CPR - Histology {4.01}

The respiratory system originates as an outgrowth from which embryonic structure at 4 weeks of development?

Foregut

What structure separates the laryngotracheal diverticulum from the pharynx and esophagus?

Tracheo-esophageal septum

From which embryonic layer is the visceral pleura derived?

Splanchnic mesoderm

The parietal pleura is derived from the _____ mesoderm.

Somatic

Identify the lung maturation period (5-16 weeks) where the lungs resemble exocrine glands and gas exchange is impossible.

Pseudoglandular period

During which maturation period (16-24 weeks) do the lumina of bronchi and bronchioles enlarge and vascularity increases?

Canalicular period

At what gestational age do respiratory bronchioles and primordial alveoli first allow for potential fetal viability and gas exchange?

24 weeks

The _____ period (24 weeks to late fetal period) is characterized by the budding of terminal sacs and the start of surfactant production.

Terminal saccular

Until what age does the Alveolar period continue to produce mature alveoli?

8 years

A failure of the tracheoesophageal septum to develop or fuse properly leads to a _____.

Tracheo-esophageal fistula

Why is esophageal atresia often associated with polyhydramnios?

The fetus is unable to swallow amniotic fluid.

What condition involving low amniotic fluid volume can lead to inadequate thoracic space and pulmonary hypoplasia?

Oligohydramnios

Name the triad of factors required for normal lung development: Adequate amniotic fluid, adequate thoracic space, and _____.

Fetal breathing

Respiratory Distress Syndrome (Hyaline Membrane Disease) in premature infants is primarily caused by a deficiency in _____.

Surfactant

The conducting portion of the respiratory tract extends from the nasal cavity to the _____.

Terminal bronchioles

What are the four components of the respiratory portion of the respiratory system?

Respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Describe the cellular classification of the standard respiratory epithelium.

Pseudostratified ciliated columnar epithelium

Which cell type in the respiratory epithelium serves as a stem cell for the other cell types?

Basal cells

Identify the respiratory epithelial cell type that functions as a neurosensory cell.

Brush cells

What is the function of Kulchitsky (K) cells in the respiratory epithelium?

They are neuroendocrine cells that contain basal granules.

From which specific cell type does Small Cell Carcinoma typically originate?

Kulchitsky (K) cells

Chronic exposure to cigarette smoke can cause respiratory epithelium to undergo _____, potentially leading to dysplasia and carcinoma.

Squamous metaplasia

Kartageners syndrome (Primary ciliary dyskinesia) is caused by a structural defect in the _____ of the cilia.

Dynein arms

What is the primary function of the venous sinuses in the lamina propria of the nasal cavity?

To warm the inhaled air.

What type of cartilage forms the septal cartilage of the nose?

Hyaline cartilage

Identify the specific area of the nasal septum that is highly vascularized and a common site for epistaxis.

Littles Area (Kiesselbachs plexus)

Which four types of tonsils constitute Waldeyers Ring?

Pharyngeal, tubal, palatine, and lingual tonsils.

What type of epithelium covers the Palatine tonsils?

Nonkeratinized stratified squamous epithelium

How does the histological structure of Palatine tonsils differ from Pharyngeal tonsils regarding surface invaginations?

Palatine tonsils have deep crypts, while Pharyngeal tonsils have few or no crypts.

The clinical term for an enlarged pharyngeal tonsil that may obstruct the airway is _____.

Adenoids

Identify the histological transition in cartilage structure as a primary bronchus branches into smaller lobar and segmental bronchi.

C-shaped rings are replaced by irregular plates of cartilage.

What are the three structural elements that disappear when a bronchus becomes a bronchiole?

Cartilage, glands, and goblet cells.

Which layer becomes the most prominent feature of the bronchiole wall to maintain patency in the absence of cartilage?

Smooth muscle

Identify the specialized nonciliated cuboidal cells found in terminal and respiratory bronchioles.

Club (Clara) cells

Club (Clara) cells produce surfactants, lysozymes, and the _____ enzyme used for detoxification.

P450

Which alveolar cell type covers the majority of the alveolar surface and facilitates gas exchange?

Type I pneumocyte

Identify the two primary functions of Type II pneumocytes.

Production of surfactant and acting as stem cells for Type I cells.

What is the clinical significance of finding carbon particles within alveolar macrophages ('dust cells')?

It indicates the phagocytosis of inhaled environmental pollutants.

What is the clinical significance of finding hemosiderin-laden macrophages within the alveoli?

Pulmonary edema/Heart failure

List the three main layers of the blood-air barrier.

Alveolar epithelium (Type I pneumocytes), fused basal lamina, and capillary endothelium.

How does pulmonary fibrosis affect lung function based on its histological changes?

Thickening of the interalveolar septum reduces lung compliance.

The conducting portion of a bronchiole is supplied by _____ arteries, while the respiratory portion is supplied by pulmonary vessels.

Bronchial

What are the eosinophilic knobs found in alveolar ducts composed of?

Smooth muscle

Each respiratory bronchiole supplies a structural unit of the lung known as a _____.

Pulmonary acinus

In the respiratory epithelium, which cell type accounts for roughly 30% of the population and possesses motile projections?

Ciliated columnar cells

Concept: MALT

Definition: Mucosa-Associated Lymphoid Tissue, which provides secondary lymphoid defense along the respiratory tract.

The sequence of development for the respiratory system is: LTfold → LTdiverticulum → _____.

Respiratory bud

What is the primary function of the seromucous glands in the nasal mucosa?

To provide humidity and filtration for inhaled air.

Which cell type in the terminal bronchiole acts as a progenitor for both ciliated and non-ciliated epithelial cells?

Club (Clara) cells

Describe the epithelial change that occurs as a terminal bronchiole transitions into a respiratory bronchiole.

The epithelium changes from simple cuboidal to simple squamous at the sites of alveolar outpocketings.

Potters Syndrome is a clinical result of _____ during fetal development.

Oligohydramnios

What is number 1?

Ciliated columnar cells

What is number 2?

Goblet cells

What is number 3?

Basal cells

What is number 1?

Respiratory endothelium

What is number 2?

Venous sinuses

What is number 3?

Seromucous glands

What is number 1?

Bony septum

What is number 2?

Respiratory endothelium

What is number 3?

Septal cartilage - hyaline

What is number 4?

Perichondrium

What is number 5?

Dilated blood vessels

What is number 1?

Crypts

What is number 2?

Lymphoid tissue

What is number 3?

Mucous glands

What is number 4?

Nonkeratinized stratified squamous epithelium

What is number 1?

Respiratory epithelium

What is number 2?

Lamina propria

What is number 3?

Seromucous glands

What is number 4?

Hyaline cartilage

What is number 5?

Adventitia

What is number 1?

Spiral smooth muscle

What is number 2?

Cartilage plates

What is number 3?

Submucosal Glands

What is number 4?

Fibroelastic CT

Ultrastructurally, cilia are comprised of which of the following?

Microtubules