General pathophysiology

1. General pathology

2. Cell injury

3. 1.Necrosis
Cell death due to an acute injury.
Mechanism:
Necrotic cells loose their membranes, spilling
their contents --------------------------
inflammation of neighboring cells.

4. 2. Apoptosis
Suicidal programmed cell death.
Mechanism:
Initiated by activation of caspases ( proteases
family)------ breaking down cellular proteins
------- cellular shrinkage and condensation
------- phagocytosed finally.

5. Apoptosis is balanced by new cellular
formation in healthy adults.
Recently ,apoptosis may play a role in
neurodegenerative diseases as
Alzheimer’s disease. Also in cancer &
autoimmunes.
Chemotherapeutic drugs can induce
cancer cell apoptosis

6. Inflammation
A defensive response triggered by
body tissue damage.
Causes:
 Microbial infection
 Physical agents (heat,& sharp objects)
 Chemical agents( acids& bases)

7. Symptoms of inflammation:
a. Redness
b. Hotness
c. Tenderness
d. Swelling (edema)

8. Stages of inflammation
 Vasodilation & increased permeability.
 Phagocytosis.
 Tissue repair.

9. Beneficial effects of inflammation
a. Destroys & removes injurious agents
&toxins
b. Limits the microbial effects on the body by
walling off these agents.
c. Repairs & replace the damaged tissues

10. Immune response
It has 2 components:
1. Antigen :
 protein or large polysaccharide.
 High MWT
 Can evoke specific immune response.

11. 2. Antibody:
 Gamma globulins
 Ab specific to each Ag
 5 types( IgM,A,G,E,D)
 Each is of 2 light & 2 heavy PP chains.

12. Primary immune response
 On first exposure to specific Ag.
 1-2 weeks latent periods.

13. Secondary immune response
 On second exposure to the same Ag.
 Shorter LP ( 1-2 days).
 Higher Ab level than primary one.

14. Forms of Ag – Ab reaction
1. Neutralization
2. Precipitation
3. Agglutination
4. Lysis

15. Ag – Ab reaction is helped by:
1. A complex group of enzymes ( complement
system)……….. C1 - C9
2. Phagocytes

16. Self tolerance
Denotes to the fact that the immune
mechanism of anyone normally recognizes
the body own tissue as self Ag forming few or
no Ab’s against them.

17. Autoimmunity
Definition:
Loss of immune self tolerance with excess Ab
production against own self antigens.
This is the basis of autoimmune diseases as:
Myathenia gravis & Rheumatic fever.