Question

What is a component of the innate immune system that plays an important role in the first line of defense?

What is a a component of the adaptive immune system that plays an important role in the third line of defense?

Answer 1

the first line of defense:

External Physical Barriers - Skin and mucous membranes

Made up of structures, chemicals, and processes that work to prevent pathogens entering the body.

Includes the skin and mucous membranes of the respiratory, digestive, urinary, and reproductive systems.

the dermis layer of skin work as a line of defense-

Contains protein fibers called collagen

- Give skin strength and pliability to resist abrasions that could introduce microorganisms

Mucous membranes line all body cavities open to the outside environment.

the two distinct layers of the mucous membrane:

Epithelium

- Thin, outer covering of the mucous membranes

- Unlike surface epidermal cells, epithelial cells are living

- Tightly packed to prevent entry of pathogens

- Continual shedding of cells carries attached microorganisms away

Deeper connective layer that supports the epithelium

the components of adaptive immune system:-

- Lymph system

- Lymphocytes: B cells, T cells

- Antibodies

B Cells

- Lymphocytes, derived from bone marrow

- Mature in bone marrow

T Cells

- Lymphocytes, derived from bone marrow

- Mature in thymus

- 90-98% of T Cells made in bone marrow are killed in thymus

Two Branches of Adaptive Immunity

- Humoral

- Cell Mediated

Humoral Branch of Adaptive Immunity

- Based on antibody (aka immunoglobulin)

- Defends against extracellular pathogens (pathogens not found within cells related to immune response)

Cell Mediated Branch of Adaptive Immunity

- Based on T Cells

- Defends against intracellular pathogens (viruses and intracellular bacteria)