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Immunology - Lecture Thirty : Introduction to immunology and the immune system

Q: What is immunology ? How does the immune system protect the body?

Immunology is the study of organisms defense system (immune system) in health and disease. The immune system is an organised system of organs, cells and molecules that interact together to defend the body against disease The immune system is composed of organs (spleen), cells (T cells) and molecules (antibodies)

Q: What are the main features of the human lymphatic system ?

PRIMARY LYMPHOID ORGANS : produce white blood cells (leukocytes) Thymus : where T Cells (White Blood Cells) become more mature and learn not to react to itself Bone Marrow : source of stem cells that develop into immune cells of the innate and adaptive immune responses SECONDARY LYMPHOID ORGANS : initiate immune responses Lymph nodes : Located along lymphatic vessels and is the site where lymph fluid is filtered into from the tissues and an immune response is initiated. Spleen : initiates immune responses against blood-borne pathogens

Q: What are the physical and chemical barriers of skin that prevent pathogen entry into the body ?

Physical barrier : Epidermis : most superficial layer. Made of dead cells, and keratin. Provide a physical barrier for pathogens trying to enter the body Dermis : thick layer of connective tissue, collagen, and blood vessels. Provide a physical barrier for pathogens trying to enter the body Both the epidermis and dermis contain phagocytic immune cells that phagocytose any pathogens Chemical barrier: Antimicrobial peptides : poke holes in microbial cell membranes Lysozyme : is an enzyme that breaks down bacterial cell walls Sebum : makes skin more acidic Salt (NaCl) : secreted in our sweat (from sweat glands). Salt creates a hypertonic environment, which dehydrates pathogens

5 important questions on Immunology - Lecture Thirty : Introduction to immunology and the immune system

What is immunology ? How does the immune system protect the body?

Immunology is the study of organisms defense system (immune system) in health and disease.

The immune system is an organised system of organs, cells and molecules that interact together to defend the body against disease
The immune system is composed of organs (spleen), cells (T cells) and molecules (antibodies)

What are the main features of the human lymphatic system ?

PRIMARY LYMPHOID ORGANS : produce white blood cells (leukocytes)

Thymus : where T Cells (White Blood Cells) become more mature and learn not to react to itself
Bone Marrow : source of stem cells that develop into immune cells of the innate and adaptive immune responses

SECONDARY LYMPHOID ORGANS : initiate immune responses

Lymph nodes : Located along lymphatic vessels and is the site where lymph fluid is filtered into from the tissues and an immune response is initiated.
Spleen : initiates immune responses against blood-borne pathogens

What are the physical and chemical barriers of skin that prevent pathogen entry into the body ?

Physical barrier :

Epidermis : most superficial layer. Made of dead cells, and keratin. Provide a physical barrier for pathogens trying to enter the body
Dermis : thick layer of connective tissue, collagen, and blood vessels. Provide a physical barrier for pathogens trying to enter the body
Both the epidermis and dermis contain phagocytic immune cells that phagocytose any pathogens

Chemical barrier:

Antimicrobial peptides : poke holes in microbial cell membranes
Lysozyme : is an enzyme that breaks down bacterial cell walls
Sebum : makes skin more acidic
Salt (NaCl) : secreted in our sweat (from sweat glands). Salt creates a hypertonic environment, which dehydrates pathogens

What are the 2 arms of the immune system ? What are the main features ?

The 2 arms of the immune system are Innate Immunity and Adaptive Immunity
INNATE IMMUNITY :

Born with it
Rapid (occurs in hours)
Fixed and has no specific memory against pathogens

ADAPTIVE IMMUNITY :

Responses starts slowly and improves over time
Slower (days to weeks)
Variable response depending on pathogen
Highly specific response to pathogen
Has long term memory

What are some examples of diseases affected by the immune response ?

Infectious diseases like HIV/AIDS - caused by pathogens, or viruses and bacteria which cause this disease
Inflammatory disease like Arthritis, allergies and autoimmune diseases
Cancer