Cell damage: necrosis, apoptosis. General Death

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Cell damage necrosis, apoptosis. General Death

• Ass.prof. Golovata Tatiana

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• 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.

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Stages

• 1 - Prene?rosis or paranecrosis
• 2 - Necrobiosis
• 3 - Actually necrosis
• 4 - Autolysis

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Prene?rosis or paranecrosis- changes similar to
necrotic, but reverse
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Necrobiosis- profound degenerative changes, in
which the prevailing catabolic over anabolic
changes
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Actually necrosis cell death when the time of
death can not be established
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Autolysis- decomposition of dead substrate under
the influence of hydrolytic enzymes
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Microscopic signs of necrosis. Changes in the
nucleus

• 1.Kariopiknosis - wrinkling nucleus (?), caused
  by condensation of chromatin

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Microscopic signs of necrosis. Changes in the
nucleus

• 2.Karyorhexis breakdown of nucleus

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Microscopic signs of necrosis. Changes in the
nucleus kariorhexis in lymph follicle

• nuclei lymph follicle appear as small fragments

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Microscopic signs of necrosis. Changes in the
nucleus

• 3. Kariolysis - total splitting of the nucleus by
  hydrolytic enzymes

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Microscopic signs of necrosis. Cytoplasm changes

• 1.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

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Microscopic signs of necrosis. Changes
intercellular substance

• In 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.

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Classification of necrosis

• I. 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-sore
• 4) allergic (develops in the sensitized organism
  as hypersensitivity reaction of immediate type)
• 5) vascular (infarction).

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Classification of necrosis

• II. According to the clinic and morphological
  forms
• 1) coagulative (dry) necrosis
• 2) colliquative (liquefactive) necrosis
• 3) gangrene (originate from Greek ltltgangrainagtgt
  fire) necrosis of tissue adjacent to the outer
  environment
• a) dry
• b) wet
• 4) sequestration
• 5) infarction.

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Classification of necrosis

• III. 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.

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Coagulative necrosis

• This 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.

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Coagulative necrosis

• In 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
  

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Colliquative necrosis

• Colliquative 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.

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Colliquative necrosis

• In 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.

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Infarction

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

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Sequestration

• Sequestration 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.

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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.

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Gangrene

• Dry 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.

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Bed-sore

• Is 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.

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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.

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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.

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Morphogenesis of apoptosis

• These 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.

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• 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.

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Death

• Depending 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)

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Stages of dying

• Agony
• Clinical (somatic ) death
• Biological (molecular) death

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Agony

• Terminal condition characterized
• Violation of the central nervous system (sopor or
  coma)
• Low blood pressure
• Centralization circulatory
• Breathing disorders
• It 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.

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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.

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Biological death

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

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Signs of biological death

• Relative Relative signs of death

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

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Reliable signs of death

• early
• postmortem lividity (PML)
• changes in the muscles (Cadaveric Rigidity)
• cooling of the body
• desiccation of the skin

• late
• preserving of the body-
• -saponification ?r
• (Adipocere formation),
• -mummification
• Which destroy the body -
• -putrefaction

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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.

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Mummification

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

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Questions to test
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And yet life is beautiful

• Thank you for your attention