anatomy

Respiratory System

• Composed of structures that aid in the ventilation & gas exchange

Functions of the respiratory system

• Provide an extensive surface area for gaseous exchange for blood that circulates through the pulmonary circuit

• Moves air to & from the exchange surfaces of the lungs throughout the passageways

• Protects surfaces from dehydration, changes in temperature, or other environmental variations such as pathogens. 

• Produces sound that we use speaking 

• Facilitates the detection of olfactory stimuli by receptors in the superior portions of the nasal cavity

• Capillaries of the lungs also help indirectly regulate blood pressure

Organization of the Respiratory System

• Can be organized from either an anatomical or functional perspective

• Anatomically we can divide the system into an upper and lower respiratory system

  • The upper respiratory system consists of the 

    • Nose

    • Nasal cavity

    • Paranasal sinuses

    • Pharynx

  • These passages will filter, warm, and humidify the incoming air; it basically helps protect the more delicate features of the lower respiratory system

  • The lower respiratory system includes the

    • Larynx (voice box)

    • Trachea (windpipe)

    • Bronchi

    • Bronchioles

    • Alveoli of the lungs

** you book uses a good divider rule: LOWER RESPIRATORY SYSTEM BEGINS WITH THE LARYNX

respiratory tract refers to the passageways that carry air to and from the exchange surfaces of the lungs

The conducting portion of the respiratory tract begins a the entrance to the nasal cavity & extends through the pharynx, larynx, trachea, bronchi, and larger bronchioles 

The respiratory portion of the tract includes the smallest, most delicate bronchioles and the alveoli that are associated with them

• Alveoli are air-filled pockets within the lungs where all gas exchange between air and blood occurs

• In order to meet the metabolic requirements of tissues in the peripheral part of the body, the surface area devoted to gas exchange in the lungs must be a very large portion;

  • It is roughly 35 times the surface area of the body

• Filtering, warming, & humidify the air that is inhaled begins at the entrance to the respiratory tract & continues as the air passes through the conducting portion

• By the time the air reaches the alveoli, most of the foreign particles & pathogens have been removed, & the humidity & temperature within are at acceptable levels

  • This is a success mostly attributed to the properties of the respiratory mucosa

The respiratory mucosa

• Lines the conducting portion of the respiratory system

• A mucosa; often times referred to as a mucous membrane

  • Consists of an:

    • Epithelium

    • Lamina propria (underlying layer of areolar tissue that supports the respiratory epithelium)

• In the upper respiratory system, trachea & bronchi, the lamina propria contains mucous glands that secrete onto the epithelial surface.

  • The lamina propria in the conducting portion of the lower respiratory system contains bundles of smooth muscle cells

  • Once it gets to the bronchioles, the smooth muscles form relatively thick bands that encircle or spiral around the lumen

• The structure of the respiratory epithelium will change through the respiratory tract

  • A pseudostratified ciliated columnar epithelium with numerous mucous cells lines the nasal cavity and the superior portion of the pharynx

  • Inferior portions of the pharynx is stratified squamous epithelium; similar to the oral cavity

• A pseudostratified columnar epithelium that compares to the nasal cavity lines the superior portion of the lower respiratory system

  • Within the smaller bronchioles