5: Respiratory System

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Questions and Answers

What is the primary function of the nasal concha?

To increase rotational movement of air for warming and moistening (correct)

To filter toxins from the air

To produce mucus for lubrication

To act as an attachment point for respiratory epithelium

Which type of epithelium lines the trachea?

Stratified squamous epithelium

Simple squamous epithelium

Transitional epithelium

Pseudostratified ciliated columnar epithelium (correct)

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

To provide structural support to the epithelium

To filter particulate matter from the air

To produce mucus for moisture (correct)

To absorb oxygen from inhaled air

What structure provides flexibility to the trachea?

C-shaped hyaline cartilaginous rings Signup and view all the answers

What is the main function of the respiratory bronchioles?

They assist in gas exchange Signup and view all the answers

Which structure is NOT part of the conducting portion of the respiratory system?

Alveolar duct Signup and view all the answers

What is the primary role of olfactory epithelium in the respiratory system?

Smell detection Signup and view all the answers

Which statement regarding the development of the left and right lungs is accurate?

They differ in size and shape. Signup and view all the answers

Which component is found in the trachea that is essential for its function?

Cartilage rings Signup and view all the answers

During fetal development, which requirement is crucial for normal lung development?

Adequate amniotic fluid Signup and view all the answers

Which structure does not contain any cartilage in its walls?

Respiratory bronchiole Signup and view all the answers

What type of epithelium is primarily found in the bronchi?

Pseudostratified ciliated columnar epithelium Signup and view all the answers

Which of the following describes the respiratory bronchiole?

Has openings leading to alveoli Signup and view all the answers

What is the primary function of the goblet cells found in the lower respiratory tract?

Secreting mucus Signup and view all the answers

Which structure has a continuous wall and lacks openings?

Bronchiole Signup and view all the answers

What distinguishes the alveolar duct from other structures in the respiratory system?

Thin walls with open spaces Signup and view all the answers

Which structure transitions from conducting to respiratory functions?

Respiratory bronchiole Signup and view all the answers

What is the primary type of cartilage found in the bronchi?

Hyaline cartilage Signup and view all the answers

Which of the following structures is characterized by having no cartilage?

Bronchioles Signup and view all the answers

In which part of the respiratory system would you find type II alveolar cells?

Alveoli Signup and view all the answers

What is a defining characteristic of respiratory bronchioles?

Are not continuous and open to alveoli Signup and view all the answers

Which type of epithelium is present in alveolar ducts?

Simple squamous epithelium Signup and view all the answers

What additional feature is present in bronchi compared to bronchioles?

Goblet cells Signup and view all the answers

Which structure is known for having continuous walls with no cartilage?

Respiratory bronchioles Signup and view all the answers

Study Notes

Respiratory System Organization

The respiratory system is divided into two portions: conducting portion and respiratory portion.
The conducting portion includes the nasal cavity, larynx, trachea, bronchi, and bronchioles.
The respiratory portion includes respiratory bronchioles, alveolar ducts/sacs, and alveoli.

Lecture Learning Objectives

Recognize and describe respiratory epithelium and its structural features (e.g., nasal concha, epithelial type).
Visually identify olfactory epithelium.
Visually identify the trachea, bronchi, bronchioles, respiratory bronchioles, alveolar ducts, and alveoli.
Describe the development of each segment of the lower respiratory system, including structure, terminology, tissue origins, and sequence of events.
Explain how left and right lungs differ during development.
Associate major events in respiratory system development with weeks/periods.
List requirements for normal lung development and explain fetal breathing.
Describe tracheoesophageal fistulas including anatomical cause, terminology, and symptoms.

Identifying Characteristics

Conducting portion: nasal cavity, larynx, trachea, bronchi, and bronchioles.
Respiratory portion: respiratory bronchioles, alveolar duct/sac, and alveoli.
Additional questions related to identifying characteristics include: What type of epithelium is present? Is cartilage present? Is cartilage continuous?

Upper Respiratory Tract Histology

Nasal cavity is structured to condition and filter air.
Nasal conchae increase rotational movement of air to warm and moisten.
Respiratory epithelium is pseudostratified ciliated columnar epithelium that filters air.
Goblet cells produce mucin for moisture.
Lamina propria is highly vascularized for warmth.
Olfactory epithelium is for special senses.

Trachea

Function is conduction only.
Lined with respiratory mucosa- pseudostratified ciliated columnar epithelium and numerous goblet cells.
Contains numerous seromucous glands that produce watery mucus in lamina propria.
Supported by C-shaped hyaline cartilaginous rings for flexibility.

Bronchial Tree Histology Defining Characteristics

Bronchi: epithelium is pseudostratified ciliated columnar, cartilage is hyaline and continuous, muscularis mucosa is present.
Bronchioles: epithelium is simple ciliated columnar to simple cuboidal, cartilage is absent (mostly) -continuous walls
Respiratory bronchioles: epithelium is simple cuboidal, cartilage is absent. Not continuous - opens to alveoli and alveolar ducts.
Alveolar ducts: epithelium is simple squamous, cartilage is absent, Not continuous - walls open to alveoli
Alveoli: epithelium is type I (simple squamous) and type II alveolar cells, cartilage is absent.

Conducting to Respiratory Transition

Bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.

Respiratory Portion

Respiratory bronchioles: openings in wall but thicker epithelium.
Alveolar ducts: open spaces with thin walls.
Alveolar sacs: border may be continuous/open.
Alveoli: Functional part of respiratory system.

Respiratory Embryology

Respiratory system develops between weeks 3 and 4.
Foregut endoderm forms epithelial lining.
Foregut mesoderm forms connective tissue, cartilage, and smooth muscle.
Laryngotracheal groove appears on ventral wall.
Laryngotracheal diverticulum becomes larynx, trachea, and lungs.
Proximal portion becomes larynx, middle portion trachea, and distal portion lungs.
Respiratory buds divide into primary bronchial buds that develop into primary, secondary, and tertiary bronchi.

Pleura

All pleura is derived from lateral plate mesoderm.
Visceral pleura is derived from splanchnic mesoderm.
Parietal pleura is derived from somatic mesoderm.

Lungs

Lungs mature relatively late (2-7 months gestation).
Pseudoglandular period (wk 5-16): All portions of the bronchi and bronchial tree are formed but not respiratory bronchioles/alveoli,
Canalicular period (wk 16-26): Airways increase in diameter and vasculature develops, primitive versions of respiratory portion develop.
Saccule period (wk 26/4-birth): Terminal sacs develop with type I and type II cells.
Alveolar/Prenatal-Childhood period: “Breathing” of amniotic fluid occurs in utero, alveoli mature from 0-3 years, and increase in number from 3-8 years.

Clinical Relevance- Tracheoesophageal Fistula (TEF)

TEF = abnormal communication between trachea and esophagus.
Occurs in 1/3000 to 1/4500 births, predominantly in males.
Often associated with esophageal atresia.
Causes incomplete division of cranial part of foregut.
Symptoms include choking, coughing, regurgitation, reflux; may result in pneumonia or pneumonitis.

Requirements for normal lung development

Adequate thoracic space.
Adequate amniotic fluid volume.
Fetal breathing movements.
Fetal breathing movements occur in utero to stimulate lung development, with fetal lungs being ½ filled with fluid from the amnion and pulmonary glands. At birth, fluid moves out through nose and mouth—pulmonary arteries, veins, or lymph vessels.

Studying That Suits You

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Description

Test your knowledge on the organization of the respiratory system, focusing on the conducting and respiratory portions. This quiz covers key structures, developmental aspects, and features of the respiratory epithelium. Challenge yourself to identify various parts and understand their functions.

5: Respiratory System - Pt. 2

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