Pathology - PowerPoint PPT Presentation

1 / 60
About This Presentation
Title:

Pathology

Description:

Macroscopic appearance visible to the naked eye. 3.Morphological changes ... After the third week, the wound undergoes constant alterations, known as remodeling, ... – PowerPoint PPT presentation

Number of Views:192
Avg rating:3.0/5.0
Slides: 61
Provided by: Isa89
Category:
Tags: blind | eye | pathology | third

less

Transcript and Presenter's Notes

Title: Pathology


1
Pathology
2
Terminology
  • Pathology
  • The study of the structural and functional
    changes leading to disease in
  • Cell
  • Tissue
  • Organs
  • Pathophysiology
  • Is the abnormal function of organs or systems due
    to disease
  • Tools
  • Molecular
  • Microbiological
  • Immunological
  • Morphological

3
Terminology
  • Pathology is divided
  • General
  • Special or systemic
  • General pathology
  • Basic reaction of cells and tissue to normal
    stimuli
  • Specific pathology
  • Specific response special organs to well defined
    stimuli

4
Four aspects of disease process
  • Aetiology
  • Pathogenesis
  • Morphological changes
  • Clinical significance

5
1.Aetiology(Cause )
  • A) Determining cause
  • Specifically known to be the soul cause of
    disease such pathogenic organism e.g. HIV
  • B) Predisposing causes
  • Leading indirectly to disease such as genetic
    predisposition

6
2.Pathogenesis
  • Is the mechanism by which a certain aetiological
    factor causes disease (In Greek pathos
    disease, genesis development).
  • Some forms of pathogenesis are
  • Inflammation
  • Malignancy
  • Tissue breakdown

7
2.Pathogenesis
  • The pathogenesis process leads to the formation
    of lesion
  • Lesion is derived from the Latin word "laesio"
    which means "injury."
  • Lesions are a result of damage to tissues. For
    example
  • A cancerous tumor is an example of a lesion
  • The surrounding tissue damaged by a tumour is
    also termed a lesion.

8
3.Morphological changes
  • Are the changes that occur in the cell tissue or
    organ as a result of the pathological process
  • These changes can be Morbid
  • Macroscopic appearance visible to the naked eye

9
3.Morphological changes
  • Are the changes that occur in the cell tissue or
    organ as a result of the pathological process
  • Or Histological
  • Microscopic appearance only visible under the
    microscope

10
4.Clinical significance
  • What impact do these changes have on the patient?

11
Progression of a disease
  • Complete cure
  • Death
  • Complication
  • Additional pathological changes which may occur
    during or after the course of any disease

12
Pathological investigation
  • During life
  • Surgical biopsy
  • Fine needle aspiration biopsy (FNAB)
  • Cytopathology
  • Molecular techniques
  • After death
  • Autopsy

13
Exposure to stress (irritant)
  • Mild irritant A) inflammation
  • Moderate B) Degeneration
  • Severe irritant Necrosis

14
Types of irritants
  • Non-living irritant
  • Physical
  • Trauma, Burns, Radiation
  • Chemical
  • Acids, Alkalies
  • Immunological
  • Ag-Ab reaction
  • Hypersensitivity reaction
  • Living irritant
  • Bacteria
  • Pathogenic fungi
  • Parasite
  • Virus

15
Inflammation
  • It is the response of the living tissue to mild
    to moderate irritant
  • The response is directed to defend the tissue for
    foreign irritants and to prevent further damage
  • The aim is to bring more blood to the damaged
    area by acceleration of the blood stream
  • It is denoted by the suffix itis

16
Inflammation
  • Examples of inflammation
  • Tonsillitis
  • Appendicitis
  • Tendonitis ,etc.
  • Lung?

17
Inflammation
18
Exudate
  • An exudate is any fluid that filters from the
    circulatory system into lesions or areas of
    inflammation
  • Its composition varies but generally includes
    water and the dissolved solutes of the blood,
    some or all plasma proteins, white blood cells,
    platelets and RBC

19
Transudate
  • A fluid that passes through a membrane which
    filters out much of the protein and cellular
    elements to yield a watery solution.
  • A transudate is due to increased pressure in the
    veins and capillaries pressure forcing fluid
    through the vessel walls or low levels of protein
    the blood serum
  • The transudated fluid accumulates in tissues
    outside the blood vessels and can cause edema

20
Difference between exudates and transudate
  • Exudate transudate
  • inflammation venous congestion
  • High above 4gm/m3 normal
  • increased normal
  • high above 1018 normal
  • turbid due to pnls clear
  • ve -ve

Cause Protein Fibrin SG Appearance Fibrin clot
on standing
21
Types of Exudate
  • Serous exudate is usually seen in mild
    inflammation, with little protein content. seen
    in certain disease states like tuberculosis
  • Purulent or suppurative exudate consists of
    plasma with both active and dead neutrophils,
    fibrinogen, and necrotic parenchymal cells.
    referred to as pus.
  • Fibrinous exudate is composed mainly of
    fibrinogen and fibrin. It is characteristic of
    rheumatic carditis, but is seen in all severe
    injuries such as strep throat and bacterial
    pneumonia
  • Hemorrhagic exudate is seen in injury that causes
    rupture of blood vessels.
  • Pleural.
  • Catarrhal exudate is seen in the nose and throat
    and is characterized by a high content of mucus.

22
Inflammation
  • Effects of inflammation
  • Vascular phenomena
  • Transient vasoconstriction rapidly followed
  • Vasodilatation
  • Stasis
  • Migration of leucocytes

23
Inflammation
  • Effects of inflammation
  • 2- Exudative stress
  • Emigration of leukocytes
  • Inflammation fluid exudate

24
Inflammation
  • Composition and function of inflammation fluid
    exudates
  • Fluid exudates
  • Dilution of bacterial toxins
  • fibrin threads help the movement of leucocytes
    and limit the spread of infection
  • Also contain antibodies

25
Inflammation
  • Composition and function of inflammation fluid
    exudates
  • Cellular part
  • Phagocytosis engulfing of and destruction of
    bacteria and necrotic tissue by phagocytes and
    PNL

26
Inflammation
  • Chemotaxis the movment of WBC in the area of
    inflammation towards the irritant
  • Emigration of leukocytes the migration of WBC
    from within the blood vessel towards the
    inflammation site
  • Diapedesis the passage and movment of RBC from
    within the blood vessel towards the inflamed area

27
Cardinal signs of inflammation
  • Redness
  • Hotness
  • Swelling (edema) due to inflammatory exudate
  • Pain due to pressure of edema on nerves and
    irritation of nerve ends by metabolites
  • Loss of function this is to make the inflamed
    part of tissue rest and heal.

28
Types of inflammation
  • Acute inflammation
  • Acute non-suppurative inflammation acute without
    the formation of pus
  • Acute suppurative inflammation with pus
  • Localized Abscess, Furuncle, Carbuncle
  • Diffused cellulitis, septic meningitis
  • Chronic inflammation
  • Chronic specific TB
  • Chronic non-specific follows acute or chronic
    from the beginning

29
Cells of inflammation
  • Acute inflammation cells
  • 1- RBC
  • 2- PNL (leukocyte)
  • Eosinophils
  • Basophils
  • Neutrophils
  • Chronic inflammation cells
  • 1- lymphocytes
  • 2- Plasma cells
  • 3- Histocytes

30
Cells of inflammation
  • Fate of acute inflammation
  • 1- Regretion by resolution for example when the
    body (immunsystem) overcomes the bacterial
    infection
  • 2- Progression which can lead to chronic
    inflammation and spread the bacteria overcome
    the immunsystem and can spread by
  • Blood septeciemia, bacterimea, toximia
    pyaemia
  • Lymphatyic lyphangitis, lyphadenites
  • Direct to other surrounding tissue

31
Type of cells
  • Contentiously dividing cells (Labile)
    epithelium, haematopoietic (blood)
  • Quiescent (Stable) hepatic, kidney and pancreas
  • Non-dividing (Permanent) nerve cells and
    skeletal muscle cells

32
Cell development
  • Proliferation increased number
  • Differentiation development through stages

33
healing
  • Tissue repair involves replacement of damaged
    tissue with new healthy living tissue when
    resolution cannot occur
  • Types
  • Usually involves two separate but coordinated
    components
  • Regeneration
  • healing by the same type of tissue cells from
    surrounding healthy living cells, this occurs
    with in small damages of labile cells and stable
    cells for examples liver cirrhosis and bone
    fractures
  • B) Fibros (scar tissue)
  • healing by granulation tissue (fibroblast with
    new capillaries formed) which mature a vascular
    fibrous tissue (scar), this occurs in the healing
    process of permanent cells and stable cells with
    high damage. for example myocardial infraction
    and wounds

34
Introduction to wond healing
  • Healing is a complex and dynamic process of
    restoring cellular structures and tissue layers.
  • The adult wound healing process can be divided
    into 4 distinct phases
  • The homeostasis phase
  • the inflammatory phase
  • the proliferative phase
  • the remodeling phase.

35
Sequence of events in healing
  • Initial phase - Hemostasis
  • Following vasoconstriction, platelets adhere to
    damaged endothelium and discharge adenosine
    diphosphate (ADP), promoting thrombocyte
    clumping, which dams the Wound
  • The inflammatory phase is initiated by the
    release of numerous cytokines by platelets.
  • Fibrinogen is cleaved into fibrin and the
    framework for completion of the coagulation
    process is formed. Fibrin provides the structural
    support for cellular constituents of
    inflammation.
  • This process starts immediately after the insult
    and may continue for a few days

36
Sequence of events in healing
  • Second phase - Inflammation
  • Within the first 6-8 hours, the next phase of the
    healing process is underway, with
    polymorphonuclear leukocytes (PMNs) or PNLs
    engorging the wound
  • These cells cleanse the wound, clearing it of
    debris. The PMNs attain their maximal numbers in
    24-48 hours and commence their departure by hour
    72
  • As the process continues, monocytes also exude
    from the vessels. These are termed macrophages.
    The macrophages continue the cleansing process
    and manufacture various growth factors during
    days 3-4.
  • Many factors influencing the wound healing
    process are secreted by macrophages. These
    include TGFs, cytokines and interleukin-1 (IL-1),
    tumor necrosis factor (TNF)

37
Sequence of events in healing
  • Third phase - Granulation
  • This phase consists of different subphases.
    These subphases do not happen in discrete time
    frames but constitute an overall and ongoing
    process. The subphases are
  • fibroplasia
  • matrix deposition
  • angiogenesis
  • and re-epithelialization
  • In days 5-7, fibroblasts have migrated into the
    wound, laying down new collagen of the subtypes I
    and III
  • The wound is suffused with GAGs and fibronectin
    that are bonded covalently to a protein core and
    contribute to matrix deposition
  • Angiogenesis is the product of parent vessel
    offshoots. The formation of new vasculature
    requires extracellular matrix and basement
    membrane degradation followed by migration,
    mitosis, and maturation of endothelial cells
  • Re-epithelization occurs with the migration of
    cells from the periphery of the wound and adnexal
    structures. This process commences with the
    spreading of cells within 24 hours. Division of
    peripheral cells occurs in hours 48-72, resulting
    in a thin epithelial cell layer, which bridges
    the wound.
  • This succession of subphases can last up to 4
    weeks in the clean and uncontaminated wound.

38
Sequence of events in healing
  • Fourth phase - Remodeling
  • After the third week, the wound undergoes
    constant alterations, known as remodeling,
  • This can last for years after the initial injury
    occurred. Collagen is degraded and deposited in
    an equilibrium-producing fashion
  • The collagen deposition in normal wound healing
    reaches a peak by the third week after the wound
    is created.
  • Contraction of the wound is an ongoing process
    resulting in part from the proliferation of the
    specialized fibroblasts termed myofibroblasts,
    which resemble contractile smooth muscle cells.

39
Types of healing
40
Types of healing
41
Types of healing
42
Complications of the healing process
  • This process can go wrong and produce an increase
    of fibroblastic proliferation with a resultant
    hypertrophic scar
  • Further exuberance can result in keloid formation
    where scar production extends beyond the area of
    the original insult. Conversely, insufficient
    healing can result in atrophic scar formation.

43
Complications of the healing process
  • Week scar this may lead to hernia
  • Cicatrisation contracture of the size of the
    scar
  • Implantation epidermiod cyst
  • Stump neuroma following amputation causing a
    painful coiled mass of nerves
  • Sinus is a track of septic granulation tissue
    connecting a cavity to the outside and has one
    blind end e.g. pilonidal sinus
  • Fistula is a tract of septic granulation tissue
    connecting 2 epithelial surfaces
  • Infection leading to delayed healing
  • Rarely scars may develop squamous cell carcinoma
  • Ulcers discontinuity of cover epithelium or
    muscle membrane

44
Bone Introduction
  • Bone is a dynamic tissue
  • Osteoblasts - osteoid (type 1 collagen)
  • Calcium and phosphate (calcium hydroxyapatite)
  • Osteoclasts are multi-nucleated cells which
    resorb bone (PTH).

45
Osteogenic cells
46
Bone Anatomy
  • Diaphysis
  • Metaphysis
  • Epiphysis Prox/Dist
  • Epiphyseal line
  • Periosteum
  • Compact cortical bone
  • Spongy bone
  • Articular Cartilage
  • Medullary cavity
  • Marrow
  • Nutrient artery

47
The Histologic Types
  • Compact bone
  • Spongy bone
  • Lamellar bone
  • Woven bone
  • Osteoid
  • Callus

48
The matrix of bone
  • Contains inorganic salt Calcium Hydroxyapatite in
    collagen framework.
  • Osteoblasts - Calcification - Mineralization
  • Minerals ? hardness
  • Collagen fibres ? Tensile strength.
  • Collagen is necessary for Calcification.

49
Fractures
  • Break in the bone.
  • Simple / Compound infection.
  • Single - Horizontal, oblique, spiral,
  • Comminuted multiple.
  • Greenstick partial children.
  • Torus compression of cortex children.

50
Types of Fracture
51
Bone Remodeling
  • 5-10 bone / year.
  • Vitamin D
  • Nutrition
  • Physical activity
  • Age, hormones
  • PTH, PHRP
  • IL1, TNF,TGF-ß

52
Stages of wound healing
Resolution/ Remodeling
Vessel regression, Collagen remodeling
Proliferation
Reepithelialization, Angiogenesis, Fibrogenesis,
Inflammation
PMNs, Macrophages, Lymphocytes
Hemostasis
Fibrin clot, platelet deposition
1D 3D 1wk
6wk 8wk
Time after injury
53
Healing in Bone
  • 1D - Hematoma formation (fibrin mesh)
  • 3D - Inflammation
  • 1W - Soft callus granulation, matrix.
  • 3-6W - Callus ossification, woven bone
  • 8W - Re-modeling absorb/deposit, strength,
    lamellate.

54
Healing in Bone
55
Healing in Bone
56
Healing in Bone
57
Healing in Bone
58
Healing in Bone
59
Factors affecting Healing
  • Systemic Local factors
  • Immobilization
  • Improper reduction abnormal position
  • Infection. Debris, dead tissue in wound
  • Joint involvement

60
Complications
  • Delayed healing.
  • Non healing.
  • Joint involvement - ankylosis
  • Abnormal position arthritis.
  • Bone necrosis nutrient artery
  • Involucrum formation.
  • Pseudoarthrosis
Write a Comment
User Comments (0)
About PowerShow.com