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Regeneration involves the reactivation of development to restore missing tissues through various mechanisms. Epimorphic regeneration occurs when differentiated cells dedifferentiate to form an undifferentiated blastema which then proliferates and redifferentiates into the new structure. Salamanders regenerate limbs through epimorphosis by forming a blastema beneath the wound epidermis/apical ectodermal cap. Blastema cells require both nerves and growth factors from the apical ectodermal cap to proliferate. Patterning molecules like retinoic acid and Hox genes help reestablish proximal-distal patterning in the regenerating limb.Establishment of axis in animals
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The document discusses four main types of animal tissues: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. It provides details on the structure and function of each type of tissue. Cell specialization or modification occurs after cell division, structurally modifying newly formed cells so they can perform functions efficiently. The summary discusses types of cell modification including those on the apical, basal, and lateral surfaces of cells.Stem cell
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Stem cells are unspecialized cells that can differentiate into specialized cell types. There are two main types of stem cells: embryonic stem cells, which are derived from embryos and are pluripotent, and adult stem cells, which are multipotent and found in adult tissues. Stem cell research holds promise for developing new treatments for diseases by enabling cell regeneration and replacement. However, there are still challenges to overcome regarding isolating and delivering stem cells safely and effectively for clinical applications.Zebrafish as a model organism for regeneration studies
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Division of labor occurs in multicellular plants through the formation of tissues and tissue systems. Tissues are groups of cells that perform similar functions. There are two main types of tissues - meristematic tissue, whose cells can divide, and permanent tissue, whose cells cannot divide. Meristematic tissue is found at growth points and gives rise to permanent tissues. Permanent tissues include simple tissues like parenchyma, chlorenchyma, and sclerenchyma, as well as complex tissues like xylem and phloem. Xylem transports water and minerals throughout the plant while phloem transports food. Together these tissues form three main tissue systems - the epidermal system which provides protection, the
Tissue regeneration is an emerging and exciting biomedical field. As.pdf
Tissue regeneration is an emerging and exciting biomedical field. As.pdfshalins6
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Tissue regeneration is an emerging and exciting biomedical field. As a scientist, choose either an
adult stem cell population or embryonic stem cells as a model system to develop a technique for
growing artificial limbs in culture. Be sure to explain why you chose your particular stem cell
and the drawbacks associated with the one that you did not choose for your experiments.
Solution
In tissue regeneration scientists choose only embryonic stem cells as a models system to develop
a technique for growing artificial limbs in culture. In case of salamanders have unusual and very
desirable characteristics of being able replicate limb. When salamanders loses a limb does not
form scab. Instead a wound epidermis forms it known as apical epithelial cells they form
blastema. This knob of stem cells is then able completely regenerate the limb, these blastemata
like MRL mice act as embryonic stem cells.
Embryonic stem cells:
1. It is pluripotent i.e., differentiate into 3 of the primary germ layers (ectoderm, endoderm,
mesoderm) this indicates that embryonic stem cells can potentially differentiate into adult human
cell if stimulated right way
Drawbacks of adult stem cells:
1.It is multipotent meaning that each can only produced limited cell type.
2. Unlike embryonic stem cells, they are much scarcer and harder to culture
so its not choosen by scientist to develop for growing artificial limbs in culture..Cell_Modifications.pptx
Cell_Modifications.pptxRichmonAlaman1
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Cell modifications allow cells to specialize and perform specific functions. Some examples of cell modifications include microvilli and stereocilia, which increase cell surface area for functions like absorption. Cilia and flagella help with cell movement. Root hairs also increase surface area for absorption. Intercellular junctions like plasmodesmata, tight junctions, and gap junctions allow communication between plant and animal cells. Other specialized cells include nerve cells with dendrites and axons, muscle cells with actin and myosin, red blood cells for oxygen transport, sperm cells for fertilization, and plant cells with cell walls, chloroplasts, and central vacuoles. These modifications enhance cells' abilities to carry out vital tissue and organism2 REGENERATIVE ABILITIES IN VARIOUS ANIMALS.pptx
2 REGENERATIVE ABILITIES IN VARIOUS ANIMALS.pptxishmish2
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Regenerative Abilities in Various Animals: A Detailed Overview
Regeneration is one of the most fascinating biological processes observed in the animal kingdom. While humans can heal wounds, many animals possess the extraordinary ability to regenerate entire body parts, a skill that has evolved through complex biological pathways. These regenerative processes can range from regenerating simple tissues to fully restoring limbs, tails, and even internal organs. This ability is not uniformly distributed among all animals but varies dramatically between species, often as a function of their habitat, evolutionary needs, and physiological structures.
In this extensive exploration, we will delve into the regenerative abilities of a diverse range of animals, spanning across different taxa. We'll discuss how these processes work at a cellular level, the evolutionary advantages of regeneration, and the ongoing scientific studies aimed at understanding and perhaps one day harnessing these abilities in humans.
### I. Regenerative Capabilities in Invertebrates
#### 1. **Planarians (Flatworms)**
Planarians are some of the most well-known organisms for their remarkable regenerative abilities. These flatworms can regenerate entire bodies from a fragment as small as 1/279th of the original organism. This regenerative feat is primarily due to a unique type of stem cell called neoblasts, which are distributed throughout their bodies. When a planarian is injured, the neoblasts migrate to the site of the injury and proliferate, replacing the lost or damaged cells.
Planarians also exhibit polarity in regeneration, meaning the anterior (head) and posterior (tail) ends regenerate differently based on the position of the injury. This polarity is guided by biochemical gradients, specifically involving Wnt signaling pathways, which determine whether the new tissue will form a head or a tail.
The study of planarian regeneration has provided valuable insights into stem cell biology and tissue regeneration in higher organisms. The discovery of key regulatory genes such as **Smed-betacatenin-1**, which controls the decision of whether to regenerate a head or tail, has been significant for developmental biology.
#### 2. **Hydra**
Hydras are simple freshwater organisms within the phylum Cnidaria. They possess exceptional regenerative abilities, to the extent that some scientists consider them potentially "immortal." When a hydra is cut into pieces, each fragment has the capability to regenerate into a fully functional organism. This regeneration is driven by interstitial stem cells located throughout their bodies, which are capable of differentiating into any cell type.
The amazing regenerative properties of hydras are closely linked to the continuous activity of their **FoxO** gene, which is believed to regulate longevity and regeneration. Studies on hydras offer insights into cellular senescence and the maintenance of tissue homeostasis, both of which are crucial formStem Cells.pptx
Stem Cells.pptxZeleke Endalew
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Define what stem cells are
The types of stem cells and their properties
The methods of stem cell culture
Medical roles of stem cells
Introduction to stem cells
Introduction to stem cellsHasnat Tariq
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Stem cells, Types of Stem cells, Adult stem cells, Embryonic Stem cells, Induced pluripotent stem cells, Characteristics of stem cells, Stem cell research, Stem cell therapy, Applications of stem cells, Uses of stem cells, Potential uses of stem cells, Stem cell Advantages, Stem cell disadvantages, Ethical issues of Stem cells, Future of stem cells.Regeneration types.how regeneration occurs, regeneration in salamanders limbs.
Regeneration types.how regeneration occurs, regeneration in salamanders limbs. Tahir Ali,Punjab University Lahore
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- 1. Introduction Name-Mamta Meghwal Semester : 4th Department of zoology KKC PG COLLEGE, SARDARSHAHAR
- 2. Topic of presentation Regeneration in invertebrates
- 3. Defination Regeneration is the reactivation of develpment in postembryonic life to restore missing tissues.
- 4. Methods of Regeneration 1: stem cells mediated regeneration 2: Epimorphosis 3: morphallaxis 4: compensatory regeneration
- 5. 1. Stem cell mediated Regeneration • Stem cells allow an organism to regrow certain organs or tissues that have been lost. • Example : • Regrowth of hair shafts from follicular stem cells in the hair bulge .
- 6. Example: Regrowth of hair shaft from follicular stem cells in the hair bulge
- 7. 2. Epimorphosis • In some species, adult structures can undergo dedifferentiation to form a relatively undifferentiated mass of cells that then differentiates to form the new structure.
- 8. Example Such epimorphosis is characteristic of planarian flatworm regeneration and also of regenerating amphibian limbs.
- 9. 3. Morphallaxis Morphallaxis is the regeneration of specific tissue in a variety of organisms due to loss or death of the existing tissue. The word comes from the Greek allazein, which means to change.
- 10. Example Such regeneration is seen in hydra (a cnidarian).
- 11. 4. Compensatory regeneration. Here, the differentiated cells divide but maintain their differentiated functions. The new cells do not come from stem cells, nor do they come from the dedifferentiation of the adult cells. Each cell produces cells similar to itself; no mass of undifferentiated tissue.
- 12. Example This type of Regeneration is a characteristic of mammalian liver .
- 13. Explanation of Regeneration in salamander
- 14. Epimorphic Regeneration of Salamander limb The new cells construct only the missing structures and no more In some way salamander limbs know where the proximal distal axis has been severed and is able to regenerate from that point on
- 15. 1: Regeneration of blastema Salamanders accomplish epimorphic regeneration by cell dedifferentiation to form a regeneration blastema. It is an aggregation of relatively dedifferentiated cells derived from the originally differentiated tissue. This blastema then proliferates and differentiates into the new limb parts. Bone, dermis, and cartilage just beneath the site of amputation contribute to the regeneration blastema, as do satellite cells from nearby muscles.
- 16. 2: Formation of apical ectodermal cap (ACE) When a salamander limb is amputated,a plasma clot formswithin 6-12 hours epidermal cells form the remaining stump migrate to cover the wound surface ,forming the wound epidermis.
- 18. 3