1
Q
EMBRIOLOGY
Respiratory (laryngotracheal) Diverticulum
A
- week 4
- from ventral wall of the foregut (endoderm)
- lower respiratory tract formation (trachea, bronchi and lungs)
- endoderm → respiratory epithelium
- mesoderm → muscles + cartilages + connective tissues
2
Q
EMBRIOLOGY
Development of Respiratory Diverticulum
A
- Respiratory Diverticulum enlarges → lung bud (distal portion)
- Bifurcation → lung bud + 2 bronchial buds
- Tracheoesophageal Septum
- Divisions → bronchial tree formation (month 6)
- main bronchi
- secondary bronchi
- terciary bronchi (bronchopulmonar)
3
Q
EMBRIOLOGY
What is the critical time for lung formation?
A
25 - 28 week
- pneumocytes (types I and II) are formed
- surfactante production is possible
- premature fetus at this time can survive (intensive care)
4
Q
EMBRIOLOGY
Clinical Correlate: Tracheoesophageal Fistula
A
- malformation of the tracheoesophageal septum
- 90% → esophagus + distal third of the trachea
- esophageal atresia + polyhydramnions
- symptoms
- regurgitation of milk
- cyanosis after feeding
- abdominal distention after crying
- pneumonitis (reflux into lungs)
5
Q
EMBRIOLOGY
Clinical Correlate: Pulmonary Hypoplasia
A
Congenital Diaphragmatic Hernia
(herniation of abdominal contents into thorax)
or
Potter’s Sequence
(bilateral renal agenesia → no urine → oligohydramnio → increase of fetal thorax pressure)
6
Q
ANATOMY
Upper Respiratory Tract
A
7
Q
ANATOMY
Trachea
A
- hollow tube
- 10 cm length
- 2 cm diameter
- bifurcation at the carina
- C-shaped hyalin cartilage rings
- 16 - 20 rings
- anterior wall
- rings are interconnected by smooth muscle
8
Q
ANATOMY
Bronchi
A
Bronchial Tree
- Primary Bronchi (enter the lung)
- Secondary Bronchi (lobar)
- 2 left lung
- 3 right lung
- Tertiary Bronchi (segmental)
- 10 segmental bronchii each lung
9
Q
ANATOMY
Lung: surfaces and regions
A
Costal
(convex + smooth + related to chest wall)
Mediastinal
(concave + related to mediastinum and heart)
Diaphragmatic
(base + concave)
Apex
(4 cm above first rib + crossed by subclavian vessels)
10
Q
ANATOMY
Right lung is superior than the left lung
True or False?
A
TRUE
liver presence in the right
11
Q
ANATOMY
Cardiac impression in the left lung is more pronuced than the right lung
True or False?
A
TRUE
12
Q
ANATOMY
Lung: lobes and fissures
A
- RIGHT LUNG
- superior lobe
- horizontal fissure
- middle lobe
- oblique fissure
- inferior lobe
- superior lobe
- LEFT LUNG
- superior lobe
- oblique fissure
- inferior lobe
- lingula (corresponds middle lobe)
- superior lobe
13
Q
ANATOMY
Lung Projections: fissures
A
- Oblique Fissure
- 5th intercostal space → 6th costal cartilage
- both lungs
- midclavicular line
- Horizontal Fissure
- only right lung
- 5th intercostal space → 4th costal cartilage
14
Q
ANATOMY
Lung Projections: lobes
A
superior → above 4th rib (anteriorly)
middle → below 4th rib (anteriorly)
inferior → below 6th rib (posteriorly)
15
Q
ANATOMY
Lung: segments
A
16
Q
PLEURAL CAVITY
Pleura
A
- mesodermal-derived membrane (serous)
- double-layered membrane
- friction-reducing movements
- parietal layer
- visceral layer
- pleural cavity → potencial space
17
Q
PLEURAL CAVITY
Parietal Pleura
A
Costal Parietal Pleura
(lateral → ribs + intercostal space)
Diaphragmatic Parietal Pleura
(inferior)
Mediastinal Parietal Pleura
(medial → reflects to become visceral pleura at hilum)
Cervical Parietal Pleura
18
Q
PLEURAL CAVITY
Visceral Pleura
A
Tightly invest the surface of the lungs
fissures + lobes
19
Q
PLEURAL CAVITY
Pleural Innervation
A
- Parietal Pleura
- somatic sensory innervation
- intercostal nerve → costal + diaphragmatic pleura
- phrenic nerve → diaphragmatic + mediastinal pleura
- Visceral Pleura
- visceral sensory innervation
- autonomic nerves
20
Q
PLEURAL CAVITY
Pleural Cavity and Pneumothorax
A
- Cavity
- potencial space
- closed space + small amount of serous fluid
- negative pressure
- Pneumothorax
- introduction of air into the pleural cavity → lost negative pressure → lung collapse
- open pneumothorax x tension pneumothorax
21
Q
PLEURAL CAVITY
Pleural Reflections
A
- pleural reflection = parietal pleura changing the direction from one wall to another wall
- 2 rib interspaces separated parietal pleura from visceral pleura
22
Q
PLEURAL CAVITY
Pleural Recesses
A
potencial spaces not occupied by long tissue (except deep inspiration)
costodiaphragmatic
+
costomediastinal
23
Q
ANATOMY
Lymphatic Drainage
A
- Plexus
- superficial (below visceral pleura)
- deep (into the lungs, drains through pulmonary nodes)
- Lymph Nodes
- bronchopulmonary (hilar) → both deep and superficial plexus
- tracheobronchial → bifurcation of the trachea
- bronchomediastinal (nodes and trunk)
24
Q
ANATOMY
Clinical Correlate: pleurisy
A
- inflammation of parietal pleura
- sharp pain uppon respiration
- costal inflammation → dermatome pain
- mediastinal irritation → shoulder dermatomes (phrenic nerve // C3-C5)
25
ANATOMY
Clinical Correlate: Pancoast Tumor
Apex
+
can result in thoracic outlet syndrome and horner syndrome
26
ANATOMY
Clinical Correlate: aspiration a foreign body
RIGHT PRIMARY BRONCHUS
(shorter + wider + more vertical)
⇒
**posterior basal segment of right inferior lobe**
(more often // if patient was in vertical position)
27
ANATOMY
Clinical Correlate: breath sounds
**Superior Lobes**
above 4th intercostal space + anterior chest wall
**Middle Lobe**
below 4th intercostal space (right) + medially toward sternum + anterior chest wall
**Inferior Lobes**
posterior chest wall
28
ANATOMY
Clinical Correlate: which lobe of the left lung drains also **across the midline** to right bronchomediastinal nodes?
LOWER LEFT LOBE
important to metastasis of lung cancer
29
HISTOLOGY
Air-Blood Barrier
* 500 ml of air per breath
* 120 square meters of air-blood barrier
* important
* susceptible to infections and pollution
* receive all cardiac output
* metabolism (endothelium) - lypoprotein and prostaglandin
* production of ACE (angiotensin conversor enzyme)
30
HISTOLOGY
Trachea
* Mucosa
* pseudostratified epithelium
* lamina propria (vessel, immune cells and connective tissue)
* muscularis mucosa (thin smooth cells layer)
* Submucosa
* blood and lymphatic vessels
* nerves
* collagen fibers
* Adventicia
* several layers
* losse connective tissue
31
HISTOLOGY
Tracheal Epithelial Cells: Columnar Cells
* 200-300 cilia (microvilia) per cell
* cilia → mucous movement (out to pharinx)
* mucociliary scalator system
32
HISTOLOGY
Tracheal Epithelium Cells: Goblet Cells
* secrete mucous (polysaccharide) with help from submucosal mixed glands
* mucous
* traps → viruses + bacteria + dust
* absorbs → water-soluted gases (ozonio)
33
HISTOLOGY
Tracheal Epithelium Cells: PNE cells
Pulmonary Neuroendocrine Cells
* comparable to the endocrine cells in the gut
* clusters + airway branch points
* **APUD** (amino-precursor-uptake-decarboxylase)
* **DNES** (diffuse neuroendocrine system)
* **K cells** (kulchitsky)
* **brush cells**
* **sensory receptors** (synapses with intraepithelial nerves)
* intermediate stages of goblet cells
34
HISTOLOGY
Tracheal Epithelium Cells: Basal Cells
* stem cells
* formation
* goblet cells
* ciliated cells
* responsible for pseudostratified appearance
35
HISTOLOGY
Bronchi
* pseudostratified epithelium (columnar ciliated cells + goblet cells + PNE cells + basal cells)
* submucosa (glands with ducts to lumen)
* cartilage plates + circular smooth-muscle (bound together by elastic fibers)
* decrease of mucous production
* - goblet cells
* - submucosal glands
36
HISTOLOGY
Bronchioles
* not pseudocolumnar epithelium → **simple columnar**
* ****ciliated cells
* goblet cells
* **clara cells**
* wall
* **no cartilage**
* **no glands**
* smooth-muscle fascicles + elastic fibers
37
HISTOLOGY
Terminal Bronchiole
+
Respiratory Bronchiole
**Terminal Bronchiole**
last conducting bronchiole
**Respiratory Bronchiole**
terminal bronchiole that is periodically interrupted by alveoli in the wall
* ciliated simple columnar epithelium
* no goblet cells
* clara cells
38
HISTOLOGY
Clara Cells
* bronchiolar **secretory** cells (non-ciliated)
* 80% of terminal bronchiole epithelium
* production of **serous fluid** similar to surfactant
* **chloride ion** transport to the lumen
* **detoxification** (increase with polutants like cigarette smoke)
* **stem cells**
* clara cells
* ciliated cells
39
HISTOLOGY
Alveoli
* alveolar sacs + ducts → basically alveoli
* alveoli = 80-85% lung volume
* 300 mi alveolu → 200 microns in diameter each
40
HISTOLOGY
Alveoli: Pneumocytes
* Pneumocyte - Type I
* "small alveolar cell"
* major cell of the alveolar surface
* gas exchange
* 40% of the alveolar cells, BUT cover 90-95% of alveolar surface
* Pneumocyte - Type II
* 60% of the alveolar cells, BUT cover only 5% of alveolar surface
* surfactant
* stem cell → type I and type II
41
HISTOLOGY
Surfactant
phospholipids + surfactant proteins
* **decrease of surface tension** (phospholipids act like detergent)
* prevent alveolar collapse (after expiration)
* cycle of surfactant
* most recycle by pneumocyte II
* some undergoes phagocytosis by macrophages
42
HISTOLOGY
Alveolar Wall
* Cells → pneumocytes + macrophage + mast cells + fibroblasts + myofibroblast + smooth-muscle cells
* Fibers → collagen (type I and II) + elastic fibers
* Blood-Gas Barrier (0,1 microns)
* surfactant
* pneumocyte type I (squamous epithelium)
* shared basal lamina
* capillary endothelium
43
HISTOLOGY
Pores of Kohn
collateral ventilation
10-15 microns
44
HISTOLOGY
Alveolar Macrophage
* derived from monocyte
* resident alveolar macrophage
* alveoli (1-3)
* interalveolar septum
* may pass through pores of Kohn
* last defence of the lung
* trap in mucous (go to pharinx)
* enter lymphatic system
45
HISTOLOGY
Clinical Correlate: Respiratory Distress Syndrome
* deficiency of surfactant
* premature infants + infants of diabetic mother + prolonged intrauterine asphixia
* treatment → thyroxine + cortisol
46
HISTOLOGY
Clinical Correlate: Hyaline Membrane Disease
* surfactant deficiency + gasping + cyanosis
* atelectasis
* eosinophilic fluid
47
HISTOLOGY
Clinical Correlate: Ineffective Mucosal Clearance
* **Cystic Fibrosis**
* fluid is viscous
* deficiency of chloride transport
* Clara Cells
* **Kartagener Syndrome**
* cilia immotile → dynein deficiency
* males → same problem at sperm
predisponition to pneumonia (bacteria) and pneumoconiosis (dust)
48
HISTOLOGY
Clinical Correlate: Squamou Metaplasia
columnar epithelium is sensitive to irritation
→
ciliated cells become taller + goblet cells increase in number
→
ciliated epithelium becomes squamous
(reversible process)
49
HISTOLOGY
Clinical Correlate: Bronchial Metastatic Tumor
arise from K cells
| (Kulchitsky cells)
50
HISTOLOGY
Clinical Correlate: COPD
Chronic Obstrutive Pulmonary Disease
* affect bronchioles
* emphysema
* loss of elastic fibers
* chronic airflow obstrution
* irreversible
* asthma
* chronic process but reversible
* narrowing of airways
51
HISTOLOGY
Clinical Correlate: Premature Fetus and Diabetic Mother
Corticosteroids induce synthesis of sulfactant
+
high insulin levels (diabetic mother) antagonize the sulfactant production
+
diabetic mother = higher incidence of respiratory distress syndrome
52
HISTOLOGY
Clinical Correlate: Alveolar Macrophage other names
**Dust Cells**
(phagocyte dust and cigarette particles)
+
**Heart Failure Cells**
(phagocyte blood cells that have scaped into alveolar space during congestive heart failure)
