ch 1 Elements of the Immune System and their Roles in Defense


what are the 4 types of pathogens?

viruses, bacteria, fungi, parasites

mucosal barrier?

Harsh digestive conditions in stomach
Has mucosal barrier to protect
Thick layer of bicarbonate-rich mucus
Tight junctions between epithelial cells
Prevent juice seeping underneath tissue
Damaged epithelial cells quickly replaced by division of stem cells
Surface cells replaced every 3-6 days

innate immune response

rapid, nonspecific, not always effective
with two stages pathogen-recognition mechanisms and effector mechanisms.

cytokines are like the key to open the _______

connective tissue

adaptive immune response

relatively slow but very specific and effective immune response controlled by lymphocytes

Adaptive immunity is better understood than innate immunity
T or F?


if we have lacking ___________ immunity we wont make it when we get sick.


The cells of the immune system derive from precursors in the __________

bone marrow

The precursor cells are called

hematopoietic stem cells

Lymphocytes mature in the ________ or the ________ and then congregate in ________________throughout the body

bone marrow
lymphoid tissues

The _________ comprises the lymphocytes of the adaptive immune system and the natural killer cells of innate immunity

lymphoid lineage

B cells and T cells

2 types of lymphocytes

B cells

produce antibodies

T cells

Cells created in the thymus that produce substances that attack infected cells in the body.

NK cells

responsible for immune surveillance

Primary Lymphoid Tissues

bone marrow and thymus

Secondary Lymphoid Tissues

spleen and lymph nodes

Adaptive immunity is initiated in ______________ lymphoid tissues


The __________ provides adaptive immunity to blood infections


Most secondary lymphoid tissue is associated with the?


First, consider POINTS OF ATTACK

Lungs, skin, oral/gut

Barriers of the immune system include:


The pathogen and the counter attack

Digestive enzymes
? Motility

Host Defense
and Another Counter-Attack

? Inflammatory Responses
Acute Phase Responses
molecules produced by liver

Signs of inflammation

redness, heat, swelling, pain

How are pathogens recognized by the host?

Pattern recognition receptors (PRRs) of the innate immune system provide an initial discrimination between self and non-self
There are a limited number of PRRs but they recognize pathogen-associated molecular patterns (PAMPs) present on major classes of pathogens-
-Molecules recognized often required for survival of the organism

Name the primary lymphoid tissues in mammals and
the main types of secondary lymphoid tissue.

The primary (or central) lymphoid tissues are the
bone marrow (and liver in the fetus) and the thymus. The main secondary (or peripheral) lymphoid tissues are the lymph nodes, spleen, and mucosa-associated lymphoid tissues (MALT). The last of these includes gut-associated lymphoid tissue (GALT), such as the tonsils, adenoids, appendix, and Peyer's patches, and bronchial-associated lymphoid tissues (BALT).

What is the difference in function between primary and secondary lymphoid tissues, and what are the principal events that take place in each?

Primary (or central) lymphoid tissues are the anatomical locations where lymphocytes complete their development and reach the state of maturation required for the recognition of, and response to, a potential pathogen. B cells mature in the bone marrow and fetal liver, and T cells mature in the thymus. Both lymphocyte lineages are derived from a common hematopoietic stem cell. Secondary (or peripheral) lymphoid tissues provide the anatomical sites where lymphocytes encounter antigen and immune responses are induced. Antigen is delivered to the secondary lymphoid tissues through an afferent lymphatic vessel, and is retained in the lymphoid tissue
for encounter with lymphocytes bearing antigen-specific receptors.

One reason that pathogenic microorganisms have an
advantage in the host they infect is because they _______.
a. have previously been encountered through natural
b. have previously been encountered through vaccination
c. strengthen the host's immu

d. reproduce and evolve more rapidly than the host can eliminate them


membrane-disrupting cytotoxic peptides


a combination of cells and fluid that is transported to the lymphatics


bathed in antimicrobial fluids that
protect underlying epithelial surfaces


accumulation of fluid across permeable endothelium


proteins in the serum that tag pathogens for destruction by effector cells

Which of the following is not a characteristic of inflammation?
a. inactivation of macrophages
b. increased vascular permeability and edema
c. vasodilation
d. pain
e. influx of leukocytes.

inactivation of macrophages

The processes of clonal selection and clonal expansion occur during _____.
a. adaptive immune responses
b. innate immune responses
c. hematopoiesis
d. self renewal
e. immunodeficiency diseases.

a. adaptive immune responses

The _____ is (are) the lymphoid organ(s) that filter(s) the
a. spleen
b. tonsils
c. Peyer's patches
d. appendix
e. adenoids.

a. spleen

Which of the following best describes the movement of a
T cell through a lymph node?
a. It enters via efferent lymphatics and exits via the
b. It enters via afferent lymphatics and exits via the
c. It enters via the bloodstream a

e. It enters via the bloodstream and exits via efferent lymphatics.

Which of the following pairs is mismatched?
a. T-cell activation: cell division and differentiation
b. effector B cell: plasma cell
c. plasma cell: antibody secretion
d. helper T cell: kills pathogen-infected cells
e. helper T cell: facilitates the differ

d. helper T cell: kills pathogen-infected cells

Which of the following pairs is mismatched?
a. plasma cell: mediation of phagocytosis and killing of microorganisms in the plasma
b. megakaryocyte: formation of platelets
c. dendritic cell: activation of adaptive immune responses
d. natural killer cell: d

a. plasma cell: mediation of phagocytosis and killing of microorganisms in the plasma

The specialized cells that provide the interface between
the lumen of the gut and the underlying lymphoid tissue _____.
a. make up the germinal center
b. are called the M cells
c. are located in the periarteriolar lymphoid sheath
d. are specialized in kil

b. are called the M cells

Explain how the adaptive and innate immune systems
work together to generate an effective immune response.

In most cases, a prior innate response to infection is necessary for lymphocytes to be activated to produce an adaptive immune response. In the innate response, macrophages activated by pathogen-associated molecules
release cytokines that promote inflammation, slow the spread of infection, and help activate an adaptive immune response in peripheral lymphoid organs.