T6 Flashcards
What is lysozyme?
An enzyme found in tears, saliva and nasal secretions that kill bacteria by breaking down the cell wall.
## Footnote
Lysozyme plays a crucial role in the body’s first line of defense against infections.
What initiates inflammation at sites of injury?
Damaged white blood cells and mast cells release histamine
Histamine is a key mediator in inflammatory responses.
What effect does histamine have on arterioles?
Causes neighbouring arterioles to dilate, increasing blood flow in capillaries at the infection site
This dilation is part of the body’s response to injury or infection.
What happens to capillary permeability during inflammation?
Increases, allowing plasma fluid, white blood cells, and antibodies to leak into the tissue
This leakage contributes to swelling (oedema) at the injury site.
What is the result of white blood cells leaking into tissue during inflammation?
Causing oedema (swelling)
Oedema is a common sign of inflammation.
What is phagocytosis?
The process where white blood cells engulf foreign matter
Phagocytosis is a critical mechanism of the immune response.
Which white blood cells are involved in phagocytosis?
First neutrophils, then macrophages
Neutrophils are usually the first responders to sites of infection.
What occurs after a white blood cell engulfs a bacterium?
It encloses the ingested material in a vacuole
This vacuole is essential for the subsequent digestion of the foreign material.
What happens when lysosomes fuse with the vacuole during phagocytosis?
Digestive enzymes cause destruction of foreign matter
This is a key step in eliminating pathogens from the body.
What forms at the site of infection after a few days?
Pus, which is often reabsorbed by tissue
Pus consists of dead cells, bacteria, and immune cells.
What do lymph nodes contain?
A mass of lymphocytes and macrophages
Lymph nodes are vital for filtering pathogens from lymphatic fluid.
What is the role of lymph nodes in the immune response?
To ensure that any live bacteria that enter the blood and lymph do not spread through the body
Failure of this function can lead to septic shock.
What is the function of interferon?
Provides defense against viruses
Interferon is a signaling protein that plays a significant role in the immune response.
How do infected cells utilize interferon?
Infected cells release interferon, which diffuses to surrounding cells
This helps inhibit microbial protein synthesis and prevents viral spread.
True or False: Phagocytosis is only performed by macrophages.
False
Neutrophils also play a critical role in phagocytosis.
What is specific immunity dependent on?
Specific immunity is dependent on lymphocytes, specifically B and T cells.
What type of cells respond to non-self antigens?
B and T cells respond to non-self antigens.
What happens during the initial pathogen entry?
Macrophage engulfs bacterium, pathogen is destroyed, macrophage presents antigens and becomes an antigen-presenting cell.
What is the role of the antigen-presenting cell (APC)?
APC binds to a T helper cell with a complementary receptor.
What occurs after a T helper cell is activated?
The T helper cell divides into active T helper cells and T memory cells.
How do B cells become antigen-presenting cells?
Antigen binds to B cell with complementary receptor.
What is the function of T Killer Cells?
T Killer Cells are activated when binding to APCs with complementary receptors.
What stimulates the differentiation of T Killer Cells?
Cytokines from T helper cells stimulate differentiation into active and memory T Killer cells.
What is clonal selection?
Clonal selection involves activated T helper cells binding to APCs and stimulating cloning of B cells.
What do B effector cells differentiate into?
B effector cells differentiate into plasma cells.
What do plasma cells secrete?
Plasma cells secrete antibodies.
What is the role of antibodies in the immune response?
Antibodies bind to antigens and mark pathogens for destruction.
What do active T Killer Cells do to infected APCs?
Active T Killer Cells bind to infected APCs and release chemicals to cause lysis.
What happens during a secondary immune response?
The immune system responds much faster due to the involvement of memory cells.
How do B memory cells contribute to the secondary immune response?
B memory cells produce antibodies at a faster rate and in greater quantities.
True or False: The rapid response during a secondary immune response means that symptoms are often noticeable.
False.
What results from the rapid response of the immune system during a secondary infection?
The person is often unaware of any symptoms and is now immune to the disease.
What are the 4 stages of inflammation?
- Damaged white blood cells and mast cells release histamine.
- Histamine causes neighbouring arterioles to dilate,increasing blood flow in capillaries at infection site, and also increasing capillary permeability.
- Plasma fluid, WBC and antibodies leak into tissue causing oedema (swelling).
- Infecting microbes can be destroyed by WBC.
What are the 3 stages of phagocytosis?
- WBC engulfs bacterium or cell debris and encloses this ingested material in a vacuole.
- Lysosomes containing digestive enzymes fuse with the vacuole, causing destruction of foreign matter.
- After a few days, the site if full of dead cells, forming pus, which is often reabsorbed by tissue.
Lymph nodes
.containing a mass of lymphocytes and macrophagesto ensure that any live bacteria which enters the blood and lymph do not spread through the body. If this fails, septic shock results.
Interferon.
Provide deference against viruses; infected cells release interferon which diffuse to surrounding cells where microbe multiplication is prevented by inhibiting microbial protein synthesis.
