Define Inflammation. What are the cardinal features of acute inflammation?

Inflammation: Inflammation is a response of vascularized tissues to infections and damaged tissues that brings cells and molecules of host defense from the circulation to the sites where they are needed, in order to eliminate the offending agents.

Cardinal features of acute inflammation:(Hallmark of acute Inflammation).

1. Rubor (Redness)
2. Tumor (Swelling)
3. Calor (Heat)
4. Dolor (Pain)
5. Functio laesa (Loss of function)

What do you mean by Apoptosis? What are the causes of Apoptosis?

Apoptosis:

Apoptosis is a pathway of cell death that is induced by a tightly regulated suicide program in which cells
destined to die activate intrinsic enzymes that degrade the cells’ own nuclear DNA and nuclear and cytoplasmic proteins.

Causes of Apoptosis:

Apoptosis occurs normally both during development and throughout adulthood, and serves to remove unwanted, aged, or potentially harmful cells. It is also a pathologic event when diseased cells become damaged beyond repair and are eliminated.

Apoptosis in Physiologic Situations:

• The destruction of cells during embryogenesis, including implantation, organogenesis, developmental involution, and metamorphosis.
• Involution of hormone-dependent tissues upon hormone withdrawal, such as endometrial cell breakdown during the menstrual cycle, ovarian follicular atresia in menopause, the regression of the lactating breast after weaning, and prostatic atrophy after castration.
• Cell loss in proliferating cell populations, such as immature lymphocytes in the bone marrow and thymus and B lymphocytes in germinal centers that fail to express useful antigen receptors.
• Elimination of potentially harmful self-reactive lymphocytes, either before or after they have completed their maturation, so as to prevent reactions against one’s own tissues.
• Death of host cells that have served their useful purpose, such as neutrophils in an acute inflammatory response, and lymphocytes at the end of an immune response.

Apoptosis in Pathologic Conditions:

• DNA damage. Radiation, cytotoxic anticancer drugs, and hypoxia can damage DNA, either directly or via production of free radicals.
• Accumulation of misfolded proteins.
• Cell death in certain infections, particularly viral infections, in which loss of infected cells is largely due to apoptosis that may be induced by the virus (as in adenovirus and HIV infections) or by the host immune response (as in viral hepatitis).
• Pathologic atrophy in parenchymal organs after duct obstruction, such as occurs in the pancreas, parotid gland, and kidney.

Define Necrosis. Classify Necrosis.

Necrosis:
The morphologic appearance of necrosis as well as necroptosis is the result of denaturation of intracellular proteins and enzymatic digestion of the lethally injured cell. The enzymes that digest the necrotic cell are derived from the lysosomes of the dying cells themselves and from the lysosomes of leukocytes that are called in as part of the inflammatory reaction.

Classification of necrosis:
1. Coagulative necrosis is a form of necrosis in which the architecture of dead tissues is preserved for a span of at least some days. Ischemia caused by obstruction in a vessel may lead to coagulative necrosis of the supplied tissue in all organs except the brain. A localized area of coagulative necrosis is called an infarct.

2. Liquefactive necrosis: in contrast to coagulative necrosis, is characterized by digestion of the dead cells, resulting in transformation of the tissue into a liquid viscous mass. It is seen in focal bacterial or occasionally fungul infections. The necrotic material is frequently creamy yellow because of the pressence of dead leukocytes and is called pus.

3. Gangrenous necrosis: is not a specific pattern of cell death but the term is commonly used in clinical practice. It is usually applied to a limb, generally the lower leg, that has undergone necrosis involving multiple tissue planes.

4. Caseous necrosis: is encountered most often infoci of tuberculous infection. The term caseous is derived from the febrile white appearance of the area of necrosis.

5. Fat necrosis: is a term that is entrenched in medical parlance but does not in reality denote a specific pattern of necrosis.

6. Fibrinoid necrosis: is a special form of necrosis usually seen in immune reactions involving blood vessels. This pattern of necrosis typically occurs when complexes of antigens and antibodies are deposited in the walls of arteries. 

Isotope: Definition, Types.

Definition:

• Atoms with same atomic number (number of proton), but different atomic weight (number of protons and neutrons).
• Atoms of same element with different atomic weight.

Types of isotope:

1. Stable isotope
• Stability of an isotope depends on the definite neutron to ration which is specific for a specific atom.
• In atoms of low atomic weight stability is usually achieved with neutron to proton ration around one.
• In atoms of high atomic stability is usually achieved with more neutron than proton
• Neutrally occurring isotopes of most of the predominant elements are stable isotopes.
2. Unstable isotope
• These are the isotopes having neutron to proton ration far away from its stability ratio.
• Neutrally occurring isotopes of heavy elements are usually unstable
• Rarely some naturally occurring isotopes of lighter elements can also be unstable
• Unstable isotopes tend to become stable by radio active decay

Isomer: Definition, Types.

Isomer:

Definition:

Isomers are substances having same molecular (chemical) formula, but different structure or having
same molecular formula and identical structural form, but different spatial configuration around one
or more carbon. Isomerism is the processes of formation of isomers.

Types of isomer:

1. Structural isomer
2. Stereo isomer (Space isomer)
• Geometric isomer
• Cis variety
• Trans variety

•  Optical isomer
• Optical enantiomers
• Diasteroisomers

Structural Isomer:

These are the substances having same molecular (chemical) formula, but different structure. These
type of isomers differ with respect to physical and chemical properties.
e.g.     CH3-CH2-CH2-CH3 (Butane)
           
                     CH3

           CH3-CH-CH3 (Isobutane)

Stereo Isomer (Space Isomer)

Substances having same molecular formula as well as identical structural form, but different with
respect to the spatial configuration of atoms or groups around one or more carbon. This type of
isomers sometimes shows identical physical and chemical properties.
Spatial configuration means
o Arrangement of atoms or groups around a carbon in relation to space,
o Three dimensional space relationship of atoms or groups around a carbon.

Types of stereo isomer:

1. Geometric isomer
2. Optical isomer
• Optical enantiomers
• Diastereoisomers