Topic 4 - Non specific diseases

Question 1

examples of mechanical barriers

Answer 1

1. GI tract (peristalsis)
2. urinary traction (urination)
3. eye - tearing and blinking
4. Lower respiratory tract (mucociliary escalator)

Question 2

Biochemical barriers

Answer 2

skin - keratin, salt, certain fatty acids
stomach - acid and low ph
respiratory tract - mucus
blood - transferrins (sequesters bodily iron and keeps it from pathogens)
lysozyme - anti-bacterial enzyme found in person’s tears, nasal secretions, and saliva
normal flora of L.I. bacteriocins

Question 3

three types who biological activity is related to their ability to damage bacterial plasma membranes

Answer 3

cationic peptides

Question 4

three types of cationic peptides

Answer 4

1. first class: linear, alpha-helical peptides that lack cysteine amino acids residues (cathelicidin - produced by a variety of cells)
2. second class: defensins (peptides that are open ended, rich in arginine and cysteine, and disulfide linked)
3. third class: larger peptides that are enriched for specific amino acids and exhibit regular structural repeats (histanine, present in human saliva, has anti-fungal activity)

Question 5

Neutrophils

percentages
most present when?
when do they arrive during inflammation?
important component of them?

Answer 5

60-70%
most numerous leukocyte during non-disease time
first ones to arrive during inflammation
important phagocytic cells

Question 6

Eosinophil

percentages?
what do they release to regulate inflammation?
when are they present? (in what kind of reaction)

Answer 6

2-4%
cytokines
allergic and parasitic reactions

Question 7

Basophils

percentages?
unique characteristic?
what do they release?

Answer 7

less than 1%
they are NOT phagocytic
release inflammatory mediators

Question 8

What percentage of leukocytes are monocytes?

Answer 8

3-8%

Question 9

When monocytes leave capillaries and enter tissues, what do they become?

Answer 9

Macrophages

Dendritic cells

Question 10

Most efficient macrophage
Secretes cytokines
APC

Answer 10

Macrophages

Question 11

In tissues
Phagocytic
Major APC of body

Answer 11

Dendritic cells

Question 12

Where do dendritic cells come from?

Answer 12

Lymphoid and myeloid lines

Question 13

Where are dendritic cells present?

Answer 13

Blood, skin, and mucous membranes of nose, lungs, and intestines

Question 14

What NK killer cells bind to?

Answer 14

Tumor cells - induce apoptosis
Viral infected host cells - induce apoptosis
Work larvae - release cytotoxic substances

Question 15

Purpose of phagocytosis

Answer 15

1. kill pathogen

2. antigen presentation - digest pathogen to present antigens to T-helper cells as a part of the specific response

Question 16

Phases of phagocytosis

Answer 16

1. Attraction/chemotaxis
2. Recognition/adherence of phagocyte to pathogen (PAMP/PRR, opsonins, can be inhibited by capsules/M proteins)
3. Indigestion (endocytosis/phagocytosis – invagination of cell membrane or with pseudopods)
4. Killing/digestion (lysosome, enzymes that digest cell, enzymes that release toxic O2 products that kill pathogen)
5. Expulsion of waste (exocytosis)
6. Antigen presentation to T helper cells

Question 17

What is complement?

Answer 17

A group of blood proteins that, when activated, function together to produce certain antibacterial chemicals

1. Inflammatory mediators (C3a, C5a) – (causes mast cell degranulation)
2. Opsonin - enhances phagocytosis (C3b)
3. Membrane attack complex (puts pores in cell membrane of prokaryotes) C5-C9

Question 18

What activates complement?

Answer 18

1. Prokaryotic polysaccharides

2. Antibody - due to prior exposure

Question 19

What is an interferon?

Answer 19

Chemical released by a host cell that has been invaded by a virus which binds to receptors on neighboring, yet to be infected cells, and induces an antiviral state in those neighboring cells

Question 20

Examples of physical barriers

Answer 20

1. epithelial cells
2. dermal cells
3. mucus membranes
4. normal flora

Question 21

Released from mononuclear phagocytes

Answer 21

Monokines

Question 22

Released from T lymphocytes

Answer 22

Lymphokines

Question 23

Released from one leukocyte and act on another leukocyte

Answer 23

Interleukins

Question 24

Stimulate growth and differentiation of immature leukocytes in bone marrow

Answer 24

Colony stimulating factors

Question 25

Stimulate chemotaxis and chemokinesis

Answer 25

Chemokines

Question 26

Acute phase protein

Answer 26

Macrophage activation by bacteria –> cytokine release –> liver stimulation –> acute phase protein production (includes C-reactive protein, mannan-binding lectin, surfactant proteins A and D [can bind bacterial surfaces and act as opsonins]