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18 Dec 2023 19:33

#internal_medicinen_SUMMARY_Lec5th

#haematology 3

@lover_medecin

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17 Dec 2023 21:06

#internal_medicinen_SUMMARY_Lec5th

#rheumatology 7

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17 Dec 2023 12:32

#internal_medicinen_SUMMARY_Lec5th

#rheumatology 5

@lover_medecin

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11 Dec 2023 15:10

تعرفون شنو ممكن يصير اذا زادت نسبة الدهون وتجمعت بالشريان ؟
.
شوفو هل مقطع وحتعرفون✨👇🏻

https://vm.tiktok.com/ZM62N3KvH/

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10 Dec 2023 21:47

#Dermatology_SUMMARY_Lec5th 7

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10 Dec 2023 11:21

#Dermatology_SUMMARY_Lec5th 5

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08 Dec 2023 09:04

#Psychiatry_SUMMARY_Lec5th 8
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07 Dec 2023 20:51

#ENT_SUMMARY_Lec5th 10

#Nose

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05 Dec 2023 21:24

#Psychiatry_SUMMARY_Lec5th 6
@lover_medecin

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29 Dec 2020 22:00

🔺️blood-thymus barrier🔻
❓Q/what is the Features of arterioles and capillary in the thymic cortex?

✔ans/

1- Arterioles and capillaries in the thymic cortex are sheathed by flattened epithelial reticular cells with tight junctions.

2- The capillary endothelium is continuous and has a thick basal lamina.


❓Q/What is the benefit of these features?

✔ans/These features create a blood-thymus barrier and prevent most circulating antigens from leaving the microvasculature and entering the thymus cortex.

🏷Note/ No such barrier is present in the medulla and mature T lymphocytes exit the thymus via venules in this zone.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔅Role of the Thymus in T Cell Maturation🔅

🔥As thymocytes mature and express T cell markers (CD4 and CD8).

🔥 they undergo positive and negative thymic selection.

🔥Differentiating thymocytesin the cortex are presented with antigens bound to class I and class II MHC proteins on the epithelial reticular cells and macrophages,.


❓Q/What is mean that the positive and negative thymic selection?

✔ans/
🎗Positive selection:-
Thymocytes whose TCRs cannot bind MHC molecules at all are nonfunctional and have no future as T cells; these cells (as many as 80% of the total) are induced to undergo apoptosis.

🎗negative selection:-
Similarly, those thymocytesthat strongly bind MHCs containing self-peptides are also deleted since such T cells could cause a damaging autoimmune response.

🏷Note/Only 2–3% of the thymocytes pass both these positive and negative selection tests and survive to migrate into the thymic medulla. The others die by apoptosis and are removed by the numerous local macrophages.

〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔰Adult thymus🔰

💡The thymus reaches its maximum development in relation to body weight immediately after birth.

💡 it undergoes involution after puberty, but continues to produce lymphocytes until old age.

💡 In adult only remain:-
➕ remnants of lymphoid tissue.
➕ adipose tissue.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
♦️spleen♦️

💚The spleen is the largest single accumulation of lymphoid tissue in the body.

💚the only one involved in filtration of blood.

💚It is also the main site of destruction of aged erythrocytes.

💚the spleen is a production site of antibodies and activated lymphocytes.

💚The spleen is surrounded by a capsule of dense connective tissue.

💚 from capsule emerge trabeculae, which partially divide the parenchyma or splenic pulp.

❓Q/The spleen is composed of what?


✔ans/ is composed of reticular tissue, which containing:-
▪️reticular cells,
▪️many lymphocytes.
▪️other blood cells.
▪️macrophages.
▪️ APCs.

❓Q/What is the components of the splenic pulp?

✔ans/It has two components,
1- the white pulp.
2- the red pulp.

💢The blood circulation of the spleen💢

❓Q/Trace the blood circulation of the spleen?

➡️The splenic artery divides inside the hilum, branching into small trabecular arteries.

➡️They leave the trabeculae and enter the parenchyma as arterioles enveloped by a sheath of T lymphocytes called (PALS), which is part of the white pulp.

➡️Surrounded by the PALS, these vessels are known as central arterioles.

➡️After coursing through the parenchyma, the (PALS) receive large numbers of lymphocytes, mostly B cells, and may form lymphoid nodules.

➡️In these nodules the arteriole occupies an eccentric position but is still called the central arteriole.

➡️During its passage through the white pulp, this arteriole sends off smaller branches that supply the surrounding lymphoid tissue .

➡️After leaving the white pulp, the sheath of lymphocytes slowly thins and the central
arteriole subdivides to form straight penicillar arterioles.

➡️From these, blood flows into either a closed circulation passing directly into splenic sinuses or an open circulation, being dumped from the vasculature into the lymphoid tissue.

🏷Note/PALS = periarteriolar lymphoid sheath .
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔺️The pulp of the spleen🔻

⚪White pulp of the spleen⚪

SBS to be a doctor 🥼

29 Dec 2020 20:22

-Mistakes are always forgivable, if one has the courage to admit them.

-الأخطاء دائما تقابل بالعفو، اذا كان الشخص لديه الشجاعه للأعتراف بها.

#تحفيز_inspiration

SBS to be a doctor 🥼

29 Dec 2020 19:00

كَايز ملخص الانسجة
Good luck 💙
#lymphoid
@lover_medecin

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29 Dec 2020 19:00

❄️Lymphoid Organs L1❄️

The cells of the immune system:
1_are distributed throughout the body in the blood, lymph, and epithelial and connective tissues.
2_are arranged in small spherical nodules called
lymphoid nodules found in connective tissues and inside several organs.
3_are organized in larger lymphoid

organs♾
🔺the lymph nodes
🔺 the spleen
🔺the thymus
🔺 and the bone marrow
➖➖➖➖➖➖➖
♦️lymphoid nodules:
Q/What is the Lymphoid nodules❓

✔️Ans /are isolated cells of the immune system.

Q/Where the Lymphoid nodules found❓
✔️Ans /
1_ in the mucosa of the digestive system including
▪️the tonsils.
▪️Peyer's patches
▪️ and appendix.

2_The respiratory system.
3_The reproductive system.
4_The urinary system.
5_They are also found within lymph nodes.
6_spleen.

🏷Note /Are collectively known as mucosa-associated lymphoid tissue (MALT).

🏷Note the Lymphoid nodules not found in the thymus.
➖➖➖➖➖➖➖
Tonsils:
Q/What is the tonsils❓
✔️Ans /
Are partially encapsulated lymphoid tissue lying beneath and in contact with the epithelium of the oral cavity and pharynx.

🏷Note /According to their location they are called
◾️ palatine
◾️ pharyngeal
◾️ or lingual tonsils
➖➖➖➖➖➖➖
♦️Palatine tonsils:
1_In the posterior parts of the soft palate, are covered by stratified squamous epithelium.

2_Each has 10–20 epithelial invaginations that penetrate the tonsil deeply, forming crypts.

3_Separating the lymphoid tissue
from subjacent structures is a band of dense connective tissue that acts as a capsule or barrier against spreading tonsil infections.
➖➖➖➖➖➖➖
♦️Lymph nodes
1_ Lymph nodes are bean-shaped، encapsulated structures، connective tissue capsule surrounds the lymph node, sending trabeculae into its interior.

2_All the lymph, derived from tissue fluid, is filtered by at least one node before returning to the circulation.

3_Have a convex surface that is the entrance site of afferent lymphatic vessels and a concave depression, the hilum through which arteries and nerves enter and veins and efferent lymphatics leave the organ.
➖➖➖➖➖➖➖
Q/From what the Lymph Nodes Consist of❓
✔️Ans /
1_Cortex
2_Paracortex
3_Medulla
➖➖➖➖➖➖➖
The cortex:
Q/From what the situated under the capsule consists of❓
✔️Ans /
1_Diffuse population of reticular cells, macrophages, APCs, and lymphocytes.

2_Lymphoid nodules, with or without germinal centers formed mainly of B lymphocytes,embedded within the diffuse population of other cells.

3_Areas immediately beneath the capsule,called the subcapsular sinuses .

4_Cortical sinuses, running between the lymphoid nodules.

🏷 They communicate with the subcapsular sinuses
➖➖➖➖➖➖➖
The paracortex:
Q/Does the paracortex have precise boundaries with
the cortex and the medulla❓

✔️Ans /
No, Does not have precise boundaries with the cortex and medulla.

Q/How It can be distinguished the paracortex from the outer cortex❓

✔️Ans //by its lack of B cell lymphoid nodules and its accumulation of T cells.

🏷Note /which can be determined by immunohistochemistry.

Q//why the Venules in the paracortex comprise an important entry point❓

✔️Ans //for lymphocytes moving from blood into lymph nodes.
➖➖➖➖➖➖➖
♦️Recirculation of Lymphocytes:

1⃣Afferent lymphatic vessels cross the capsule and pour lymph into the subcapsular sinus.

🏷Note /From there lymph passes through the cortical sinuses and then into the medullary sinuses.

2⃣The lymph is collected by efferent lymphatics at the hilum.

3⃣lymphocytes that leave the lymph nodes by efferent lymphatics eventually reach the bloodstream.

4⃣These lymphocytes may then leave the blood vessels by entering the tissues and return with other lymph to another lymph node.

5⃣However، most 90% lymphocytes return to a lymph node by crossing the walls of
specific postcapillary venules in the
paracortex، the high endothelial venules (HEVs) .

Q/What is the HEVs❓
✔️Ans /These vessels have an unusual endothelial lining of tall cuboidal cells.
➖➖➖➖➖➖➖
🔺Medulla

SBS to be a doctor 🥼

28 Dec 2020 21:01

إنتهى وقت الكوز والاجوبة ح تكون وية السؤال موجودة .

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28 Dec 2020 20:10

الاسئلة انتهت والامتحان ينتهي ع الساعه 11:00pm
*كلعادة يتم الرد ع الاجوبة الخاصة بلبوت بعد انتهاء الوقت, موفقين ...💝
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17 Dec 2023 22:52

#internal_medicinen_SUMMARY_Lec5th

#rheumatology 8

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17 Dec 2023 12:33

#internal_medicinen_SUMMARY_Lec5th

#rheumatology 6

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17 Dec 2023 12:32

#internal_medicinen_SUMMARY_Lec5th

#rheumatology 4

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11 Dec 2023 15:04

كلنا عدنا اطفال بالبيت ومنعرف شنو نسوي اذا اتعرضو ل اختناق
ف من الافضل نشوف المقطع الي سوته الكم دكتورة نور ✨
من فريق SBS✨
👇🏻👇🏻

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10 Dec 2023 15:26

#Dermatology_SUMMARY_Lec5th 6

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10 Dec 2023 08:35

#Dermatology_SUMMARY_Lec5th 4

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07 Dec 2023 20:51

#ENT_SUMMARY_Lec5th11

#Nose

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05 Dec 2023 22:54

#Psychiatry_SUMMARY_Lec5th 7
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05 Dec 2023 21:24

#Psychiatry_SUMMARY_Lec5th 5
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29 Dec 2020 22:00

Histology/ lymphoid/ lec2

🔮Thymus🔮

⭐The thymus is a bilateral organ.

⭐ located in the mediastinum.

⭐it attains its peak development during youth.

❓Q/The thymus is considered a central or primary lymphoid organ?

✔ans/ because T lymphocytes form there.

🏷Note/ all other lymphoid
organs originate exclusively from mesoderm.

❓Q/What is mean that the thymus has a dual embryonic origin?

✔ans/ Its precursor lymphoblasts originate in the bone marrow, but then move to invade epithelium that developed from the endoderm.

❓Q/The thymus has a connective tissue capsule what is the function of this capsule.

✔ans/It's penetrates the parenchyma and divides it into incomplete lobules, with continuity between the cortex and medulla of adjoining lobules.

🏷Note/Each lobule has:-
▪️ the cortex.
▪️ the medulla.

❓Q/Why the cortex stains more is darkly?

✔ans/The cortex is richer in small lymphocytes than the medulla and therefore it stains more darkly.

📌The epithelial reticular cells

▪️usually stellate with long processes.

▪️ have large euchromatic nuclei.

▪️They are typically joined to similar adjacent cells by desmosomes, forming an unusual cytoreticulum.


📌Thymic (Hassall's) corpuscles

▪️consist of epithelial reticular cells arranged concentrically.
▪️ function for these structures in humans has not been established.

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29 Dec 2020 20:05

السلآم عليكم 👋🏻
⭕أن شاء الله يوم الجمعة راح يكون اكو كوز بالمادة الي تخص المرحلة الأولى اخر محاضرتين(7,8).
🕓الوقت راح يكون الساعة 5 مساءا ولمدة ساعة واحدة .
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#المرحلة_الأولى

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29 Dec 2020 19:00

Q/What is the Medullary cords❓
✔️Ans /are branched cordlike extensions of lymphoid tissue arising from the paracortex. They contain primarily B lymphocytes and often plasma cells and macrophages.

Q/by what the medullary cords are separated❓

✔️Ans //by dilated spaces frequently bridged by reticular cells and fibers, called medullary sinuses.

⭐️These sinuses are continuous with the cortical sinuses and join at the hilum to deliver lymph to the efferent lymph vessel of the lymph node).
➖➖➖➖➖➖➖
♾MEDICAL APPLICATION♾

1_ As each satellite node receives lymph from a limited region of the body, malignant tumor cells often reach lymph nodes and are distributed to other parts of the body via the efferent lymph vessels and blood vessels.

🏷Note //a process known as metastasis.

2_Infection often cause lymph nodes to enlarge.

🏷Note //These swollen nodules,which may be palpated under the skin as indicators of inflammation, have multiple germinal centers with active cell proliferation.
➖➖➖➖➖➖➖
#Histology
#lymphoid
#lec_1
@lover_medecin

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28 Dec 2020 21:12

FIRST QUIZ OF EXCITABLE TISSUE OF PHYSIOLOGY (page 1-4)
#Physiology
*THIS QUIZ IS WITHOUT ANSWER.
@lover_medecin

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28 Dec 2020 20:51

الوقت كافي الكم؟ لو نمدده؟
@medecin0_bot

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28 Dec 2020 20:06

Q11\ what does RMP means?

send the question with answer here >> @medecin0_bot <<

Ans\ The membrane interior is negative in relation to the membrane exterior.