3-A Development of the Celomic Sacs and Mesenteries Flashcards
Describe general characteristics of a celomic sac
double walled (parietal/visceral walls), closed sacs enclosing a fluid-filled space
What cells produce the water fluid in celomic sacs
the mesothelium that line the CT of the sac produce fluid
Name the 4 adult celomic sacs
pericardial, right and left pleural, peritoneal
Describe in general terms (overview) the formation of celom in the embryo
start with a trilaminar disk, fold the disc dosoventrally forming a cylindrical embryo with a midline gut and R/L celomic tubes that are later divided
Describe the mesodermal elements that contribute to formation of the intraembryonic celom
the lateral plate splits into two layers which will form the serous membranes,
Explain how growth and folding of the of the embryo contribute to the formation of the gut
the aminotic cavity folds around the embryo causing formation of the gut tube and two lateral pockets of the lateral plate, the right and left intraembryonic celomic tubes
Contrast the splanchnic mesoderm with the somato mesoderm
lines the surface v. lines the inside of the body wall (respectively)
Describe the orinal position of the cardiogenic mass and how its position changes as a result of the embryo’s growth
craniocaudal folding causes the position of the cardiogenic mass to move from the forhead to the center of the future chest, anterior to the foregut due to differential growth
Describe the role of the cardiogenic mass in completing the single n shaped intraembryonic coelom
cavitation of the cardiogenic mass anterior to the gut tube connects thte bilateral celomic tubes
Define mesentery
two layers of serous membranes which suspend organs from the body wall: dorsal mesentery between gut tube and dorsal body wall and ventral mesentery between gut tube and ventral body wall (during development, mesenteries will persist if they are functional)
Which mesenteries are present in the adult?
in the foregut, both the dorsal and ventral mesentary persist as the lever develops between the gut tube and the ventral body wall and in the hindgut only the ventral mesentery persists and a single peritoneal cavity is formed
Explain how the intraembryonic coelom is partitioned into its pericarial pleural
first the partitioning of the pericardial sac is created by the fusing of the pleuropericardial folds
Describe the two layers of the pericaridial sac
the parietal pericardium Is fibrous and the visceral pericardium (epicaridum) is thin and delicate on the surface of the heart
Explain how the intraembryonic coelom is partitioned into its pleural and peritonial cavities
the formation of the diagphragm by 4 elements: spetum transversum, right and left pleuroperitoneal folds, esophageal mesentery and body wall myocytes
Name the parts of the adult diaphragm
central tendon (septum transversum), muscular diaphragm (septum transversum, pleuroperitoneal folds and body wall myocytes) and right and left crura (esophageal mesentery)
What event intiates the growth of the lungs?
tubular buds grow off the foregut and form the trachea, growing into the pleural sacs
Visceral and parietal pleura are continuous at the _____ of the lung and the ____ of the heart
hilus of the lung and the great vessels of the heart
What does adult somatic mesoderm line?
the body wall or fibrous pericardium
What does the adult splanchnic mesoderm line?
visceral layers line the outside of the organs
Where is the phrenic nerve found on dissection of the thorax (between which membranes)?
fibrous pericardium and mediastinal parietal pleura
Do branches of the bronchus run with the pulmonary artery or pulmonary veins?
branches of the bronchus and pulmonary artery run together while branches of darker pulmonary veins have an independent course
Which vagus nerve (left/right) crosses the arch of the aorta in its decent through the thorax
left Bonus: its recurrent laryngeal branch recurs around the arch of the aorta and past the ligamentum arteriosum
Name the veins that accompany the coronary arteries
LAD and circumflex (great coronary vein); posterior inter ventricular artery (middle coronary vein); right marginal branch (small coronary vein)
Pectinate muscles in the atria are analogous to which feature of the ventricle
trabeculae carneae
The bodies cavities are derived first from _______ (early structure) which has formed from lateral plate mesoderm and a portion of the cardiogenic mass
intraembryonic celom
The layer of mesoderm associated with the roof of the yolk sac (from epiblast that has replaced hypoblast) is called the _______ mesoderm
splanchnic
The layer associated with the presumptive body wall/ectoderm is called ________ mesoderm
somatic
The earliest space between somatic and splanchinic mesoderm is called?
intraembryonic celom
Double layers of mesoderm that suspend between gut tube and apposing layers of mesoderm is called?
mesentery
Pleuropericaridal folds form on either side of the embryo where the portions of the celom derived from ____ ____ mesoderm and cardiogenic mass fused
lateral plate mesoderm
space between the epicaridum and the parietal pericardium is called the
pericardial cavity
The ______ folds will separate the pleural portion of the celomic tube form the peritoneal parts
peluroperitoneal
The mesentery of the abdominal ____gut and ____gut degenerates so that the two celomic tubes become continuous across the midline
mid and hind
The small, tongue-like projection below the cardiac notch is the
lingula
What is the surface projection of the oblique and horizontal fissures?
during exhalation the oblique/major fissure of both lungs follow the 5th intercostal spaces, in the right lung, the horizontal/minor fissure runs from the right 4th constochondral junction to the right 5th intercostal space
Fluid can be removed from the pleural cavity at the costodiaphragmatic recess at the midaxillary line by in the ___ or____ intercostal space
8th or 9th
Pain sensation to the parietal pleura is mediated by which nerves?
intercostal and phrenic nerves for the costal pleura and mediastinal/diaphragmatic respectively
A common site of a chest tube is the ____ or ____ intercostal space at the midaxillary line.
5th or 6th
Where does the aorta travel in relation to the trachea
it crosses anteriorly above the carina
