Chapter 14

Innate Immunity

Host defenses including anatomical barriers, sensor systems, and phagocytic cells that provide immediate protection against pathogens.

Anatomical Barriers

Physical barriers like skin and mucous membranes that prevent microbes from entering the body and have innate antimicrobial properties.

Phagocytosis

Process where cells engulf and digest foreign material, crucial for removing pathogens from the body.

Inflammation

Protective response triggered by tissue damage or invasion, characterized by swelling, redness, heat, and pain to eliminate invaders and restore tissue function.

Fever

Host defense mechanism where the body raises its temperature above normal to inhibit pathogen growth and enhance other immune responses.

Cytokines

Proteins involved in cell communication, regulating cell growth, differentiation, movement, and immune responses.

Complement System

Series of proteins that enhance the immune response by promoting inflammation, opsonization, and lysis of foreign cells.

Macrophages

Phagocytic cells found in tissues that engulf and destroy pathogens, produce cytokines, and play a key role in the immune response.

Neutrophils

Granulocytes that are the first responders during inflammation, recruited to sites of damage to phagocytize and destroy pathogens.

Pattern Recognition Receptors

Receptors on immune cells that identify specific microbial patterns, triggering phagocytosis and immune responses.

Pattern recognition

what sensor systems are used to detect certain microbes

Adaptive immunity

immunity that comes from exposure to microbes and is a specialized defense system of vertebrates

Physical Barriers

all exposed surfaces are lined with epithelial cells tightly packed resting on a thin fibrous basement membrane

Dermis

tightly woven fibrous connective tissue

Epidermis

layers of epithelial cells becoming progressively

Lysozyme

degrades peptidoglycan in tears, saliva, mucus

peroxidase enzymes

Saliva and milk. Break down hydrogen peroxide producing harsh oxidizing compounds

Lactoferrin

saliva, mucus, Mild (Transfirin in blood and tissue fluids.)

Red blood cells

erythrocytes, carry oxygen

platelets

megakaryocytes, clotting

white blood cells

leukocytes: hosts defenses

Eosinophils

• Thought to function in expelling parasitic worms

• involved in allergic reactions - causing and alleviating symptoms

• Granules contain antimicrobial substances and histaminase

Granulocytes

cytoplasmic granules containing biologically active chemicals

Basophils

• Allergic reactions and inflammation.

• Granules contain histamine and other chemicals that increase capillary permeability

• similar to mast ceil but found in blood

Mononuclear Phagocytes - MPS

monocytes circulate in the blood for a few days then enter tissues and differentiate into macrophages or dendritic cells

Cell Communication

Immune System Cells need to communicate with each other and their environment to Successfully combat invasion or trauma

• endogenous pyrogens

produced by the body-cytokines

exogenous pyrogens

produced externally by microbial products

Phagocytosis

Cells that engulf and digest material