MORPHOLOGY Flashcards

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
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2
Q

EMBRIOLOGY

Development of Respiratory Diverticulum

A
  1. Respiratory Diverticulum enlarges → lung bud (distal portion)
  2. Bifurcation → lung bud + 2 bronchial buds
  3. Tracheoesophageal Septum
  4. Divisions → bronchial tree formation (month 6)
    • main bronchi
    • secondary bronchi
    • terciary bronchi (bronchopulmonar)
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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)
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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)
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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)

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6
Q

ANATOMY

Upper Respiratory Tract

A
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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
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8
Q

ANATOMY

Bronchi

A

Bronchial Tree

  1. Primary Bronchi (enter the lung)
  2. Secondary Bronchi (lobar)
    • 2 left lung
    • 3 right lung
  3. Tertiary Bronchi (segmental)
    • 10 segmental bronchii each lung
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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)

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10
Q

ANATOMY

Right lung is superior than the left lung

True or False?

A

TRUE

liver presence in the right

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11
Q

ANATOMY

Cardiac impression in the left lung is more pronuced than the right lung

True or False?

A

TRUE

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12
Q

ANATOMY

Lung: lobes and fissures

A
  • RIGHT LUNG
    • superior lobe
      • horizontal fissure
    • middle lobe
      • oblique fissure
    • inferior lobe
  • LEFT LUNG
    • superior lobe
      • oblique fissure
    • inferior lobe
    • lingula (corresponds middle lobe)
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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
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14
Q

ANATOMY

Lung Projections: lobes

A

superior → above 4th rib (anteriorly)

middle → below 4th rib (anteriorly)

inferior → below 6th rib (posteriorly)

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15
Q

ANATOMY

Lung: segments

A
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16
Q

PLEURAL CAVITY

Pleura

A
  • mesodermal-derived membrane (serous)
  • double-layered membrane
    • friction-reducing movements
    • parietal layer
    • visceral layer
    • pleural cavity → potencial space
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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

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18
Q

PLEURAL CAVITY

Visceral Pleura

A

Tightly invest the surface of the lungs

fissures + lobes

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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
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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
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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
Q

ANATOMY

Clinical Correlate: Pancoast Tumor

A

Apex

+

can result in thoracic outlet syndrome and horner syndrome

26
Q

ANATOMY

Clinical Correlate: aspiration a foreign body

A

RIGHT PRIMARY BRONCHUS

(shorter + wider + more vertical)

posterior basal segment of right inferior lobe

(more often // if patient was in vertical position)

27
Q

ANATOMY

Clinical Correlate: breath sounds

A

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
Q

ANATOMY

Clinical Correlate: which lobe of the left lung drains also across the midline to right bronchomediastinal nodes?

A

LOWER LEFT LOBE

important to metastasis of lung cancer

29
Q

HISTOLOGY

Air-Blood Barrier

A
  • 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
Q

HISTOLOGY

Trachea

A
  • 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
Q

HISTOLOGY

Tracheal Epithelial Cells: Columnar Cells

A
  • 200-300 cilia (microvilia) per cell
  • cilia → mucous movement (out to pharinx)
  • mucociliary scalator system
32
Q

HISTOLOGY

Tracheal Epithelium Cells: Goblet Cells

A
  • secrete mucous (polysaccharide) with help from submucosal mixed glands
  • mucous
    • traps → viruses + bacteria + dust
    • absorbs → water-soluted gases (ozonio)
33
Q

HISTOLOGY

Tracheal Epithelium Cells: PNE cells

A

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
Q

HISTOLOGY

Tracheal Epithelium Cells: Basal Cells

A
  • stem cells
  • formation
    • goblet cells
    • ciliated cells
  • responsible for pseudostratified appearance
35
Q

HISTOLOGY

Bronchi

A
  • 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
Q

HISTOLOGY

Bronchioles

A
  • not pseudocolumnar epithelium → simple columnar
    • ciliated cells
    • goblet cells
    • clara cells
  • wall
    • no cartilage
    • no glands
    • smooth-muscle fascicles + elastic fibers
37
Q

HISTOLOGY

Terminal Bronchiole

+

Respiratory Bronchiole

A

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
Q

HISTOLOGY

Clara Cells

A
  • 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
Q

HISTOLOGY

Alveoli

A
  • alveolar sacs + ducts → basically alveoli
  • alveoli = 80-85% lung volume
  • 300 mi alveolu → 200 microns in diameter each
40
Q

HISTOLOGY

Alveoli: Pneumocytes

A
  • 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
Q

HISTOLOGY

Surfactant

A

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
Q

HISTOLOGY

Alveolar Wall

A
  • 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
Q

HISTOLOGY

Pores of Kohn

A

collateral ventilation

10-15 microns

44
Q

HISTOLOGY

Alveolar Macrophage

A
  • 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
Q

HISTOLOGY

Clinical Correlate: Respiratory Distress Syndrome

A
  • deficiency of surfactant
  • premature infants + infants of diabetic mother + prolonged intrauterine asphixia
  • treatment → thyroxine + cortisol
46
Q

HISTOLOGY

Clinical Correlate: Hyaline Membrane Disease

A
  • surfactant deficiency + gasping + cyanosis
  • atelectasis
  • eosinophilic fluid
47
Q

HISTOLOGY

Clinical Correlate: Ineffective Mucosal Clearance

A
  • 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
Q

HISTOLOGY

Clinical Correlate: Squamou Metaplasia

A

columnar epithelium is sensitive to irritation

ciliated cells become taller + goblet cells increase in number

ciliated epithelium becomes squamous

(reversible process)

49
Q

HISTOLOGY

Clinical Correlate: Bronchial Metastatic Tumor

A

arise from K cells

(Kulchitsky cells)

50
Q

HISTOLOGY

Clinical Correlate: COPD

A

Chronic Obstrutive Pulmonary Disease

  • affect bronchioles
  • emphysema
    • loss of elastic fibers
    • chronic airflow obstrution
    • irreversible
  • asthma
    • chronic process but reversible
    • narrowing of airways
51
Q

HISTOLOGY

Clinical Correlate: Premature Fetus and Diabetic Mother

A

Corticosteroids induce synthesis of sulfactant

+

high insulin levels (diabetic mother) antagonize the sulfactant production

+

diabetic mother = higher incidence of respiratory distress syndrome

52
Q

HISTOLOGY

Clinical Correlate: Alveolar Macrophage other names

A

Dust Cells

(phagocyte dust and cigarette particles)

+

Heart Failure Cells

(phagocyte blood cells that have scaped into alveolar space during congestive heart failure)