FIS2603 EXAM PACK
2025
QUESTIONS AND
ANSWERS
FOR ASSISTANCE CONTACT
EMAIL:
, lOMoARcPSD|46589353
PHYSIOLOGICAL DEFENCE MECHANISMS
Table of Contents
1. What is the Immune System?..................................................................................................................................... 3
2. Hematopoiesis.............................................................................................................................................................. 5
3. Erythropoiesis............................................................................................................................................................... 6
4. Regulation of Hematopoietic Stem Cells................................................................................................................... 7
5. May-Grunwald Giemsa Staining: A Method to Stain Bone Marrow Cells..............................................................8
6. Differentiation of Common Myeloid Progenitor Cells............................................................................................. 10
7. Phagocytosis............................................................................................................................................................... 11
8. Inflammation................................................................................................................................................................ 12
9. Phases of Wound Repair........................................................................................................................................... 15
10. Inflammatory Response I: Vascular and Cellular............................................................................................... 17
11. Inflammatory Response II: Inflammatory Exudate and Tissue Repair............................................................18
12. Cell-mediated Immune Responses..................................................................................................................... 19
13. Humoral Immune Responses............................................................................................................................... 21
14. Antibody Structure................................................................................................................................................. 23
15. Affinity and Avidity.................................................................................................................................................. 25
16. Cross-reactivity...................................................................................................................................................... 27
17. Infection.................................................................................................................................................................. 29
18. Stages of Infection................................................................................................................................................. 30
19. Defense Mechanism Against Infection................................................................................................................ 31
20. Cancer Prevention................................................................................................................................................. 32
21. Cancer Therapies.................................................................................................................................................. 34
22. Retrovirus Life Cycles........................................................................................................................................... 35
23. Viral Mutations....................................................................................................................................................... 37
24. Blood Transfusion and Agglutination................................................................................................................... 38
25. Allergic Reactions.................................................................................................................................................. 40
26. Allergic Drug Reactions........................................................................................................................................ 42
27. Phases of Wound Repair...................................................................................................................................... 43
28. X-linked Traits........................................................................................................................................................ 45
29. Introduction to the Integumentary System.......................................................................................................... 46
30. Accessory Structures of the Skin: Sweat Glands.............................................................................................. 47
31. Thermosensation................................................................................................................................................... 49
32. Homeostatic Imbalance........................................................................................................................................ 51
33. Mechanisms of Heat Transfer I............................................................................................................................ 52
34. Mechanisms of Heat Transfer II........................................................................................................................... 53
, lOMoARcPSD|46589353
PHYSIOLOGICAL DEFENCE MECHANISMS
1. What is the Immune System?
Transcript
The immune system is the body's natural system of the innate and adaptive defences, in
charge of providing resistance to diseases.
In the innate system, the first barriers, the skin and associated mucus membranes keep
invading microorganisms out of the body via a number of protective mechanisms.
For example, skin is both acidic and contains various bactericidal chemicals to inhibit
bacterial growth and elements like mucus-coated hairs in the nose trap inhaled particles
to prevent passage through the nasal passages.
Although these surface barriers are rather effective, when they are compromised, the
second line of internal defense is activated.
Now, phagocytic cells such as macrophages and mast cells, along with other non-
specific cells and chemicals are in charge. They mount an inflammatory response to
prevent the spread of infection.
The third line of defense, the adaptive system, responds by employing specific cells
called lymphocytes to precisely destroy the infectious agent themselves or through
circulating antibodies.
However, before such protection can be provided, the system must be primed, that is it
must have previously encountered the foreign substance, forming a memory to produce
a stronger attack.
Abstract
Overview
The immune system comprises diverse biological structures and processes that protect
the body from disease. These processes can be classified into innate and adaptive
immunity. To work effectively, the immune system needs to detect pathogens by
distinguishing the body’s own structures from foreign elements. If this determination fails,
autoimmune diseases occur in which the immune system reacts against the body’s own
tissue.
The Innate Immune System Acts Fast and Non-specifically
The innate immune system is the first line of defense against infection. It comprises
physical barriers and a variety of cells that act quickly and non-specifically against
elements that are foreign to the host (i.e., non-self). Examples of physical barriers in
mammals are skin, the lining of the gastrointestinal tract, and secretions, such as mucus
, lOMoARcPSD|46589353
or saliva. Once an invader overcomes physical barriers, cells of the inflammatory
response are recruited to the entry site: mast cells release a plethora of chemicals that
attract other cells of the innate immune system and activates the adaptive immune
system. Phagocytic cells, such as neutrophils and macrophages, ingest and destroy
pathogens. Natural killer cells, a special type of white blood cell, destroy virus-infected
cells. Together, cells of the innate immune system eradicate the invader or hinder its
spread and activate the adaptive immune system.
Pattern Recognition Receptors Enable Organisms to Distinguish Self from Non-self
How can an organism distinguish its own tissue (self) from a foreign element or invader
(non-self)? This ability is conferred by pattern recognition receptors (PRRs). These
receptors recognize microbe-associated molecular patterns (MAMPs) that are unique to
bacteria, viruses, parasites, or fungi. Examples are parts of the bacterial outer
membrane or double-stranded RNA of viruses. MAMPs are not specific to a distinct
species or pathogen variant but represent a hallmark of a broad class of pathogens (i.e.,
gram-negative bacteria or fungi). The innate immune system, therefore, acts non-
specifically against pathogens.
The Adaptive Immune System Is Highly Specific
Vertebrates evolved the adaptive immune system, which stores a “memory” of a previous
attack and can subsequently mount a stronger response against specific pathogens.
While the innate immune system employs a broad range of cell types, the adaptive
immune system relies on two kinds of white blood cells to target pathogens: B cells and
T cells. While T cells are part of the cell-mediated immunity, B cells constitute the
humoral branch of adaptive immunity.
B cells can directly destroy a foreign particle or differentiate into plasma cells that release
antibodies. Antibodies then target the invader for destruction by other cells. T cells
perform several functions, depending on their surface receptor composition and chemical
arsenal. All T cells carry surface receptors that are each specific to a single antigen. After
encountering the antigen, T cells can stimulate other parts of the immune system or
actively destroy infected or cancerous cells. Some B and T cells remain available long
after the infection has been cleared and, upon repeated exposure to the same foreign
element, mount a stronger and faster immune response.
2025
QUESTIONS AND
ANSWERS
FOR ASSISTANCE CONTACT
EMAIL:
, lOMoARcPSD|46589353
PHYSIOLOGICAL DEFENCE MECHANISMS
Table of Contents
1. What is the Immune System?..................................................................................................................................... 3
2. Hematopoiesis.............................................................................................................................................................. 5
3. Erythropoiesis............................................................................................................................................................... 6
4. Regulation of Hematopoietic Stem Cells................................................................................................................... 7
5. May-Grunwald Giemsa Staining: A Method to Stain Bone Marrow Cells..............................................................8
6. Differentiation of Common Myeloid Progenitor Cells............................................................................................. 10
7. Phagocytosis............................................................................................................................................................... 11
8. Inflammation................................................................................................................................................................ 12
9. Phases of Wound Repair........................................................................................................................................... 15
10. Inflammatory Response I: Vascular and Cellular............................................................................................... 17
11. Inflammatory Response II: Inflammatory Exudate and Tissue Repair............................................................18
12. Cell-mediated Immune Responses..................................................................................................................... 19
13. Humoral Immune Responses............................................................................................................................... 21
14. Antibody Structure................................................................................................................................................. 23
15. Affinity and Avidity.................................................................................................................................................. 25
16. Cross-reactivity...................................................................................................................................................... 27
17. Infection.................................................................................................................................................................. 29
18. Stages of Infection................................................................................................................................................. 30
19. Defense Mechanism Against Infection................................................................................................................ 31
20. Cancer Prevention................................................................................................................................................. 32
21. Cancer Therapies.................................................................................................................................................. 34
22. Retrovirus Life Cycles........................................................................................................................................... 35
23. Viral Mutations....................................................................................................................................................... 37
24. Blood Transfusion and Agglutination................................................................................................................... 38
25. Allergic Reactions.................................................................................................................................................. 40
26. Allergic Drug Reactions........................................................................................................................................ 42
27. Phases of Wound Repair...................................................................................................................................... 43
28. X-linked Traits........................................................................................................................................................ 45
29. Introduction to the Integumentary System.......................................................................................................... 46
30. Accessory Structures of the Skin: Sweat Glands.............................................................................................. 47
31. Thermosensation................................................................................................................................................... 49
32. Homeostatic Imbalance........................................................................................................................................ 51
33. Mechanisms of Heat Transfer I............................................................................................................................ 52
34. Mechanisms of Heat Transfer II........................................................................................................................... 53
, lOMoARcPSD|46589353
PHYSIOLOGICAL DEFENCE MECHANISMS
1. What is the Immune System?
Transcript
The immune system is the body's natural system of the innate and adaptive defences, in
charge of providing resistance to diseases.
In the innate system, the first barriers, the skin and associated mucus membranes keep
invading microorganisms out of the body via a number of protective mechanisms.
For example, skin is both acidic and contains various bactericidal chemicals to inhibit
bacterial growth and elements like mucus-coated hairs in the nose trap inhaled particles
to prevent passage through the nasal passages.
Although these surface barriers are rather effective, when they are compromised, the
second line of internal defense is activated.
Now, phagocytic cells such as macrophages and mast cells, along with other non-
specific cells and chemicals are in charge. They mount an inflammatory response to
prevent the spread of infection.
The third line of defense, the adaptive system, responds by employing specific cells
called lymphocytes to precisely destroy the infectious agent themselves or through
circulating antibodies.
However, before such protection can be provided, the system must be primed, that is it
must have previously encountered the foreign substance, forming a memory to produce
a stronger attack.
Abstract
Overview
The immune system comprises diverse biological structures and processes that protect
the body from disease. These processes can be classified into innate and adaptive
immunity. To work effectively, the immune system needs to detect pathogens by
distinguishing the body’s own structures from foreign elements. If this determination fails,
autoimmune diseases occur in which the immune system reacts against the body’s own
tissue.
The Innate Immune System Acts Fast and Non-specifically
The innate immune system is the first line of defense against infection. It comprises
physical barriers and a variety of cells that act quickly and non-specifically against
elements that are foreign to the host (i.e., non-self). Examples of physical barriers in
mammals are skin, the lining of the gastrointestinal tract, and secretions, such as mucus
, lOMoARcPSD|46589353
or saliva. Once an invader overcomes physical barriers, cells of the inflammatory
response are recruited to the entry site: mast cells release a plethora of chemicals that
attract other cells of the innate immune system and activates the adaptive immune
system. Phagocytic cells, such as neutrophils and macrophages, ingest and destroy
pathogens. Natural killer cells, a special type of white blood cell, destroy virus-infected
cells. Together, cells of the innate immune system eradicate the invader or hinder its
spread and activate the adaptive immune system.
Pattern Recognition Receptors Enable Organisms to Distinguish Self from Non-self
How can an organism distinguish its own tissue (self) from a foreign element or invader
(non-self)? This ability is conferred by pattern recognition receptors (PRRs). These
receptors recognize microbe-associated molecular patterns (MAMPs) that are unique to
bacteria, viruses, parasites, or fungi. Examples are parts of the bacterial outer
membrane or double-stranded RNA of viruses. MAMPs are not specific to a distinct
species or pathogen variant but represent a hallmark of a broad class of pathogens (i.e.,
gram-negative bacteria or fungi). The innate immune system, therefore, acts non-
specifically against pathogens.
The Adaptive Immune System Is Highly Specific
Vertebrates evolved the adaptive immune system, which stores a “memory” of a previous
attack and can subsequently mount a stronger response against specific pathogens.
While the innate immune system employs a broad range of cell types, the adaptive
immune system relies on two kinds of white blood cells to target pathogens: B cells and
T cells. While T cells are part of the cell-mediated immunity, B cells constitute the
humoral branch of adaptive immunity.
B cells can directly destroy a foreign particle or differentiate into plasma cells that release
antibodies. Antibodies then target the invader for destruction by other cells. T cells
perform several functions, depending on their surface receptor composition and chemical
arsenal. All T cells carry surface receptors that are each specific to a single antigen. After
encountering the antigen, T cells can stimulate other parts of the immune system or
actively destroy infected or cancerous cells. Some B and T cells remain available long
after the infection has been cleared and, upon repeated exposure to the same foreign
element, mount a stronger and faster immune response.
