NEET MDS Lessons
General Pathology
Microbiological examination
This is a method by which body fluids, excised tissue, etc. are examined by microscopical, cultural and serological techniques to identify micro-organisms Microbiological examination responsible for many diseases.
Eosinopenia:
Causes
-Corticoid effect (Cushing's syndrome or therapy).
-Stress.
Congenital heart defect
Congenital heart defects can be broadly categorised into two groups,
o acyanotic heart defects ('pink' babies) :
An acyanotic heart defect is any heart defect of a group of structural congenital heart defects, approximately 75% of all congenital heart defects.
It can be subdivided into two groups depending on whether there is shunting of the blood from the left vasculature to the right (left to right shunt) or no shunting at all.
Left to right shunting heart defects include
- ventricular septal defect or VSD (30% of all congenital heart defects),
- persistent ductus arteriosus or PDA,
- atrial septal defect or ASD,
- atrioventricular septal defect or AVSD.
Acyanotic heart defects without shunting include
- pulmonary stenosis, a narrowing of the pulmonary valve,
- aortic stenosis
- coarctation of the aorta.
cyanotic heart defects ('blue' babies).
obstructive heart defects
cyanotic heart defect is a group-type of congenital heart defect. These defects account for about 25% of all congenital heart defects. The patient appears blue, or cyanotic, due to deoxygenated blood in the systemic circulation. This occurs due to either a right to left or a bidirectional shunt, allowing significant proportions of the blood to bypass the pulmonary vascular bed; or lack of normal shunting, preventing oxygenated blood from exiting the cardiac-pulmonary system (as with transposition of the great arteries).
Defects in this group include
hypoplastic left heart syndrome,
tetralogy of Fallot,
transposition of the great arteries,
tricuspid atresia,
pulmonary atresia,
persistent truncus arteriosus.
Nonspecific or Innate Immunity
1. Genetic factors
- Species: Guinea pig is very susceptible to tuberculosis.
- Race: Negroes are more susceptible to tuberculosis than whites
- Sickle cells (HbS-a genetic determined Haemoglobinopathy resistant to Malarial parasite.
2. Age Extremes of age are more susceptible.
3. Hormonal status. Low resistance in:
- Diabetes Mellitus.
- Increased corticosteroid levels.
- Hypothyroidism
4. Phagocytosis. Infections can Occur in :
- Qualitative or quantitative defects in neutrophils and monocytes.
- Diseases of mononuclear phagocytic system (Reticuloendothelial cells-RES).
- Overload blockade of RES.
5. Humoral factors
- Lysozyme.
- Opsonins.
- Complement
- Interferon (antiviral agent secreted by cells infected by virus)
HYPERTROPHY
Increase in the size of an organ or tissue due to increase in the size of its Constituent cells.
1. Skeletal muscle due to -exercise.
2. Cardiac muscle of:
- Left ventricle in:
o Hypertension.
o Aortic valvular lesion.
o Severe anaemia.
- Right ventricle in :
o Mitral stenosis
o Cor pulmonale
3. Smooth muscle of:
- GIT proximal to strictures.
- Uterus in pregnancy.