User:Z3330986: Difference between revisions

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Lab 3
Lab 3
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)
--[[User:Z3330986|Z3330986]] 10:33, 8 August 2012 (EST)
Lab 4
--[[User:Z3330986|Z3330986]] 10:21, 15 August 2012 (EST)


==Individual Assessment==
==Individual Assessment==

Revision as of 11:21, 15 August 2012

Lab Attendance

Lab 1 --Z3330986 11:49, 25 July 2012 (EST)

Lab 2 --Z3330986 10:25, 1 August 2012

Lab 3 --Z3330986 10:33, 8 August 2012 (EST)

Lab 4 --Z3330986 10:21, 15 August 2012 (EST)

Individual Assessment

Lab 1

1) As with many medical terms, in vitro is derived from Latin, translating to "in glass." It is so named, as early experiments involving tissue cultures outside of the specimen (as opposed to in vivo, inside the body) were undertaken in glass containers. In Vitro Fertilization was developed by Robert G. Edwards. He was awarded the Nobel prize in 2010 in the field of medicine and physiology for his work. A link to the Nobel prize web page can be found here:[[1]]

2) Sperm counts and sperm sex ratio in male infertility patients[[2]]

In this study, the sex chromosomes and sperm count of infertile men were analysed in order to determine whether infertility plays a role in the determination offspring gender. Infertility is a fairly arbitrary categorization though for the purposes for this experiment, it was taken to mean couples who had greater than or equal to two recurrent pregnancy losses or two failed IVF treatments. The subsequent results found that in men with a low sperm concentration, semen volume and total motile sperm count, there was a significantly lower proprortion of the Y-bearing sperm. Thus there is a direct link between spermatogenesis and sex ratio.

The precise mechanisms for a diminished Y-bearing proportion of sperm is unclear. It is suggested that perhaps societal stresses or individual wants and needs may play a role in the genetic makeup of sperm. Biologically, it is reasoned that an infertile man will produce less male heirs so as to minimise the chance that his offspring may encounter the same problems.

Lab 2

Mouse oocytes in vitro

In order for successful implantation to occur, estrogen controlled proliferation of the uterine epithelium must be attenuated by the hormone progesterone. Previously the mechanisms of attenuation were not well understood however recent study has shown the helix-loop-helix protein, Hand2, plays an integral role in suppressing estrogen-driven growth of uterine epithelium. It does this by stopping the induction of Fibroblast growth factors (FGF) which are responsible for maintaining estrogen mediated growth of the epithelium. [1]

From a clinical perspective it may also direct research to improve treatments which target over-proliferative disorders such as endometriosis and endometrial cancer. Particularly endometriosis, which currently resists progesterone targeted medications.

Reference

1. The Antiproliferative Action of Progesterone in Uterine Epithelium Is Mediated by Hand2 Quanxi Li, Athilakshmi Kannan, Francesco J. DeMayo, John P. Lydon, Paul S. Cooke, Hiroyuki Yamagishi, Deepak Srivastava, Milan K. Bagchi, and Indrani C. Bagchi Science 18 February 2011: 331 (6019), 912-916. [DOI:10.1126/science.1197454]

Lab 3

1) Gestational age refers to the age of the foetus/embryo beginning at the first day of the mother's last menstrual cycle. In contrast the post-fertilisation age, as its name infers, begins at the time of fertilisation of the oocyte.

2) Somites mainly generate: Skeletal muscle and dermis (from the dermomyotome) as well as intervertebral discs and vertebral bodies (from the sclerotome)

Histology

  • Skeletal muscle - Contains densely packed fibers called myofibrils. These are cylindrical, long and multinucleated fibres with nuclei residing peripherally. Each myofibril is composed of the proteins actin and myosin (referred to collectively as myofilaments). Skeletal muscle can be divided into either red fibres or white fibres:
  • Red fibers are named due to the presence of myoglobin, an oxygen transporting protein, analagous to haemoglobin in the blood. They contain many mitochondria and are responsible for for slow twitch contractile movements.
  • White fibers are larger with less myoglobin and mitochondria. These represent fast twitch fibers
  • Dermis - Bilaminar structure composed of Papillary layer and Reticular layer.
  • Papillary layer - Superficial layer interdigitating with the dermis. Composed of loose connective tissue with thin type III collagen fibers. Also contains macrophages, fibroblasts and mast cells along with capillary loops which function in thermoregulation.
  • Reticular layer - Deepest layer containing intermingling thick elastic fibers and collagen fibers.
  • Intervertebral disc - made up of fibrocartilage. The matrix contains cartilage cells, enclosed within lacunae which align in pairs or short rows between bundles of type I collagen fibers.