Microbiology: Chapter 14 Intro to Host Defenses

What is immunology?

the study of how the immune system protects the body (system of white blood cells and other players that help white blood cells)

Adaptive immunity invovles _________

memory

What is immunology?

the study of how the immune system protects the body (system of white blood cells and other players that help white blood cells)

Adaptive immunity invovles _________

memory

Innate immunity is ____ and the reaction is _____

always there, always the same

What is the first line of defense?

innate, nonspecific

What are barriers to the first line of defense?

Physical: skin, tears, coughing, sneezing

Chemical: low pH, lysosome, digestive enzymes

genetic: resistance inherent in genetic makeup of host

What is the second line of defense?

innate, mostly nonspecific

What are barriers to the second line of defense?

phagocytosis, inflammation, fever, interferon, complement

What is the third line of defense?

acquired, specific

What are barriers to the third line of defense?

T lymphocytes, B lymphocytes, antibodies

Acid mantle -

acidic

Physical or Anatomical Barriers: First Line of Defense

skin and mucous membranes of respiratory, urogenital, eyes, and digestive tracts

Outermost layer of skin is composed of ____

epithelial cells compacted, cemented together, nd impregnated with keratin

First Line of Defense-

flushing effect of sweat glands, blinking and tear production, stomach acid, mucous coat, nasal hair

Genetic defense-

sickle cell traits

What are the functions of a healthy immune system?

1.Recognize foreign invaders

2.Not attack itself

3.Fight disease

White blood cells-

cells of the immune system that defend our body

Self-

don’t attack own tissue

Non self-

attack unclaimed bacteria (not a part of body - viruses)

What is NOT an example of a first line defense?

white blood cells

What are examples of first line defenses?

lysozyme, hydrochloric acid in stomach, sneeze reflex, cilia in respiratory tract

What is plasma?

liquid

What happens if you purify plasma?

serum

What are formed elements?

platelets

Platelets are also known as _____

thrombocytes

Red blood cells are also known as ____

erythrocytes

White blood cells are also known as ___

leukocytes

Stem cells come from ___

red bone marrow

Neutrophils can serve as ___

EMTs, they are the first responders to infection or acute inflammation

What do basophils secrete?

histamine and heparin

What is histamine?

a potent vasodilator (vasoconstriction), released by mast cells during allergies

What is heparin?

an anticoagulant (blood thinner)

Humoral immunity pertains to __

blood

B cells can differentiate ______

plasma cells to make antibodies

Antigens -

surface macromolecules found on cells, viruses

Monocytes can differentiate into ____

macrophages

What are the functions of macrophages?

1.Act as cellular housekeepers

2.Secrete chemicals that can identify immune responses

3.Act as antigen presenting cells

Dendritic cells -

trap pathogens and participate in immune reactions

Functions of the lymphatic system

1.Provides an auxiliary route for return of extracellular fluid to the circulatory system

2.Act as a drain-off system for the inflammatory response

3.Renders surveillance, recognition, and protection against foreign material

What travels in the lymphatic system?

white blood cells, cancer cells, bacteria cells

Lymph vessels ____

carry the lymph

Lymphatic organs _____

white blood cells hang out spot

When is lymphatic fluid formed?

when blood components move out of blood vessels into extracellular spaces

What is lymphatic fluid composed of?

water, dissolved salts, 2-5% proteins

What does lymphatic fluid do?

transports white blood cells, fats, cellular debris, and infectious agents

Primary lymphoid organs -

white blood cells originate and develop

What are examples of primary lymphoid organs?

red bone marrow (T & B cells originated)

thymus (where T cells mature)

Secondary lymphoid organs-

where white blood cells get activated

What are examples of secondary lymphoid organs?

lymph nodes, tonsils, spleen

What is the distal portion of the small intestine?

Peyer’s patch

T cells mature in the ____

thymus

What are the actions of the second line of defense?

recognition, inflammation, phagocytosis, interferon, complement

Interferons inhibit ____

viral replication

Complements are _____

proteins that help the immune system

What is the main purpose of inflammation?

to mobilize white blood cells and be mediators to site of injury

Redness-

vasodilation (increase in diameter of a blood vessel, blood rushesto injury)

Swelling -

all the fluids rushing to one area, mediators make blood vessels leaky, liquid falls out and builds up

Pain-

fluid causes pressure and stimulate nerve endings

Exogenous pyrogens-

outside of the body, products from bacteria and viruses

Endogenous pyrogens -

white blood cells will release products

Meningitis -

inflammation of the meninges

What are the benefits of a fever?

1.sign of an illness

2.Inhibit the proliferation of heat sensitive microbes (polio virus)

3.Increase reaction rates (increase the rate white blood cells are made)

What are the general activities of phagocytes?

1.To survey tissue compartments and discover microbes, particulate matter, and dead or injured cells

2.To ingest and eliminate these materials

3.To extract immunogenic information from foreign matter

What are interferons?

small proteins produced by certain white blood and tissue cells in response to viruses, rna, immune products and various antigens

Interferon alpha -

lymphocytes and macrophages

Interferon beta -

fibroblasts and epithelial cells

Interferon gamma -

T cells