Anatomy exam 1 2021: immune lecture Flashcards


Set Details Share
created 5 weeks ago by obhill
4 views
updated 5 weeks ago by obhill
show moreless
Page to share:
Embed this setcancel
COPY
code changes based on your size selection
Size:
X
Show:
1

what are antigens made of?

usually made of a protein, but can be polysaccharides, lipids, nucleic acids complexed w a protein and polysaccharide

2

examples of innate immune cells

phagocytic cells (macrophages, dendritic cells, all granular lymphocytes)

NK cells

complement proteins

mast cells

3

what progenitor cells make innate? adaptive?

myeloid, lymphoid

4

NK cells: what do they attack?

what kind of cell?

these are SPECIAL lymphocytes

these attack virus-infected cells or tumor cells ("transformed cells")

5

Humoral factors of innate immune system

Humoral factors of adaptive immune system

innate: cytokines and complement system

lymphokines, antibodies/immunoglobulins

6

function of cytokines

to coordinate and enhance immune responses

(are small proteins)

7

what kind of molecules are the complement system?

what are they produced by?

plasma proteins

produced by liver

8

what do complement proteins do?

once activated by abnormal circumstances, the complement protein will bind to pathogen membrane and create holes to lyse the organism (MAC attack) ;

or stimulate phagocytic cells

innate

9

Specific/Adaptive Immune mechanisms

Specificity:

Diversity:

Memory:

B and T cells recognize SPECIFIC DOMAINS of antigens

lymphocytes can modify receptors and change them to respond to varying number of antigen domains

after first exposure to antigen, memory calls and clonal expansion allow for quicker response second time (a few memory cells are waiting around until the antigen comes again)

10

what are lymphokines

type of cytokine secreted by T cells: specific/adaptive

11

MHC molecules per individual

each individual has a different "fingerprint" arrangement of MHC molecules

12

MHC1 vs II (cell they are found on, purpose)

MHC I molecules: found on all nucleated cells and displays all protein sequences actively synthesized by the cell (tattoo explaining what proteins it has within)

MHC II: found only on antigen-presenting cells (APC) and displays self proteins with partially digested foreign proteins to Helper T cells (mixes foreign antigen w some self proteins. Important bc t lymphocyte needs mhcII to help recognize foreign bc educated in thymus when developing)

13

Examples of antigen presenting cells

card image
14

formation and location of dendritic cells

arise in the bone marrow and travel to lymphoid organs including the thymus

15

T cell Activation:

what must there be in order for it to recognize the foreign antigen btw?

co-receptor

card image
16

why are T cells called "cell-mediated immunity"

because T lymphocytes actually bind to the foreign antigen

17

Cluster of Differentiation molecules (CD)

expressed by T cells... act as co-receptors for mediating T cell activation

18

Subsets of T cells (4)

card image

Helper T cells:

Recognize and bind to antigen-MHC II complexes on APC

Interact with B cells to stimulate B cell differentiation into plasma cells

Cytotoxic (cytolytic) T cells:

Recognize “abnormal” MHC I on transformed cells (infected, tumor, transplanted)

Destroy transformed cells by 2 mechanisms:

Release perforins which induce cell membrane damage

Activate genes which regulate apoptosis (programmed cell death) in transformed cells.

Suppressor T cells: decrease activity of B and T cells.

Memory T cells

19

T-cell activation process

card image

notice that cytokines help T cells mature and then t cell secretes more cytokines which help w growth of more t cells too`

20

cytokine roles w t cells (3)

cytokines help T cells mature during activation

and then t cell secretes more cytokines which help w growth of more t cells too

also: T helper cells secrete cytokines that attract other cells (including other cytokines) to direct things at scene of issue

21

Lymphokine functions

activation of other T cells

and B cell differentiation into plasma cells.

22
card image
card image
23

Ab vs Ig

B cells synthesize both:

immunoglobulins which are membrane-bound in immature B cells and secreted by plasma cells.

Circulating immunoglobulins are referred to as antibodies (Ab).

24

Why is it called humoral immunity

Since circulating Abs bind to foreign antigens, it is referred to as humoral immunity.

25

what acts as a BCR?

card image

Immature B cells express membrane-bound immunoglobulin (IgM) on their surface which, along with other proteins, acts as a B cell receptor (BCR) and serves as the antigen binding site. (see better pic)

26

How to inactivate antigens (antibodies)

card image
27

...

Foreign antigen bind to the BCR, are endocytosed, partially digested and complexed with MHC II molecules.

B cells then act as APC allowing Helper T cells to bind to antigen.

Helper T cells secrete lymphokines which stimulate B cell differentiation into plasma cells as well as proliferation of Memory B cells.

After final differentiation into plasma cells, immunoglobulins are synthesized in a soluble form (antibodies) which are secreted.

((Immature B cells can’t secrete antibodies. Only plasma cells secrete antibodies!! ))

Antigen-antibody complexes are then cleared by complement cascade or by liver and spleen

28

Immature vs. mature vs. plasma cell

card image

While maturing, expresses IgD on surface. Once differentiates into plasma cell, can now release immunoglobulins. First to release is IgM (early infection)

29

B-cells with non-complementary receptors to antigens

remain inactive...

"Each B or T cell carries receptors for specific antigen domains. Therefore, under normal conditions, there will be very small numbers of each type of lymphocyte present in the body."

30

Clonal expansion:

  • Upon second exposure to an antigen, memory B and T cells undergo rapid proliferation (clonal expansion)
31

Histology of Lymphoid tissue: what to look for

purple dark blueish dots (either inflammatory response or lymphoid tissue)

DOTS FOR INFLAMMATION are outside the vessels

32

Diffuse vs nodular lymphoid tissue:

what is in it?

card image

Diffuse: may contain B or T cells

Nodular: B cell accumulation; spherical... solitary or aggregates

33
card image
card image
34

Germinal centers

pale areas in middle of activated nodules: immature B cells proliferating

35

Lymphoid tissue: what kind of organs can it be in?

where else can it be?

both non-lymphoid and lymphoid

connective tissue

blood

36

MALT

card image

mucosa ASSOCIATED lymphoid tissue (not a lymph organ)

is under the epithelium, in CT

exposed to external environments!

37

Tonsils:

in general

unique thing about them

components

Tonsils

Basically are distinct accumulations of MALT

Only lymphoid organ with a surface epithelium

Lymphoid tissue and underlying partial CT capsule

38

Lymphoid Organs (4)

tonsils

lymph nodes

spleen

thymus

39

Palatine tonsils:

where

epithelium

unique

type of lymphoid tissue

card image

Palantine tonsils: located in lateral walls of oropharynx

stratified squamous surface epithelium

deep crypts

Diffuse and nodule lymphoid tissue

40

Pharyngeal tonsils

location

epithelium

crypt?

card image

NO CRYPTS

located in the posterior wall of the nasopharynx

pseudostratified columnar surface epithelium

41

adenoid

enflamed pharyngeal tonsils

42

Lingual Tonsils

location

epithelium

crypts?

card image

: Lingual tonsils: numerous

located at the base of the tongue

stratified squamous surface epithelium

1 crypt/tonsil

43

Where is the thymus

Maturation

card image

Located in the superior mediastinum, anterior to the heart and great vessels.

Grows until puberty, then gradually regresses with adipocyte infiltration

44

thymus nodules

trick question, there are none! no b cells

45

thymus structure:

2 important parts, what happens in each

card image

2 "lobules" formed from dense connective tissue

Cortex: Site of T cell maturation

T cells become immunocompetent in the cortex before entering the medulla

notice the capsule btw

46

Hassal’s corpuscles

in medulla: concentric layers of thymic epithelial cells and keratin...

47

How to T cells "learn" to recognize ___ antigens?

Thymic epithelial cells and dendritic cells ( another type of APC) present self protein sequences to developing T cells so they “learn” to recognize self proteins.

Endocytose and expose self-antigens to developing t cells

48

Autoimmune regulator (Aire) protein.

thymic epithelial cells and dendritic cells possess the Autoimmune regulator (Aire) protein.

This protein functions as a transcriptional activator that promotes expression of peripheral tissue –specific proteins in the thymus. In this manner, developing T cells are exposed to all self-antigens bound to MHC on epithelial cells or dendritic cells.

49

Cortical blood-thymus barrier

purpose

components

In the cortex, envelope developing T cells and form a barrier between developing T cells and the blood:

(protects them from foreign antigens, don’t want to mix up education on selfantigen education with foreign antigens!):

2 components:

Continuous capillary endothelium on a basal lamina

Thymic Epithelial cells (main part of barrier)

50

Blood Supply of thymus

arteries, then arterioles. It the flows into capillaries in the cortex and then drains into venules in the medulla.

51

Cells that survive post thymus

Needs to get weak affinity at least. If does not, will undergo apoptosis.

They may bind really strongly and attack, also don’t want those. Are killed off by existing macrophages

Mature immunocompetent T cells recognize self proteins (have a “weak” interaction with self proteins) but don’t bind to and react strongly are allowed to pass to venules in the medulla and gain access to the circulation.

52
card image

also, what is in M?

what is in P?

S?

card image

Lymph node

Notice the cortex and medulla

Nodules on outside: Nodules, B cells

T cells: paracortex (P) (inner cortex)

Medulla: medullay cords with lymphocytes, plasma cells, and macrophages and Lymph sinuses: spaces between cords surrounded by macrophages, reticular cells and fibers

53

Lymph nodes: how do the vessels leave and enter

what provides SUPPORTIVE FRAMEWORK

Afferent lymphatic vessels enter convex surface

Efferent lymphatic vessel exits hilum

reticular fibers offer supportive framework

54

Histological Lymph Flow

Lymph flow

Lymph enters through the afferent lymphatic vessels

and flows through the subcapsular sinus,

then cortical sinuses,

then enters the medullary sinuses

and exits the efferent vessel.

SNAP CRACKLE MOP

55

Spleen:

white pulp... 2 components

card image

white: areas around blood vessels

Periarterial lymphatic sheath (PALS). The PALS consists of T cells and surrounds central arteries and arterioles

Lymphoid nodules: located at intervals along PALS

(so, it has both B and T but T are closer to the vessel?

56

Spleen

red pulp

2 main components

card image

Red pulp: mesh of the sponge

Reticular fibers surround sinusoidal capillaries (splenic sinuses )forming a “cage”

Splenic cords: Located around the sinuses, consist of many RBCs, WBCs, macrophages, plasma cells

57

marginal zone of spleen

card image

between red & white pulp: macrophages involved in RBC breakdown

58

Splene functions

Filters blood

RBC breakdown: hemoglobin breakdown products then travel in the blood to the liver

Blood cell production in embryo and in some disease states in adult

Blood storage

Primary defense organ: Activation of B and T cells

59

spleen circulation

card image

Into spleen, into smaller and smaller vessels, in arterioles, goes to the red pulp instead of venules like normal

Has some closed circulation, but red pulp is mostly open circulation! Before sinusoidal capillaries, is in red puip

60

follicular vs parafollicular hyperplasia

Follicular hyperplasia: if response is mainly humoral, nodules in outer cortex enlarge due to B cell proliferation

Parafollicular hyperplasia: T cell activation

61

cancer of lymphocytes where it starts location

thymus

lymph nodes

bone marrow

spleen

62

hodgkins

Hodgkin’s Lymphoma

Different subtypes, usually manifests first in lymph nodes but can spread to other lymphoid organs and bone marrow

Characteristic Reed-Sternberg cells: tumor cells that arise mainly from activated B cells.

Different subtypes have different prognoses

63

non hodgkins

Non-Hodgkin’s Lymphoma

Most tumor cells arise from B cells,

Usually manifests first in lymph nodes but may arise from any lymphoid tissue, very commonly arises from MALT

malt is better prognoses

can be fro t