Immunity and Disease Flashcards

1
Q

2 main pathways of the immune system

A

Innate

Adaptive

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2
Q

Innate immunity

A
Defense mechansims present even before infection or activated in a non-specific way
Skin, mucous membranes
Phagocytic cells (neutrophils, macrophages), inflammation, fever
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3
Q

Adaptive immune reponse

A

Cell-mediated immunity

Humoral immunity

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4
Q

Non-specific defenses

A

Non-specific defenses are designed to prevent infections by viruses and bacteria
These include
Intact skin
Mucus and Cilia

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5
Q

Skin

A

Outer layer of keratin – mechanical barrier
Dead skin cells constantly sloughed off
hard for invading bacteria to colonize
Sweat and oils contain anti-microbial chemicals

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6
Q

Mucus Membranes

A

Normal flow of mucus washes bacteria and viruses off of mucus membranes
Cilia (hair-like projections on cells) – respiratory tract
Acid – stomach, vagina
Enzymes – saliva, eye

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7
Q

Chemical barriers

A

Proteins
Complement - works with other defence mechanisms of the body
Interferons - inhibit the replication of many viruses

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8
Q

Cellular defenses - Phagocytosis

Granulocytes

A

Neutrophils, eosinophils, basophils
Remove dead cells and micro-organisms
Attracted by an inflammatory response of damaged cells

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9
Q

Cellular defenses - Phagocytosis

Monocytes

A

macrophages
In tissues which serve as filters for trapping microbes
Macrophages live longer than granulocytes
Attracted by different stimuli and usually arrive at sites of invasion later than granulocytes
Stimulate specific immune response (‘antigen-presenting’)

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10
Q

Non-specific responses to infection

A

Macrophages release protein signals
interleukin-1 (IL-1) and interleukin-6 (IL-6)
Fever
Most bacteria grow optimally at temp below body temp
Pain, swelling, redness
Increasing capillary permeability, promoting blood flow, bringing more phagocytic cells
Acute-phase proteins released from liver
Bind to bacteria and activate complement proteins

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11
Q

Specific (adaptive) immunity

A

Relies on antigens
specific substances found in foreign microbes
Lymphocytes
Can travel swiftly around the body when carried along in the blood or lymph
Approx 2 x 10^12 lymphocytes in human body
Approx 1 % are in the bloodstream
Rest in lymphatic system

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12
Q

Lymphocytes

A

Produced in bone marrow
B-cells mature in bone marrow then concentrate in lymph nodes and spleen
T-cells mature in thymus
B and T-cells mature then circulate in the blood and lymph
Circulation ensures they come into contact with pathogens and each other

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13
Q

B-cells

A

Secrete antibodies
Humoral immunity
Recognise pathogens outside cells

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14
Q

T-Cells

A

Do not recognise free antigen - only recognise antigen presented by major histocompatibility complex – class I (all cells) or class II (APC)
Directly attack invaders (cytotoxic, CD8+, MHC I)
Cell-mediated immunity
Recognise pathogens that have entered cells
Also help B-cells (helper cells, CD4+, MHC II)

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15
Q

Cytotoxic T-cells

A

Seek out and destroy any antigens in the system, and destroy microbes “tagged” by antibodies
Some cytotoxic T-cells can recognize and destroy cancer cells
Variable region on T-cell receptor

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16
Q

Helper T-Cells

A

Stimulate B-cells

Activate cytotoxic - cells and macrophages to attack infected cells

17
Q

How do T-cells recognise an invader?

A

Detect antigen – protein marker on cell surface
If an antigen (“not self”) protein is encountered by a macrophage, it will bring the protein to a helper T-cell for identification.

If the helper T-cell recognizes the protein as “not self,” it will launch an immune response.

18
Q

Epitope

A

Fragment of antigen

19
Q

Signalling immune response

A

Helper T-cells (CD4+) stimulated by antigen  cytokines to stimulate B-cell division

20
Q

HIV destroys…

A

helper T-cells so immune response diminished

21
Q

B-Cells produce antibodies

A

Glycoproteins
Specific, hypervariable region
Different subtypes IgG, IgM, IgA, IgE, IgD

22
Q

Immune System

A

Vital for survival but can be a double-edged sword
Immunodeficiency – prone to infections
Overactive immune system- hypersensitivity reactions
Failure to recognise self- autoimmune diseases

23
Q

deficient immune system

A
Drugs-
Chemotherapy
Immunosuppressive Medication 
Splenectomy
Bone Marrow Dysfunction
HIV – Human Immunodeficiency Virus
- Retrovirus               
- Infects CD4+ T cells
- causes AIDS (Acquired Immunodeficiency Syndrome)
Important to know if a patient is immunosupressed
More prone to infection
Significantly alter the immune response of the patient to infection
Malnutrition
Burns
Uremia
Diabetes mellitus
Immunotoxic medications
Self-medication of recreational drugs and alcohol
24
Q

AIDS

A

Acquired Immunodeficiency Syndrome

AIDS - decline in CD4+ T-cells, opportunistic infections

25
Q

HIV

A

Human Immunodeficiency Virus

26
Q

Hyperactive immune system

A

Hypersensitivity
Excessive immune reaction against harmless antigen.
Type 1 – Type 4 – based on mechanism.
Type 1 – Anaphylaxis/Allergy
e.g. Asthma, Rhinitis (Hay fever), Peanut allergy.
- Sensitization first step.

Over reaction to pathogen
Systemic Inflammatory Response Syndrome

27
Q

Autoimmune Diseases

A

Type 1 Diabetes Mellitus
Coeliac Disease
Multiple Sclerosis
Hashimoto’s Thyroiditis

28
Q

Type 1 Diabetes Mellitus

A

In type 1 diabetes, the pancreas doesn’t produce any insulin – the hormone that regulates blood glucose levels. This is why it’s also sometimes called insulin-dependent diabetes.
If the amount of glucose in the blood is too high, it can, over time, seriously damage the body’s organs.

29
Q

Coeliac Disease

A

Coeliac disease isn’t an allergy or an intolerance to gluten.
In cases of coeliac disease, the immune system mistakes substances found inside gluten as a threat to the body and attacks them.
This damages the surface of the small bowel, disrupting the body’s ability to absorb nutrients from food.

30
Q

Multiple Sclerosis

A

MS is an autoimmune condition. This means your immune system mistakes the myelin for a foreign substance and attacks it. The myelin becomes inflamed in small patches (called plaques or lesions), which can be seen on an MRI scan.
This can disrupt the messages travelling along nerve fibres. It can slow them down, jumble them, send them down a different nerve fibre, or stop them from getting through completely.
When the inflammation goes away, it can leave behind scarring of the myelin sheath (known as sclerosis). These attacks can eventually start to destroy the myelin sheath (demyelination), which can damage the underlying nerve fibre.

31
Q

Hashimoto’s Thyroiditis

A

Hashimoto’s thyroiditis is an autoimmune condition. This means your immune system mistakenly attacks your thyroid gland, causing it to gradually swell and become damaged.
As the thyroid gland is slowly destroyed over time, it is unable to produce sufficient amounts of thyroid hormone. The medical term for low levels of thyroid hormone in the blood is hypothyroidism.
This leads to symptoms of an underactive thyroid gland, which are very general and can include:
fatigue
weight gain
constipation
dry skin
depression
The swollen thyroid gland may also cause a lump to form in your throat, known as a goitre.
It may take months or even years for the condition to be detected, because the disease progresses very slowly.
The cause of Hashimoto’s thyroiditis is not understood, but it sometimes appears to run in families, suggesting your genes may make you more likely to develop the condition.
Hashimoto’s thyroiditis is also associated with other autoimmune conditions, such as Addison’s disease and type 1 diabetes. It is usually seen in women aged 30 to 50.
Hashimoto’s thyroiditis cannot be cured, so the low levels of thyroid hormone are usually permanent. However, the symptoms are often easily treated with the thyroid hormone replacement medication levothyroxine, which is usually taken for life.
Surgery is only rarely needed, for instance if your goitre is particularly uncomfortable or there are suspicions of cancer.

32
Q

Vaccination

A

Active Immunity

Stimulate own immune system to elicit adaptive immune response, prevent future infection.

33
Q

Live (Attenuated) Vaccines

A

live, weakened pathogen

e.g. MMR

34
Q

Inactivated Vaccines

A

inactivated, part of pathogen

e.g. Hepatitis B

35
Q

Toxoid Vaccines

A

bacterial toxin

e.g. Diptheria

36
Q

Conjugated Vaccines

A

antigen linked to protein carrier

e.g. Pneumococcal