Respiratory System and Skin Flashcards
Ventilation
Movement of air in and out of the lungs
Respiration
Exchange of gases between lungs and blood, or blood and tissue.
Conduction Zone
Parts of the body that only participate in ventilation.
Nose - nasal cavity - pharynx - larynx - trachea - bronchi - terminal bronchioles - respiratory bronchioles* - alveolar ducts* - alveoli*
Also part of the Respiratory zone
Respiratory Zone
Parts of the body that participate in gas exchange.
Respiratory bronchiole - Alveolar duct (walls consist of alveoli) - Alveolus
Alveoli are only one cell thick except where capillaries cross the surface.
Note, the respiratory bronchiole is identical to the terminal bronchioles except that it has some alveolar cells that permit gas exchange.
Alternate functions of the respiratory system
pH regulation.
Thermoregulation.
Protection from disease and particulate matter.
Hyperventilation
Results in an alkalinization of the blood, also known as respiratory alkalosis.
Hypoventilation
Results in an acidification of the blood also known as respiratory acidosis.
Larynx
Three functions:
1. Made entirely of cartilage and keeps the airway open
- Contains the epiglottis
- Contains the vocal cords
Trachea
Airway that must remain open for air flow.
Cartilage helps to maintain its structure.
Branches into two bronchi - also supported by cartilage. Bronchioles (1 mm) do not have any cartilage support but are made of smooth muscle.
Terminal Bronchioles
The walls here are too thick for gas exchange. No gas exchange occurs here.
Respiratory tract constitution
Epithelial cells cover from the nose all the way down into the bronchioles.
Specifically, COLUMNAR Epithelial cells. These cells are too thick to allow gas exchange though.
Goblet cells
Specialized epithelial columnar cells that secrete mucus.
The mucociliary escalator
Cilia on the apical surface of the respiratory tract constantly sweep mucus from goblet cells toward the pharynx, where mucus containing pathogens can be coughed out or swallowed.
Gas exchanging surface constitution
A thin, single layer of squamous epithelial tissue also referred to as SIMPLE SQUAMOUS EPITHELIUM.
Mucous cannot be on these surfaces, so alveolar macrophages patrol these surfaces.
Surfactant
A soapy substance that prevents collapse of alveoli. Reduces surface tension.
A mixture of phospholipids, proteins, and ions secreted by cells in the alveolar wall.
Types of Alveolar Cells
Type 1 Alveolar Cells - simple squamous epithelium that exhibit gas exchange
Type 2 Alveolar Cells - large fat cuboidal cells that secrete surfactant. Metabolically active with lots of mitochondria.
Inspiration
The active process driven by a contraction of the diaphragm that draws air in.
Expiration
The passive process driven by elastic recoil of the lungs that does not require muscle contraction.
Note, it can be active if abdominal muscles are used to expel air. Referred to as Forced Expiration.
Are the lungs directly connected to the chest cavity?
No.
Membranes (pleura) surrounding the lungs
Parietal Pleura - lines the inside of the chest cavity
Visceral Pleura - lines the surface of the lungs
Pressure in the pleural space, pleural pressure, is negative. Some fluid helps hold them together.
Diaphragm
Relaxed - dome shape
Contracted - flat
*intercostal muscles (between ribs) also contract during inspiration