Respiratory System Histology

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Questions and Answers

What is the most abundant cell type in the respiratory epithelium?

Neuroendocrine cells

Goblet cells

Ciliated columnar cells (correct)

Basal cells

What type of epithelium is found in the nasal vestibule?

Ciliated columnar epithelium

Stratified squamous epithelium (correct)

Olfactory epithelium

Respiratory epithelium

What is the function of goblet cells in the respiratory epithelium?

To produce mucus (correct)

To produce hormones

To move mucus and trapped particles to the oropharynx

To replenish the epithelium

What type of cartilage is found in the epiglottis?

Elastic cartilage Signup and view all the answers

What is the function of cilia in the respiratory epithelium?

To beat in unison and move mucus and trapped particles Signup and view all the answers

What is the name of the muscle that bridges the dorsal opening of the trachea?

Trachealis muscle Signup and view all the answers

What type of epithelium is found in the olfactory area?

Olfactory epithelium Signup and view all the answers

What type of glands are found in the lamina propria of the trachea?

Seromucous glands Signup and view all the answers

What is the correct sequence of structures in the wall of a bronchus?

E → LP → SM → C Signup and view all the answers

What type of epithelium is present in smaller bronchioles?

Low columnar Signup and view all the answers

What is the function of Clara cells in bronchioles?

Secretory function Signup and view all the answers

At what week of fetal development are respiratory bronchioles present and lungs vascularized?

Week 24 Signup and view all the answers

What happens to the connective tissue as bronchi branching progresses?

It decreases in thickness Signup and view all the answers

What type of cartilage is present in the trachea?

Hyaline cartilage Signup and view all the answers

What is the consequence of smooth muscle constriction in bronchioles during asthma?

Difficulty breathing Signup and view all the answers

How many branchings do bronchi undergo?

9-12 Signup and view all the answers

Which of the following is NOT a function of the respiratory system?

Hormone production Signup and view all the answers

What is the main function of the conducting portion of the respiratory system?

Conditioning the air and conducting it to the alveoli Signup and view all the answers

Which of the following develops from the foregut?

Respiratory system and digestive system Signup and view all the answers

What is the role of mesoderm in the development of the respiratory system?

Gives rise to the connective tissue, cartilage, and smooth muscle of the respiratory tract Signup and view all the answers

What is the function of the respiratory bronchioles?

Gas exchange Signup and view all the answers

What develops from the endoderm in the respiratory system?

Epithelium and glands of the larynx, trachea, and bronchi Signup and view all the answers

What is the role of the pleura in the respiratory system?

Not mentioned in the text Signup and view all the answers

What is the function of the haematopoietic progenitors in the respiratory system?

Platelet biogenesis Signup and view all the answers

Study Notes

Respiratory System Functional Components

The respiratory system has three functional components: conducting portion, respiratory portion, and pleura
The conducting portion includes the nasal cavity, larynx, trachea, bronchi, and bronchioles
The respiratory portion includes respiratory bronchioles and alveoli, responsible for gas exchange

Respiratory System Functions

The respiratory system has seven main functions:
Gas exchange and acid-base balance
Olfaction
Phonation
Haematopoiesis: platelet biogenesis and reservoir for haematopoietic progenitors
Pulmonary defense
Compression of abdominal cavity
Pulmonary metabolism and handling of bioactive materials

Embryology of the Respiratory System

The respiratory system develops from the foregut
The respiratory diverticulum (bud) develops and eventually forms the bronchi and bronchioles
Endoderm gives rise to the epithelium and glands of the larynx, trachea, bronchi, and pulmonary epithelium
Mesoderm gives rise to the connective tissue, cartilage, and smooth muscle of the respiratory tract

Anatomy of the Respiratory System

The walls of the conducting system change in thickness and composition from region to region
The components of the conducting system include epithelium, lamina propria, mucous and serous glands, cartilage, smooth muscle, and adventitia

Respiratory Epithelium Cell Types

Ciliated columnar cells: most abundant cell type, responsible for moving mucus and trapped particles
Goblet cells: produce mucus
Basal cells: stem cells that replenish epithelium
Brush cells: columnar cells with apical microvilli
Neuroendocrine cells: epithelial cells containing hormones

Nasal Cavity

Respiratory epithelium is present everywhere except at the top (which has specialized olfactory epithelium)
Serous and mucous glands and numerous blood vessels are present in lamina propria
The nasal septum is a midline structure consisting of bone and hyaline cartilage
The nasal fossa are chambers on each side of the septum
Three types of epithelium are found in the nasal cavity: nasal vestibule (stratified squamous epithelium), nasal cavity proper (respiratory epithelium), and olfactory area (olfactory epithelium)

Larynx and Epiglottis

The epiglottis covers the laryngeal opening during swallowing and has a core of elastic cartilage
The superior surface of the epiglottis has nonkeratinized stratified squamous epithelium, while the inferior surface has respiratory epithelium
Vocal folds are covered by nonkeratinized stratified squamous epithelium
Laryngeal cartilages support the wall of the larynx and serve as attachments for vocalis muscles
False vocal folds are covered by respiratory epithelium

Trachea

The trachea extends from the larynx and divides into two primary bronchi
It contains 16-20 C-shaped hyaline cartilage rings with the dorsal opening bridged by smooth muscle (trachealis muscle)
It is lined by respiratory epithelium and has seromucous glands in lamina propria and submucosa
The trachea has four layers: mucosa, submucosa, cartilage framework, and adventitia

Bronchi

The trachea divides into two primary bronchi, which divide into secondary bronchi
Secondary bronchi divide into tertiary bronchi, which supply bronchopulmonary segments
Tertiary bronchi divide into smaller bronchi, which divide into bronchioles
Bronchi undergo 9-12 branchings

Bronchioles

Bronchioles have no glands or cartilage
Larger bronchioles have respiratory epithelium
Smaller bronchioles have low columnar epithelium
In asthma, the smooth muscle in the bronchioles constricts, causing difficulty breathing

Terminal Bronchioles

Terminal bronchioles have simple cuboidal epithelium with cilia
They also have Clara cells (non-ciliated epithelial cells with secretory granules)
Terminal bronchioles produce surfactant components, break down mucus, detoxify harmful substances, transfer IgA, and fight bacteria

Fetal Development

By week 24, respiratory bronchioles are present, and lungs are vascularized
Respiration is possible, but chances of survival outside the placenta are slim

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Description

This quiz covers the functional components of the respiratory system, including the conducting and respiratory portions, nasal cavity, larynx, trachea, bronchi, and alveoli.