General pathology
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General Pathology. Basic Principles of Cellular and Organ Pathology Autogenous Pigments. Jaroslava Dušková Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague. Pigments. Definition: colored substances in the organism or environment. Pigments. Classification: endogenous

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General Pathology

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General pathology

General Pathology

Basic Principles of Cellular and Organ Pathology

Autogenous Pigments

Jaroslava Dušková

Inst. Pathol. ,1st Med. Faculty, Charles Univ. Prague


Pigments

Pigments

Definition:

colored substances

in the organism

or environment


Pigments1

Pigments

Classification:

  • endogenous

    • autogenous

    • hemoproteins derived

  • exogenous


  • Autogenous pigments

    Autogenous Pigments

    -color substances formed in the organism as metabolism products

    • melanin

    • ceroid

    • lipofuscin


    Melanin

    Melanin

    • oculocutaneous

      (origin from tyrosine in melanocytes)

    • neuromelanin - subst. nigra

      (origin from dopamin)


    Melanin types

    Melanin - types

    • eumelanin – insoluble , brown-black

    • phaeomelanin – soluble, yellow-red (high sulphur content)


    Melanin production

    Melanin - production

    Melanocytes

    • derived from the neural crest

    • present in the basal layer of epidermis, dermis, hair folicles, mucose membranes, uveal tract of the eye, meninges, inner ear

    • secretory in the contact with the epithelial cells - cytocrinia


    Melanin functions 1

    Melanin Functions – 1.

    • cytoprotective

      • light absorption & conversion of the photon energy into heat

      • uvea – absorption of the light retina protection of light overexposure

      • retina - visual acuity preventing light reflexion from the fundus


    Melanin functions 2

    Melanin Functions -2.

    • Ion exchanging capacity

      Melanosomes can also act as detoxyfiing and excretory components accumulating great number of drugs and toxic component e.g. heavy metals.

      Scavengers of the free radicals.

      Rarely cytotoxic – photosensibilisation


    Melanin features

    Melanin - Features

    • brown

    • destained with H2O2

    • reducing AgNO3


    Disorders of melanin pigmentation

    Lack

    generalized

    total albinism

    parcial albinism

    local

    vitiligo

    leucoderma

    Disorders of Melanin Pigmentation


    Albinism

    Albinism

    • autosomal recessive heredity

      • tyrosinase deficiency

      • tyrosinase positive – melanosomes defect

    • oculo-cutaneous albinoidism – dominant inheritance


    Disorders of melanin pigmentation1

    Lack

    generalized

    total albinism

    parcial albinism

    local

    vitiligo

    leucoderma

    Disorders of Melanin Pigmentation


    Vitiligo

    Vitiligo

    • familial aggregation

    • polygenic nature

    • association with other autoimmune diseases (DM, thyroiditis, gastritis)

    • ab against tyrosinase in the serum

    • autoreact . T- cellular cytotoxicity


    Disorders of melanin pigmentation2

    Lack

    generalized

    total albinism

    parcial albinism

    local

    vitiligo

    leucoderma

    Disorders of Melanin Pigmentation


    Leucoderma

    Leucoderma

    • postinflammatory circumscribed depigmentation e.g.

      • leucoderma syphyliticum

      • leucoderma psoriaticum


    Disorders of melanin pigmentation3

    Increase

    generalized

    Adison disease

    local

    freckles, nevi

    chloasma /melasma

    melanodermia

    melanoma

    Disorders of Melanin Pigmentation


    Disorders of melanin pigmentation4

    Increase

    generalized

    Adison disease

    local

    freckles, nevi

    chloasma

    melanodermia

    melanoma

    Disorders of Melanin Pigmentation


    Disorders of phenylalanine and tyrosine metabolism

    Disorders of Phenylalanine and Tyrosine Metabolism

    1. Phenylalanine hydroxylase PHENYLKETONURIA

    2. Homogentisic acid oxydase

    ALKAPTONURIA

    3. Tyrosinase ALBINISM


    Disorders of phenylalanine and tyrosine metabolism1

    Disorders of Phenylalanine and Tyrosine Metabolism

    Phenylalanine

    Tyrosine

    1

    3

    Homogentisic

    acid

    DOPA

    2

    cc

    methyl–

    acetoacetic

    acid

    Norepinephrine

    Epinephrine

    MELANIN


    Ceroid

    Ceroid

    • features

      • light brown

      • PAS +

      • acidoresistent

      • Sudan +-

    • origin

      • fagocytosis od lipid substances by macrophages

      • oxidation of non–saturated lipid acids


    Ceroid1

    Ceroid

    • localisation

      • places of erythrocytes destruction

      • necroses of adipous tissue

      • avitamonosis E

      • melanosis coli

      • Dubin - Johnson syndrome


    Lipochrom

    Lipochrom

    • ubiquitous pigment

    • exogenous origin

    • lipid solvent

    • histologically unprovable


    Lipofuscin

    Lipofuscin

    • features

      • dark brown

      • Sudan +-

      • autofluorescence


    Lipofuscin1

    Lipofuscin

    • origin

      • autophagocytosis

        "wear and tear" pigment

        from the accumulation

        of autophagolysosomes over time.


    Lipofuscin2

    Lipofuscin

    • localisation

      • CNS, epithels, muscles, liver

        ATROPHIA FUSCA


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