From Embryology

ANAT2341 Embrology

Progressive Assessment

Lab 1 Questions

1. What is the zona pellucida protein that binds spermatozoa to the oocyte surface?

A: ZP3 glocoprotein allows binding of zona pellucida to spermatozoa. Zona pellucida is a glycoprotein membrane surronding the plamsa membrane of an oocyte. In addition, there are three major types of glycoprotein of zona pellucida. Such as ZP1, ZP2 and ZP3. ZP3 is responsible for sperm binding, adhering to proteins on the sperm plasma membrane.

Zona pellucida

2. Name the 3 main stages of follicle development in the ovary?

A: There are 3 main stages of follicle development in the ovary. These stages are primodial follicle stage, pre-antral/primary follicle stage, and antral/secondary follicle stage. In addition, there is stage after antral/secondary follicle stage, which is Graffian follicle stage, or mature cell.

follicle development

Lab 2 Questions

1. What factor do the synctiotrophoblast secrete to support the ongoing pregnancy?

A: Syntiotrophoblast secrete Human Chorionic Gonadotropin to support the ongoing pregnancy. In addition, Human Chorionic Gonadotropin is a peptide hormone produced in pregnancy, which is made by the embryo soon after conception and later by synctiotrophoblast. Its main role is to prevent the disintegration of the copus luteum of the ovary and therefore maintain progesterone production which is critical for a pregnancy in humans.


2. What does the corpus luteum secrete to prevent continuation of the menstrual cycle?

A: Corpus luteum secretes estrogens and progesterone to prevent continuation of the menstrual cycle. In addition, estrogens and progesterone are steroid hormones responsible for the thickening of the endometrium and its development as well as maintenance.

Corpus Luteum

3. What are the 2 main issues to be derived from the germ cell layer continuous with the lining of the amniotic sac?

A: There are 2 main issues derived from the germ cell layer continuous with the lining of the amniotic sac. These issues are ectoderm which forms the nervous tissue, and epithelium of epidermis.

Lab 3 Questions

1. What period of human development (in weeks) do the 23 Carnegie stages over?

A: Appoximately 8 to 9 weeks.

2. What part of the somite will contribute to the vertebral column?

A: Sclerotome of somite contributes to the formation of axial vertebral column.

Somite in Vertebral Column

3. At what Carnegie stage does the human neural tube normally completely close?

A: Human neural tube normally completely close at Carnegie stage 13(appox.4 weeks).

Lab 4 Questions

1. Into what structure do most blood vessels empty before they enter the embryonic heart?

A: sinus venosus. Sinus venosus is a cavity into which all major embryonic paired veins supply/empty(Lecture7,2009 Dr.Hill,UNSW Embryology)

2. What do the dorsal aortas become in the adult?

A: descending aorta. The right and left dorsal aortas develop in parallel with the heart and gain access to it via the aortic arches. Eventually, the paired dorsal aorta will unite and form the unpaired descending aorta in adult.

Vessels of Dorsal Aorta

3. What are the layers of cells found in a tertiary villi?

A: layers of cells of tertiary villi are cytotrophoblast cells, extra-embryonic mesoderm, and cells that line the blood capillaries. Tertiary Villi - cytotrophoblast + extraembryonic mesoderm+ blood vessels (Lecture 4,2009 Dr.Hill,UNSW Embryology)

Lab 5 Questions

1. What was the question i said in the respiratory lecture would be part of this week's assessment?

A: The question is "What is Congenital diaphragmatic hernia and how does it affect the fetal lungs?

2: What is the answer to the above question?

A: Congenital diaphragmatic hernia is the absence of diaphragm, or a hole in the diaphragm.This can occur on either left or right side, but is most common on the left. In addition, diaphragm is the breathing muscle that separates the chest cavity and the abdominal cavity. This condition will have a significant effect on development of fetal lung, as it will cause lung deformity or deficiency. More specifically, the contents of the abdomen, including stomach, intestines, liver and spleen may go through the hole in the diaphragm into the chest. The contents prevent the normal development of the lung on that side, and may affect the growth of the other lung. As a result, after birth the infant will have difficulty breathing if the lung is not developed enough.


Lab 6 Question

1. What is more common clefting, cleft lip or cleft palate?

A: Cleft lip is more common in infant than cleft palate.

Cleft Lip/Palate

2. What structures does pharyngeal pouch 1 form?

A: The following structures are generated from pharyngeal pouch 1: tympanic cavity, tympanic membrane, mastoid antrum and auditory tube.

3. Neural crest forms which cells within the skin?

A: Neural crest forms melanocytes within the skin.

Neural crest progenitors of the melanocyte

Lab 7 Questions

1. Briefly what is a myotube and how is it formed?

A: Myotube is a multinucleated and undifferentiated contractile apparatus. Myotube is formed by fusion of myoblast during skeletal muscle development.

Myotube formation

2. What changes would i expect to see in the muscle fibre types in my leg if i:

a) suffered a spinal cord injury;

A: Muscle fibre transformation will occur if an individual suffered a spinal cord injury. Slow twitch muscle fibre will be lost. In addition, fast twitch muscle fibre will be the predominant muscle fibre.

b)Took up marathon running;

A: if one took up marathon running, he/she will utilise slow twitch muscle fibres. As this type of muscle fibre are more efficient at using oxygen to generate more fuel, ie. ATP, for continuous, extended muscle contraction over a long period of time. Slow twitch muscle fibre fire more slowly than fast twitch fibres and can go for a long time before they fatigue.


Lab 8 Questions

This week's task is assessing peer group project. Evaluations of the group project can be found on students discussion page.

Lab 9 Questions

We established peer comments. And based on those comments, we identified the key changes and distribute tasks to our group members.

Lab 10 Questions

1. Identify and name 3 tissue types which contain adult(somatic) stem cells that were used/studied from the 5 articles during the tutorial;

A: There are three tissue types which contain adult stems cells that were used from the 5 articles during the tutorial. And they are muscle tissue, bone marrow tissue and neural stem cells tissue.

2. Name 2 reprogramming strategies/methods used in generating human induced pluripotent stem cells(iPSC) from the 5 articles discussed during the tutorial;

A: There are 2 reprogramming strategies used in generating human iPSC such as viral injection method and non viral injection method. In addition, viral injection method involves injecting the gene using lentiviruses. And non viral injection method involves use of plasmid.

3. Is the following statement true or false: "Unlike the nuclear genome, the mitochondrial DNA in the embryo is derived almost exclusively from the egg, that is, it is of maternal origin."

A: True.

--Antonio Lee 15:20, 31 October 2009 (EST) 3/3 Correct.