greater splanchnic orginate and what is its destination?
T5-T9–>celiac ganglia
what does the lesser splanchnic orginate and what is its destination?
T10-T11–>superior mesenteric ganglia
what does the least splanchnic orginate and what is its destination?
T12–>aorticorenal ganglia
where is the destination of the lumbar splanchnic nerve?
inferior mesenteric ganglia
what is the destination of the sacral splanchnic nerve?
hypogastric plexus
what are the parasympathetic, preganglionic splanchnic nerves and what is their path of innervation?
S2-S4 directly to intrinisic ganglia of descending colon, sigmoid colon, rectum, pelvic viscera
should also include the vagus nerve (brain stem–>thoracic viscera, foregut, midgut)
what is the main venous drainage ssytem of the gastrointestinal structures below the diaphragm?
hepatic portal system (hepatic portal vein)
where is the hepatic portal vein formed? what drains into it?
formed posterior to the neck of the pancreas when the SMV unites with the splenic vein
normally the IMV drains intot he splenic vein, but can drain into the SMV or all 3 may merge at a single point
what drains the foregut?
splenic vein
what drains the midgut?
SMV
what drains the hind-gut?
IMV, which usually empties into the splenic vein
which veins empty directly into the portal vein other than the splenic and SMV (perhaps IMV)?
left and right gastric veins which drain the stomach including the lesser curvature and abdominal part of the esophagus
hepatic veins
NOT the same as the hepatic portal vein
drain blood from hepatic sinusoids and empty into the IVC just below the diaphragm
how do portal-systemic anastomoses occur?
in cirrhosis of the liver, obstruction of the portal vein and hypertension in the portal system occur which causes retrograde flow of portal venous blood from GI strctures entering the liver
retrograde flow forces portal venous blood into capillary beds which also drain into tributaries of the superior or inferior vena cava and here portacaval anastomoses are established to bypass the liver
what are the sites of portacaval anastomosis?
- esophageal varices: wall of esophagus at junction of capillary bed draining into the left gastric/coronary vein and esophageal tributaries of azygos vein
- wall of rectum at junction of internal rectal plexus (drains into rectal veins) and external rectal plexus (middle/inferior rectal veins)–>internal hemorrhoids
- anterior abdominal wall at junction of capillary beds draining into para-umbilical veins (course in falciform ligament) and tributaries of superficial epigastric veins (drain anterior abdominal wall)–>caput medusa: varicose superficial epigastric veins radiating from umbilicus
Names the veins
what are the parts of the mediastinum and what are the boundaries?
- Superior (between first thoracic vertebra and first rib and between sternal angle and intervertebral disc between T4 and T5) 2. Middle 3. Posterior (above the sternal angle and between the pericardium, vertebral column, and diaphragm) 4. Anterior
what structures does the superior mediastinum include?
trachea, brachiocephalic vein, thymus, aortic arch, esophagus, thoracic duct
what structures does the middle mediastinum contain?
heart, ascending aorta, pulmonary trunk, pulmonary veins, phrenic nerve
what structures does the posterior mediastinum contain?
esophagus with vagus nerves, descending aorta, thoracic duct, sympathetic trunks
what structures does the anterior mediastinum contain?
smaller vessels and nerves, fat and connective tissue, thymus in child or remnant of thymus
what are the layers of the superior mediastinum?
endocrine, venous, arterial, respiratory, digestive
what is contained in the endocrine layer of the superior mediastinum?
contains thymus in children or remants of thymus in adults (will extend inferiorly into the anterior mediastinum in children)
what is contained in the venous layer of the superior mediastinum?
SVC (descends on right side and drains into RA)
left and right brachiocephalic veins
where are the brachiocephlic veins formed?
- formed posterior to a sternoclavicular joint by union of an internal jugular vein and subclavian vein
what is the pathway of the brachiocephalic vein and where does it receive from?
- left brachiocephalic vein crosses the midline behind the thymus or remnants and recieves interior thyroid veins and the left superior intercostal vein
what is contained in the arterial layer of the superior mediastinum?
arch of the aorta and its 3 branches
what are the 3 branches of the aorta and what do they divide into?
brachiocephalic, left common carotid, left subclavian
the brachiocephalic artery divides into the right common carotid and the right subclavian
ligamentum arteriosum
remnant of the fetal ductus arteriosus between the left pulmonary artery and arch of the aorta
ductus arteriosus
in fetal life, shunts blood from the pulmonary trunk directly into the arch of the aorta to bypass the lungs (oxygenated blood comes from the mother via placenta)
what is contained in the respiratory layer of the superior mediastinum?
trachea (bifurcates at sternal angle to L and R main bronchi)
which vessels cross over the left and right main bronchi?
arch of aorta passes over left main bronchus and azygos vein passes over the right main bronchus
if the trachea is seen in a cross-section image, which area must the cross-section be through? what main structure of the mediastinum will not be present?
the neck of the superior mediastinum
the heart will not be seen since it lies in themiddle mediastinum interior to the trachea bifurcation
what is contained in the digestive layer of the superior mediastinum?
esophagus, thoracic duct, left and right vagus nerves, left recurrent laryngeal nerve, left and right phrenic nerves
what indents/constricts the esophagus?
indented on the left by arch of aorta and indented anteriorly by left main bronchus
also, origin of esophagus at neck and at esophageal hiatus of diaphragm
what is the course of the thoracic duct?
arises from the cisterna chyli below the diaphragm and courses therough the posterior and superior mediastinum posterior to esophagus
terminates in the root of the neck on the left at the origin of the left brachiocephalic vein (at junction of the left subclavian and left internal jugular vein) to drain lymph