White blood cells, or leukocytes, are cells of the immune system that defend the body against infectious disease and foreign materials. There are five main types of leukocytes - granulocytes (neutrophils, basophils, eosinophils) and agranulocytes (lymphocytes, monocytes). Granulocytes contain granules that help them digest pathogens, while agranulocytes do not contain granules. Leukocytes are produced in the bone marrow and circulate throughout the body in blood and lymph fluid. An abnormal increase or decrease in the number of leukocytes can indicate certain diseases.
Quick notes on Hematopoiesis and brief into about the types of cells are forming during the process.
For UG and PG students.
Different colors, themes and video is used to make it more interesting and easy to go through the contents.
An immature red blood cell without a nucleus, having a granular or reticulated appearance when suitably stained.
Reticulocytes are the immature RBC that contain nucleus.
They are originally seen at the site of their formation i.e. bone marrow. They take 2-3 (lays for maturation only about 1-2% of circulating RBCs are Reticulocytes.
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Quick notes on Hematopoiesis and brief into about the types of cells are forming during the process.
For UG and PG students.
Different colors, themes and video is used to make it more interesting and easy to go through the contents.
An immature red blood cell without a nucleus, having a granular or reticulated appearance when suitably stained.
Reticulocytes are the immature RBC that contain nucleus.
They are originally seen at the site of their formation i.e. bone marrow. They take 2-3 (lays for maturation only about 1-2% of circulating RBCs are Reticulocytes.
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For Health benefits and medicine videos Subscribe youtube channel - https://www.youtube.com/playlist?list=PLKg-H-sMh9G01zEg4YpndngXODW2bq92w
Blood is a fluid tissue with a complex structure.
Blood consists of plasma (55%) and blood cells (45%).
Blood cells are of three types. i.e.
RBC, WBC & Platelets.
WBC: WBC also known as Leucocytes.
Do not possess any pigment, they appear colorless.
Provide immunity to the body, is the main function of WBC.
Blood is a fluid tissue with a complex structure.
Blood consists of plasma (55%) and blood cells (45%).
Blood cells are of three types. i.e.
RBC, WBC & Platelets.
WBC: WBC also known as Leucocytes.
Do not possess any pigment, they appear colorless.
Provide immunity to the body, is the main function of WBC.
Leukocytes constitute the cellular components of the innate and adaptive immune system and are critical for host defense. These cells mediate acute and chronic inflammation, modulate immune responses, and protect the host against numerous pathogens.
Disorders affecting leukocytes can be divided broadly into malignant disorders (tumors of leukocytes or their progenitors) and non-malignant disorders.
The malignant disorders are uncommon but clinically important entities
Non- malignant leukocyte disorders can involve any any of the leukocytes (neutrophils, eosinophils, basophils, monocytes, B cells, T cells, and natural killer cells)
but the disorders of greatest clinical relevance affect neutrophils; these will be our major focus.
Cells of the Innate Immune System:
The innate immune system provides rapid, nonspecific defense mechanisms against a wide range of pathogens. These cells respond quickly to infections but do not have the ability to develop long-lasting immunity. Some important cells of the innate immune system include:
Neutrophils: These are the most abundant white blood cells and are among the first responders to infections. They are highly effective at engulfing and destroying bacteria and other pathogens.
Macrophages: Macrophages are large immune cells that are involved in phagocytosis (engulfing and digesting) of pathogens and cellular debris. They also play a role in antigen presentation and can initiate an inflammatory response.
Dendritic Cells: These cells are important antigen-presenting cells (APCs) that capture antigens, process them, and present them to other immune cells, primarily helper T cells.
Natural Killer (NK) Cells: NK cells are specialized in recognizing and destroying virus-infected cells and tumor cells. They play a role in immune surveillance and defense against abnormal cells.
Mast Cells: As discussed earlier, mast cells release inflammatory mediators in response to allergens, pathogens, and tissue damage, contributing to inflammation and immune responses.
Cells of the Adaptive Immune System:
The adaptive immune system is more specific and has memory, meaning it can "remember" previously encountered pathogens and respond more effectively upon re-exposure. Some key cells of the adaptive immune system include:
T Cells: T cells include helper T cells (Th), cytotoxic T cells (CTLs), regulatory T cells (Tregs), and memory T cells. They play roles in coordinating immune responses, directly killing infected or abnormal cells, suppressing immune reactions, and maintaining memory for future encounters.
B Cells: B cells produce antibodies, which are proteins that recognize and neutralize specific pathogens. Memory B cells and plasma cells are two important subsets of B cells that contribute to long-lasting immunity.
Antigen-Presenting Cells (APCs): Dendritic cells, macrophages, and B cells are all important APCs. They capture antigens, process them, and present them to T cells, initiating and shaping the adaptive immune response.
Memory Cells: Both memory T cells and memory B cells are long-lived cells that "remember" antigens encountered in previous infections. This memory allows for a faster and more effective response upon re-exposure to the same pathogen.
These immune cells work in coordination to detect, respond to, and eliminate pathogens and abnormal cells. Their interactions are complex and tightly regulated, ensuring an appropriate and effective immune response while preventing excessive inflammation or self-damage.
Read| The latest issue of The Challenger is here! We are thrilled to announce that our school paper has qualified for the NATIONAL SCHOOLS PRESS CONFERENCE (NSPC) 2024. Thank you for your unwavering support and trust. Dive into the stories that made us stand out!
Acetabularia Information For Class 9 .docxvaibhavrinwa19
Acetabularia acetabulum is a single-celled green alga that in its vegetative state is morphologically differentiated into a basal rhizoid and an axially elongated stalk, which bears whorls of branching hairs. The single diploid nucleus resides in the rhizoid.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
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students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
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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.
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This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
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1. www.wiki.org/wiki/Blood Cell
White blood cell
A scanning electron microscope image of normal circulating human blood. In addition to
the irregularly shaped leukocytes, both red blood cells and many small disc-shaped
platelets are visible.
White blood cells, or leukocytes (also spelled "leucocytes"), are cells of the immune
system defending the body against both infectious disease and foreign materials. Five[1]
different and diverse types of leukocytes exist, but they are all produced and derived from
a multipotent cell in the bone marrow known as a hematopoietic stem cell. Leukocytes
are found throughout the body, including the blood and lymphatic system.[2]
The number of leukocytes in the blood is often an indicator of disease. There are
normally between 4×109
and 11×109
white blood cells in a litre of blood, making up
approximately 1% of blood in a healthy adult.[3]
In conditions such as leukemia, the
number of leukocytes is higher than normal, and in leukopenia, this number is much
lower. The physical properties of leukocytes, such as volume, conductivity, and
granularity, may change due to activation, the presence of immature cells, or the presence
of malignant leukocytes in leukemia.
2. Etymology
The name "white blood cell" derives from the fact that after centrifugation of a blood
sample, the white cells are found in the buffy coat, a thin layer of nucleated cells between
the sedimented red blood cells and the blood plasma, which is typically white in color.
The scientific term leukocyte directly reflects this description, derived from Greek leukos
- white, and kytos - cell. Blood plasma may sometimes be green if there are large amounts
of neutrophils in the sample, due to the heme-containing enzyme myeloperoxidase that
they produce.
3. Types
There are several different types of white blood cells. They all have many things in
common, but are all different. One primary technique to classify them is to look for the
presence of granules, which allows the differentiation of cells into the categories
granulocytes and agranulocytes:
• Granulocytes (polymorphonuclear leukocytes): leukocytes characterised by the
presence of differently staining granules in their cytoplasm when viewed under
light microscopy. These granules are membrane-bound enzymes which primarily
act in the digestion of endocytosed particles. There are three types of
granulocytes: neutrophils, basophils, and eosinophils, which are named according
to their staining properties.
• Agranulocytes (mononuclear leucocytes): leukocytes characterized by the
apparent absence of granules in their cytoplasm. Although the name implies a
lack of granules these cells do contain non-specific azurophilic granules, which
are lysosomes[4]
. The cells include lymphocytes, monocytes, and macrophages.[5]
4. Overview table
Type
Microscopi
c
Appearanc
e
Diagram
Appro
x. %
in
adults[
6]
See also:
Blood valu
es
Diame
ter
(μm)[6]
Main targets[3] Nucleus[
3]
Granules[
3] Lifetime[6]
Neutro
phil
54-
62%[5] 10-12
bacteria
fungi
multilob
ed
fine,
faintly
pink
6 hours-few days
(days in spleen
and other tissue)
Eosino
phil
1-6% 10-12
parasites
in allergic
reactions
bi-lobed
full of
pink-
orange
(when
stained)
8-12 days
(circulate for 4-5
hours)
Basop
hil
<1% 12-15
in allergic
reactions
bi- or
trilobed
large blue
Lymp
hocyte
25-
33%
7-8
B cells: various
pathogens
T cells:
CD4+ (helper):
extracellular
bacteria broken
down into
peptides
presented by
MHC class 2
molecule.
CD8+ cytotoxic T
deeply
staining,
eccentric
NK-cells
and
Cytotoxic
(CD8+) T-
cells [7]
weeks to years
5. cells: virus-
infected and
tumor cells.
γδ T cells:
Natural killer
cells: virus-
infected and
tumor cells.
cells.
Mono
cyte
2-8% 14-17
Monocytes
migrate from the
bloodstream to
other tissues and
differentiate into
tissue resident
macrophages or
dendritic
kidney
shaped
none
hours-days
Macro
phage
21
(huma
n)[8]
13
(rat)[9]
Phagocytosis
(engulfment and
digestion) of
cellular debris
and pathogens,
and stimulation of
lymphocytes and
other immune
cells that respond
to the pathogen.
activated=days
immature=month
s-years
Dendri
tic
cells
Main function is
as an antigen-
presenting cell
(APC) that
activates T
lymphocytes.
similar to
macrophages
6. Neutrophil
Main article: Neutrophil
Neutrophils defend against bacterial or fungal infection and other very small
inflammatory processes that are usually first responders to microbial infection; their
activity and death in large numbers forms pus. They are commonly referred to as
polymorphonuclear (PMN) leukocytes, although technically PMN refers to all
granulocytes. They have a multilobed nucleus which may appear like multiple nuclei,
hence the name polymorphonuclear leukocyte. The cytoplasm may look transparent
because of fine granules that are faintly pink in color. Neutrophils are very active in
phagocytosing bacteria and are present in large amount in the pus of wounds. These cells
are not able to renew their lysosomes used in digesting microbes and die after having
phagocytosed a few pathogens.[citation needed]
Eosinophil
Main article: Eosinophil
Eosinophils primarily deal with parasitic infections and an increase in them may indicate
such. Eosinophils are also the predominant inflammatory cells in allergic reactions. The
most important causes of eosinophilia include allergies such as asthma, hay fever, and
hives; and also parasitic infections. Generally their nucleus is bi-lobed. The cytoplasm is
full of granules which assume a characteristic pink-orange color with eosin stain.
Basophil
Main article: Basophil granulocyte
Basophils are chiefly responsible for allergic and antigen response by releasing the
chemical histamine causing inflammation. The nucleus is bi- or tri-lobed, but it is hard to
see because of the number of coarse granules which hide it. They are characterised by
their large blue granules.
Lymphocyte
Main article: Lymphocyte
Lymphocytes are much more common in the lymphatic system. Lymphocytes are
distinguished by having a deeply staining nucleus which may be eccentric in location,
and a relatively small amount of cytoplasm. The blood has three types of lymphocytes:
• B cells: B cells make antibodies that bind to pathogens to enable their destruction.
(B cells not only make antibodies that bind to pathogens, but after an attack, some
B cells will retain the ability to produce an antibody to serve as a 'memory'
system.)
7. • T cells:
o CD4+ (helper) T cells co-ordinate the immune response and are important
in the defense against intracellular bacteria. In acute HIV infection, these
T cells are the main index to identify the individual's immune system
activity. Research has shown [10]
that CD8+ cells are also another index to
identify human's immune activity.
o CD8+ cytotoxic T cells are able to kill virus-infected and tumor cells.
o γδ T cells possess an alternative T cell receptor as opposed to CD4+ and
CD8+ αβ T cells and share characteristics of helper T cells, cytotoxic T
cells and natural killer cells.
• Natural killer cells: Natural killer cells are able to kill cells of the body which are
displaying a signal to kill them, as they have been infected by a virus or have
become cancerous.
Monocyte
Main article: Monocyte
Monocytes share the "vacuum cleaner" (phagocytosis) function of neutrophils, but are
much longer lived as they have an additional role: they present pieces of pathogens to T
cells so that the pathogens may be recognized again and killed, or so that an antibody
response may be mounted. Monocytes eventually leave the bloodstream to become tissue
macrophages which remove dead cell debris as well as attacking microorganisms. Neither
of these can be dealt with effectively by the neutrophils. Unlike neutrophils, monocytes
are able to replace their lysosomal contents and are thought to have a much longer active
life. They have the kidney shaped nucleus and are typically agranulated. They also
possess abundant cytoplasm.
Macrophage
Main article: Macrophage
Once monocytes move from the bloodstream out into the body tissues, they undergo
changes (differentiate) allowing phagocytosis and are then known as macrophages.
8. Medications causing leukopenia
Some medications can have an impact on the number and function of white blood cells.
Leukopenia is the reduction in the number of white blood cells, which may affect the
overall white cell count or one of the specific populations of white blood cells. For
example, if the number of neutrophils is low, the condition is known as neutropenia.
Likewise, low lymphocyte levels are termed lymphopenia. Medications which can cause
leukopenia include clozapine, an antipsychotic medication with a rare adverse effect
leading to the total absence of all granulocytes (neutrophils, basophils, eosinophils).
Other medications include immunosuppressive drugs, such as sirolimus, mycophenolate
mofetil, tacrolimus, and cyclosporine. Interferons used to treat multiple sclerosis, like
Rebif, Avonex, and Betaseron, can also cause leukopenia.
9. White blood cells seen under the dark field microscope
White blood cells can be seen as live cells with the dark field microscope. This method
allows judgement of the viability of the white blood cells, which is not possible with
stained samples. [11]
10. Fixed leukocytes
Some leukocytes migrate into the tissues of the body to take up a permanent residence at
that location rather than remaining in the blood. Often these cells have specific names
depending upon which tissue they settle in, such as fixed macrophages in the liver which
become known as Kupffer cells. These cells still serve a role in the immune system.
• Histiocytes
• Dendritic cells (Although these will often migrate to local lymph nodes upon
ingesting antigens)
• Mast cells
• Microglia