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28 Dec 2020 20:03

Q8\ there are two glial cells have the same functions, what are they?, mentioned the system that they present in.

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

Ans\ astrocytes and satellite cells.

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28 Dec 2020 19:58

Q1\ which channel is closed during RMP?

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

Ans\ fast sadium channel is closed.

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28 Dec 2020 11:32

الامتحان اليوم ع الساعة 10:00pm كونوا جاهزين ☻ ....
الوقت ساعة كذلك
@lover_medecin

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27 Dec 2020 20:00

❓Q/where APCs are found?

✔ans/APCs are found in many tissues and constitute a heterogeneous population of cells that includes dendritic cells, macrophages, and B lymphocytes., but are also abundant in
epidermis, where they are called Langerhans cells.


🏷Note/APCs present antigens to helper lymphocytes, are essential for triggering and developmentof a complex immune response.

#Histology
#innate_and_adaptive_immunity
@lover_medecin

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27 Dec 2020 20:00

Cytokines❄️

Q/What is the function of the Cytokines❓
✔️The functions of cells in the immune system are regulated by a large number of molecules.

Q/What is the cytokines❓

✔️Ans /which are peptides or glycoproteins usually with low molecular masses .
➖➖➖➖➖➖➖➖➖
The complement system🔺

Q/What is the complement system❓
☑️Ans /A group of around 20 plasma proteins produced mainly in the liver.

Q/What One of the most important proteins of the complement system❓
✅ Ans /is the component called C3.

1_stimulate phagocytosis of microorganisms
because of opsonization due to the binding of C3 fragments to specific C3 receptors on the surface of phagocytic cells.

2_ induce lysis of microorganisms by acting on their cell membranes.
➖➖➖➖➖➖➖➖➖
🛑Mechanisms of antigen inactivation

1⃣Agglutinationin: which antibodies bind to antigens forming aggregates and reducing the amount of free antigens, aggregates may be ingested by phagocytes.

2⃣ opsonization of antigens by complement stimulates their phagocytosis.

3⃣opsonization of antigens by antibodies stimulates phagocytosis.

4⃣neutralization: in which the binding of antibody to microorganisms blocks their adhesion to cells and inactivates toxins.

5⃣ cytotoxicity mediated by cells:which involves antibodies adhering to the surface of worms activating cells of the immune system (macrophages and eosinophils) and inducing them to liberate molecules that attack the surface of the worm.

6⃣ complement activation: in which the binding of antibodies to the initial protein of the complement system triggers the complement cascade and causes cell lysis.
➖➖➖➖➖➖➖➖➖
Q/What is the types of Immune Responses❓
✔️Ans /
1_Innate response
2_Adaptive response.

Q/What is the types of Adaptive response ❓
✔️Ans /
🅰Humoral
🅱Cellular

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26 Dec 2020 21:29

الكوز الجاي بلقناة ح يكون بمحاضرات الاولى والثانية الخاصة ب اول محاضرتين بلفسلجة (excitble tissue or nerve and muscle) يعني الانترودكشن مال نيرف والRMP كذلك .. كونوا مستعدين ☻💝
@lover_medecin

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26 Dec 2020 09:46

طلاب المرحلة الاولى اكو كلمة (knob) نذكرت بلشرح منو يعرف شلون تنلفظ؟ دزوا لفظها هنا☻

@medecin0_bot

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25 Dec 2020 23:16

قناة (🩺 Medical faculty )تختص بنشر كل ما يتعلق بالمجال الطبي + المعلومات الطبية🌿
اسئلة طبية تفاعلية💊

للأعلان #مجاناً يرجى التواصل مع 👇🏻👇🏻:
@medical_adv_o

رابط الاشتراك بالقناة 👇🏻👇🏻
/channel/medical_faculty_o

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25 Dec 2020 15:26

♦️السلام عليكم
اليوم راح تكون هذه اخر محاضرة بسلسلة المصطلحات الي تخص المرحلة الأولى وبما انه خلصنا المصطلح الطبي وشلون يتكون فبهذه المحاضرة راح نحجي شوية عن مصطلحات تخص التشريح بشكل خاص ونحجي شوية على العظام واشكالها وكذلك المفاصل وانواعها.

🔮اول شي لازم نعرفة انه العضام إلي موجودة بجسم الانسان انواع مختلفة مو نوع واحد بس وهاي الانواع هي كالاتي:-

1- Long bones.
2- Short bones.
3- Flat bones.
4- Irregular bones.
5- Sesamoid bones.

🔮 وهسة راح نعرف شنو المصطلحات او التسميات الي نطلقها على اجزاء العظام

🔷️Body: main part.
🔹️الجسم وهو الجزء الاساسي في العظم.

🔷️Head: enlarged end.
🔹️الرأس وهو الجزء كبير او متضخم من العظم.

🔷️Neck: constriction between head and body.
🔹️الرقبة او العنق وهي منطقة ضيقة تقع بين راس العظم وجسمه.

🔷️ Margin or border: edge.
🔹️عبارة عن حافة العظم.

🔷️Angle: bend.
🔹️الزاوية الخاصة بالعظم.

🔷️ Ramus: branch off body.
🔹️الفرع وهو جزء يخرج من جسم العظم.

🔷️Condyle: smooth rounded articular surface.
🔹️عبارة عن سطح مفصلي مستدير.

🔷️ Facet: small flattened articular surface.
🔹️الواجهة او السطح وهي عبارة عن مناطق مسطحة توجد في بعض العظام.

🔮وطبعا كل عظم من عظام الجسم يحتوي على بروزات وفتحات وغيرها من العلامات او ما يسمى bony markings الي الها وظائف مختلفة مثلا اكو فتحات تمر منها الاوعية الدموية واكو تمر منها الاعصاب واكو بروزات تساعد بالتمفصل وهاي أن شاء الله راح تندرس ويه كل عظم راح تدرسوا مستقبلا بس هسة احنة راح نعرف هاي الفتحات والبروزات شنو مصطلحاتها وشنو يسموها بالتشريح.



🔥اول شي راح نتطرق اله هو Projections البروزات او النتوءات

🌀 Process: prominent projection
▪️بروز ضاهر

🌀Tubercle: small rounded bump
▪️نتوء دائري صغير.

🌀 Tuberosity: knob.
بروز او عقدة صغيرة مدورة على سطح العظم.

🌀Trochanter: tuberosities on proximal femur.
▪️بروز على نهاية عظم الفخذ القريبة.

🌀 Epicondyle: near or above condyle.
▪️بالقرب من او فوق القمة.

🔥هسة نحجي عن الفتحات إلي موجودة بالعظم او الي نسميها Openings

🎀 Foramen: hole
▪️ثقب .

🎀Canal or meatus: tunnel.
▪️نفق او قناة .

🎀Fissure: cleft.
▪️شق.

🎀Sinus or labyrinth: cavity.
▪️تجويف.


🔥هسة نتكلم عن الحواف او الاطراف (Ridges)

⭐ Line or linea: low ridge
▪️حافة منخفضة.

⭐Crest or crista: prominent ridge
▪️قمة بارزة.

⭐Spine: very high ridge
▪️قمة مرتفعة جدا.


🔥اما اخر شي بقى راح نحجي عنها هو Depressionsاو المنخفضات

🔺️ Fossa: general term for a depression
▪️المصطلح الاساسي المنخفضات.

🔺️Notch: depression in bone margin
▪️ انخفاض في حافة العظم.

🔺️Fovea: little pit
حفرة أو انخفاض صغير حصل

🔺️ Groove or sulcus: deeper, narrow depression
▪️اخدود او ثلم انخفاض عميق وضيق.

🔮هاي المصطلحات الي راح نحتاجها لمن ندرس العظام هسة نجي ناخذ انواع المفاصل الي موجودة بالجسم وتربط العظام مع بعض والي هية

1️⃣Fibrous Joints
2️⃣Cartilaginous Joints
3️⃣Synovial Joints
A- Ball-and-Socket joint
B- Condyloid joint
C- Hinge joint
D- Pivot joint
E- Saddle joint

🔮هسة نجي نحجي عن الحركات الي تسويها هاي المفاصل

➕Rotation:-
▪️تحريك جزء حول محور(لف الرأس من جانب إلى آخر).

➕Circumduction:-
▪️تحريك جزء بحيث تتبع نهايته مسار دائري (تحريك إصبع في حركة دائرية دون تحريك اليد).

➕Pronation:-
▪️قلب اليد بحيث تكون راحة اليد لأسفل أو تدير القدم بحيث يتم خفض الهامش الإنسي.

➕Supination:-
▪️لف اليد بحيث تكون راحة اليد لأعلى أو تدير القدم بحيث يتم رفع الهامش الإنسي.

➕Eversion:-
▪️قلب القدم بحيث يكون النعل إلى الخارج.

➕ Inversion:-
▪️لف القدم بحيث يكون النعل إلى الداخل.

➕Retraction:-
▪️تحريك جزء للخلف (سحب الذقن للخلف).

➕ Protraction:-
▪️تحريك جزء للأمام (دفع الذقن للأمام).

➕Elevation:-
▪️رفع جزء (هز الكتفين).

➕Depression:-
▪️إنزال جزء (إسقاط الكتفين).


⛔وهيج نكون خلصنا كل محاضرات هذه السلسلة اتمنى تكونون استفاديتوا منها وبالتوفيق للجميع .
#المرحلة_الأولى
#8
@lover_medecin

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24 Dec 2020 22:09

♻️consist of a single layer of endothelium and an incomplete basal lamina.

♻️The larger lymphatic vessels have a structure similar to that of veins except that they have thinner walls and lack a clear- cut separation between tunics.

♻️They also have more numerous internal valves.

#Histology
#CVS
#Lec2
@lover_medecin

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24 Dec 2020 20:00

مساء النور كَايز 💙
ملخص الانسجة
Lec1
Good luck ✨
@lover_medecin

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24 Dec 2020 20:00

⭕️Histology of the Circulatory System Lec1

♦️The circulatory system

▪️ pumps and directs blood cells and substances carried in blood to all tissues of the body.
▪️ It includes both the blood and lymphatic vascular systems.
▪️and in an adult the total length of its vessels is estimated at between 100,000 and 150,000 kilometers.
▪️The blood vascular system, or cardiovascular system consists of the heart and blood vessels.

🔶Structural Plan of Blood Vessels

1_The tunica intima has one layer of endothelial cells supported by a thin subendothelial layer of loose connective tissue.

🏷Note /In arteries, the intima is separated from the media by an internal elastic lamina.

2_The tunica media, the middle layer, consists chiefly of concentric layers of helically arranged smooth muscle cells Interposed among the smooth muscle cells are variable amounts of elastic fibers and reticular fibers of collagen type III .
🏷Note /In arteries, the media has a thinner external elastic lamina, which separates it from the tunica adventitia.

3_The tunica adventitia or tunica externa consists principally of type I collagen and elastic fibers .

🏷 Note /This adventitial layer is gradually continuous with the stromal connective tissue of the organ through which the blood vessel runs.

The endothelium
Q/What is the endothelium?
✔️Ans /is a special type of simple squamous epithelium.

Q/What is the Functions of the endothelium?
✔️Ans /
1_acts as a semipermeable barrier between two internal compartments: the blood plasma and the interstitial tissue fluid.

2_ production of vasoactive factors that affect the vascular tone, such as nitric oxide, endothelins, and vasoconstrictive agents.

3_conversion of circulating angiotensin I to angiotensin II.

4_contain unique very small, elongated vesicles called Weibel-Palade bodies, which contain selectin and von Willebrand factor involved in blood coagulation.

🛑MEDICAL APPLICATION

1_The endothelium also has an antithrombogenic action, preventing blood coagulation. When endothelial cells are damaged by atherosclerotic lesions.

🔺for example, the uncovered subendothelial connective tissue induces the aggregation of blood platelets.

2_This aggregation produces fibrin from circulating fibrinogen.

3_An intravascular clot, or thrombus is formed that may grow until there is complete obstruction of the local vascular flow.

4_From this thrombus, solid masses called emboli may detach and be carried by the blood to obstruct distant blood vessels. In both cases the vascular flow may stop.

🏷Note /a potentially life-threatening condition.

Arteries:
1_Large Elastic Arteries
2_Muscular arteries.
3_Arterioles


🛑Large Elastic Arteries :

1_The elastic arteries include the aorta and its large branches.
2_The intima is thicker than the corresponding tunic of a muscular artery.
3_The media consists of elastic fibers and a series of concentrically arranged, perforated elastic laminae whose number increases with age (there are about 40 in the newborn, 70 in the adult). Between the elastic laminae are smooth muscle cells, reticular fibers.
4_The tunica adventitia is relatively underdeveloped.

🛑Muscular arteries

1_The intima has a very thin subendothelial layer and the internal elastic lamina, the most external component of the intima, is prominent.

2_The tunica media may contain up to 40 layers of more prominent smooth muscle An external elastic lamina, the last component of the media, is present only in the larger muscular arteries.

3_The adventitia consists of connective tissue. Lymphatic capillaries, vasa vasorum, and nerves.

🛑Arterioles

1_Are generally less than 0.5 mm in diameter, with lumens approximately as wide as the wall is thick.
2_The subendothelial layer is very thin, the elastic laminae are absent.
3_The media is composed of 1-3 layers of circularly arranged smooth muscle cells.
4_ In both small arteries and arterioles, the tunica adventitia is very thin.

🟣Capillaries :

4_The total diameter of the capillaries is approximately 800 times larger than that of the aorta.

SBS to be a doctor 🥼

23 Dec 2020 22:22

اني احب افيدكم ماكَدر ف خلص اكللكم
الجداول الخاصة بلعضلات متجي ب الامتحان ! مجرد بس تعرفوهة وخلص (بلنسبة للمحاضرة الثالثة طبعاً)

*اكو ناس عرفوا البشرى 😂💔

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23 Dec 2020 22:11

بشرى سارة بهاي المحاضرة ☻ تردون تعرفوهة شنو؟
خل اشوف الي يردون يعرفون حت اكللكم
@medecin0_bot

SBS to be a doctor 🥼

23 Dec 2020 22:04

2️⃣Zygomatic branch:
▪️emerges from the anterior border of the gland.
▪️supplies orbicularis oculi.

3️⃣ Buccal branch:
▪️ emerges from the anterior border of the gland below the parotid duct.
▪️supplies buccinator and muscles of nostrils and upper lip.

4️⃣Mandibular branch:
▪️emerges from the anterior border of the gland.
▪️supplies muscles of lower lip.

5️⃣Cervical branch:
▪️emerges from the lower border of the gland and passes near the lower border of mandible. ▪️supply platysma muscle.

🎀Clinical significance🎀

🎶Trigeminal neuralgia:

➕As the sensory supply to the skin of face is carried by the three branches of trigeminal nerve.

➕the face is susceptible to a condition of acute excruciating pain usually occurs:-

▪️through the distribution of maxillary and mandibular nerves.
▪️rarely through the ophthalmic nerve called trigeminal neuralgia.
▪️usually due to a compression on the nerve in a special area by a tumor or other pathologies.


🎀Facial palsy🎀
➕ As the facial nerve emerges from the parotid gland and divides into many branches supplying face muscles, so it is susceptible to trauma or affected by tumor of the gland, resulting in paralysis of some of facial muscles, a condition called facial palsy.

🎀Cavernous sinus thrombosis🎀

➕As the facial vein communicates with the cavernous sinus through the ophthalmic veins , so any infection or boils occurring in the face may cause thrombosis of the facial vein and this may be transmitted to the cavernous sinus causing thrombosis , a serious condition and may be fatal unless treated.

🎀Pulse checking🎀

As the facial artery winds on the lower border of mandible in the anterior border of masseter, and the superficial temporal artery ascends in front of the auricle above the zygomatic arch, so the pulse can be checked by putting fingers on these landmarks.

🎀Blood supply🎀

As the arterial supply to the face is profuse, so there will be rare conditions of necrosis to the skin of face after plastic surgeries.

🔥Muscles of mastication🔥

🔷️ Represent musculature of 1st pharyngeal arch.

🔷️All insert on mandible and are innervated by mandibular nerve (CN V3).

🔷️ Four muscles on each side:-

1- Temporalis: closes jaw, posteroinferior part retracts jaw

2- Masseter: closes jaw.

3- Medial pterygoid: closes jaw with bilateral contraction; moving jaw side to side with unilateral contraction.

4- Lateral pterygoid: Protrudes mandible; opens mouth; unilateral contraction moves mandible from side to side.

#anatomy
#head_and_neck
#lec_3
@lover_medecin

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28 Dec 2020 20:02

Q6\ what does the important function of myeline?

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

Ans\ it is provide electrical insulation.

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28 Dec 2020 19:58

قبل ماانزل الاسئلة شباب الاجوبة الي ح تكون ع البوت تدزون السؤال الي جاوبتوا عليه وياهة يعني تحطون السؤال وجوة جوابه لطفاً

SBS to be a doctor 🥼

27 Dec 2020 20:00

طلاب هذا ملخص الانسجة النظري.
Good luck 💙
#innate_and_adaptive_immunity
@lover_medecin

SBS to be a doctor 🥼

27 Dec 2020 20:00

🔰The innate immune system🔰

🏷Note/it's called the first line of defense.

❓Q/What is the innate immune system made of?
✔ans/consists of
1- Skin, mucous membranes.

2- Cells such as:-
▪️neutrophils.
▪️macrophages.
▪️mast cells.
▪️natural killer cells.

3- Complements.

❓Q/How does the body facilitate the clearance of pathogens from epithelial surfaces?

✔ans/
🔺️Rapid epithelial regeneration.
🔺️Blinking.
🔺️Flow of tears.
🔺️Ear wax.
🔺️Nasal hairs.
🔺️Coughing.
🔺️Sneezing.
🔺️Mucociliary escalator.
🔺️Vomiting.
🔺️Digestive enzymes.
🔺️Peristaltic gut movement.
🔺️Regular urine flow.

❓Q/what is the cells of Innate Immunity system?
✔ans/
➕Macrophage, Monocyte ➡️ Phagocytosis & Presentation to lymphocytes.

➕Neutrophil PMN ➡️Phagocytic Anti-bacterial.

➕Eosinophil➡️ Anti-parasite Immunity -Allergy.

➕Basophil ➡️ Protection of mucosal surfaces- Allergy.

➕Mast cell ➡️ Protection of mucosal surfaces - Allergy.

➕NB - Also Natural Killer cells.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔰Adaptive immune system 🔰

🏷Note/which depends on the initial recognition of antigens by B and T lymphocytes.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔮Lymphocytes🔮

❓Q/what is the classification of Lymphocytes?

✔ans/Lymphocytes are classified as:-
▪️ B Lymphocytes.
▪️T Lymphocytes.
▪️natural killer(NK) cells.

🏷Note/The B and T cells are the only cells that have the ability to selectively recognize a specific epitope.

🏷Note/B and T cells differ based on their life history, surface receptors, and behavior during an immune response.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔥B Lymphocytes🔥

❓Q/What does the epitope encounter with a B lymphocyte lead?

✔ans/ leads to differentiation of most of these lymphocytes into plasma cells.


🔅This population of plasma cells secretes
antibodies against the same epitope.

🏷Note/In most cases, the activation of B cells requires the assistance of a subclass of T lymphocytes known as (T helper cells).


❓Q/is all activated B cells become plasma cells?

✔ans/No, not all activated B cells become plasma cells; some remain as long-lived B memory cells, which are able to react very rapidly to a second exposure to the same epitope.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️
🔥T Lymphocytes🔥

❓Q/what is the percentage of T Lymphocytes ?

✔ans/Cells constitute 65–75% of blood lymphocytes.

❓Q/How the T Lymphocytes can recognize epitopes?

✔ans/To recognize epitopes, all T cells have on their surfaces a molecule called a T cell receptor (TCR).


❓Q/ What is the different between B,T Lymphocytes?

▪️B cells, which recognize soluble
antigens or antigens present on cell surfaces.

▪️T lymphocytes recognize only epitopes (mostly small peptides) that form complexes with special proteins on the cell surface of other cells.

❓Q/What is the Types of T cells and it's function?

✔ans/

1️⃣Helper cells:-

➕Function
📌produce cytokines that :-
▪️promote differentiation of B cells into plasma cells

▪️activate macrophages to become phagocytic.

▪️ activate cytotoxic T lymphocytes
called CD4+ T cells.

2️⃣Cytotoxic T cells are( CD8+ )

➕Function
📌 act directly against foreign cells or virus-infected cells by cell lysis or apoptosis.

3️⃣Regulatory T cells are( CD4+CD25+)

➕Function
📌 play crucial roles in allowing immune tolerance.
📌maintaining unresponsiveness to self-antigens.
📌suppressing excessive immune responses.
〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️

🔥Natural Killer Cells🔥

🏷Note/The natural killer lymphocytes lack the marker molecules characteristic of B and T cells.

❓Q/what is the percentage of Natural Killer Cells ?

✔ans/They comprise about 10–15% of the
lymphocytes of circulating blood.

❓Q/Where is its name derived from?

✔ans/Their name derives from the fact that they attack virus-infected cells, transplanted cells, and cancer cells without previous stimulation.

❓Q/why they are involved in innate immune response?

✔ans/ because they attack virus-infected cells, transplanted cells, and cancer cells without previous stimulation.

〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️〰️

✳Antigen-Presenting Cells (APCs)✳

SBS to be a doctor 🥼

27 Dec 2020 20:00

Innate and Adaptive Immunity

♦️The Immune System
Q/What is the Immune System❓
✔️Ans /
Is a system of cells that has the ability to distinguish self (the organism's own molecules) from (non-self)
(foreign substances).

Q/What is the bility for the Immune System❓

✔️Ans /This system has the ability to neutralize, inactivate or destroy foreign molecules

such as soluble molecules as well as those present in
▪️viruses
▪️bacteria
▪️ and parasites
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Q/What is the Cells of the Immune System❓
✔️Ans /
1_Lymphocytes
2_Plasma cells
3_Macrophages.
4_Antigen-presenting cells
5_Neutrophils
6_ Eosinophils
7_Mast cells
8_Basophils
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🛑The cells of the immune system:

➖are distributed throughout the body in the blood, lymph, and epithelial and connective tissues.

➖ are arranged in small spherical nodules called lymphoid nodules found in connective tissues and inside several organs.

➖are organized in larger lymphoid organs:
▪️the lymph nodes
▪️the spleen
▪️the thymus
▪️and the bone marrow.

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26 Dec 2020 11:24

لفظ كلمة knob☻ , عاشت ايدكم الكل جاوب صح معناها بشارة خير هاي

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26 Dec 2020 09:40

ترجمة تشريح الجمجمة المحاضرة الثانية



#مترجمة
#anatomy
#اناتومي
#تشريح
@lover_medecin

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25 Dec 2020 15:28

هاي اخر محاضرة بالنسبة لهاي السلسلة اتمنى تكونون استفاديتوا منها واعتذر على الانقطاع والتاخير الي صار موفقين.
@lover_medecin

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24 Dec 2020 22:10

السلآم عليكم
ملخص انسجة lec2
@lover_medecin

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24 Dec 2020 22:09

Histology/ lec 2/CVS

♦️Microcirculation♦️

1- Capillary beds are supplied by one or more terminal arteriole branches called (metarterioles), which are continuous with thoroughfare channels connected with the postcapillary venules.

2- Capillaries branch from the metarterioles, which are encircled by smooth muscle cells, act as precapillary sphincters that control blood flow into the capillaries that converge into the thoroughfare channels, which lack muscle.

3. These sphincters contract and relax cyclically, with 5-10 cycles per minute, causing blood to pass through capillaries in a pulsatile manner.

4. When the sphincters are closed blood flows directly from the metarterioles and thoroughfare channels into postcapillary venules.


🏷Note/🔰Tissues with high metabolic rates, such as:-
▪️the kidney▪️liver▪️cardiac and skeletal muscle.
have an abundant capillary network.

🔰the opposite is true of tissues with low metabolic rates, such as:- ▪️ smooth muscle ▪️dense connective tissue.

🔱Sub-Division of Veins is :-
1- Venules.
2- Small / Medium Veins.
3- Large Veins.

1️⃣Venules

🎗 Venules have a typieal endothelium of simple squamous epithelial cells but the intima lacks sub-endothelial tissue.

🎗The media consists of a few smooth muscle cells or pericytes.

🎗The Adventitia is very thin and consists of a few strands of collagen.

2️⃣Small & Medium - Sized Veins

Small and medium sized veins are characterised by:-
➕ an intimal layer containing sub - endothelial tissue.
➕ a tunica media containing a small amount of elastic tissue and smooth muscle.

➕ an adventitia which is thicker than the media and contains collagen with small amounts of smooth muscle and elastic fibres.

🏷Note/ In general the larger the vein the larger the amount of smooth muscle found in both the media and adventitia.

🏷Note/The larger vessels contain valves which are intimal extensions & ensure unidirectional blood flow.

3️⃣ Large Veins
🔺️ These have:-

♦️ well- developed intimal layers.

♦️relatively thin media with alternating smooth muscle and connective tissue.

♦️The tunica adventitia is thicker than the media in large veins and frequently contains longitudinal bundles of smooth muscle.

🏷Note/Both the media and adventitia contain elastic fibers.

♻️Vasa vasorum♻️

📌Walls of the larger vessels, as the aorta, contain in the tunica adventitia a supply of microvasculature.

📌These arterioles , capillaries and venules constitute the vasa vasorum (vessels of vessels).

❓Q/what is the function of Vasa vasorum?

✔ans/ bring O2 , and nutrients to local cells too far from the lumen to be nourished by blood there.


❤Heart❤

💢 The walls of all four heart chambers consist of three major layers or tunics:-
▪️the internal endocardium.
▪️ the middle myocardium.
▪️the external epicardium.

1️⃣Endocardium

⭐ consists of:-
▪️ a thin inner layer of endothelium and supporting connective tissue.

▪️a middle myoelastic layer of smooth muscle fibers and connective tissue.

▪️a deep layer of connective tissue called the subendocardial layer.

⭐ Branches of the heart's impulse-conducting system, consisting of modified cardiac muscle fibers, are also located in the subendocardial layer.


2️⃣Myocardium
⭐the thickest layer.

⭐ consists mainly of cardiac muscle with its fibers arranged spirally around each heart chamber.


❓Q/the myocardium is much thicker in the walls of the ventricles, particularly the left, than in the atrial walls?

✔ans/Because strong force is required to pump blood through the systemic and pulmonary circulations.

3️⃣Epicardium

⭐is a simple squamous mesothelium supported by a layer of loose connective tissue containing blood vessels and nerves.

⭐The epicardium corresponds to the visceral layer of the pericardium.

🔮The Conducting System🔮

🌀These conduction myofibers or Purkinje fibers have one or two central nuclei.

🌀Myofibrils are sparse and restricted to the periphery of the cytoplasm.

✳Lymphatic Vascular System✳

♻️ The lymphatic capillaries originate in the various tissues as thin, closed- ended vessels.

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24 Dec 2020 20:00

5_The velocity of blood in the aorta averages 320 mm/s, but in capillaries blood flows only about 0.3 mm/s.

Q/why in the capillaries the blood flows only about 0.3 mm/s?
✔️Ans /
Because of their thin walls and slow blood flow.

🏷Note /capillaries are a favorable place for the exchange of water, solutes, and macromolecules between blood and tissues.

🟣Types of capillaries

1_ Continuous capillaries:
▪️ the most common type.
▪️have tight.
▪️occluding junctions sealing the intercellular clefts between all the endothelial cells to produce minimal fluid leakage
▪️ All molecules exchanged across the endothelium must cross the cells by diffusion or transcytosis.
▪️found in all kinds of muscle tissue, connective tissue, exocrine glands, and nervous tissue.
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2_ Fenestrated capillaries also have tight junctions:
▪️but perforations (fenestrations)
through the endothelial cells allow greater exchange across the endothelium.
▪️Fenestrated capillaries are found in organs where molecular exchange with the blood is important, such as endocrine organs, intestinal walls, and choroid plexus.
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3_ Sinusoids, or discontinuous capillaries:
▪️have a wider diameter and discontinuities between the endothelial cells.
▪️large fenestrations through the cells, and a partial, discontinuous basement membrane.
▪️ Sinusoids are found in organs where exchange of macromolecules and cells occurs.

♾such as in bone marrow, liver, and spleen.

🟣pericytes:

1_Are cells of mesenchymal origin with long cytoplasmic processes partly surrounding the endothelial layer at various locations along capillaries and postcapillary venules.

2_These cells' primary
have contractile function.

3_After tissue injuries, pericytes proliferate and differentiate to form new blood vessels.

#Histology
#CVS
#Lec1
@lover_medecin

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24 Dec 2020 17:53

طلاب ماراح يهمكم هواي هذا الفيديو الي يريد يستخدم بث ببرنامج الزوم هذا الفيديو ح يفيدة .
*مو فيديو دراسي .
#zoom
@lover_medecin

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23 Dec 2020 22:19

اوك متردوهة أغير رأيي☻؟

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23 Dec 2020 22:04

صباح النور كَايز
ملخص التشريح
Lec3
Good luck 💙
@lover_medecin

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23 Dec 2020 22:04

lid and the skin of the lower part of forehead close to the midline.

4️⃣The infratrochlear nerve:-
supplies skin and conjunctiva of the medial part of the lower eyelid and the nose sides.

5️⃣The external nasal nerve:-
supplies the skin on both sides of the nose down to its tip.

🔔Maxillary nerve:

🔺️supplies the:-
▪️ skin of the posterior part of the sides of nose ▪️the lower eyelid▪️the cheek▪️the upper lip ▪️the lateral sides of orbital opening.

🔺️It has three branches:-

1️⃣The infraorbital nerve:-
supplies the skin of the lower eyelid and cheek, the sides of nose and the upper lip.

🏷Note/ is the direct continuation of maxillary nerve.

2️⃣The zygomaticofacial nerve:-
supplies skin over prominence of cheek.

3️⃣The zygomaticotemporal nerve:-
supplies skin over the temple.

🔔Mandibular nerve:
🔺️supplies the:-
▪️ lower lip ▪️the temporal region▪️the lower part of face ▪️part of auricle.

🔺️It has three branches:-

1️⃣The mental nerve:-
supplies skin of lower lip and chin.

2️⃣The buccal nerve:-
supplies skin over small area of the cheek.

3️⃣ The auriculotemporal nerve:-
supplies the skin of the auricle, the external auditory meatus, the outer surface of tympanic membrane and the scalp area above auricle.

🔴Arterial supply of the face🔴

📌The face has a rich blood supply which makes an anastomosis.

📌There are main arteries supplying the face with many small arteries that accompany the sensory nerves of the face.


🔱The facial artery:-

➕It arises from the external carotid artery.

➕Curves around the inferior margin of the body of mandible at the anterior border of masseter muscle (here the pulse can be felt), runs upward to the angle of mouth in a tortuous course.

➕It gives many branches through its course.

➕ It runs to the side of the nose till reaching the medial angle of the eye as angular artery (the terminal part of facial artery); here it anastomoses with the terminal branches of ophthalmic artery.

➕Branches:-

1- Submental artery:
▪️arises near the lower border of mandible.
▪️supplies the skin of chin and lower lip.

2- Inferior labial artery:
▪️arises near the angle of mouth and runs medially in the lower lip and anastomose with the opposite inferior labial artery.

3- Superior labial artery:
▪️arises near the angle of mouth and runs medially in the upper lip.
▪️ supply the ala and septum of nose.

4- Lateral nasal artery:
▪️ arises on the side of the nose.
▪️supply the skin of dorsum and side of nose.


🔱 Superficial temporal artery:

➕the smaller terminal branch of external carotid artery.

➕begins in the parotid gland and ascends in front of the ear .

➕supplying the scalp.

➕it gives a branch within the parotid gland which is the transverse facial artery crossing the cheek just above the parotid duct.

🔵Venous drainage of face🔵

🌀When supraorbital and supratrochlear veins unite at the medial angle of the eye, the facial vein is formed.

🌀There is a communication between the facial vein and cavernous sinus through the superior ophthalmic vein.

🌀The facial vein is connected to the pterygoid venous plexus by the deep facial vein.

🌀 The facial vein descends to the lower margin of the body of mandible superficial to the submandibular gland and ends by draining into the internal jugular vein.


🟢Lymphatic drainage of face🟢

♻️The lymphatic drainage of the forehead and the anterior part of face is into the submandibular lymph nodes.

♻️ The drainage of the lateral part of face and lateral part of eyelids is into the parotid lymph nodes.

♻️ The drainage of lips and skin of chin is into the submental lymph nodes.


🟡The facial nerve🟡

🎗There is a clinical importance of the facial nerve as it passes through the parotid gland; hence it is susceptible to problems occurring in the gland as in trauma or tumors.

🎗 It is derived from the second pharyngeal arch so it supplies all the muscles of facial expression.

🎗It doesn’t supply the skin.

🎗Branches:-
1️⃣The temporal branch:
▪️emerges from the upper border of the gland. ▪️supplies frontalis, orbicularis oculi.