PULMONARY Flashcards
EMBRIOLOGY
Respiratory (laryngotracheal) Diverticulum
- 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
EMBRIOLOGY
Development of Respiratory Diverticulum
- 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)
EMBRIOLOGY
What is the critical time for lung formation?
25 - 28 week
- pneumocytes (types I and II) are formed
- surfactante production is possible
- premature fetus at this time can survive (intensive care)
EMBRIOLOGY
Clinical Correlate: Tracheoesophageal Fistula
- 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)
EMBRIOLOGY
Clinical Correlate: Pulmonary Hypoplasia
Congenital Diaphragmatic Hernia
(herniation of abdominal contents into thorax)
or
Potter’s Sequence
(bilateral renal agenesia → no urine → oligohydramnio → increase of fetal thorax pressure)
ANATOMY
Upper Respiratory Tract
ANATOMY
Trachea
- 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
ANATOMY
Bronchi
Bronchial Tree
- Primary Bronchi (enter the lung)
- Secondary Bronchi (lobar)
- 2 left lung
- 3 right lung
- Tertiary Bronchi (segmental)
- 10 segmental bronchii each lung
ANATOMY
Lung: surfaces and regions
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)
ANATOMY
Right lung is superior than the left lung
True or False?
TRUE
liver presence in the right
ANATOMY
Cardiac impression in the left lung is more pronuced than the right lung
True or False?
TRUE
ANATOMY
Lung: lobes and fissures
- 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
ANATOMY
Lung Projections: fissures
- Oblique Fissure
- 5th intercostal space → 6th costal cartilage
- both lungs
- midclavicular line
- Horizontal Fissure
- only right lung
- 5th intercostal space → 4th costal cartilage
ANATOMY
Lung Projections: lobes
superior → above 4th rib (anteriorly)
middle → below 4th rib (anteriorly)
inferior → below 6th rib (posteriorly)
ANATOMY
Lung: segments
PLEURAL CAVITY
Pleura
- mesodermal-derived membrane (serous)
- double-layered membrane
- friction-reducing movements
- parietal layer
- visceral layer
- pleural cavity → potencial space
PLEURAL CAVITY
Parietal Pleura
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
PLEURAL CAVITY
Visceral Pleura
Tightly invest the surface of the lungs
fissures + lobes
PLEURAL CAVITY
Pleural Innervation
- Parietal Pleura
- somatic sensory innervation
- intercostal nerve → costal + diaphragmatic pleura
- phrenic nerve → diaphragmatic + mediastinal pleura
- Visceral Pleura
- visceral sensory innervation
- autonomic nerves
PLEURAL CAVITY
Pleural Cavity and Pneumothorax
- 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
PLEURAL CAVITY
Pleural Reflections
- pleural reflection = parietal pleura changing the direction from one wall to another wall
- 2 rib interspaces separated parietal pleura from visceral pleura
PLEURAL CAVITY
Pleural Recesses
potencial spaces not occupied by long tissue (except deep inspiration)
costodiaphragmatic
+
costomediastinal
ANATOMY
Lymphatic Drainage
- 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)
ANATOMY
Clinical Correlate: pleurisy
- inflammation of parietal pleura
- sharp pain uppon respiration
- costal inflammation → dermatome pain
- mediastinal irritation → shoulder dermatomes (phrenic nerve // C3-C5)
ANATOMY
Clinical Correlate: Pancoast Tumor
Apex
+
can result in thoracic outlet syndrome and horner syndrome
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)
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
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
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)
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
HISTOLOGY
Tracheal Epithelial Cells: Columnar Cells
- 200-300 cilia (microvilia) per cell
- cilia → mucous movement (out to pharinx)
- mucociliary scalator system
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)
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
HISTOLOGY
Tracheal Epithelium Cells: Basal Cells
- stem cells
- formation
- goblet cells
- ciliated cells
- responsible for pseudostratified appearance
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
HISTOLOGY
Bronchioles
- not pseudocolumnar epithelium → simple columnar
- ciliated cells
- goblet cells
- clara cells
- wall
- no cartilage
- no glands
- smooth-muscle fascicles + elastic fibers
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
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
HISTOLOGY
Alveoli
- alveolar sacs + ducts → basically alveoli
- alveoli = 80-85% lung volume
- 300 mi alveolu → 200 microns in diameter each
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
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
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
HISTOLOGY
Pores of Kohn
collateral ventilation
10-15 microns
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
HISTOLOGY
Clinical Correlate: Respiratory Distress Syndrome
- deficiency of surfactant
- premature infants + infants of diabetic mother + prolonged intrauterine asphixia
- treatment → thyroxine + cortisol
HISTOLOGY
Clinical Correlate: Hyaline Membrane Disease
- surfactant deficiency + gasping + cyanosis
- atelectasis
- eosinophilic fluid
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)
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)
HISTOLOGY
Clinical Correlate: Bronchial Metastatic Tumor
arise from K cells
(Kulchitsky cells)
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
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
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)
