3-A Development of the Celomic Sacs and Mesenteries

Question 1

Describe general characteristics of a celomic sac

Answer 1

double walled (parietal/visceral walls), closed sacs enclosing a fluid-filled space

Question 2

What cells produce the water fluid in celomic sacs

Answer 2

the mesothelium that line the CT of the sac produce fluid

Question 3

Name the 4 adult celomic sacs

Answer 3

pericardial, right and left pleural, peritoneal

Question 4

Describe in general terms (overview) the formation of celom in the embryo

Answer 4

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

Question 5

Describe the mesodermal elements that contribute to formation of the intraembryonic celom

Answer 5

the lateral plate splits into two layers which will form the serous membranes,

Question 6

Explain how growth and folding of the of the embryo contribute to the formation of the gut

Answer 6

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

Question 7

Contrast the splanchnic mesoderm with the somato mesoderm

Answer 7

lines the surface v. lines the inside of the body wall (respectively)

Question 8

Describe the orinal position of the cardiogenic mass and how its position changes as a result of the embryo’s growth

Answer 8

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

Question 9

Describe the role of the cardiogenic mass in completing the single n shaped intraembryonic coelom

Answer 9

cavitation of the cardiogenic mass anterior to the gut tube connects thte bilateral celomic tubes

Question 10

Define mesentery

Answer 10

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)

Question 11

Which mesenteries are present in the adult?

Answer 11

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

Question 12

Explain how the intraembryonic coelom is partitioned into its pericarial pleural

Answer 12

first the partitioning of the pericardial sac is created by the fusing of the pleuropericardial folds

Question 13

Describe the two layers of the pericaridial sac

Answer 13

the parietal pericardium Is fibrous and the visceral pericardium (epicaridum) is thin and delicate on the surface of the heart

Question 14

Explain how the intraembryonic coelom is partitioned into its pleural and peritonial cavities

Answer 14

the formation of the diagphragm by 4 elements: spetum transversum, right and left pleuroperitoneal folds, esophageal mesentery and body wall myocytes

Question 15

Name the parts of the adult diaphragm

Answer 15

central tendon (septum transversum), muscular diaphragm (septum transversum, pleuroperitoneal folds and body wall myocytes) and right and left crura (esophageal mesentery)

Question 16

What event intiates the growth of the lungs?

Answer 16

tubular buds grow off the foregut and form the trachea, growing into the pleural sacs

Question 17

Visceral and parietal pleura are continuous at the _____ of the lung and the ____ of the heart

Answer 17

hilus of the lung and the great vessels of the heart

Question 18

What does adult somatic mesoderm line?

Answer 18

the body wall or fibrous pericardium

Question 19

What does the adult splanchnic mesoderm line?

Answer 19

visceral layers line the outside of the organs

Question 20

Where is the phrenic nerve found on dissection of the thorax (between which membranes)?

Answer 20

fibrous pericardium and mediastinal parietal pleura

Question 21

Do branches of the bronchus run with the pulmonary artery or pulmonary veins?

Answer 21

branches of the bronchus and pulmonary artery run together while branches of darker pulmonary veins have an independent course

Question 22

Which vagus nerve (left/right) crosses the arch of the aorta in its decent through the thorax

Answer 22

left Bonus: its recurrent laryngeal branch recurs around the arch of the aorta and past the ligamentum arteriosum

Question 23

Name the veins that accompany the coronary arteries

Answer 23

LAD and circumflex (great coronary vein); posterior inter ventricular artery (middle coronary vein); right marginal branch (small coronary vein)

Question 24

Pectinate muscles in the atria are analogous to which feature of the ventricle

Answer 24

trabeculae carneae

Question 25

The bodies cavities are derived first from _______ (early structure) which has formed from lateral plate mesoderm and a portion of the cardiogenic mass

Answer 25

intraembryonic celom

Question 26

The layer of mesoderm associated with the roof of the yolk sac (from epiblast that has replaced hypoblast) is called the _______ mesoderm

Answer 26

splanchnic

Question 27

The layer associated with the presumptive body wall/ectoderm is called ________ mesoderm

Answer 27

somatic

Question 28

The earliest space between somatic and splanchinic mesoderm is called?

Answer 28

intraembryonic celom

Question 29

Double layers of mesoderm that suspend between gut tube and apposing layers of mesoderm is called?

Answer 29

mesentery

Question 30

Pleuropericaridal folds form on either side of the embryo where the portions of the celom derived from ____ ____ mesoderm and cardiogenic mass fused

Answer 30

lateral plate mesoderm

Question 31

space between the epicaridum and the parietal pericardium is called the

Answer 31

pericardial cavity

Question 32

The ______ folds will separate the pleural portion of the celomic tube form the peritoneal parts

Answer 32

peluroperitoneal

Question 33

The mesentery of the abdominal ____gut and ____gut degenerates so that the two celomic tubes become continuous across the midline

Answer 33

mid and hind

Question 34

The small, tongue-like projection below the cardiac notch is the

Answer 34

lingula

Question 35

What is the surface projection of the oblique and horizontal fissures?

Answer 35

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

Question 36

Fluid can be removed from the pleural cavity at the costodiaphragmatic recess at the midaxillary line by in the ___ or____ intercostal space

Answer 36

8th or 9th

Question 37

Pain sensation to the parietal pleura is mediated by which nerves?

Answer 37

intercostal and phrenic nerves for the costal pleura and mediastinal/diaphragmatic respectively

Question 38

A common site of a chest tube is the ____ or ____ intercostal space at the midaxillary line.

Answer 38

5th or 6th

Question 39

Where does the aorta travel in relation to the trachea

Answer 39

it crosses anteriorly above the carina