Chapter 9 - immunity and infection Flashcards
What is the presence of countless microscopic organisms around, on, and in us referred to?
Microbiota or Microbiome.
Are most microbes beneficial or harmful?
Most microbes are beneficial, but some can cause disease.
How is an infection defined?
An infection is the invasion of the body by microorganisms.
What is a pathogen?
A pathogen is a microorganism that causes disease.
What is a reservoir?
A reservoir is a natural environment in which a pathogen typically lives.
What does the portal of exit refer to?
The portal of exit refers to how the pathogen exits the reservoir.
What are the two means of transmission?
Means of transmission can be direct or indirect.
What are vectors in the context of pathogens?
Vectors are insects, rodents, or other organisms that carry and transmit a pathogen from one host to another.
How can a pathogen enter the body through the portal of entry?
The portal of entry can either be through direct contact or penetration of the skin, inhalation, or ingestion.
What is a systemic infection?
A systemic infection is an invasion by a microorganism that spreads through the blood or lymphatic system to large portions of the body.
what are factors that determine whether the pathogen will be able to establish itself and cause infection?
the host’s immune response, the type of pathogen, the portal of entry, and the overall health and susceptibility of the host.
How does the process of pathogen entry into the body begin?
It starts when a pathogen, like bacteria, enters the body through means such as touching contaminated surfaces or inhaling airborne particles.
What happens during the incubation period of an infection?
The pathogen needs time to replicate and establish itself in the body, a phase known as the incubation period, during which the infection takes hold.
Are symptoms typically present during the incubation period?
No, often, the person doesn’t experience symptoms during the incubation period, even though the pathogen is present and replicating.
When do symptoms of an infection usually begin to appear?
Symptoms start to appear as the pathogen multiplies and begins affecting tissues or organs.
What is the goal of the body’s immune system during an infection?
The goal is to recognize and eliminate harmful bacteria, initiating a response to clear the infection.
What preventive measure is emphasized today to interrupt the chain of infection?
Continuous handwashing is emphasized as a highly effective preventive measure, helping remove pathogens from the hands and reducing the risk of transmission
What is the immune system?
It’s the body’s collective physical and chemical defenses against foreign organisms and pathogens.
What role does the immune system play in the body?
It serves as our first line of defense, protecting against foreign invaders and pathogens.
What is the primary function of the skin in relation to microorganisms?
The skin prevents microorganisms from entering the body.
How do membranes contribute to protecting the body against unwanted organisms?
Membranes protect us when the skin does not cover an area, as the cells within the membrane are designed to prevent the passage of unwanted organisms and particles.
What are cilia, and how do they function in the body’s defense?
Cilia are cells with hair-like protrusions that sweep foreign matter up.
Example: in the lungs; trapping particles like smoke.
What is the function of neutrophils in the immune system?
Neutrophils act as first responders, traveling in the bloodstream to areas of invasion, attacking, and ingesting pathogens.
Neutrophils are a type of white blood cell, also known as leukocytes.
Describe the role of neutrophils in infections.
Neutrophils are pivotal in the initial immune response, swiftly reacting to infections or foreign pathogens upon the body’s encounter with them.
What is the primary function of macrophages in the immune system?
Macrophages are large immune cells that engulf and devour pathogens and worn-out cells, serving as frontline defenders stationed in various tissues throughout the body.
Where are macrophages notably present, and how do they contribute to tissue defense?
Present in the lungs and contribute to tissue defense by engulfing and digesting foreign particles or pathogens.
They play a critical role in the body’s defence system.
What is the unique ability of natural killer (NK) cells in the immune system?
NK cells directly destroy virus-infected and cancerous cells.
Where do dendritic cells reside, and what is their role in the immune system?
- Dendritic cells reside in tissues.
- They eat pathogens, and activate lymphocytes.
What is the role of B cells in immune responses, and what is their natural ability?
Relationship to antibodies.
B cells play a key role in immune responses by producing antibodies, and they have a natural ability to create antibodies that recognize and neutralize harmful particles in the body.
Antibodies play a crucial role in the immune system’s defense against in
What is the function of T cells in the immune system, and where do they arise?
T cells coordinate immune responses, arise in bone marrow, and are crucial for the body’s defense against infections.
Where do T cells mature, and where do B cells mature?
T cells mature in the thymus after arising in the bone marrow, while B cells mature in the bone marrow.
What is the role of Helper T cells in the immune system?
Helper T cells activate other T cells and may help B cells.
What is the function of Killer T cells in the immune system?
Killer T cells kill body cells invaded by foreign organisms and cells that have turned cancerous.
How long do Memory T and B cells last, and why are they crucial?
Memory T and B cells last for years and are crucial for recognizing specific pathogens to prevent illness.
What are antibodies, and what is their role in the immune system?
Antibodies are specialized proteins produced by white blood cells that recognize and neutralize specific microbes.
Define autoimmune disease, and provide an example of its occurrence.
An autoimmune disease is when the immune system attacks the person’s own body. An example is lupus.
What are antigens, and how do immune system cells recognize them?
Antigens are like identification tags that help the immune system recognize and respond to foreign invaders, such as bacteria, viruses, or other harmful substances. They can also be found on the surface of cells, including our own cells.
When antigens enter circulation, what does the immune system do?
The immune system identifies antigens, and the body responds based on whether it recognizes the antigen as harmful or not.
Describe the process when the immune system identifies a harmful cell.
If the antigen is identified as a harmful cell, the immune system engulfs it to neutralize the threat.
Explain the targeting process of harmful cells by the immune system.
The immune system targets and tackles harmful cells through interactions between antibodies and antigens.
How are antibodies and antigens viewed in the immune system?
Antibodies are considered good, while antigens are recognized as bad in the immune system.
What is the role of histamine in allergic reactions?
Histamine, produced by MAST cells (white cell that is part of the immune system), causes the dilation and increased permeability of blood vessels in allergic reactions.
What are the effects of histamine in the body during an allergic reaction?
Histamine leads to increased heat, swelling, and redness in the affected area.
What is the potential impact of taking antihistamines daily on the body’s adaptation response to exercise?
jeopardize the body’s adaptation response to exercise by blocking the benefits of exercise-induced adaptations.
What are the two types of immune responses to invading pathogens?
The two types of immune responses are natural (innate) and acquired (adaptive).
Which cells are part of the natural immune response, and what is their characteristic regarding past infections?
Neutrophils, macrophages, dendritic cells, and natural killer cells are part of the natural immune response, and they have no memory of past infections.
Which cells are involved in the acquired immune response, and what distinguishes them in terms of memory?
T and B cells are part of the acquired immune response, and they develop a memory for the antigen. This memory lasts throughout an individual’s life.
What is the usual outcome when an individual with acquired immunity encounters an antigen?
With acquired immunity, encountering an antigen typically does not result in illness, as the immune system remembers and effectively responds to the antigen.
what is immunity?
to mechanisms that defend the body against infection; specific defenses against specific pathogens
what is acquired immunity?
the body’s ability to mobilize the cellular memory of an attack by a pathogen to throw off subsequent attacks; acquired through vaccination and the normal immune response.
immune response: phase 1
Viruses invade the body and replicate within body cells
immune response: phase 2
helper t cells trigger the production of killer t cells and b cells.
immune response: phase 3
killer t cells and natural killer cells destroy infected cells, while b cells produce antibodies to mark viruses for destruction
immune response: phase 4
t cells halt the immune response. memory b and t cells are preserved for future quick responses to the same virus.
What is incubation?
the phase when bacteria or viruses multiply within the body’s cells. it often lacks symptoms but can be contagious, as infectious microbes can be present.
what is immunization?
the process of conferring immunity to a pathogen by administering a vaccine.
what is a vaccine?
a preparation of killed or weakened microorganisms, inactivated toxins, or components of microorganisms that is administered to stimulate an immune response
what does a vaccine protect against?
future infection by the pathogen.
what is an allergy?
the body’s defence system goes haywire.
what do allergies result from?
a hypersensitivity and overactive immune system.
what are allergy symptoms?
stuffy nose, sneezing, wheezing, skin rashes, and so on
what are some common allergens?
pollen
animal dander
dust mites and cockroaches
molds an mildew
foods
insect stings
what are most allergic reactions due to the production of?
a special antibody know as immunoglobulin
what is immunotherapy?
a treatment that enhances the body’s immune system to fight diseases. can be used for cancer or allergies.
what is anaphylaxis?
severe hypersensitive reaction to an allergen characterized by difficulty breathing, low blood pressure, heart arrhythmia, seizure and sometimes death
how do you treat anaphylaxis?
epinephrine
what percentage of infectious diseases are responsible for death each year?
25 % (15 million)
what are bacteria?
microscopic single-celled organisms. Most abundant living things on earth. can be both helpful or harmful.
what is pneumonia?
inflammation of the lungs
what is meningitis?
infection of membranes covering brain and spinal cord
what is tuberculosis?
affect the lungs
what are anti biotics?
synthetic or naturally occurring substances used as drugs that kill bacteria. they interrupt the production of new bacteria.
when does antibiotic resistance occur?
when antibiotics are misused or overused, and pathogens become resistant to their effects.
what is the structure of a virus?
composed of nucleic acid surrounded by a protein coat.
What distinguishes viruses from normal cells in terms of metabolism and reproduction?
Viruses lack independent metabolism and can only reproduce within a host cell. They lack enzymes for energy production and protein synthesis found in normal animal cells
How do viruses obtain what they need for growth and reproduction?
Viruses are parasitic and take what they need from the cells they invade. They cannot grow or reproduce independently.
What is a characteristic of contagious diseases caused by viruses?
Viruses cause contagious diseases, as they invade host cells, take resources for growth, and can be transmitted from person to person.
What are common symptoms of influenza?
Influenza, an infection of the respiratory tract, can lead to symptoms like fever, extreme fatigue, and, in severe cases, life-threatening complications such as pneumonia. It is highly contagious.
what is an outbreak?
a greater than expected number of new cases of a disease in a defined area
what is an epidemic?
a greater than expected number of new cases of a disease affecting a larger population or region
what is a pandemic?
a greater than expected number of new cases of a disease affecting multiple countries around the world at the same time.
What gives the COVID-19 virus a “crown-like” effect on its surface?
The COVID-19 virus has spike proteins on its surface, giving it a “crown-like” appearance.
Why was everyone initially susceptible to COVID-19?
COVID-19 was a novel virus, and there was no pre-existing immunity, making everyone susceptible. Over 6 million people are known to have died from COVID-19.
How is COVID-19 primarily spread?
COVID-19 is primarily spread through aerosol and droplet transmission. Wastewater surveillance, tracking the virus in sewage, provides information on disease burden trends.
What is a cytokine storm in the context of COVID-19?
In severe cases of COVID-19, a cytokine storm may occur. This involves an excessive immune response, where the immune system releases an overabundance of small proteins called cytokines. This robust response can lead to widespread inflammation and organ damage.
What is Long COVID?
the lingering symptoms or new health issues experienced by some individuals even after recovering from the acute phase of COVID-19. Symptoms can vary and affect different organs, including persistent fatigue, shortness of breath, chest pain, and difficulty concentrating.
