Healing

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(Redirected from
Recuperation (recovery)
)
Diagram featuring stages of tissue healing

With physical trauma or disease suffered by an organism, healing involves the repairing of damaged

organs will heal using a mixture of both mechanisms.[citation needed
]

Within surgery, healing is more often referred to as recovery, and postoperative recovery has historically been viewed simply as restitution of function and readiness for discharge. More recently, it has been described as an energy‐requiring process to decrease physical symptoms, reach a level of emotional well‐being, regain functions, and re‐establish activities[1]

Healing is also referred to in the context of the grieving process.[citation needed]

In

traditional spiritual healing.[citation needed
]

Regeneration

In order for an

ischaemia and most toxins do not destroy collagen, it will continue to exist even when the cells around it are dead.[citation needed
]

Example

epithelial cells that line the kidney are destroyed by either a lack of oxygen (such as in hypovolemic shock, when blood supply to the kidneys is dramatically reduced), or by toxins (such as some antibiotics, heavy metals or carbon tetrachloride).[citation needed
]

Although many of these epithelial cells are dead, there is typically patchy necrosis, meaning that there are patches of epithelial cells still alive. In addition, the collagen framework of the tubules remains completely intact.[citation needed]

The existing epithelial cells can replicate, and, using the basement membrane as a guide, eventually bring the kidney back to normal. After regeneration is complete, the damage is undetectable, even microscopically.[citation needed]

Healing must happen by repair in the case of injury to cells that are unable to regenerate (e.g. neurons). Also, damage to the collagen network (e.g. by

infarct) cause healing to take place by repair.[citation needed
]

Genetics

Many genes play a role in healing.[2] For instance, in wound healing, P21 has been found to allow mammals to heal spontaneously. It even allows some mammals (like mice) to heal wounds without scars.[3][4] The LIN28 gene also plays a role in wound healing. It is dormant in most mammals.[5] Also, the proteins MG53 and TGF beta 1 play important roles in wound healing.[6]

Wound healing

Red Cross Hospital in Tampere, Finland during the 1918 Finnish Civil War

In response to an incision or wound, a wound healing cascade is unleashed. This cascade takes place in four phases: clot formation, inflammation, proliferation, and maturation.

Clotting phase

Healing of a wound begins with

fungi. Clotting is followed by neutrophil invasion three to 24 hours after the wound has been incurred, with mitoses beginning in epithelial cells after 24 to 48 hours.[citation needed
]

Inflammation phase

In the inflammatory phase,

epithelial cells and endothelial cells which make new capillaries to migrate to the area and divide.[citation needed
]

Proliferative phase

In the proliferative phase, immature granulation tissue containing plump, active fibroblasts forms. Fibroblasts quickly produce abundant type III collagen, which fills the defect left by an open wound. Granulation tissue moves, as a wave, from the border of the injury towards the center.[citation needed]

As granulation tissue matures, the fibroblasts produce less collagen and become more spindly in appearance. They begin to produce the much stronger type I collagen. Some of the fibroblasts mature into myofibroblasts which contain the same type of actin found in smooth muscle, which enables them to contract and reduce the size of the wound.[citation needed]

Maturation phase

During the maturation phase of wound healing, unnecessary vessels formed in granulation tissue are removed by apoptosis, and type III collagen is largely replaced by type I. Collagen which was originally disorganized is cross-linked and aligned along tension lines. This phase can last a year or longer. Ultimately a scar made of collagen, containing a small number of fibroblasts is left.[citation needed]

Tissue damaged by inflammation

After inflammation has damaged tissue (when combatting bacterial infection for example) and pro-inflammatory eicosanoids have completed their function, healing proceeds in 4 phases.[7]

Recall phase

In the recall phase the adrenal glands increase production of cortisol which shuts down eicosanoid production and inflammation.[citation needed]

Resolution phase

In the Resolution phase, pathogens and damaged tissue are removed by macrophages (white blood cells). Red blood cells are also removed from the damaged tissue by macrophages. Failure to remove all of the damaged cells and pathogens may retrigger inflammation. The two subsets of macrophage M1 & M2 plays a crucial role in this phase, M1 macrophage being a pro inflammatory while as M2 is a regenerative and the plasticity between the two subsets determine the tissue inflammation or repair.[citation needed]

Regeneration phase

In the Regeneration phase, blood vessels are repaired and new cells form in the damaged site similar to the cells that were damaged and removed. Some cells such as neurons and muscle cells (especially in the heart) are slow to recover.[citation needed]

Repair phase

In the Repair phase, new tissue is generated which requires a balance of anti-inflammatory and pro-inflammatory eicosanoids. Anti-inflammatory eicosanoids include lipoxins, epi-lipoxins, and resolvins, which cause release of growth hormones.[citation needed]

See also

References

External links