cell damage: necrosis, apoptosis. general d eath

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Cell damage: necrosis, apoptosis. General D eath. Ass.prof. Golovata Tatiana. Necrosis (from the Greek. Nekros - dead) . It’s death of cells and tissues in living organism. Necrosis may be in one cell, a group of cells, part of the body or organ. Stages. 1 - Preneс rosis or paranecrosis - PowerPoint PPT Presentation

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  • Cell damage: necrosis, apoptosis. General DeathAss.prof. Golovata Tatiana

  • Necrosis (from the Greek. Nekros - dead). Its death of cells and tissues in living organism. Necrosis may be in one cell, a group of cells, part of the body or organ.

  • Stages1 - Prenerosis or paranecrosis2 - Necrobiosis3 - Actually necrosis4 - Autolysis

  • Prenerosis or paranecrosis- changes similar to necrotic, but reverse

  • Necrobiosis- profound degenerative changes, in which the prevailing catabolic over anabolic changes

  • Actually necrosis cell death when the time of death can not be established

  • Autolysis- decomposition of dead substrate under the influence of hydrolytic enzymes

  • Microscopic signs of necrosis. Changes in the nucleus1.Kariopiknosis - wrinkling nucleus (), caused by condensation of chromatin

  • Microscopic signs of necrosis. Changes in the nucleus2.Karyorhexis breakdown of nucleus

  • Microscopic signs of necrosis. Changes in the nucleus kariorhexis in lymph folliclenuclei lymph follicle appear as small fragments

  • Microscopic signs of necrosis. Changes in the nucleus3. Kariolysis - total splitting of the nucleus by hydrolytic enzymes

  • Microscopic signs of necrosis. Cytoplasm changes1.Plasma-coagulation: protein denaturation and coagulation 2. Plasmorhexis -cytoplasm decomposition 3. Plasmolysis - hydrolytic fusion of cytoplasm The process ends with a complete dissolution of cells

  • Microscopic signs of necrosis. Changes intercellular substanceIn the interstitial substance of the intercellular space depolymerization with glucosamineglycane and saturation with blood plasma proteins develops. As a result interstitial substance becomes swollen and fuses. The collagen and elastic fibers are fused too. Reticular fibers are preserved longer than the other structures. Then they dissociate to lumps.

  • Classification of necrosisI. According to the cause:1) traumatic (caused by chemical or physical factors);2) toxic (toxins of bacteria, chemicals);3) trophoneurotic (in disturbances of nervous trophic)- bed-sore4) allergic (develops in the sensitized organism as hypersensitivity reaction of immediate type);5) vascular (infarction).

  • Classification of necrosisII. According to the clinic and morphological forms:1) coagulative (dry) necrosis;2) colliquative (liquefactive) necrosis;3) gangrene (originate from Greek fire) necrosis of tissue adjacent to the outer environment:a) dry b) wet4) sequestration;5) infarction.

  • Classification of necrosisIII. According to mechanism of its development it may be direct and indirect.Direct necrosis arise immediate action of causal factor (toxic and traumatic);Indirect (mediate) necrosis may be vascular and trophoneurotic.

  • Coagulative necrosisThis is the most common type of necrosis which is caused by ischemia, and less often by bacterial and chemical agents. The organs commonly affected are the heart, kidneys and spleen.

  • Coagulative necrosisIn gross examination the foci of coagulative necrosis in the early stage are pale, firm and slightly swollen. Microscopic change probably results from denaturation of structural and enzymatic proteins

  • Colliquative necrosisColliquative necrosis due to ischemic injury and bacterial infections. Because of hydration and colliquation of tissue by the action of powerful hydrolytic enzymes. The common examples are brain infarct and abscess cavity.

  • Colliquative necrosisIn gross examination the affected area is soft and swollen. Late a cyst wall is formed. Microscopically, the cystic space contains necrotic cell detritus. Macrophages filled with phagocytosed material.

  • InfarctionInfarction is vascular necrosis.The causes of infarction are prolonged vascular spasm, thrombosis or embolism .

  • SequestrationSequestration is an area of dead tissue which does not experience autolization and is freely located in the living tissue. It is characteristic for osteomyelitis - purulent inflammation of the bone marrow.

  • Gangrene Wet gangrene. Occurs under the action of putrefactive microorganisms. Tissue to swell, become swollen, emit a fetid smell, demarcation zone is not defined.

    Wet gangrene occur in the lungs, intestines and uterus.

  • GangreneDry gangrene begins in the distal part of a limb due to ischemia. The typical example is the dry gangrene in the toes and feet of an old patient due to arteriosclerosis.

  • Bed-soreIs a kind of gangrene, death of the tissue under the influence of pressure (sacral area, spinous processes, great trochanter). It is trophoneurotic necrosis in severily ill patients.

  • Outcome of necrosis Favorable: organization, replacement by connective tissue with formation of a scar or a capsule; petrifaction; ossification, formation of bone; aseptic autolysis. Unfavorable: saprogenic fusion of necrotic tissue followed by sepsis.

  • APOPTOSIS Apoptosis - genetically programmed necrosis unwanted or defective cells in living organism and is aimed at the destruction of cells during embryogenesis and physiological involution: death epithelium of the skin, red and white blood cells.Biological meaning of apoptosis is the elimination of damaged cells.Between 50 and 70 billion cells die each day due to apoptosis in the average human adult.

  • Morphogenesis of apoptosisThese changes include :- blebbing, cell shrinkage;- nuclear fragmentation; - chromatin condensation and chromosomal DNA fragmentation;- formation of apoptotic bodies;- phagocytosis of apoptotic bodies by macrophages or parenchymal cells.

  • In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury, apoptosis, in general, confers advantages during an organism's life cycle.

  • DeathDepending on the cause distinguish natural (physiological) death from old age and wear on the body, violent death from injury or other negative effects on the body ending in death, and from diseases (inviolent)

  • Stages of dyingAgony Clinical (somatic ) death Biological (molecular) death

  • Agony

    Terminal condition characterized:Violation of the central nervous system (sopor or coma) Low blood pressure Centralization circulatory Breathing disordersIt was during the agony of the body loses 60 ... 80 grams of weight (due to complete combustion and depletion of cellular ATP reserves), which in some scientific-sounding articles called weighing souls who left after the agony of the body.

  • Clinical death

    Clinical death is characterized by respiratory and cardiac arrest during 5-6 minutes while live brain cells. Clinical death is reversible process of dying. Reversibility depends on the degree of hypoxic changes in the brain.

  • Biological deathBiological death is the permanent (irreversible) cessation of all biological functions that sustain a living organism.

  • Signs of biological deathRelative Relative signs of death:

    Byeloglazovs sign(cat eye)While squeezing the eyeball from a deceased pupil becomes oval.

    passive bodys position

    pale colour of the skin

    loss of reflexes and sensority

    loss of pulse and breathing

    cooling of extremities

    Byeloglazovs sign

  • Reliable signs of death

    early:postmortem lividity (PML)changes in the muscles (Cadaveric Rigidity)cooling of the bodydesiccation of the skin

    late:preserving of the body- -saponification r (Adipocere formation), -mummificationWhich destroy the body - -putrefaction

  • Postmortem Lividity (PML)After termination of cardiac activity and loss of tone of the vascular wall is a passive movement of blood through the vessels by gravity and concentration it in below the body parts.

  • MummificationMummification means a modification of process of putrefaction in which there is a dehydration or dessication of all body after death.

  • Questions to test

  • And yet life is beautiful Thank you for your attention