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- Sclerotome--> vertebrae and rib cartilages are developed from it, where different type of bone cells are present. The extracellular matrix of bone is formed through inorganic material such as phosphate along with some organic component being collagen fibres and ground substance.
 
- Sclerotome--> vertebrae and rib cartilages are developed from it, where different type of bone cells are present. The extracellular matrix of bone is formed through inorganic material such as phosphate along with some organic component being collagen fibres and ground substance.
  
--[[User:Z8600021|Mark Hill]] 16:41, 11 September 2012 (EST) Question 1 has been clearly and correctly answered. The somite compartments and major tissues correctly identified. The one error is the answer for dermatome suggests that the epidermis is also a component of this compartment, while it is ectodermal in origin. '''9/10'''
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--[[User:Z8600021|Mark Hill]] 16:41, 11 September 2012 (EST) Question 1 has been clearly and correctly answered. Question 2 the somite compartments and major tissues correctly identified. The one error is the answer for dermatome suggests that the epidermis is also a component of this compartment, while it is ectodermal in origin. '''9/10'''
  
 
==Lab 4 assessment==
 
==Lab 4 assessment==

Revision as of 16:41, 11 September 2012

Lab Attendance

Lab 1--Z3331330 11:49, 25 July 2012 (EST) Lab 2--Z3331330 10:41, 1 August 2012 (EST) Lab 3--Z3331330 13:00, 8 August 2012 (EST) Lab 4--Z3331330 10:07, 15 August 2012 (EST) Lab 5--Z3331330 10:08, 22 August 2012 (EST) Lab 6--Z3331330 10:10, 29 August 2012 (EST)

Lab 1 Assessment

(1)Identify the origin of In Vitro Fertilization and the 2010 nobel prize winner associated with this technique and add a correctly formatted link to the Nobel page.

Many studies and experiments were conducted and they all contributed to the development of In Vitro Fertilization as it is today. Some early studies have used hamster gametes to prove the possibility of mammalian gametes being fertilized in vitro, done by Yanagimachi and Chang in1963. Chang, in 1959 has also done a study that demonstrated the normal development of a rabbit egg that was fertilized in vitro. Numerous experiments were done using different animals and species which proved the success of in vitro fertilization. Capacitation of the sperm in the uterus of the mother was a significant discovery to in vitro fertilisation. On July 25, 1978, the first successful 'test-tube' baby was born. Dr. Patrick Steptoe, a gynecologist and Dr. Robert Edwards, a physiologist, the team who pioneered the IVF were accredited for their contribution to IVF.

In 2010, Robert Edwards was awarded the 'Nobel prize in physiology or medicine' for his contribution in the development of "In Vitro Fertilization", see [1]


(2)Identify and add a PubMed reference link to a recent paper on fertilisation and describe its key findings (1-2 paragraphs).

'Genes required for the common miracle of fertilization in Caenorhabditis Elegans' [2]

Fertilization is a result of various sperm-egg interactions and together these interactions lead to gamete fusions and egg activation.This paper describes the identity of genes that are responsible for the interactions between gametes during ferilization and the function of protein products that are produced by these specific genes. The paper focuses on the fertilization process in Caenorhabditis Elegans which is a type of worm. There are two main types of molecules that are essential in fertilization and they are sperm function molecules and egg function molecules. Spe-9 gene produces a single-pass transmembrane molecules with extracellular domain that contain 10 epidermal growth factor and it is responsible for adhesion or ligand receptor functions. Its critical presence on the surface of the sperm allow the sperm to bind to the oocytes during fertilization. Other genes such as Spe-38 is also identified with similar function.

Egg function genes such as egg-1 and egg-2 genes lead to the production of type II transmembrane molecules. Loss of these gene can lead to complete hermaphrodite fertility. Sperms will not be able to enter the oocytes.The main function of these genes is to act as oocyte surface receptor for sperms during fertilization. These discoveries and results in C.elegans provide a blueprint of the genetic control involved in the process of fertilization and encouraged discoveries of similar genes that are involved in fertilization in humans.[1]

--Mark Hill 16:30, 11 September 2012 (EST) Question 1 is answered well and I like that you have discussed earlier research. Question 1 is also answered well, though a 2008 paper is not as recent as I was seeking as an answer. You will need to fix your referencing (ref 1 is blank because it is incorrectly formatted and should only contain the PMID (not PMC number) number without text)10/10

lab 2 assessment

Degradation of ooctyes by sperm proteasomes

(1)Degradation of oocytes by sperm proteasomes.png

(2) Rac-1 is a member of the Rho GTPases family of proteins. It was discovered that with the activation of the Rac-1 gene, its protein product can regulate the motility of the human endometrial stromal cells (HESCs) in reponse to the implantation of the embryo in the uterine wall. Rac-1 promotes the lamellipodial protrusion at front of the migrating cells. This protein also encourage the migration of HESCs away from the implantation site which then facilitate the invasion of trophoblast and lead to the inplantation of the embryo into the stromal compartment. [2]

--Mark Hill 16:32, 11 September 2012 (EST) Question 1 image is well named and contains all the requested information (though png files are quite large 125 KB, jpg are smaller). Question 2 is also relevant to implantation. Rac proteins regulate the actin cytoskeleton and this is further explored in the 3rd year Cell Biology course. 10/10

Lab 3 assessment

(1)Identify the difference between "gestational age" and "post-fertilisation age" and explain why clinically "gestational age" is used in describing human development.

Answer: Gestational age is classified as the time elapsed from the first day of a women's last menstrual period, and the post-fertilization age is referred as the time since the fertilzation of the egg in the woman's uterus. The main difference is their starting date and gestational age is often two weeks earlier than the post-fertilization age. Clinically, gestational age is often used in describing human development because the start date of the gestational age can be clearly defined while the exact time of fertilization can be confusing. It is also essential for predicting consequences to the development of fetus from toxin exposure of infection during the gestational age.It is also important for evaluation of physical findings such as fetal growth and screening markers.

(2)Identify using histological descriptions at least 3 different types of tissues formed from somites.

3 types of tissues formed from somites: - dermatome --> Skin are formed from dermatome. There are 3 layers to skin, epidermis which contain stratified squamous cells with epidermal ridges with thick layer of keratin. Dermis layer contain a lot of the vasculature such as blood vessels and glands, there are also dense collagen and irregular elastic fibres. Usually, this layer contains a lot of type I collagen fibre. The last layer is the hypodermis layer where its mainly adipose tissue.

- myotome--> skeletal muscle are developed from myotome. Skeletal muscle has a lot of myocytes and they are long and elongated with multiple nucleus. Their nucleus are often pushed to the periphery of the cells. They also contain myosin and actin which are called the thick and thin filament which cause striation appearance of the muscle cells.

- Sclerotome--> vertebrae and rib cartilages are developed from it, where different type of bone cells are present. The extracellular matrix of bone is formed through inorganic material such as phosphate along with some organic component being collagen fibres and ground substance.


--Mark Hill 16:41, 11 September 2012 (EST) Question 1 has been clearly and correctly answered. Question 2 the somite compartments and major tissues correctly identified. The one error is the answer for dermatome suggests that the epidermis is also a component of this compartment, while it is ectodermal in origin. 9/10

Lab 4 assessment

(1)Identify the 2 invasive prenatal diagnostic techniques related to the placenta and 2 abnormalities that can be identified with these techniques.

The first invasive prenatal diagnostic techniques is called "chorionic villus sampling" and it involves a catheter passed via the vagina through the cervix and into the uterus to the placenta, under the guidance of ultrasound. There can be other approaches as well such as transvaginal and transabdominal. The catheter will then collect sample of the chorionic villus which is placental tissue. The sample will then be analyse for any chromosomal abnormalities or genetic disorders, and the karotype of the fetus will be determined.

The second technique is "Placental biopsy", it is similiar to the chorionic villus sampling, but it has a transabdominal approach to it. It can be performed at a later stage of the pregnancy. It is used to obtain a rapid result. The karyotype of the fetus can be determined and genetic disorders can be detected such as trisomy 21 and monosomy X.


(2)Identify a paper that uses cord stem cells therapeutically and write a brief (2-3 paragraph) description of the paper's findings.

"Transplantation of microencapsulated umbilical-cord-bloodderived hepatic-like cells for treatment of hepatic failure" [3]

The paper aim to investigate intraperitoneal transplantation of microencapsulated hepatic-like cells from human umbilical cord blood for treatment of hepatic failure in rats. There are a few candidates for this experiment but human umbilical cord blood (UCB) cells were thought to be the best as they have some advantages that other cells do not have. The frequencies of UCB hematopoietic stem or progenitor cells is much higher than those from bone marrow and peripheral blood. The paper also mentioned that there are three ways of inducing the UCB cells into hepatocytes-like cells and they are Co-culture with injured liver cell, growth factor-assisted and MNC transplantation.

In the experiment, CD34 cells are isolated from the UCB cells and through the combination of fibroblast growth factor and hepatocyte growth factor, the CD34 cells are induced to hepatocytes-like cells. It was found that in the cultured cells, the level of human albumin, alpha-fetoprotein and GATA-4 mRNA and albumin positive cells have increased significantly suggesting the transformation of the CD34 cells into hepatic-like cells. The cultured system with growth factors have the ability to convert these UCB cells into hepatocytes phenotype and it is confirmed through PCR and immunohistochemcial staining. Then these hepatic-like cells are encapsulated and transplanted into the abdominal cavity of rats with acute hepatic failure. The transplantation occurs 48 hours after the onset of an acute hepatic failure.The microencapsulation of the cells provide a possibility to overcome the immuno-rejection from the AHF rats.

The result obtained from this experiment was that CD34 cells from the UCB cells can be converted into hepatic-like cells under suitable conditions with appropriate growth factors. The transplantation of these encapsulated hepatic-like cells have resulted in decreased mortality of the AHF rats. But these hepatic-like cells can only offer short term metabolic effect to these AHF rats and cannot interrupt or repair the damaged hepatocytes. Therefore the conclusion of this paper suggests the possibility of UCB cells used in conversion to hepatic-like cells that can temporarily alleviate the symptoms of Acute hepatic failure in rats bur not regenerating healthy hepatocytes. [3]

Lab 7 assessment

(1) Provide a one sentence definition of a muscle satellite cell (b) In one paragraph, briefly discuss two examples of when satellite cells are activated ?

It is a mononuclear stem cell that are found in mature skeletal muscle fibres and promote their growth, repair and regeneration, they are usually situated between sarcolemma and basement membrane of muscle fibres.

Satellite cells are activated after muscle strains such as trauma, where myogenic regulatory factors will be expressed and they are similar to those produced by muscle precursor cells during muscle development. These cells proliferate and fuse with each other to form myotubes and slowly mature into myofibres. They can also fuse with damaged segments of muscle fibres. These cells can also give rise to new satellite cells. Heavy exercise can induce muscle hypertrophy which also encourage the growth and proliferation of these muscle satellite cells.


(2)In one brief paragraph, describe what happens to skeletal muscle fibre type and size when the innervating motor nerve sustains long term damage such as in spinal cord injury?

In situations of long term motor nerve damage, since skeletal muscles are activated by these motor nerves, when they are damaged, the muscles will often lose their function and movement. There can be a complete loss of function or only a part of, depending on the severity of the damage to the nerve. When the muscle lose their initiation, they can present symptoms such as muscle twitching, cramping and muscle can become stiff due to the lack of movement. Muscle will become weak, muscle fibres will degenerate, muscle mass will also decrease and undergo atrophy.

References

  1. <pubmed>PMC18649278</pubmed>
  2. <pubmed>PMC2562412</pubmed>
  3. <pubmed>PMC3051145</pubmed>