Unit 4 AOS 1 Biology - Dealing With Disease

What are antigens?

Molecules that can interact with the immune system, made of DNA, RNA, sugars, or protein.

What distinguishes self-antigens from non-self antigens?

Self-antigens identify cells as 'self' to prevent immune system attack, while non-self antigens are recognized as foreign.

What are MHCs?

Major Histocompatibility Complexes that are important self-antigens; MHC class I is found on all nucleated body cells, and MHC class II is found on specialized immune cells.

Why is blood type important in transfusions?

Receiving incompatible blood can cause the immune system to attack the transfused cells, posing serious health risks.

What is the significance of Type O blood?

Type O blood has no antigens, making it a universal donor, but individuals with Type O can only receive Type O blood.

What defines cellular pathogens?

Living agents with a cellular structure, including bacteria, fungi, worms, and protozoa.

What are examples of cellular pathogens?

Bacteria, fungi, worms, protozoa.

What are non-cellular pathogens?

Non-living agents that cannot replicate independently, including viruses and prions.

What happens when pathogens disrupt normal cell function?

Disease occurs.

What is an allergy?

A malfunction of the immune system that initiates a strong reaction to an allergen.

What is an allergen?

A non-pathogenic antigen that does not cause harm to the body.

What are common allergens?

Dust, insects, peanuts, and eggs.

What is the role of the immune system in recognizing non-self antigens?

The immune system responds to eliminate non-self antigens recognized as foreign.

What are the two categories of pathogens?

Cellular pathogens and non-cellular pathogens.

How do pathogens vary?

They can differ in shape and size.

What are some examples of viral diseases?

Viral diseases can be transmitted through vectors, reservoirs, and various routes.

What are fungal infections?

Infections caused by fungi, examples include tinea, ringworm, and thrush.

What is the immune response initiation process?

It includes antigen presentation and the distinction between self and non-self antigens.

What is the difference between cellular and non-cellular pathogens?

Cellular pathogens are living and have a cellular structure, while non-cellular pathogens are non-living and lack a typical cellular structure.

What is the innate immune system?

A system composed of generalized and non-specific defenses and responses to pathogens.

What characterizes the first line of defence in the immune system?

The presence of physical, chemical, and microbiological barriers to keep pathogens out.

What are physical barriers in plants?

Thick bark, waxy cuticles of leaves, galls, thorns, trichomes, and closing of stomata.

What is the role of chemical barriers in plants?

To inhibit the growth of pathogens and/or destroy them using harmful chemicals.

What are some examples of chemical barriers in plants?

Chitinases, phenols, defensins, saponins, oxalic acid, and glucanases.

What are the physical barriers in animals?

Intact skin and mucous secretions in various tracts that prevent pathogen entry.

How do mucous secretions and cilia function in the respiratory tract?

They trap organisms and sweep them away into the throat for destruction.

What are some chemical barriers in animals?

Lysozymes in tears, acidic sweat, stomach acid, antibacterial compounds in earwax, and low pH in the vagina.

What is the function of lysozyme enzymes?

To destroy bacterial cell walls in tears and saliva.

How does stomach acid act as a chemical barrier?

It destroys pathogens that have been ingested.

What are microbiological barriers in animals?

The presence of non-pathogenic bacteria that prevent the growth of pathogenic microorganisms.

Where can normal flora be found in the body?

On the skin, in the lower gastrointestinal tract, and in the vagina.

What is the overall function of the first line of defence?

To prevent or impede the entry of pathogens into the host organism.

How do physical barriers prevent pathogen entry?

By acting as a barrier to block pathogens from entering the body.

What is the role of chemical barriers in the immune response?

To inhibit the growth or development of pathogens and/or destroy them.

What do microbiota barriers do?

They compete for space and resources to prevent the colonization of pathogenic microorganisms.

What is the significance of the first line of defence in the immune system?

It serves as the initial protective layer against infections and diseases.

What happens when physical barriers are compromised?

Pathogens may enter the body and cause infections.

What is the effect of closing stomata in plants?

It prevents pathogen invasion during carbon dioxide uptake.

What are trichomes and what is their function?

Hair-like structures on plants that deter insects and grazers.

What do phenols do in response to wounding in plants?

They repel or kill invading microorganisms.

What is the function of saponins in plants?

They disrupt the cell membranes of various fungi.

What is the role of glucanases in plant defense?

They defend plants against fungal infections.

What is the second line of defence in the immune system?

The second line of defence consists of various leukocytes (white blood cells) that destroy pathogens and prevent infection spread.

What type of immune response does the second line of defence represent?

The innate immune response, which is non-specific and immediate.

What are the key components of the innate immune response?

Physical barriers like skin and mucous membranes, phagocytes, natural killer cells, antimicrobial peptides, and proteins.

What role do phagocytes play in the immune response?

Phagocytes, such as macrophages and neutrophils, engulf and digest foreign invaders.

What are natural killer (NK) cells responsible for?

NK cells target and destroy infected or cancerous cells.

What are the signs of inflammation in the innate immune response?

Redness, heat, swelling, and pain.

How do macrophages and dendritic cells connect the innate and adaptive immune responses?

They act as antigen-presenting cells (APCs) that present foreign antigens to the adaptive immune system.

What is phagocytosis?

The process by which phagocytes engulf and destroy foreign or dead material.

What are the steps in antigen presentation by antigen-presenting cells?

1. Engulf pathogen via endocytosis. 2. Fuse vesicle with lysosome. 3. Degrade pathogen with enzymes. 4. Present fragments on cell surface via MHC Class II.

What is the role of MHC Class II in antigen presentation?

MHC Class II presents foreign antigens from digested pathogens to the adaptive immune system.

What happens when natural killer cells detect an infected or cancerous cell?

They recognize the abnormal cell and release toxic chemicals to induce apoptosis.

What are perforin and granzymes?

Perforin is a protein that forms pores in target cells, while granzymes are toxic proteins that enter through these pores to trigger cell death.

What is the function of complement proteins in the immune response?

Complement proteins help to destroy pathogens and promote inflammation.

What is the primary characteristic of the innate immune response?

It is non-specific and responds immediately to a wide range of pathogens.

How do macrophages contribute to tissue repair during an infection?

They help isolate the infected area and recruit other immune cells to promote healing.

What is the difference between the innate and adaptive immune responses?

The innate response is immediate and non-specific, while the adaptive response is slower but provides a targeted and long-lasting defense.

What is the role of eosinophils in the immune response?

Eosinophils are involved in combating multicellular parasites and certain infections, as well as in allergic reactions.

What triggers the inflammatory response?

Infection or injury to tissues, leading to the recruitment of immune cells and the release of inflammatory mediators.

What types of cells are included in the category of leukocytes?

Neutrophils, macrophages, dendritic cells, eosinophils, natural killer cells, and mast cells.

What is the significance of the innate immune system's physical barriers?

They serve as the first line of defense against invading pathogens.

How do mast cells contribute to the immune response?

Mast cells release histamines and other chemicals that promote inflammation and recruit other immune cells.

What is the role of dendritic cells in the immune system?

Dendritic cells capture antigens and present them to T cells, linking the innate and adaptive immune responses.

What triggers apoptosis in target cells?

Granzymes trigger apoptosis, leading to controlled cell destruction without inflammation.

What are eosinophils?

Eosinophils are large granulated cells that contain toxic chemical mediators to help destroy invading pathogens.

How do eosinophils destroy large pathogens?

Eosinophils degranulate on contact with large pathogens, releasing chemical mediators.

What are the main cells involved in the innate immune response?

Phagocytes, Antigen-Presenting Cells (APCs), and Granulocytes.

What role do macrophages play in the immune response?

Macrophages are phagocytes that engulf and digest pathogens and debris.

What are interferons?

Interferons are proteins released by host cells in response to viruses, tumors, or other pathogens, acting as signaling molecules.

What is the function of complement proteins?

Complement proteins enhance the immune response by opsonization, chemotaxis, and lysis of pathogens.

What is opsonization?

Opsonization is the process where complement proteins bind to pathogens, making them easier for phagocytes to recognize.

What is chemotaxis in the context of the immune response?

Chemotaxis is the process where complement proteins attract phagocytes to the site of infection.

What is lysis in relation to complement proteins?

Lysis occurs when complement proteins form a membrane attack complex (MAC) that creates pores in pathogen membranes, causing them to burst.

What is the inflammatory response?

The inflammatory response increases blood flow to an injured area, bringing immune cells to help clear debris and fight pathogens.

What are the characteristic signs of inflammation?

Swelling, pain, heat, and redness.

What initiates the inflammatory response?

Macrophages and damaged cells release cytokines and histamine, activating the response.

What effect does histamine have during inflammation?

Histamine causes vasodilation, increasing blood flow and permeability of blood vessels.

What is the role of mast cells in the immune response?

Mast cells degranulate and release histamine in response to injury or allergens.

What happens during the migration phase of inflammation?

Phagocytes and complement proteins leave the bloodstream to enter the site of injury.

What is a fever?

A fever is an increase in body temperature that helps fight infection by creating an unfavorable environment for pathogens.

What can happen if a fever lasts too long?

If a fever lasts too long, it can be harmful as it may impair cell function.