Transcript 01-RESPIRATORY SYSTEM.ppt

RESPIRATORY SYSTEM
RESPIRATORY SYSTEM
(I) Conducting portion (Mention……)
(II) Respiratory portion ( “
…….)
RESPIRATORY SYSTEM
NASAL CAVITY
(N.C.)
(1) Vestibule.
(2) Nasal Fossae (posterior portion of N.C.):
a- Olfactory portion.
b- Respiratory portion.
Nasal septum divides the nasal cavity into
two halves.
NASAL CAITY
& LARYNX
VESTIBULE OF
NASAL CAVITY
Lining: is lined with skin.
1- Epidermis (Keratinized stratified Squamous epithelium).
2- Dermis.
3- Vibrissae.
4- Sebaceous glands.
5- Sweat glands.
Wall:-----------
RESPIRATORY AREA OF NASAL CAVITY
(RESP. PORTION OF NASAL FOSSA)
(A) Epithelium:
Pseudo-stratified ciliated columnar epithelium with
goblet cells (Respiratory epithelium).
(B) Lamina propria (Corium):
1- C.T.: richly (highly) vascularized.
2- Large arterial plexuses & venous sinuses
(Highly vascular),especially in region of conchae &
anterior part of nasal septum.
3- Many seromucous glands (acini).
4- Abundant lymphoid elements:
Including lymphoid nodules, plasma cells & mast cells.
RESPIRATORY EPITHELIUM
L/M: Pseudo-stratified columnar ciliated
epithelium with goblet cells.
E/M: 6 cell types ( all touch the basement m)
1- Ciliated columnar cells: 30%
2- Goblet cells: 30%
3- Basal cells: are stem cells (30%)
4- Brush cells (small granule mucous cells): (3%)
are sensory receptors or degranulated goblet cells.
5- DNES cells (small granule cells) (K cells) : 3-4%
are neuroendocrine cells
6- Serous cells: 3%
RESPIRATORY MUCOSA OF NASAL CAVITY
RESPIATORY EPITHELIUM
PARANASAL SINUSES
Lining: 1- Respiratory epith. (Mention…….)
2- Lamina propria.
CLINICAL APPLICATION:
Sinusitis.
MEDICAL APPLICATION
IMMOTILE CILIA SYNDROME:
C.P.:
1- Chronic respiratory tract infection ( M & F)
2- Infertility in males (M).
Etiology:
Immobility of cilia & flagella
(induced by deficiency of dynein protein)
MEDICAL APPLICATION
Smoking & resp. epith.:
1- ↑ Goblet cells → ↑ Mucus
2- ↓ Ciliated cells ( due to CO ):
→ ↓ Movement of the mucus layer.
3- Metaplasia: Transformation of resp. epith.
into str.squamous epith.(non-keratinized).
4- Squamous cell carcinoma.
MEDICAL APPLICATION
Allergic reactions & inflammation →
Abnormal engorgement of swell bodies
( large arterial plexuses & venous sinuses in
lamina propria over the conchae) →
Restrict air flow.
OLFACTORY MUCOSA
OLFACTORY MUCOSA
OLFACTORY MUCOSA
OLFACTORY MUCOSA
OLFACTORY MUCOSA
OLFACTORY AREA OF NASAL CAVITY
OLFACTORY MUCOSA
Site: 1-Roof of nasal cavity.
2-Upper part of nasal septum.
3-over superior concha.
Structure:
(A)
Olfactory epithelium:
Pseudo-stratified columnar epith.
1- Supporting (sustentacular) cells
2- Olfactory cells (olfactory nerve cells)
1 & 2 are connected together by junctional complexes.
3- Basal cells.
(B) Lamina propria: contains:
1- Highly (richly) vascularized loose to dense C.T.
2- Bowman’s glands (serous acini).
3- Axons of olfactory nerve cells + Schwann cells.
4- Rich vascular plexus.
5- Numerous lymphoid elements.
OLFACTORY EPITHELIUM
1- Sustentacular (supporting) cells:
Columnar cells with:
Apical striated border (microvilli).
Oval Nucleus.
Apical cytoplasm has secretory granules with
yellow pigments.
Junctional complexes with olf. Vesicles.
Function:
Physical support, nourishment & electrical insulation for
olfactory cells.
OLFACTORY EPITHELIUM
2- Olfactory cells:
Are bipolar neurons
Dendrite has olfactory vesicle.
Olfactory vesicle has 6-8 olfactory cilia.
Olfactory cilia are nonmotile
Microtubules of olfactory cilia: (9x2+2x1 then 9x1+2x1).
Cell body with spherical nucleus.
Axons are unmyelinated with Schwann cells.
Axons will collect to form the olfactory nerve.
OLFACTORY EPITHELIUM
3- Basal cells:
Short basophilic pyramidal cells.
Function:
Replacement of sustentacular & olfactory
cells.
LARYNX
(A) Mucous membrane:
1- Epithelium: (2 types: a- respiratory epith.
b- non-keratinized str.sq. epith.----Where?)
2- Lamina propria (contents:---------)
There are 2 pairs of shelf-like mucosal folds:
1- Vestibular folds:
Are immovable.
L/M: a- Resp. epith.
b- Lamina propria:
Loose C.T. with seromucous glands
lymphoid elements & adipose cells.
2- VOCAL FOLDS (CORDS): have:
a- Vocal ligament: bundles of parallel
elastic fibers (dense regular elastic C.T.).
b- Vocalis muscle: Skeletal muscle.
(B) Cartilages:
1- Hyaline cartilages:
Thyroid,
Cricoid,
Body of arytenoids.
2- Elastic cartilages:
Epiglottis,
Corniculate,
Cuneiform,
Tips of arytenoids.
(C) Extrinsic and intrinsic muscles: all are skeletal.
(D) Ligaments.
LARYNX
LARYNX
LARYNX
Glands
Thyroid cartilage
LARYNX
Vocal fold
Respiratory epith.
Bundles of skeletal muscle fibers
LARYNX
LARYNX
VOCAL FOLD (CORD)
TRACHEA
The wall of trachea is formed of:
(1) Mucosa.
(2) Submucosa.
(3) Adventitia.
TRACHEA
TRACHEA
TRACHEA (POST. WALL)
TRACHEA
MUCOSA OF TRACHEA
(1) Epithelium: Respiratory epithelium
(2) Lamina propria:
Loose, fibroelastic C.T. containing:
a- Lymphoid elements
(e.g. lymphoid nodules & lymphocytes).
b- Mucous & seromucous glands.
(3) Elastic lamina:
Dense layer (thick bundle) of elastic fibers.
It separates lamina propria from submucosa.
N.B. Mucosa is non-folded except posteriorly.
SUBMUCOSA OF TRACHEA
Contents:
1- Dense irregular fibroelastic C.T. (others:loose)
2- Numerous mucous & seromucous glands.
3- Lymphoid elements.
4- Rich blood & lymph supply.
N.B. Other textbooks reported that
submucosa of trachea is loose C.T.
ADVENTITIA OF TRACHEA
Contents:
1- Fibroelastic C.T.
2- C-shaped rings (12-16) of hyaline cartilage.
Trachealis muscle (bundle of SMF) bridges (connects)
the open ends of each C-shaped ring of cartilage.
Perichondrium of C-shaped rings of hyaline cartilage
are connected together by dense fibroelastic C.T.
EXTRAPULMONARY BRONCHUS
(1ry BRONCHUS)
Generally have the same histological
appearance as the trachea.
INTRAPULMONARY BRONCHUS
2ry & 3ry BRONCHI)
1234-
Mucosa.
Muscle coat.
Submucosa.
Adventitia.
BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
INTRAPULMONARY BRONCHUS
(1) Mucosa:
It has longitudinal mucosal folds.
a- Epithelium: Respiratory epith.
b- L.P.:
Fibroelastic C.T.
(loose C.T. rich in elastic fibers).
It contains seromucous glands.
“ “
lymphoid elements.
N.B. No elastic lamina.
INTRAPULMONARY BRONCHUS
(2) Muscle coat (complete):
Two distinct layers of SMF spirally
arranged in opposite direction
(crisscrossing bundles of spirally arranged
SMF).
INTRAPULMONARY BRONCHUS
(3) Submucosa:
It 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 neighbouring
bronchial tree.
b- Irregular plates of hyaline
cartilage (complete layer).
c- Solitary lymphoid nodules.
d- Seromucous glands.
INTRAPULMONARY BRONCHUS
2ry Bronchi (lobar bronchi): 3+2
3ry Bronchi (segmental bronchi): 10+10
BRONCHIOLES
1- Preterminal ( 1ry ) Bronchioles (Bronchioles).
2- Terminal ( 2ry ) Bronchioles.
3- Respiratory ( 3ry ) Bronchioles.
PRETERMINAL BRONCHIOLES
Are 1mm or less in diameter.
Each bronchiole supplies pulmonary lobule.
Preterminal Bronchioles
(1) Mucosa: has longitudinal folds:
(A) Epithelium:
S. col. ciliated Epith. with occasional
goblet cells only in the initial segments.
Then, s. cuboidal partially ciliated with
occasional Clara cells (in smaller pret. Br.)
(B) Lamina propria: C.T. (rich in elastic fibers)
(2) Smooth muscle: hellicaly arranged SM layers.
(3) Adventitia: loose fibroelastic C.T.
N.B. No cartilage, No glands, No lymphoid nodules.
Terminal Bronchioles
Similar structure, but:
Epithelium:
Simple cuboidal partially ciliated epithelium
With Clara cells.
Are 0.5mm or less in diameter.
Each supplies lung acinus.
BRONCHIOLE
BRONCHIOLE
TERMINAL BRONCHIOLE
Respiratory Bronchioles
Similar structure to terminal bronchioles
But their walls is interrupted by the presence
of few pulmonary alveoli.
RESPIRATORY BRONCHIOLE
RESP. BRONCGIOLE & ALVEOLUS
RESP. BRONCHIOLE & ALV. DUCT
TERMINAL & RESPIRATORY BRONCHIOLES
Clara cells
Clara cells
CLARA CELLS
Structure:
columnar cells (non ciliated).
Dome-shaped apices with microvilli.
Numerous apical secretory granules
(of glycoproteins).
Abundant rER.
CLARA CELLS
Function:
1- Protect the bronchiolar epith. By their
secretion.
2- Degrade toxins in inhaled air by
cytochrome p-450 enzymes (produced by sER)
3- Divide to regenerate the bronchiolar epith
4- May produce surfactant-like material.
ALVEOLAR DUCTS
The wall of alveolar duct consists almost of
pulmonary alveoli.
(1) Lining Epith.: Squamous alveolar cells
( Type I Pneumocytes )
(2) Lamina propria:
a- Elastic & Reticular fibers.
b- Smooth muscle cell surrounds the opening
of alveolus (small muscle knob).
N.B. Alveolar duct → ends by: atrium →
communicates with: 2-3 alveolar sacs
PULMONARY ALVEOLI
Definition:
They are small outpouchings of respiratory
bronchioles, alveolar ducts & alveolar sacs.
PULMONARY ALVEOLI
*Interalveolar septa.
*Blood-air barrier ( Blood-gas barrier)
*Alveolar epithelium.
*Lung macrophages (alveolar macrophages)
*Alveolar pores.
INTERALVEOLAR SEPTA
(A) Alveolar Epithelium:
(B) Interstitium
INTERALVEOLAR SEPTA
& PULMONARY ALVEOLI
ALVEOLAR EPITHELIUM
Type I Pn.
Type II Pn.
Basal Laminae (fused)
Type I Pn.
N. Of cap. Endothelium
Cap. Endothelium
Type II Pneumocyte (E/M)
Type II Pneumocytes
Type II Pneumocyte (E/M)
Type I Pn
Cap. Endoth.
Basal Laminae
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
(1) Type I Pneumocytes:
- line 95% of the alveolar surface.
- L/M: simple squamous epith. ,highly attenuated cells.
- E/M: Abundant pinocytotic vesicles,
Are connected together and with type
II cells by occluding junctions.
-Functions:
1- Exchange of gases.
2- may play role in surfactant turnover.
Type II Pneumocytes(septal alveolar cells):
- 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 or vesicular cytoplasm.
Nucleus: central, rounded, vesicular.
Type II Pneumocytes(septal alveolar cells):
- E/M:
connected with type I cells by occluding junctions
Dome-shaped apical surface.
Short apical microvilli.
Abundant mitochondria, RER , Well-developed
Golgi.
Membrane-bound Lamellar bodies (contain
concentric or parallel lamellae limited by a unit
membrane) (contain surfactant).
Type II Pneumocytes(septal alveolar cells):
- Renewal:
By mitotic cell division
( Type II cells can divide to replace:
1- Their own population
2- Type I cells).
Type II Pneumocytes(septal alveolar cells):
- Function:
1- Synthesis & secretion of pulmonary
surfactant ( phospholipids+GAGs+Pr.):
a- lower ( ↓ ) alveolar surface tension→
reduce effort to inflate pulm. Alveoli.
b- Phagocytosis of pulmonary surfactant.
b- has bactericidal effect.
2-Renewal of alveolar epithelial cells.
Interstitium of interalveolar septa
(1) 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 & reticular.
b- C.T. Cells: Fibroblasts, Macrophages,
Mast cells, Leucocytes.
BLOOD-GAS BARRIER
Definition:
It is the region of the interalveolar septum
that is traversed by O2 and CO2
Blood-air barrier
BLOOD-GAS BARRIER
BLOOD-AIR BARRIER
Components:
1- Thin layer of surfactant.
2- Type I pneumocyte.
2- Fused basal laminae of type I pneumocytes &
endothelial cells of the pulmonary capillary.
3- Endothelial cells of the pulmonary capillary.
Thickness:
0.1- 1.5 µm.
CLINICAL APPLICATION
Respiratory Distress Syndrome
Etiology:
Deficiency of surfactant in premature infants
→ Pulmonary alveoli are collapsed
( They failed to inflate).
Treatment:
Administration of glucocorticoids→
Induces synthesis of surfactant.
Alveolar Macrophages
(Dust Cells)
Sites:
(1) In lumen of pulmonary alveoli.
(2) In pulmonary interstitium.
ALVEOLAR PORES
Diameter:
8-60 µm.
Function:
Equalize air pressure in the alveoli.
CLINICAL APPLICATION
Emphysema
• Etiology:
Major cause is: smoking
→ Destruction of interalveolar septa
→ Enlargement of pulmonary alveoli
→ Respiratory insufficiency.
PLEURA
(1) Parietal pleura.
(2) Visceral pleura.
L/M:
1- Simple squamous mesothelial cells.
2- Lamina propria:
Fine C.T. layer that contains collagen & elastic
fibers.