respiratory metacognition L4

What are the 4 major functions of the respiratory system?

• 1. Pulmonary ventilation: moving air into and out of the lungs (breathing)

• 2. External respiration: gas exchange between the lungs and the blood

• 3. Transport of respiratory gases: transport of oxygen and carbon dioxide between the lungs and tissues via blood

• 4. Internal respiration: gas exchange between systemic blood vessels and tissues

What respiratory structures are included in the conducting zone? What does it provide?

Conducting zone: provides rigid conduits for air to reach the sites of gas exchange; includes all other respiratory structures (e.g., nose, nasal cavity, pharynx, trachea)

 What respiratory structures are included in the respiratory zone? What is this zone the site of?

Respiratory zone: Site of gas exchange; consists of bronchioles, alveolar ducts, and alveoli (all are microscopic structures)

Which are the functions of the nose?

1.  Providing an airway for respiration

2. Moistening and warming the entering air

3. Filtering inspired air and cleaning it of foreign matter

4. Serves as a resonating chamber for speech

5. Houses the olfactory (smell) receptors

 What are two types of mucous membrane lining the nasal cavity?

1) Olfactory mucosa: lines the superior nasal cavity; contains smell receptors

 2) Respiratory mucosa: lines the majority of the nasal cavity;  glands secrete mucus containing lysozyme and defensins to help destroy bacteria

What type of epithelium does the respiratory mucosa have? What does it contain? What is its function?

• a ciliated pseudostratified columnar epithelium containing scattered goblet cells and underlying C.T (lamina propria)….Functions to filter the inhaled air

Describe the lamina propria of the nasal mucosa.

• contains compound tubuloalveolar glands that contain mucous cells (secretes mucus) and serous cells (secrete a watery fluid containing digestive enzymes).

What do nasal conchae create?

• The conchae creates turbulence of the inhaled air, which increases the amount of contact between the nasal mucosa and the air.

What is the function of the pharynx?

-Function: serves as a common passageway for both food and air.

 What is the function of the nasopharynx? What epithelium does it have?

• The nasopharynx is lined with ciliated pseudostratified columnar epithelium

• Propels mucus downward from the nasal cavity, where pathogens are destroyed by the pharyngeal tonsils prevents food from entering nasopharyngeal cavity

What is the function of the oropharynx? What epithelium does it have?

• Serves as a common passageway for food and air

•  The epithelial lining is protective stratified squamous epithelium

What is the function of the laryngopharynx? What epithelium does it have?

Serves as a common passageway for food and air

- The epithelial is stratified squamous epithelium

What is the function of the larynx? What epithelium does it have?

 3 functions of the larynx: (voice box)

 1) provide a patent (open) airway 

 2) act as a switching mechanism to route air (open) and food (closed) into the proper channels,  3) produce vocalizations

ciliated columnar epithelium

What is the epiglottis?

• Is elastic cartilage covered with mucosa; during swallowing entire larynx is pulled superiorly and epiglottis tips inferiorly to cover the laryngeal inlet during swallowing

 What are the vocal folds?

The vocal ligaments are composed of elastic fibers and form the core of a pair of mucosal folds called the vocal folds (true vocal cords)

What is the rimma glottis?

Rimma glottis: medial opening between vocal folds through which air passes

What is the glottis?

-Glottis: rimma glottis + vocal folds

What are the vestibular (false) vocal cords?

• Vestibular (false) vocal cords: = mucosal folds; have no role in voice production but enhance high-frequency sounds

What is the trachea?

Trachea (wind pipe): flexible and mobile tube extending from the larynx into the mediastinum where it branches into two primary bronchi

Describe the branching of the bronchi.

The carina of the last tracheal cartilage marks the end of the trachea and the beginning of the right and left primary bronchi (main brochi)

• Bronchi subdivide into secondary (lobar) bronchi, each supplying a lobe of the lungs tertiary (segmental) bronchi etc.

-Air passages undergo 23 orders of branching in the lungs 

-Branches smaller than 1 mm are called bronchioles; the smallest (>0.5 mm) are called terminal   bronchioles

 What does smooth muscle do as the conducting tubes become smaller?

• Smooth muscle becomes important:

• A layer of smooth muscle forms helical bands that wrap around the smaller bronchi and bronchioles and regulate the amount of air entering the alveoli.

What do alveoli provide?

• Alveoli accounts for most of the lungs’ volume, provide tremendous surface area for gas exchange (~300 million alveoli)

• • The wall of each alveolus consists of a single layer of squamous epithelial cells called type I cells surrounded by a delicate basal lamina.

•  The external surfaces are covered with a “cobweb” of pulmonary capillaries.

• • Note: The basal laminas that form the walls of the alveoli and capillary walls are fused together…forming the respiratory membrane.

• Site of gas exchange

 Describe the parietal pleura, visceral pleura, and the pleural cavity.

Parietal pleura: covers the internal surface of the thoracic wall, the superior surface of the diaphragm, and the lateral surfaces of the mediastinum.

-Viceral pleura: continuous with the parietal pleura; covers the external lung surface

-Pleural cavity: the space between the parietal and visceral pleurae that is filled with a lubricating fluid that reduces friction

Which surface of the lung rests on the diaphragm?

Base: inferior surface that rests on the diaphragm

What is the difference between the right and left lung?

• a) Left lung: smaller than right lobe (Cardiac notch (impression) –cavity that accommodates the heart); separated into upper and lower lobes by the oblique fissure

• b) Right lung: separated into three lobes (upper, middle, and lower lobes) by the oblique and horizontal fissures