Types of organs system.
∆Primary organs
Immature lymphocytes generated in hematopoiesis mature and become committed to a particular antigenic specificity within the primary lymphoid organs
Only after a lymphocytes has matured within a primary lymphoid organ is the cell immunocompetent (capable of mounting an immune response).
T cells arise in the thymus, and in many mammals—humans
-Bone marrow -supports self-renewal and differentiation of hematopoietic stem cells (HSCs) into mature blood cells.
bone marrow is the site of B-cell origin and development
the long bones (femur, humerus), hip bones (ileum), and sternum tend to be the most active
contains several cell types that coordinate HSC development.
-Thymus
∆secondary organs
Lymph nodes and the spleen are the most highly organized of the secondary lymphoid organs and are compartmentalized from the rest of the body by a fibrous capsule.
lymphoid tissue is organized into structures called lymphoid follicles,
Until it is activated by antigen, a lymphoid follicle—called a primary follicle—comprises a network of follicular dendritic cells and small resting B cells.
After an antigenic challenge, a primary follicle becomes a larger secondary follicle—a ring of concentrically packed B lymphocytes surrounding a center (the germinal center)
-Spleen
-Lymph nodes
-Associated tissue
-MALT
-GALT
-BALT
-CALT
Types of immune cells
∆Lymphoid cells
-lymphocytes
constitute 20%–40% of the body’s white blood cells and 99% of the cells in the lymph
continually circulate in the blood and lymph and are capable of migrating into the tissue spaces and lymphoid organs
lymphocytes enlarge into 15 µm-diameter blast cells, called lymphoblasts; these cells have a higher cytoplasm : nucleus ratio and more organellar complexity than small lymphocytes.
Lymphoblasts proliferate and eventually differentiate into-
effector cells or into
memory cells.
* B-lymphocytes
*T-lymphocytes
* Natural killer cells
∆mononuclear phagocytes
The mononuclear phagocytic system consists of monocytes circulating in the blood and macrophages in the tissues.
-macrophages
-monocytes
∆granulocytes cells
Granulocytes are at the front lines of attack during an immune response and are considered part of the innate immune system.
Granulocytes are white blood cells (leukocytes) that are classified as neutrophils, basophils, mast cells, or eosinophils on the basis of differences in cellular morphology and the staining of their characteristic cytoplasmic granules
The cytoplasm of all granulocytes is replete with granules that are released in response to contact with pathogens.
These granules contain a variety of proteins with distinct functions:
Some damage pathogens directly;
some regulate trafficking and activity of other white blood cells, including lymphocytes
-neutrophills
-basophils
-eosinophils
-dendritic cells
-mast cells
It is in these organs where the cells of the immune system do their actual job of fighting off germs and foreign substances.
Bone marrow. Bone marrow is a sponge-like tissue found inside the bones. ...
Thymus. The thymus is located behind the breastbone above the heart. ...
Lymph nodes. ...
Spleen. ...
Tonsils. ...
Mucous membranes.
This presentation gives you the detailed description of various cells & organs of immune systems that participates (particularly, in combination), make communication between themselves to regulate the whole immune system very precisely.
Types of immune cells
∆Lymphoid cells
-lymphocytes
constitute 20%–40% of the body’s white blood cells and 99% of the cells in the lymph
continually circulate in the blood and lymph and are capable of migrating into the tissue spaces and lymphoid organs
lymphocytes enlarge into 15 µm-diameter blast cells, called lymphoblasts; these cells have a higher cytoplasm : nucleus ratio and more organellar complexity than small lymphocytes.
Lymphoblasts proliferate and eventually differentiate into-
effector cells or into
memory cells.
* B-lymphocytes
*T-lymphocytes
* Natural killer cells
∆mononuclear phagocytes
The mononuclear phagocytic system consists of monocytes circulating in the blood and macrophages in the tissues.
-macrophages
-monocytes
∆granulocytes cells
Granulocytes are at the front lines of attack during an immune response and are considered part of the innate immune system.
Granulocytes are white blood cells (leukocytes) that are classified as neutrophils, basophils, mast cells, or eosinophils on the basis of differences in cellular morphology and the staining of their characteristic cytoplasmic granules
The cytoplasm of all granulocytes is replete with granules that are released in response to contact with pathogens.
These granules contain a variety of proteins with distinct functions:
Some damage pathogens directly;
some regulate trafficking and activity of other white blood cells, including lymphocytes
-neutrophills
-basophils
-eosinophils
-dendritic cells
-mast cells
It is in these organs where the cells of the immune system do their actual job of fighting off germs and foreign substances.
Bone marrow. Bone marrow is a sponge-like tissue found inside the bones. ...
Thymus. The thymus is located behind the breastbone above the heart. ...
Lymph nodes. ...
Spleen. ...
Tonsils. ...
Mucous membranes.
This presentation gives you the detailed description of various cells & organs of immune systems that participates (particularly, in combination), make communication between themselves to regulate the whole immune system very precisely.
cytokines play a key role in controlling the immune system. It facilitate other cells and organs to work, with this presentation you will be able to learn about what are cytokines, their types, & their biological roles along with diseases related to cytokines and cytokines based therapies.
Identify the organs of primary and secondary immune system- lymphoid organs, Know the functions of lymphoid organs, Understand the importance of lymphoid organs and Lymphatic circulatory system
A number of morphologically and functionally diverse organs and tissue organs and tissue contribute to the development of immune responses .
These organs can be distinguished by function as the primary and secondary lymphoid organs .
cytokines play a key role in controlling the immune system. It facilitate other cells and organs to work, with this presentation you will be able to learn about what are cytokines, their types, & their biological roles along with diseases related to cytokines and cytokines based therapies.
Identify the organs of primary and secondary immune system- lymphoid organs, Know the functions of lymphoid organs, Understand the importance of lymphoid organs and Lymphatic circulatory system
A number of morphologically and functionally diverse organs and tissue organs and tissue contribute to the development of immune responses .
These organs can be distinguished by function as the primary and secondary lymphoid organs .
This Power Point provides quality information about the cells and organs of the human immune system and how these cell and organs work and coordinate with other organ-system in the body.
Immunology is the study of the immune system and is a very important branch of the medical and biological sciences. The immune system protects us from infection through
The lymphatic system consists of organs, ducts, and nodes. It transports a watery clear fluid called LYMPH distributes immune cells and other factors throughout the body.
Immunology is the study of the immune system and how it protects us from infection and disease123. It is a branch of biology and medicine2. Are you looking for something specific about immunology?
DEFINITION
RHIZOSPHERE EFFECT
MICROORGANISMS FOUND IN RHIZOSPHERE
FACTORS INFLUENCING THEIR GROWTH AND ACTIVITIES
POSITIVE EFFECT OF RHIZOSPHERIC MICROORGANISMS ON PLANTS
NEGATIVE EFFECT OF RHIZOSPHERIC MICROORGANISMS ON PLANTS
DEFINITION OF PHYLLOSPHERE
PARTS OF PHYLLOSPHERE
MICROORGANISM OF PHYLLOSPHERE
PHYLLOSPHERE MICROORGANISMS OF STEM (CAULOSPHERE)
PHYLLOSPHERE MICROORGANISMS OF LEAVES(PHYLLOPLANE)
PHYLLOSPHERE MICROORGANISMS OF FLOWER (ANTHOSPHERE)
PHYLLOSPHERE MICROORGANISMS OF FRUIT(CARPOSPHERE)
FACTORS INFLUENCING MICROBIAL GROWTH AND ACTIVITIES
POSITIVE EFFECT OF PHYLLOSPHERE MICROORGANISMS
NEGATIVE EFFECT OF PHYLLOSPHERE MICROORGANISMS
Carbon cycle is a biogeochemical in which carbon is exchanged among the biosphere, pedosphere, geosphere, hydrosphere and atmosphere of earth.
In earth’s atmosphere , CO2 is only 0.32%.
The process of photosynthesis, respiration, decomposition move carbon through carbon cycle partly as CO2.
Carbon is the backbone of life on Earth.
SOURCES
CARBON CYCLE
MAJOR DIVISIONS OF CARBON CYCLE
TYPES
SLOW CARBON CYCLE
FAST CARBON CYCLE
CATEGORIES OF CARBON
PROCESS INVOLVED
PHOTOSYNTHESIS
COMBUSTION
RESPIRATION
DECOMPOSITION
MINERALISATION
IMMOBILISATION
ASSIMILATION
IMPORTANCE OF CARBON CYCLE
Mutation
A mutation is a change in the DNA’s nucleotide sequence.
An abrupt shift in the nucleotide sequence causes an organism’s morphological traits to change. Such a change is referred to as a mutation if it is heritable.
So, mutation is defined as any heritable change in the sequence of nucleotide of DNA.
Features
Change in number- it is the change in the number or arrangement of nucleotide sequence of a gene.
It is heritable change in the DNA sequence.
Permanent structural change inherited material DNA effects
Can be harmful/beneficial or have no effects.
Can be sometimes attributed to random chance events.
Can be caused by mistakes during cell division or
May be caused by exposure to DNA damaging agents to the environment such as radiation and Mutagenic chemicals.
Types
Point mutation
-Silent Mutation
-Non sense Mutation
-Mis sense Mutation
Frame shift mutation
Substitution
Addition
Deletion
Causes
MUTAGENS
Physical
Chemical
Biological
ELISA (enzyme-linked immuno sorbent assay) by Pranzly.pptPranzly Rajput
INTRODUCTION
The term ELISA was first used by Engvall & Perlma in 1971.
high sensitivity
useful & powerful method in estimating ng/mL to pg/mL ordered materials in the solution.
Similar To RIA, Except No Radio-labelling.
Alkaline phosphatase, horseradish peroxidase and beta-galactosidase are the enzymes used in the EIA tests.
PRINCIPLE
MATERIAL REQUIRED
REAGENTS
TYPES
NON-COMPETITIVE ELISA
DIRECT ELISA
INDIRECT ELISA
SANDWICH ELISA
COMPETITIVE ELISA
ELISA RESULT
QUALITATIVE
QUANTITATIVE
SEMI-QUANTITATIVE
PRECAUTIONS
PHOSPHATE SOLUBILIZERS
INTRODUCTION
Phosphate SOLUBILIZERS are a group of beneficial micro-organisms capable of breaking down of organic and inorganic insoluble phosphorous compounds to soluble P form that can easily be assimilated by plants.
Phosphorous (P) is a major growth-limiting nutrient, Plants acquire phosphorus from soil solution as phosphate anion.
TYPES
MECHANISM
ISOLATION
INOCULANT PRODUCTION
INOCULANT APPLICATION
ROLE OF PHOSPHATE SOLUBILIZERS
The glutamate family :-
Conversion of a-Ketoglutarate to Glutamate
In the presence of enzyme glutamate dehydrogenase.
Synthesis of Glutamine -two step process.
Synthesis of Proline
Synthesis of Arginine- more complex pathway
∆Phosphorous cycle
∆Sources of phosphorus
-ROCK DEPOSITS (SEDIMENTS)
-AGRICULTURE CROPS CONTAIN 0.05-0.5%
-ORGANIC FORMS- IN FORM OF PHYTIN, PHOSPHOLIPIDS, NUCLEIC ACID, PHOSPHORYLATED SUGAR, COENZYMES, ACID
-ADENOSINE TRIPHOSPHATE(ATP)
-SOIL IS RICH IN ORGANIC PHOSPHOROUS
∆Steps in phosphorus cycle
WEATHERING OF ROCKS
ABSORPTION BY PLANTS
ABSORPTION BY ANIMALS
RETURNING TO THE ENVIRONMENT THROUGH DECOMPOSITION
∆Process involved in phosphorus cycle
ALTERATION OF SOLUBILITY OF INORGANIC COMPOUNDS OF phosphorus.
MINERALISATION
IMMOBILISATION OF PHOSPHOROUS
ASSIMILATION
OXIDATION/REDUCTION
Importance of phosphorus cycle
Types of Normal flora
Association between human and normal flora .
Characteristics of normal flora
Tissue specificity
Specific aadherence
Biofilm formation
Normal flora of skin
Normal flora of oral cavity
Normal flora of conjunctiva
Normal flora of respiratory tract
Normal flora of gastro intestinal tract
Normal flora of urogenital tract
Beneficial effect of normal flora
Harmful effect of normal flora
Disease caused by normal flora
Factors that affect microbial growth by Pranzly.pptxPranzly Rajput
Intrinsic and extrinsic factors
Intrinsic factors include
Characteristics of the food itself are called intrinsic factors.
These include naturally occurring compounds that influence microbial growth,
MOISTURE CONTENT
pH AND ACIDITY
NUTRIENT CONTENT
BIOLOGICAL STRUCTURE
REDOX POTENTIAL
NATURALLY OCCURING AND ADDED ANTIMICROBIAL
Extrinsic factors are those that refer to the environment surrounding the food.
TYPES OF PACKAGING AND ATMOSPHERES
EFFECT OF TIME/TEMPERATURE CONDITIONS ON MICROBIAL GROWTH
STORAGE AND HOLDING CONDITION
PROCESSING STEPS
antibiotic susceptibility testing
disk diffusion method
Kirby Bauer disc diffusion method
Stokes method
diluted method
agar dilution
test tube dilution
epsilometer test (E test)
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
The Art Pastor's Guide to Sabbath | Steve ThomasonSteve Thomason
What is the purpose of the Sabbath Law in the Torah. It is interesting to compare how the context of the law shifts from Exodus to Deuteronomy. Who gets to rest, and why?
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
2. TYPES
PRIMARY LYMPHOID
ORGANS
• Bone marrow
• Thymus
where maturation of
lymphocytes takes place
SECONDARY LYMPHOID
ORGANS
• Spleen
• Lymph nodes
• Mucosal associated
lymphoid tissues (MALT)
• gut-associated lymphoid
tissue (GALT)
which trap antigen and
provide sites for mature
lymphocytes to interact with
that antigen
3. PRIMARY LYMPHOID ORGANS
• Immature lymphocytes generated in hematopoiesis
mature and become committed to a particular
antigenic specificity within the primary lymphoid
organs
• Only after a lymphocytes has matured within a
primary lymphoid organ is the cell
immunocompetent (capable of mounting an
immune response).
• T cells arise in the thymus, and in many mammals—
humans
• B cells originate in bone marrow
4. BONE MARROW
• supports self-renewal and differentiation of hematopoietic stem cells
(HSCs) into mature blood cells.
• bone marrow is the site of B-cell origin and development
• the long bones (femur, humerus), hip bones (ileum), and sternum tend to be
the most active
• contains several cell types that coordinate HSC development, including
1. OSTEOBLASTS, versatile cells that both generate bone and control the
differentiation sites of hematopoiesis of HSCs,
2. ENDOTHELIAL CELLS that line the blood vessels and also regulate HSC
differentiation,
3. RETICULAR CELLS that send processes connecting cells to bone and
blood vessels, and, unexpectedly,
4. SYMPATHETIC NEURONS, which can control the release of
hematopoietic cells from the bone marrow
5. microenvironments within
the bone marrow
ENDOSTEAL NICHE
the area directly
surrounding the bone and
in contact with bone-
producing osteoblasts) .
appears to be occupied by
quiescent HSCs in close
association with
osteoblasts that regulate
stem cell proliferation
VASCULAR NICHE
the area directly
surrounding the blood
vessels and in contact with
endothelial cells
•appears to be occupied by
HSCs that have been
mobilized to leave the
endosteal niche to either
differentiate or circulate
6. Thymus
• the site of T-cell development and maturation.
• It is a flat, bilobed organ situated above the heart.
• Each lobe is surrounded by a capsule and is divided
into lobules, which are separated from each other
by strands of connective tissue called trabeculae.
Lobules consists of two compartments
CORTEX
the outer compartment, is densely
packed with immature T cells, called
thymocytes
MEDULLA
the inner compartment, is sparsely
populated with thymocytes
7. composed of epithelial cells, dendritic cells, and macrophages, which make up
the framework of the organ and contribute to the growth and maturation of
thymocytes.
in the outer cortex, called nurse cells, have long membrane extensions that
surround as many as 50 thymocytes, forming large multicellular complexes
FUNCTION- to generate and select a repertoire of T cells that will protect the
body from infection.
8. SECONDARY LYMPHOID ORGANS
• Lymph nodes and the spleen are the most highly
organized of the secondary lymphoid organs and are
compartmentalized from the rest of the body by a
fibrous capsule.
• lymphoid tissue is organized into structures called
lymphoid follicles,
• Until it is activated by antigen, a lymphoid follicle—
called a primary follicle—comprises a network of
follicular dendritic cells and small resting B cells.
• After an antigenic challenge, a primary follicle
becomes a larger secondary follicle—a ring of
concentrically packed B lymphocytes surrounding a
center (the germinal center)
9. SPLEEN
• It is a large, ovoid secondary lymphoid organ
situated high in the left abdominal cavity.
• the spleen specializes in filtering blood and
trapping blood-borne antigens; thus, it can respond
to systemic infections.
• Functions- in iron metabolism, thrombocyte
storage, haematopoiesis)
• compartments
1. the red pulp and white pulp, which are separated
by a specialized region called the marginal zone
10.
11. • THE SPLENIC RED PULP
consists of a network of
sinusoids populated by
red blood cells,
macrophages, and some
lymphocytes. It is the
site where old and
defective red blood
cells are destroyed and
removed
• THE SPLENIC WHITE
PULP surrounds the
branches of the splenic
artery, and consists of
the periarteriolar
lymphoid sheath (PALS)
populated by T
lymphocytes as well as
B-cell follicles.
The marginal zone, which borders the white pulp, is
populated by unique and specialized macrophages and B
cells, which are the first line of defense against certain
blood-borne pathogen
12. LYMPH NODES
divided into three roughly
concentric regions
THE CORTEX
The outermost layer,,
contains lymphocytes
(mostly B cells), macro-
phages, and follicular
dendritic cells arranged in
primary follicles
THE PARACORTEX
which is populated
largely by T
lymphocytes and also
contains
interdigitating
dendritic cells
THE MEDULLA
The innermost layer,
is more sparsely
populated with
lymphoid-lineage cells;
of those present, many
are plasma cells
actively secreting
antibody molecules
13.
14. WHEN A FOREIGN ANTIGEN GAINS ENTRANCE TO THE TISSUES, IT IS PICKED UP BY THE LYMPHATIC SYSTEM
(WHICH DRAINS ALL THE TISSUES OF THE BODY) AND IS CARRIED TO VARIOUS ORGANIZED LYMPHOID TISSUES
SUCH AS LYMPH NODES
ANTIGEN-PRESENTING CELLS THAT ENGULF AND PROCESS THE ANTIGEN ALSO CAN GAIN ACCESS TO LYMPH
AS LYMPH PASSES FROM THE TISSUES TO LYMPHATIC VESSELS, IT BECOMES PROGRESSIVELY
ENRICHED IN SPECIFIC LEUKOCYTES, INCLUDING LYMPHOCYTES, DENDRITIC CELLS, AND
MACROPHAGES.
WHERE THE LYMPHOCYTES CAN INTERACT WITH THE TRAPPED ANTIGEN AND UNDERGO ACTIVATION
ALL IMMUNE CELLS THAT TRAFFIC THROUGH TISSUES, BLOOD, AND LYMPH NODES ARE GUIDED
BY SMALL MOLECULES KNOWN AS CHEMOKINES. THESE PROTEINS ARE SECRETED BY STROMAL
CELLS, ANTIGENPRESENTING CELLS, LYMPHOCYTES, AND GRANULOCYTES, AND FORM
GRADIENTS THAT ACT AS ATTRACTANTS AND GUIDES FOR OTHER IMMUNE CELLS
16. MUCOSA-ASSOCIATED LYMPHOID TISSUE
(MALT)
• MALT INCLUDES
1. TONSILS
2. PEYER’S PATCHES (IN THE SMALL INTESTINE),
3. THE APPENDIX,
4. AS WELL AS NUMEROUS LYMPHOID FOLLICLES
WITHIN THE LAMINA PROPRIA OF THE INTESTINES
AND IN THE MUCOUS MEMBRANES LINING THE
UPPER AIRWAYS, BRONCHI, AND GENITOURINARY
TRACT
17. TONSILS
• THE TONSILS ARE FOUND IN THREE LOCATIONS:
1. LINGUAL AT THE BASE OF THE TONGUE;
2. PALATINE AT THE SIDES OF THE BACK OF THE
MOUTH;
3. AND PHARYNGEAL (ADENOIDS) IN THE ROOF OF
THE NASOPHARYNX
ALL THREE TONSIL GROUPS ARE NODULAR
STRUCTURES CONSISTING OF A MESHWORK OF
RETICULAR CELLS AND FIBERS INTERSPERSED
WITH LYMPHOCYTES, MACROPHAGES,
GRANULOCYTES, AND MAST CELLS.
18. PEYER’S PATCHES
• Peyer’s patches, nodules of 30 to 40 lymphoid
follicles, extend into the muscle layers that are
just below the lamina propria.
19. GUT-ASSOCIATED LYMPHOID
TISSUE (GALT)
• The outer mucosal epithelial layer contains intraepithelial
lymphocytes (IELs), many of which are T cells.
• The lamina propria, which lies under the epithelial layer, contains
large numbers of B cells, plasma cells, activated T cells, and
macrophages in loose clusters
• In the digestive tract, specialized M cells transport antigen across
the epithelium, they are flattened epithelial cells lacking the
microvilli that characterize the rest of the mucosal epithelium.
• M cells have a deep invagination, or pocket, in the basolateral
plasma membrane; this pocket is filled with a cluster of B cells, T
cells, and macrophages
20. M cells are located in so-called
inductive sites—small regions of
a mucous membrane that lie
over organized lymphoid
follicles.
Antigens transported across the
mucous membrane by M cells
can activate B cells within these
lymphoid follicles.
The activated B cells
differentiate into plasma cells,
which leave the follicles and
secrete the IgA class of
antibodies.
21. Cutaneous-Associated Lymphoid
Tissue (CALT)
• The epidermal (outer) layer of
the skin is composed largely of
specialized epithelial cells
called keratinocytes.
• These cells secrete a number
of cytokines that may function
to induce a local inflammatory
reaction.
• These cells express high levels
of class II MHC molecules and
function as potent activators of
naive TH cells
• The epidermis also contains so-
called intraepidermal
lymphocytes.