Exam 2 Flashcards
The inner layer of the uterine wall is?
Endometrium
The fetal membranes include the?
Chorion, amnion, allantois, and umbilical vesicle
The placenta is a?
Fetomaternal organ
What are the placentas two components?
Fetal part and maternal part
The fetal part develops from where?
The chorionic sac (outermost fetal membrane)
The maternal part of placenta is derived from where?
The endometrium (inner layer of the uterine wall)
The endometrium of the uterus in a pregnant woman is the?
Decidua
Parturition is what?
Childbirth
The embryo/fetus and membranes together are called what?
The conceptus
Decidua enlarge to form what?
Decidual cells
What are the three regions of the decidua?
Decidua basalis, decidua capsularis, and decidua parietalis
The two parts of the placenta are held together by what?
Stem chorionic villi
The five principal activities of the placenta are what?
Metabolism (synthesis of glycogen, cholesterol and fatty acids), respiratory gas exchange, transfer of nutrients (vitamins, hormones, and antibodies), elimination of waste, and endocrine secretion (hCG) for maintenance of pregnancy
The common type of twins is what?
Dizygotic twins with two amnions, two chorions, and two placentas that may or may not be fused
Monozygotic twins commonly have what?
One chorion, two amnions, and one placenta
Twins with what are always monozygotic?
One amnion, one chorion, and one placenta
The umbilical vesicle and allantois are what type of structures?
Vestigial structures
What cells originate in the wall of the umbilical vesicle?
Primordial germ cells
The umbilical vesicle and allantois are both early sites of what?
Blood formation
What are the amniotic fluids three main functions?
A protective buffer, room for fetal movements, and fetal body temperature regulation
What regulates placental development that is expressed in the trophoblast and its blood vessels?
Homeobox genes (HLX and DLX3)
The decidua basalis forms the bushy area of the chorionic sac, the ________
Villous chorion or chorion frondosum
As the chorionic sac grows, the villi associated with the ___________ become compressed and soon degenerate.
Decidua capsularis
The avascular bare area produced after the decidua capsularis degenerates is called what?
The smooth chorion or chorion laeve
The fetal part of the placenta is formed by what?
Villous chorion or chorion frondosum
The maternal part of the placenta is formed by what?
Decidua basalis
The fetal part is attached to the maternal part of the placenta by what?
The cytotrophoblastic shell, the external layer of trophoblastic cells on the maternal surface of the placenta
Chorionic villi invade and erode decidua basalis thus producing wedge shaped areas of decidua called what?
Placental septa
Placental septa divide the fetal part of the placenta into irregular convex areas called what?
Cotyledons
Each cotyledon consists of what?
Two or more stem villi and many branch villi
By the end of the fourth month, the decidua basalis is almost entirely replaced by what?
Cotyledons (the fetal part of the placenta)
The decidua capsularis overlays what?
The chorionic sac or conceptus
After disappearance of decidua capsularis, smooth chorion fuses with what?
Decidua parietalis
What are the four layers of the placental membrane?
Syncytiotrophoblast, cytotrophoblast, connective tissue of the villi, and endothelium of fetal capillaries
Fetal hypoxia results primarily from what?
Factors that diminish either the uterine blood flow or the embryo/fetal blood flow
What important nutrients are transferred to the embryo/fetus?
Glucose by active diffusion, cholesterol, fatty acids, amino acids, and vitamins.
What are the steroid hormones synthesized by the placenta?
Progesterone and estrogen
The placenta takes over the production of progesterone from what?
The corpus luteum
Labor is what?
A sequence of involuntary uterine contractions which dilate the uterine cervix.
What are the three stages of labor?
Dilation of cervix, expulsion of fetus, placenta expulsion
Amniotic fluid has what critical functions for the fetus?
Acts as a barrier to infection, permits lung development, cushions embryo/fetus against injuries, enables fetus to move aiding muscle development, controls body temperature
The umbilical vesicle is important for what four reasons?
The transfer of nutrients, blood cell development, forms primordial gut from endoderm of umbilical vesicle, primordial germ cells in it migrate to form spermatogonia in males oogonia in females
The intraembryonic coelom becomes what during the fourth week?
The embryonic body cavity
What are the three cavities of the embryonic body cavity?
A Pericardial cavity, a peritoneal cavity, and two pericardioperitoneal cavities
The peritoneal cavity is connected with what and where at?
Is connected with the extraembryonic coelom at the umbilicus
A double layer of peritoneum is what?
Mesentery
The septum transversum is what?
A plate of mesodermal tissue
What are bronchial buds?
The primordia of bronchi and lungs
The primordial mediastinum consists of what?
A mass of mesenchyme that separates the lungs
What are myoblasts?
Primordial muscle cells
What separates the thoracic and abdominal cavities?
The diaphragm
What are the four embryonic components of the diaphragm?
Septum transversum, pleuroperitoneal membranes, dorsal mesentery of esophagus, muscular ingrowth from lateral body walls
The septum transversum composed of mesodermal tissue forms what?
The central tendon of diaphragm
The septum transversum separates what?
The heart from the liver
What fuses with the pleuroperitoneal membranes and also with the dorsal mesentery of the esophagus?
The septum transversum
What fuses with the septum transversum and also with the dorsal mesentery of the esophagus?
The pleuroperitoneal membranes
What develops from myoblasts that grow into the dorsal mesentery of the esophagus?
The crura of the diaphragm
The right and left parts of the ____________ merges to form the peritoneal cavity
Intraembryonic coelom
A birth defect (opening) in the ___________ on the left side becomes a CDH
Pleuroperitoneal membrane
The embryonic pericardial cavity communicates with the peritoneal cavity through what?
paired pericardioperitoneal canals
Fusion of the cranial pleuropericardial membranes with mesoderm ventral to the esophagus separates what?
The pericardial cavity from the pleural cavities
Fusion of the caudal pleuroperitoneal membranes during formation of the diaphragm separates what?
The pleural cavities from the peritoneal cavity
The parietal layer of mesoderm lining the peritoneal cavities become what?
The parietal peritoneum
The parietal layer of mesoderm lining the pleural cavities become what?
Parietal pleura
The parietal layer of mesoderm lining the pericardial cavities become what?
Serous pericardium
Splanchnic mesoderm surrounding the heart tube forms what?
The primordial myocardium
Mesenchymal cells derived from splanchnic mesoderm proliferate and form isolated cell clusters, which soon develop into two heart tubes that join to form what?
The primordial vascular system
What are the four chambers of the heart primordium?
The bulbous cordis, ventricle, atrium, and sinus venosus
The truncus arteriosus is the primordium of what?
The primordium of the ascending aorta and pulmonary trunk
What are the three systems of paired veins which drain into the primordial heart?
The vitelline system, the cardinal veins which form the caval system, and the umbilical veins
During the sixth to eight weeks, the pharyngeal arch arteries are transformed into the adult arterial arrangement of which arteries?
The carotid, the subclavian, and the pulmonary arteries
What do vitelline veins do?
Return poorly oxygenated blood from the umbilical vesicle
What do umbilical veins do?
Carry well-oxygenated blood from the chorionic sac to sinus venosus
What do cardinal veins do?
Return poorly oxygenated blood from the body of the embryo to the heart
The cardinal veins constitute what?
The main venous drainage system of the embryo
The superior vena cava forms from what?
The right anterior cardinal vein and right common cardinal vein
The endothelial tube becomes what?
Endocardium or internal endothelial lining of the heart
Epicardium is derived from what?
Mesothelial cells
Development of blood and blood vessels is what?
Angiogenesis
Hematopoiesis begins where?
The liver
