RESPIRATORY SYSTEM (II)

EXTRAPULMONARY الرئه خارجBRONCHUS

(primry BRONCHUS)

Generally have the same histological appearance as the trachea.

للتفاصيل السابق الدرس راجع اذا

INTRAPULMONARY الرئه داخلBRONCHI

(2ry & 3ry BRONCHI)

1- Mucosa.

2- Muscle coat.

3- Submucosa.

4- Adventitia.

هيستولوجيا تتكونمن

تفصل الحقا

INTRAPULMONARY BRONCHUS

INTRAPULMONARY BRONCHUS

INTRAPULMONARY BRONCHUS

(1) Mucosa: It has longitudinal طولي mucosal folds. a- Epithelium: Respiratory epith. b- L.P.: (Lamina propria) من يتكون Fibroelastic C.T. (loose C.T. rich in elastic fibers). It contains seromucous glands. “ “ lymphoid elements. N.B. No elastic lamina ( ) نو كلمه يقول الدكتور

عليها ركز يعني سؤال . معناها

INTRAPULMONARY BRONCHUS(2) Muscle coat (complete):

Two distinct مختلفتين layers of SMF ( smooth muscle fibers ) spirally حلزوني arranged in opposite direction

(crisscrossing متقاطعه bundles of spirally arranged smooth muscle fibers “SMF”).

(3) Submucosa:

C.T. contains:

a- Seromucous glands.

b- Lymphoid elements.

INTRAPULMONARY BRONCHUS

(4) Adventitia: Contents: a- Loose C.T.: Contains radially arranged elastic fibers to connect with counterparts of neighboring bronchial tree.

b- Irregular plates of hyaline cartilage (complete layer). c- Solitary lymphoid nodules.

وعليه احمر شيء ايعليه ركز هذا خطكل في وهذا الدكتورالمحاضره

BRONCHIOLES غضاريفوال بها يوجد الاسمه انسىشيء هنا من كذا عشان بعدها بالتي

غضاريف1- Preterminal النهائيه ( 1ry ) قبل

Bronchioles (Bronchioles):

Are less than 1mm in diameter.

Each bronchiole supplies pulmonary lobule.

2- Terminal النهائيه ( 2ry ) Bronchioles.

3- Respiratory ( 3ry ) Bronchioles.

BRONCHIOLE

Preterminal Bronchioles(1) Mucosa: has longitudinal folds:

A- Epithelium:

1- Simple ciliated columnar epith نوع معرفه جدا مهمهالقادمه التراكيب في يتغير سوف النه مقارنه محل النه .االبيثيلويم

with occasional goblet cells (in larger preter. br.).

منها : مهمه -2 االخير الجزء تركيب Simple cuboidal mostly ciliated with occasional Clara cells BUT NO goblet cells (in smaller preter. bronchioles).

B- Lamina propria: Fibroelastic C.T. (rich in elastic Fs.)

(2) Smooth muscle: 2 helically arranged SM layers.

(3) Adventitia: loose fibroelastic C.T.

N.B جدا جدا No cartilage, No seromucous glands, No lymph .مهمهnoduLes.

TERMINAL BRONCHIOLE

Terminal Bronchioles

Similar structure to preterminal. bronchioles, but:

Epithelium:

Simple cuboidal partially ciliated epithelium

With Clara cells. من االخير الجزء تركيب مثل السابقه

N.B. Are less than 0.5mm in diameter.

N.B. Each supplies lung acinus.

RESP. BRONCHIOLE & ALV. DUCT

Respiratory Bronchioles

Are similar in structure to terminal bronchiolesBut: their walls are interrupted by the presence of few pulmonary alveoli. وخصوصا جدا مهمه

بالعملي

Clara cells تقوم مرطبه خالياالقلوبليت مقام

CLARA CELLSStructure:

columnar cells (non ciliated).

Dome-shaped apices with microvilli.

Numerous apical secretory granules (of glycoproteins).

Abundant rER.

Function: مهمه1- Protect the bronchiolar epith. by their glycoproteins secretion.

2- Degrade toxins in inhaled air.

3- Divide to regenerate the bronchiolar epith.

4- Produce surfactant-like material.

جدا ( ) : مهمه انتشارها مواقع1 -last portion of preterminal bronchioles

2 -all terminal bronchioles3 -all respiratory portion

ALVEOLAR DUCTS

The wall of alveolar ducts consist almost ofpulmonary alveoli.

Alveolar ducts do NOT have walls of their own; They are merely فقط linear arrangement of

pulmonary alveoli. N.B. Alveolar duct → ends by: atrium → communicates with: 2-3 alveolar sacs

PULMONARY ALVEOLIDefinition:

They are small outpouchings خارجي Aب of تجيrespiratory bronchioles, alveolar ducts & alveolar sacs.

Topics: مناقشتها ستتم التي العنوانين*Interalveolar septa.

*Blood-air barrier ( Blood-gas barrier)

*Alveolar epithelium.

*Lung macrophages (alveolar macrophages).

1- INTERALVEOLAR SEPTA

Definition:

The region between 2 adjacent متجاوه alveoli.

Components:

(A)Alveolar Epithelium:

lines both sides of interalveolar septum.

(B) Interstitium.

INTERALVEOLAR SEPTA& PULMONARY ALVEOLI

ALVEOLAR EPITHELIUM

(1) Type I Pneumocytes (Type I alveolar cells) (Squamous alveolar cells).(2) Type II Pneumocytes (Type II alveolar cells) ( Septal cells) ( Great alveolar cells)

ALVEOLAR EPITHELIUM

Type I Pn.

Type II Pn.

ALVEOLAR EPITHELIUM(1) Type I Pneumocytes: - line 95% of the alveolar surface. - Count: less numerous كبير حجمها than type II الن

pneumocytes.

- L/M: simple squamous epith. ,highly attenuated cells.

- E/M: Abundant pinocytotic vesicles, Are connected together and with type II cells by occluding junctions. -Function: Exchange of gases.

Type II Pneumocyte (E/M)

Type II Pneumocytes

(2) Type II Pneumocytes:- Line 5% of the alveolar surfaces.- Are more numerous than type I pneumocytes.

- L/M: Are cuboidal cells ( other textbooks: rounded

cells). Usually found in groups of 2-3 cells.

Usually found at sites of union of septa. Foamy -رائغ .or vesicular cytoplasm منتفخ Nucleus: central, rounded, vesicular.

هو الخاليا من النوع هذاالتعويض عن المسؤول

تايب خاليا يعوض 1فهو 2وتايب

Type II Pneumocytes:

- E/M: connected with type I cells by occluding junctions Dome-shaped الشكل .apical surface قبي Short apical microvilli. Abundant mitochondria, RER , Well-developed

Golgi. Membrane-bound Lamellar bodies (contain

concentric or parallel lamellae limited by a unit membrane) (contain pulmonary surfactant).

Function:

1- Synthesis & secretion of pulmonary

surfactant وظائفه : التي a- It reduces effort to inflate pulm. Alveoli.

b- It has bactericidal effect.

2- Phagocytosis of pulmonary surfactant.

3-Renewal of alveolar epithelial cells:

Type II cells can divide to regenerate both type I & type II pneumocytes.

Type II Pneumocytes:

Interstitium of interalveolar septa(1) Continuous Pulmonary Capillaries:

-The richest capillary network in the body

- Continuous blood capillaries

- Endothelium shows numerous

pinocytotic vesicles.

(2) Interstitial C.T.:

a- C.T. Fibers: elastic fibers &

type III collagen (reticular fibers).

b- C.T. Cells: Fibroblasts, Macrophages,

Mast cells, Lymphocytes.

Blood-air barrier

BLOOD-GAS BARRIER(BLOOD-AIR BARRIER)

Definition:It is the region of the interalveolar septum that is

traversed by O2 & CO2

Components:1- Thin layer of surfactant.2- Type I pneumocyte.3- Fused basal laminae of type I pneumocytes & endothelial cells of the pulmonary capillary.4- Endothelial cells of the pulmonary capillary.

Alveolar Macrophages(Dust Cells)

Sites:

(1) In lumen of pulmonary alveoli.

(2) In pulmonary interstitium.

Function:

1- Phagocytose particulate matter (e.g. dust & bacteria)in the lumen of pulm. alveoli &

in the interalveolar septa.

2- Phagocytose part of the surfactant.