Histology Flashcards
Define trachea?
1 rigid tube 10cm long
2 extends from The larynx to the upper part of the thorax where it bifurcates to right and left primary bronchi
Wall of trachea?
Is supported by 16 to 20 C shaped rings of hyaline cartilage joined at the free ends by (dense ct) which is continuous with the perichondrium of each cartilaginous ring
طبعًا فيه defecated من ورا بعضلة اسمها trachealis muscle عبارة عن سموث مسل مرتبطة بال oesophagus وهذا كويس عشان ناكل مرتاحين
Describe the three layer of trachea in general?
Mucosa: Epithelium + CT (lamina propria)
Submucosa: loose ct + seromucous gland
Adventitia: outer layer + hyaline cartilage
Describe the mucosa of trachea?
زي ما قلنا حاجتين
Epithelium: pseudo stratified columnar
ciliated epithelium with goblet cells
Lamina propria: loose ct rich in ct cells + lymphatics + blood vessels + elastic fibres and membrane وهذا الممبرين يفصل الطبقة ذي عن اللي بعد شوي نتكلم عنها submucosa
Describe the five types of cells in Respiratory epithelium
- Ciliated Columnar Cells (the most abundant, each with 250-300
cilia on its apical surface) - Goblet Cells (e also numerous, apical domains filled with
granules of mucin glycoproteins) - Pyramidal Basal Cells (mitotically active stem)
- Brush cells (chemosensory receptors)
- Small granule cells (or Kulchitsky cells) Neuroendocrine Cell
اقسم بالله اسهل شيء بالعالم
Describe submucosa structure?
نفس ct structure of mucosa بالضبببببط
المميز فيها seromucos secreting glands
Describe adventitia layer?
هي ٢ بارت
1 cartilaginous layer layer of ct contain C shaped hyaline cartilage انعاد نفس الكلام ان الفراغ يتغطى بتركيالس مسل
2 adventitia loose ct
قالت اهم شيء لما أعطيكم سكشن يكون فيه كارتلج + respiratory epi عشان نقول ان هذا المقطع في القصبة الهوائية
We finish trachea
Starting with??? Bronchial tree
Primary (main) (extra pulmonary) نفس الشيء بالضبط ماعدا أنها راح تكون completed cartilaginous ring
Secondary (lobar) (intrapulmonary bronchi): هنا بيكون نفس الترتيب ماعدا ان submucosa replaced by muscle
Mucosa the same ✅
Muscle: ⭕️ smooth muscle fibers
Adventitia اهم شييييييييء قالت irregular plate of hyaline cartilage, lymph follicles & glands
Tertiary (segments) same with lobar
Describe bronchioles?
برضو نفس الشيء
٣ طبقات
Mucosa
Muscle: well developed حلوة ✅
Adventitia no❌❌❌❌❌❌
الفرق كل ما نزلنا تحت تقل cilia and goblet cells وتزيد elastic fibres
طيب مين أولى يختفي؟ goblet cells
لان لو اختفت السيليا اللي تحرك افرازات القوبلت راح يصير trapping the body can’t move it and secret it outside
What’s Clara cells? (Club cells, bronchial exocrine)
Start in the end of conducting zone and at the beginning of respiratory zone
LM/ Columnar non-ciliated cells with rounded apex & the
nucleus is rounded and central
EM/ The apical cytoplasm contains dense secretory
Granules, Golgi complex and long mitochondria & sER
اهم شيء فيها أنها تصنع protective proteins بس تحتاج طاقة وهذا يفسر وجود المايتوكندريا
sER مهمة في إيش؟ أنها تسوي ديتوكس للهواء اللي داخل
وزيادة لها مكنزم في regeneration لان لها stem cells
Describe respiratory bronchioles?
نفسسسسس التركيب حق terminal bronchiole except
INTERRUPTED by numerous alveoli
بتكون في البداية ciliated cuboidal & Clara cells وكل ما ننزل تحت تختفي السيليا ذي
ومهم * ماعاد فيه قوبلت خلاص ولى زمنها
Smooth muscle & elastic CT مهمة عشان تدعم جدار التنفس
Terminate at alveolar duct
سؤال وش يفرق respiratory bronchioles of alveolar duct
نووع الخلية !! Squamous cells
في البداية تكون فيها Lamina propria surrounds the alveoli formed of
delicate C.T. and smooth muscle fibers (sphincter
regulating the diameter of opening of each alveolus) سموث مهمة في أنها تنظم تدفق الهواء عن طريق التحكم ب diameter
بس كل ما ننزل لتحت نفقد السموث ذي ويحل محلها elastic وتعطي شعور أنها سموث ليه؟ لأنها recoil and give sphincter like structure
NO smooth muscle
Terminate at common space (atrium) جيران فاتحين على بعض ويتواصلون مع alveolar sacs
What is alveolar sacs and alveoli ???
Alveolar sac: is cluster of alveoli
Lined mostly by (alveolar
squamous epi)
What’s the alveoli?
Basic structural and functional units of the lung
Rounded or oval
It is the site of exchange
They are responsible for the spongy structure of the lung.
wall lies between neighboring alveoli is termed interalveolar
septum.
The alveoli are Lined by alveolar epithelium
Define type 1 pneumocystis?
Number: 95% of the alveolar epithelium
• LM: flat simple squamous epithelium less than 0.2μm with
slightly thickened area containing flat nuclei
• EM: Golgi, mitochondria, ER and nucleus are grouped in wide
area
- Attached by occluding junctions to each other and to Type II pneumocystes
have thin basement that fuse with the basement membrane of
the capillary
function:
• Gas exchange
• Share in formation of blood air barrier
And what about type 2 pneumocystis
Number: 5% of the alveolar epithelium
• LM: cuboidal cells with central rounded nuclei
at the angle of the alveolus
EM:- thicker than type 1 with rounded apical surface that is covered Short
microvilli
Joined with type I By tight junction
Cytoplasm: Well developed golgi
complex, RER and mitochondria
& lamellar bodies
lamellar bodies: electron dense lamellated granules
rich in phospholipid and surrounded by membrane
Functions
• Have the capacity to divide and replace type I and
type II
• secretion of phospholipid substance (pulmonary
surfactant)
What is inter-alveolar septum?
def. it is the space between alveoli
Formed of
• Alveolar epithelium on either side
• Continuous capillary network
• C.T. (reticular and elastic fibers)
• Fibroblast, macrophages & mast cells
• Basement mebrane of both (alveolar epith. & blood capillary)
Alveolar pores is interrupte?? Pores of kohn
The interalveolar Septa
importance:
- Connect adjacent alveoli
- Equalize air pressure
Describe the origin, site, and the cytoplasm of alveolar macrophage?
From monocyte
in the interstitium, on the surface of the alveoli, or
in the alveolar lumen
contains lysosomes phagocytosed
bacteria, foreign material, carbon or dust
عندنا ٢ تايب وحده إذا تتكون من كربون وغبار نسميها خلية الغبار
وحده نسميها هارت فيلير لان تأخذ صبغة الRBCs
Describe the layer in blood air barrier
Air in alveoli is separated from blood in capillaries by:
1- The surfactant layer on the alveolar surface
2- The cytoplasm of the alveolar cells (type I).
3- The fused basal laminae of type I cell & endothelial cells of the
capillary.
4- The cytoplasm of the endothelial cells
What’s pleura? And describe its microscopic structure.
The serous membrane covering the lung.
Consists of two layers; parietal & visceral which are
continuous in the hilum.
A cavity between the two layers called pleural cavity, &
contains fluid that acts as a lubricating agent
Both membranes are composed of mesothelial (Simple
Squamous epithelium) cells resting on a fine CT layer
(collagen & elastic fibers as well as few macrophages &
fibroblast
