A Somitic Compartment of Tendon Progenitors Summary
Tendons are some of the most important tissues in the body of any organism, transferring the power created by the muscles to the bones and allowing coordinated body movements to occur. However, until recently there was very little known about the origin of this tissue and most of the research performed focused on the limbs and the tendons associated with them. Along with the limited amount of research seemingly none of it was focused on the axial and ventrolateral body wall tendons. It was not until the discovery of Scleraxis (Scx), a bHLH transcription factor found in progenitor cells and mature tendons, that tendons could be observed through the embryonic stages (Schweitzer et al.
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Upon confirming that axial and intercostal tendons originated from the somites, the researchers wanted to determine if the other somitic compartments affected the syndetome fate. Double whole-mount in situ hybridization was used to compare Scx in progenitor cells, Pax1 in sclerotome, and MyoD in myotome. Scx expression was restricted to the anterior and posterior borders while MyoD expression was present in the center of the myotome with no overlap of the two markers. When Scx was compared to Pax1 it appeared that they existed in the same region; however, Pax1 was expressed more ventromedial and Scx was closer to the myotome, these markers did not have any overlap either. Additionally, Scx expression occurred much later in development compared to MyoD and Pax1(Kiefer and Hauschka, 2001; Stockdale et al., 2000). It showed that the Scx expression progenitor cells had a distinct fate producing a separate compartment of tendon progenitor cells, which did not overlap with the adjacent tissues.
To establish the origin of the syndetome a fate map was created using a chick-quail chimera where two successive sclerotomes or dermomyotomes were transplanted from a quail to a chick embryo.
Utilizing in situ hybridization to visualize Scx expression and QCPN to identify quail cells, sclerotome and Scx expressing tendon
It's function is to hold the tendons in position. It's dysfunction can cause is tenosynovitis and carpal tunnel syndrome.
Usually this tendon will be harvested from the leg that is not used as the plant foot in the pitcher's delivery. The removal of either of these tendons has a negligible effect on function.
A tendon is a tough group of fibrous connective tissue that can with stand a lot of tension. Tendons are similar to ligaments; however, they connect muscles to bones. It is the tendon which pulls on the bone when a muscle contracts.
3-6: This slide shows a section of a tendon with regularly arranged closely packed collagen fibers running in the same direction. This results in a flexible tissue with great resistance to pulling forces. With its enormous tensile strength, this tissue forms cord like tendons, which join muscles to bones, sheet-like aponeuroses, which attach muscles to muscles or muscles to bones, and ligaments, which bind bones together at joints.
Longitudinal bone growth occurs at the epiphyseal plate, which is a thin layer of cartilage between the epiphyseal and metaphyseal bone at the distal ends of the long bones. Bone growth is the result of maturation, growth of chondrocytes, their production of bone matrix, and finally calcification (47). The growth plate is a complex structure consisting of different layers of cells, as shown in figure 3. The most immature cells, the stem cells, are found towards the epiphyseal end of the growth plate in the stem cell zone, or resting zone; the proliferating zone contains more mature chondrocytes and the hypertrophic zone contains the larger chondrocytes. The resting stem cells in the resting zone are recruited, whereupon proliferation and differentiation
In this study, the Morgridge Institute of Research’s regenerative biology team asked when a limb is getting regenerated, what genes play a role in that process and is there a recipe that can be replicated in a different species. To observe that question, researchers observed 17 different developmental stages of axolotl embryos and found that as the axolotl grows, it goes through 3 unusual changes in gene expression that level out over time. The changes occur when the genome is first activated, during the formation of the gut and during the formation of the nervous system. With these results the scientist were given the opportunity to compare that with existing information on the axolotl limb regeneration. Also during this experiment, some pieces of the axolotl’s transcriptome or messenger RNA molecules were able to be put together so that the scientist could compare them to the transcriptomes of humans and frogs in hopes of finding common
Introduction: Many model organisms have been used in order to advance human medicine. The primary one being the lab mouse, but there are several other different species that give rise to advancements in human treatment. Planaria and axolotls have been a prominent source of how signaling mechanisms work in order to regenerate parts in eukaryotic organisms. If researchers can figure out how to turn these signaling pathways on in the conserved regeneration part of the human genome, then doctors will likely be able to use this to their advantage. This can be achieved by manipulating human signaling pathways to regenerate tissues within the heart, lungs, nervous system, and even systems with multiple tissue types like the limbs. This is where the study of axolotls comes in.
V1 cells, which can be subdivided by function into Renshaw cells, Ia and other inhibitory subtypes, project their axons ipsilaterally. Experiments in embryonic chick suggest that many of these cells synapse with motor neurons (Wenner et al., 1998), and that selectively ablating these cells removes the V1-motor neuron inhibitory contact. The well-documented Renshaw cells appear to require Foxd3 transcription factor for cell differentiation and development (Stam et al., 2012). V1 neurons extend to the dorsal portion of the lateral motor column and navigate a short distance. V2 neurons exist in a more lateral region, ventral to V1 cells, during development. They are ipsilateral, descending and have varying transmitter phenotypes depending on the subtype. Mib1 protein is a key factor in V2 differentiation; if Mib1 is affected in mice, improper cell specification occurs leading to altered cell fate (Kang et al., 2013). V3 neurons comprise many subtypes which migrate to different locations, and consequently project
Tendons – a cord of tissue serving to connect a muscle with a bone or part
Timeless novels that emulate true greatness inspire and give us wonderful characters to cling to. These types of novels aren’t always widely approved of by society during the time of publication. Classic stories that address a prominent issue of the time period in a unique method always come into conflict with certain groups of society for moral disagreements. A perfect example of this is Harper Lee’s, To Kill A Mockingbird. The closest example of perfection in a character is illustrated within Atticus, due to his burning desire to protect his children, cool headed logic, and personal beliefs on different races.
Planned Parenthood wants Disney to create a princess who had had an abortion and is pro-choice, according to the Daily Wire.
The Red Badge of Courage by Stephen Crane is a very interesting book about war. This book highlights what it is really like to be in a war and shows the colorful details and how it truly is something horrible. Where as normally when you hear war stories they are romanticized and have a hero of some sorts. That is exactly what the main character of Stephen Crane’s book believes. Henry is still a very young boy who believes that life is just like the stories. Today I am going to be talking about if Henry Fleming matured through the course of this book.
Type II syndactyly or synpolydactyly(SPD) is a semi dominant inherited limb malformation that involves a fusion of digits. It is caused by mutations in HOXD13 on chromosome 2 due to polyalanine repeat expansions. Polyalanine repeats in SPD are mitotically and meiotically stable, causing polymorphisms to be rare, unlike other nucleotide repeat expansions such as Friedreich’s ataxia. HOXD13 is a member of the HOX family, a family of transcription factors that are proteins which contain homeodomain that are important for controlling cell fate along the limb axes and body. HOXD13 is a part of the HOXD gene cluster and crucial for limb development, particularly during the early and late stages of limb development. The stage occurs during the creation of the limb buds at week 4, during this stage the limbs have AP polarity through the expression of sonic hedgehog(shh) signaling from the zone of polarizing
1. Many experiments were conducted during the 1950s and 1960s with chick embryos and they showed that two patches of tissue essentially controlled the development of the pattern of bones inside limbs. Describe at
A very strong ligament called the transverse carpal ligament connects the arch of bones, which makes a complete “tunnel”. The transverse carpal ligament is a heavy band of fibers which runs between the hamate and pisiform medially to the scaphoid and trapezium laterally, and forms a fibrous sheath which contains the carpal tunnel. These bones and this ligament form a circle Carpal Tunnel Syndrome -5- from which tendons and major nerves travel. This complete circle is called the Carpal Tunnel, hence the name of this disease “Carpal Tunnel Syndrome”.