Ma2 - Intestines And Rectum (1-14) And Lymphatic Tissue (15-52)

Front 1

Hormone found in Enteroendocrine cells - Secretin - secretes what (2)

Back 1

pancreatic bicarbonate & water secretion

Front 2

Hormone found in Enteroendocrine cells - Cholecystokinin - secretes what (1)/function (1)

Back 2

pancreatic enzyme secretion;

gall bladder contraction

Front 3

Hormone found in Enteroendocrine cells - Motilin - function (1)

Back 3

increased gut motility

Front 4

Hormone found in Enteroendocrine cells - GIP (Gastric Inhibitory Peptide) - function (1)/inhibits what release (1)

Back 4

insulin release from pancreatic islets of Langerhans;

inhibits gastric acid release

Front 5

Hormone found in Enteroendocrine cells - VIP (Vasoactive Intestinal Peptide - secretes what (1), inhibites what (1)

Back 5

is a Neurocrine Hormone --> pancreatic water secretion

inhibits smooth muscle contraction

Front 6

Hormone found in Enteroendocrine cells - GLP-1 (Glucagon-like Peptide) - secretion (1), inhibits what (2), produced where (2)

Back 6

Is a “candidate hormone” --> promotes insulin secretion, inhibition of food intake.

Inhibits gastric acid secretion and gastric emptying.

Produced in ileum, colon.

Front 7

Hormone found in Enteroendocrine cells - Peptide YY - inhibits what (1), produced where (2)

Back 7

Another “candidate hormone” that is released after eating - sends signal to brain conveying a sense of satiety to curb appetite

inhibits gastric acid secretion and gastric emptying.

Produced in ileum, colon.

Front 8

Muscularis Externa of Small Intestine is responsible for (2)?

Back 8

1) Segmentation - local contractions that mix the luminal contents

2) Peristalsis - projects food into large intestine

Front 9

what digestive enzymes are produced in the enterocytes?

Back 9

disaccharidases, dipeptidases, and enterokinase (cleaves trypsinogen to trypsin)

Front 10

What are the cells found in the VILLI (3)

Back 10

enterocytes, goblet cells, enteroendocrine cells

Front 11

What are the cell types found in the CRYPTS (3)

Back 11

Undifferentiated Stem Cells

Paneth Cells

Enteroendocrine Cells

Front 12

Difference between sodium and water entrance into ileum and colon versus the duodenum and jejunum

Back 12

In the ileum and colon, the zonulae occludentes (tight junctions) are relatively impermeable, so that sodium and water enter the cell at the apical membrane and must pass through enterocytes to enter the intercellular space.

In the duodenum and jejunum, the tight junctions are leakier so that the water from the hypotonic luminal contents can go IN BETWEEN the epithelial cells, bringing with it sodium (Solvent Drag)

Front 13

Most lipid absorption occurs in the (2)

Back 13

duodenum and upper jejunum

Front 14

How are micelles formed?

Back 14

Pancreatic Lipase hydrolyzes triglycerides to monoglycerides and free fatty acids (long and short ones). Bile Salts combine with the monoglycerides and the Long Chain Fatty Acids to form Micelles.

Front 15

Immune function has two main modes of action

Back 15

1) Humoral immune function-antibodies in blood from B-cells

2) Cellular immune function-T-cells recognize and destroy viruses, fungi, foreign tissues, and malignant tissues

-Lots of overlap between these two system

Front 16

Cells of the Immune System - Lymphocytes (3)

Back 16

1) B cells make antibodies

2) T cells help B cells and kill cells with foreign antigens

3) NK cells kill cells with foreign antigens-”naturally”, without preprogramming

Front 17

Cells of the Immune System - Structural Supporting Cells (2)

Back 17

1) Reticular Cells in lymph nodes and spleen make Reticular Fibers to support organ

2) Epithelioreticular Cells in thymus create environment for T cell differentiation

Front 18

Cells of the Immune System - Functional Supporting Cells - what do they do and the 4 types

Back 18

Present Antigens and Regulate Lymphocyte Response

1) Monocytes and macrophages

2) Neutrophils, eosinophils and basophils

3) Reticular, dendritic, and thymic epithelioreticular cells

4) Langerhans cells (in epidermis)

Front 19

Subpopulations of Lymphocytes - 70% of them are in what and the other 30%?

Back 19

-Most (70%) lymphocytes in blood and lymph are in CIRCULATING POOL
+moving between blood and lymph/lymphatic vessels where they perform immune surveillance of tissues before returning to blood
+Mostly mature, long-lived T cells with ability to recognize foreign antigens

-Remaining 30% are immature or activated, destined to leave capillaries and enter specific tissues, especially Mucosa-Associated Lymphoid Tissue (MALT)

Front 20

Interleukins - why are they secreted and info on Interleukin 1 (IL-1) (secreted by what and function)

Back 20

-At least 17 different kinds of regulatory proteins

-Basically, secreted from one cell in response to some change to induce a second change in another cell type

-Important soluble modulators and mediators of immune function

-Interleukin 1 (IL-1)
+produced by neutrophils, monocytes, macrophages, and endothelial cells
+Stimulates inflammation, causes fever, facilitates helper T cell function, stimulates B cells

Front 21

CD Markers - what are they, what are they used for, when can they be expressed, which 2 markers useful in clinical diagnosis for which 2 diseases?

Back 21

-Different cells in the immune system have unique cell surface molecules related to functional states

-Called CD markers for “Cluster of Differentiation” molecules - used to define subsets of lymphocytes

-Can be expressed throughout life of cell or only at specific stages of development

-Useful in clinical diagnosis of myeloproliferative disease:
+CD10 –common marker for Acute Lymphoblastic Leukemia
+CD5 -high levels in Chronic Lymphocytic Leukemia

Front 22

T Cells - differentiate where, in circulating pool or MALT?, 3 important subsets

Back 22

-T cells differentiate in the Thymus

-60-80% of circulating pool

-All express CD2, CD3, CD7, and T-cell receptors (TCR)

-Important Subsets
*Helper CD4+ T cells
*Cytotoxic CD8+ T cells
+Gamma/delta T cells

Front 23

T Cell Subsets: Helper CD4+ T cells - what do Th1 and Th2 cells produce?

Back 23

-Th1 cells Produce
Interact with cytotoxic CD8+ T cells, NK cells, and macrophages in cellular immune responses essential for control of intracellular pathogens such as viruses and other microorganisms

-Th2 cells
Interact with B cells in humoral immune response

Front 24

T Cell Subsets: Cytotoxic CD8+ T cells - what do they do

Back 24

Kill microorganism - infected, transformed, and foreign cells

Front 25

T Cell Subsets: Gamma/delta T cells - what do they do and importance in terms of line of defense?

Back 25

These colonize epithelial tissues and stay there.

First line of defense at external/internal interface

Front 26

B Cells - first IDed as what, in circulating pool or MALT?, differentiate into what

Back 26

-First identified as antibody-producing cells programmed to differentiate in bird MALT called Bursa of Fabricius

*Bursa equivalent in humans is MALT and bone marrow

*B cells about 20-30% of circulating lymphocytes

-When appropriately stimulated by foreign antigens, with help of APCs and Helper T cells, they differentiate into plasma cells, which synthesize and secrete antibodies (immunoglobulins)

Front 27

Antibodies - what are they, what are they secreted by, what are their 2 fragments and what do they do?

Back 27

*Blood proteins secreted by B cell-derived plasma cells

*Fab Fragment has constant and variable (antigen binding site)

*Fc Fragment binds complement or cells

-By genetic mixing and matching of DNA regions coding for immunoglobulins, humans can make an astronomical number of different molecules, one for each antigen in nature

Front 28

Antibodies - 4 groups of them

Back 28

1) IgG
2) IgA
3) IgM and IgD
4) IdE

Front 29

Antibodies - IgG - amount in blood, produced in what response,

Back 29

-75% of blood Abs

-Produced in humoral response

-Stays in plasma

-Crosses placenta

Front 30

Antibodies - IgA - found where, what does it do

Back 30

found in sweat, tears, milk, mucus-secretions-

neutralizes surface pathogens

Front 31

Antibodies - IgM and IgD - does what, complexes with what to trigger what

Back 31

bound to surfaces of B cells lymphocytes (Ag receptor)- antigens stimulates B cell proliferation->plasma cells

in plasma, complexes with Ag and triggers complement cascade

Front 32

Antibodies - IgE - binds to what and triggers what type of reactions

Back 32

binds to mast cells and basophils and when these cells see Ag, triggers allergic reactions

Front 33

Role of Antibodies (3) - how do Abs kills Antigens (Ags), what does the Abs/Ags complex trigger and activate

Back 33

-Abs against bacterial antigens coat bacteria,
+making them more recognizable to immune system b/c phagocytes have Fc receptors on their surface
+OPSONIZATION (The process by which antibodies enhance the ability of phagocytic cells to attack bacteria), then ingest and kill bacteria

*Abs bind to surface of many cells, including B cells
+When these cells see Ag, Ag/Ab complex on surface triggers production of more B cell, more plasma cells, and more Ab

-Ab/Ag complexes activate Complement System

Front 34

Histocompatibility Antigens: MHC I, MHC II, Self, Nonself

Back 34

*MHC I expressed on surface of all nucleated cells and platelets

*MHC II expressed only on surface of antigen-presenting cells (APCs)

-Each individual has different unique set of MHCs, to define chemical self and nonself

*Self is your own normal tissues

*Nonself is either foreign cells or diseased tissues with altered MHC expression

-Thus, immune system recognizes foreign cells or diseased (virus-infected or malignant) self cells as nonself and destroys them

Front 35

How Humoral Immunity Works - B Cells do one of two things

Back 35

-APCs (Antigen-Presenting Cells) in either surface of body or lymph nodes display antigens as part of MHC II to Helper T Cell

-B cell that recognize Ag are activated by Helper T Cell, divide many times, then EITHER differentiate in Plasma Cells to produce Ab against Ag

-OR Some B cells remain as Memory B Cells, for more rapid response to a new bout of same Ag

-Most immunizations work this way

Front 36

How Cellular Immunity Works - cytotoxic T cells activated by what and become one of 2 things

Back 36

-Nonself Cells (virus-infected, malignant, or transplant) have nonself Ag on MHC I

-These nonself antigens are presented to Cytotoxic T Cells (CD8+), which when activated by Helper T Cell (CD4+), proliferate, and become EITHER Effector Cytotoxic T Cells (to kill nonself cells) OR Memory Cytotoxic T Cells (if nonself Ag reappears).

Front 37

Differences between Primary Nodules and Secondary Nodules and which cells, either B or T, are found there

Back 37

• Primary nodules do NOT have a germinal center-contain B cells

• Secondary nodules have a germinal center, which is the site of active immune response and B cell differentiation

• Everywhere else, you find T cells

Front 38

MALT - what 5 types of cells found in MALT

Back 38

-In Mucosae of gut, respiratory, and urogenital systems, there are numerous Associated Lymphoid Tissues

-Scattered lymphocytes and plasma cells in pulmonary lamina propria

-Small nodules in wall of vagina

-Large nodules (some with germinal centers) in Peyer patches in ileum, vermiform appendix, and tonsils

-In addition to mostly B cells, MALT has APCs, a few Helper T cells, reticular cells, and reticular fibers (type III collagen)

Front 39

Tonsils (3 Types) - Palatine Tonsils- found where, epithelium

Back 39

Palatine tonsils- one on each side of tongue-in lateral wall of oropharynx-associated with deep cryptic recesses with stratified squamous unkeratinized epithelium

Front 40

Tonsils (3 Types) - Pharyngeal Tonsil - found where

Back 40

Pharyngeal (adenoidal) tonsil- superior posterior nasopharynx-mucosal fold-associated with PCC epithelium

Front 41

Tonsils (3 Types) - Lingual Tonsils, found where, epithelium

Back 41

Lingual tonsils- several at base of tongue-small crypts with single nodule-associated with stratified squamous unkeratinized epithelium

Front 42

Lymph Nodes - dedicated to what, differences found in afferent and efferent lymphatics in the lymph nodes

Back 42

*Dedicated to Immune Surveillance of Lymph

*Essentially an immune response collective placed strategically in lymph stream

-Small, encapsulated organs along lymphatic vessels 1 mm-2 cm concentrated in axilla, groin, mediastinum, neck, and mesenteries

-Have many peripheral Afferent Lymphatics and a fewer hilar Efferent Lymphatics; afferent lymphatics enter on periphery, a few efferents that exit (drain) node through hilum

-In peripheral tissue, capillaries leak fluid→taken up by lymphatic capillaries -> drain back into heart/circulatory system

-When bacterial antigen comes through, lymph nodes produce antibodies (immune response) against bacterial antigens

Front 43

What are found in the superficial cortex, deep cortex, and medulla of lymph nodes?

Back 43

-Superficial Cortex
+primary nodules (no Germinal Centers (GC)
+secondary nodules (with GC) Mostly B cells

-Deep Cortex
+between superficial cortex and medulla
+mostly T cells

-Medulla
+Medullary cords
+medullary sinuses

Front 44

Lymph Circulation in Nodes

Back 44

Systemic Circulation
Leaks from blood capillaries
Lymphatic capillaries
*Afferent Lymphatics
*Afferent lymphatic to Subcapsular Sinus
**Trabecular Sinus then EITHER through superficial cortex then into Medullary Sinus OR directly to medullary sinus by bypassing cortical follicles
*Efferent lymphatics
Large Lymphatics (e.g., Thoracic duct)
Large veins
Systemic Circulation

Front 45

High Endothelial Venules (HEVs) - what are they and where, what do they regulate, where do most lymphocytes in node come from?, how is flow of lymph created?

Back 45

*Unusual blood vessels in Deep Cortex of lymph nodes.

-Have cuboidal or columnar epithelium

*Regulate passage of lymphocytes from systemic circulation to parenchyma of lymph node

*Most lymphocytes in node come from HEVs rather than afferents

-Return 35% of lymph from afferents back to systemic circulation

*Pumping fluids from deep cortex back into HEVs creates Flow Of Lymph

Front 46

Spleen - dedicated to what, also functions to do what with old RBCs, what type of pulps found here (2) and which one is more abundant? function of each pulp?

Back 46

*Dedicated to Immune Surveillance of Blood Therefore, rich blood supply

-Also functions to remove old RBCs, recovers iron from Hb in old RBCs, and removes old platelets

-Large, fist-sized organ in UL quadrant of abdominal cavity covered by peritoneal reflection

-Mostly Red Pulp (removal of aged and damaged RBCs), RBCs and vascular channels with islands of White Pulp (lymph nodules - immune surveillance of the blood))

-Thick mesothelium-covered capsule with dense CT trabeculae

Front 47

Blood Flow in Spleen (Everything Starred)

Back 47

Afferent arteries enter at capsule

Trabecular arteries and veins

Central Arteries-PALS - (that’s where immune surveillance of RBCs in blood and turnover of RBCs occurs)

Penicillar arterioles

Sheathed capillaries

Open into red pulp or remain closed and join splenic sinus

Trabecular Veins

Efferent Veins

Front 48

How old RBCs are killed in Spleen during blood flow

Back 48

c. RBCs can quickly enter into closed circulation

d. Old RBCs not as deformable -> takes long time to squeeze through

e. Open part of circulation of spleen has important role in regulating age of RBCs

-younger RBCs allowed to pass, older are killed

Front 49

Immune Function in Spleen - central arteries surrounded by what, which make what 4 types of cells for immune system

Back 49

*Central arteries surrounded by PeriArterial Lymphatic Sheaths-PALS

-Similar to lymphatic nodules in lymph nodes except for central artery

-Contain many B Cells for making antibodies and Helper T Cells as well as Macrophages and other APCs

-Antigens in blood seen by these lymphocytes and immune responses are mounted to them

Front 50

Thymus - what cell's differentiation occurs here, consists mainly of what 2 types of cells?

Back 50

*Organ for T cell Differentiation

-Bilobed, superior mediastinal organ

-Has CT capsule and trabeculae to define thymic lobules

-Has deep medullary tissue and superficial cortical tissue

*Consists mainly of Thymic Epithelioreticular Cells and T Cells in different stages of maturation

Front 51

Development of Thymus - what leads to production of thymic epithelioreticular cells, what leads to production of CFU-L (colony forming unit lymphocyte), 2 periods of leukemia happen in what 2 individuals?

Back 51

-Cranial Foregut Epithelium (endoderm) from 3rd and 4th pharyngeal pouches -> Thymic Epithelioreticular Cells

-Bone Marrow (mesoderm) -> CFU-L (colony forming unit lymphocyte)

-Becomes populated by immature lymphocytes in embryo

-During childhood, thymus grows and T cell function matures. At puberty growth stops, after which thymus slowly involutes as it becomes depleted of its supply of T cells

*Two periods of leukemia are young children and older adults. 2 peaks in Leukemia:
-Childhood peak due to fact that T-cell function is not yet fully differentiated
–abnormalities in programming of lymphocytes in thymus gland

-Old age peak b/c T cell function starts to decline à ability to combat malignant transformation is declining


-Senior citizens get cancers, shingles (reactivation of suppressed viral infections), fungal diseases, etc. because of declining T cell function (added to lifetime of exposure to carcinogens).

Front 52

Educating T Cells in Thymus: CFU-L enters embryonic thymus thru? THen migrates to? Derangements in positive selection process can lead to?

Back 52

*CFU-L enters embryonic thymus thru Postcapillary Venules in medulla.

-CFU-L migrates to Cortex, express early CD markers in association with epithelioreticular cells ERCs

-Now, T cells interact with ERC (some of which express MHC I and MHC II), pass through negative (removes nonself recognizing T cells) and positive (removes self-recognizing T cells) selection processes, and become helper CD4+ or cytotoxic CD8+ T cells

-Derangements in positive selection process can lead to Autoimmune Diseases, where patient raises antibodies to own antigens and kills cells, as in diabetes mellitus, myasthenia gravis, Hashimoto thyroiditis, and a host of other autoimmune diseases

-Finally, T cells return to postcapillary venule and are distributed to body.

Front 53

Where to trabecular arteries and veins drain into? (SPLEEN)

Back 53

Trabecular Arteries are afferents to central arteries of WHITE PULP. In the white pulp, u can see PALS - Periarterial Lymphatic Sheaths- with their germinal centers and central arteries. Young healthy RBCs are collected in veins that drain into trabecular veins and then splenic veins that exit at the hilum. Small branches from the central arteries of the PALS are afferent to the splenic sinusoids in the red pulp.

Trabecular Veins drain RED PULP.