2. Reactivity and resistance. Factors, influencing reactivity and resistance. Types of reactivity and resistance.

REACTIVITY AND RESISTANCE. FACTORS INFLUENCING THEM. TYPES

• ⭐ Reactivity - the ability of an organism to alter the functional capacity of its system + organs in order to adapt to the new conditions for survival
• ❏ It can be divided into:

1. Biological

• ❏ Morphological and physiological changes that occur within an entire species
• ❏ This is primary reactivity and is genetically coded for each individual

2. Group

• ❏ Reactivity that is specific to certain groups e.g. gender groups and age groups

3. Individual

• ❏ Reactivity of each individual and is deformed by age, sex, genetics, constitution, functional conditions of an organisms’ regulatory system, external environmental influences
• ❏ It can also be divided into:

1. Specific - controlled by the immune system
2. a) Physiological

• ❏ Form specific resistance against certain antigens such as bacteria, viruses, fungi, tumour cells

1. b) Pathological

• ❏ Include allergic reactions, diseases, and development of immunodeficiencies or immunosuppressive conditions

2. Nonspecific - controlled by nervous system reactions such as CNS, vegetative NS, endocrine system reactions, barrier systems, cell reactions, and humoural reactions
3. a) Physiological

• ❏ Nonspecific mechanisms are the vital reactions of a healthy organism in normal life conditions

1. b) Pathological

• ❏ Abnormal life conditions → as a result of decrease in the adaptive potential of organisms (shock, collapse)

Classification

• ❏ Based on degree of sensitivity towards antigens:

1. Normoergic - having the degree of reactivity toward an allergen typical of age group and community
2. Hypoergic - having decreased sensitivity to an allergen
3. Hyperergic - having increased sensitivity to an allergen
4. Anergic - lack of reaction to specific antigens → usually self-antigens + prevent body from developing an autoimmune reaction → positive = effective defense mechanism → negative = due to undeveloped or exhausted defense mechanism

Influencing factors

• Environmental factors - chemical, biological, physical, societal
• Constitutional - gender, age, neural system

Resistance

• ❏ State of insusceptibility of an organism to the influence of pathogenic factors (or ability of a living system to oppose irritants)
• ❏ Can be natural or acquired in postnatal period
• ❏ Acquired as:
• Artificial - active (vaccination), passive (serotherapy, blood transfusion)
• Natural - active (overcoming disease), passive (Abs via placenta or breast milk)

Immunological resistance

• ❏ Compex mechanism of defensive and adaptive reactions
• ❏ Highly specific response, aimed against external threats (bacteria, viruses) + internal threats (functionally ineffective and mutated cells)