Week 11 Flashcards
(35 cards)
What are host defenses categorized into?
Host defenses are categorized into innate (nonspecific) and adaptive (specific) defenses.
What is the goal of the body’s host defenses?
To detect, fight, and eliminate invading pathogens.
What is innate immunity?
Rapid, lacks specificity and memory
What are the components of the first line of defense in the body?
The physical and biochemical barriers of the skin and mucous membranes.
What is the role of epidermal dendritic cells in the skin?
They are immune cells that engulf and destroy pathogens through phagocytosis.
What is the biochemical role of the skin in immunity?
The skin maintains a dry, slightly acidic environment to discourage microbial growth and has fatty acids that are toxic to certain bacteria.
How do lysozymes contribute to immune defense?
They are enzymes found in sweat, tears, and saliva that break the NAM-NAG bonds in bacterial peptidoglycan, damaging bacterial cell walls.
What are defensins?
Small proteins with broad-spectrum activity against pathogens.
What role do mucous membranes play in immunity?
They provide a physical and chemical barrier against pathogen entry in systems like the respiratory, digestive, and urogenital tracts.
What are the components of mucous?
Mucous is made of carbohydrates and glycoproteins, which trap pathogens and prevent attachment to epithelial cells.
How do mechanical defenses like sloughing work in immunity?
Continuous shedding of epithelial cells removes pathogens from the body surface.
What is peristalsis?
Rhythmic muscular contractions in the GI tract that help expel microbes.
What is MALT (Mucosa-Associated Lymphoid Tissue)?
Clusters of immune cells located in mucosal tissues that detect and respond to pathogens.
What is the function of the lacrimal apparatus in immunity?
It flushes microbes from the eyes and prevents infection by tearing.
What are the mechanisms of defense in the respiratory tract?
Mucous traps inhaled microbes, cilia move trapped pathogens upward towards the throat, and coughing/sneezing expel irritants and microbes.
How does the stomach contribute to the first line of defense?
The stomach’s acidic environment destroys many ingested pathogens, and iron-binding proteins limit pathogen growth by restricting iron access.
What is the role of transferrin?
Transferrin is an iron-binding protein that circulates in the blood, isolating iron to prevent microbial access.
What are siderophores?
Molecules secreted by some bacteria that bind iron with high affinity, helping them steal iron from host, promoting growth of bacteria
How does normal microbiota contribute to immune defense?
It competes for nutrients and space, produces essential vitamins, and stimulates the innate immune system, enhancing the first line of defense.
What are the key properties of the innate nonspecific immune response?
It is rapid, lacks specificity, has no memory, and cannot distinguish between self and non-self.
What are granulocytes and their role in immunity?
Basophils, mast cells, neutrophils, and eosinophils are involved in inflammatory responses and phagocytosis.
How do neutrophils and eosinophils contribute to immunity?
They phagocytize pathogens and can move out of blood vessels to infection sites through diapedesis.
What do natural killer cells do?
They target and destroy infected or abnormal cells without prior exposure to them.
What is the role of monocytes and macrophages?
Monocytes mature into macrophages that process and present antigens and participate in phagocytosis.
