Respiratory System

Question 1

What does the upper and lower respiratory tract and the lungs consist of?

Answer 1

• upper respiratory tract includes the nasal cavity, paranasal sinuses, pharynx and the portion of the larynx above the vocal cords (lie outside the thorax, more specifically above the cricoid cartilage and vocal cords)
• lower respiratory tract includes the larynx below the vocal cords, the trachea, bronchi, bronchioles and the lungs
• lungs contain the respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli

Question 2

What do the lateral walls of the nasal cavity contain?

Answer 2

three bony projections called nasal conchae (superior, middle and inferior), which increase the surface area of the nasal cavity and help humidify and warm up the air to body temperature

Question 3

nasal cavity epithelium

Answer 3

roof of the nasal cavity consists of olfactory epithelium containing specialized sensory receptors , they transform airborne odorant molecules via the olfactory nerve to the cerebral cortex, allowing the brain to register them and provide a sense of smell.

Question 4

How does the nasal cavity prevent entrance of harmful particles / pathogens ?

Answer 4

nares and anterior portion of the nasal cavity contain sebaceous glands and hair follicles (vibrissae that filter out larger particles from inspired air) which prevent this

Question 5

What happens to epithelium at limen nasi?

Answer 5

membrane transitions from keratinized stratified squamous epithelium to pseudostratified columnar ciliated epithelium with goblet cells (aka respiratory epithelium)

Question 6

What is the function of goblet cells in the airways?

Answer 6

secrete mucin and create a protective mucus layer and immunoregulation

Question 7

After passing through the nasal cavity and paranasal sinuses, the inhaled air exits into the pharynx ( funnel-shaped muscular tube), describe the 3 parts:

Answer 7

• nasopharynx: first and superior most part of pharynx, found posterior to the nasal cavity. serves as airway and lined with respiratory epithelium.
• oropharynx: found posterior to the oral cavity, pathway for air incoming from nasopharynx and food coming from oral cavity. Lined with the more protective non-keratinizing stratified squamous epithelium
• laryngopharynx (hypopharynx): most inferior part of the pharynx. point at which the digestive and respiratory systems diverge. Anteriorly, laryngopharynx continues into the larynx, whereas posteriorly it continues as the esophagus.

Question 8

How is food prevented from entering the nasal cavity?

Answer 8

Inferiorly, the uvula and soft palate swing upwards during swallowing to close off the nasopharynx and prevent food from entering nasal cavity

Question 9

Describe larynx
cartilages function

Answer 9

• found anterior to the esophagus and inferior part of pharynx (laryngopharynx)
• 9 cartilages; 3 unpaired, and 6 paired. They form the laryngeal skeleton, which provides rigidity and stability.
• 3 unpaired cartilages are the epiglottis, thyroid and cricoid cartilages.

Question 10

Describe the 3 unpaired cartilages in larynx

Answer 10

• thyroid cartilage: composed of two sheets (laminae), which join anteriorly to form laryngeal prominence (Adam’s apple). Above vocal cords, larynx is lined with stratified squamous epithelium. Below it’s pseudostratified ciliated columnar epithelium with goblet cells (respiratory epithelium)
• cricoid cartilage: complete ring of hyaline cartilage, consisting of a broad sheet posteriorly and a much narrower arch anteriorly. marking the inferior border of the larynx at the level of C6
• epiglottis: leaf shaped plate of elastic cartilage. During swallowing, the epiglottis flattens and moves posteriorly to close off the larynx and prevent aspiration.