Lecture Exam One Flashcards
define external respiration
movement of oxygen from the lungs to the blood and of carbon dioxide from the blood to the lungs
define internal respiration
movement of oxygen from the blood to the tissue cells and of carbon dioxide from tissue cells to blood
define cellular respiration
the actual use of oxygen and production of carbon dioxide by tissue cells
list four functions of the respiratory mucosa
moistens air, warms air, cilia filter air, enzyme lysozyme destroys bacteria
list three divisions of the pharynx
nasopharynx, oropharynx, and laryngopharynx
which division of the pharynx do the eustachian tubes drain into?
the eustachian tubes drain into the lateral walls of the nasopharynx
which division of the pharynx assists in swallowing
the laryngopharynx assists in swallowing
where do the respiratory and digestive systems become distinct
in the laryngopharynx the respiratory and digestive pathways diverge and the larynogophraynx is continuous with the esophagus posteriorly
define and describe the larynx
larynx is also known as voice box. attaches to the hyoid bone and opens into the laryngopharynx. Inferiorly it is continuous with trachea.
what are the functions of the larynx
- to provide a patent (open) airway 2. to act as a switching mechanism to route air and food into the proper channels. 3. voice production
describe the structure of the vocal chords
are under the laryngeal mucosa on each side. attach the arytenoid cartilages to the thyroid cartilage. composed largely of elastic fibers, form the core of mucosal folds called true vocal chords. Appear pearly white because they lack blood vessels. function is voice production
describe the structure of the glottis
it is the vocal folds (chords) and the medial opening that goes between them.
describe the structure of the epiglottis
composed of elastic cartilage and is almost entirely covered in taste bud-containing mucosa. is flexible and spoon shaped. extends from the posterior aspect of the tongue to its anchoring point on the anterior rim of the thyroid cartilage
discuss the trachea
descends from the larynx through the neck and into the mediastinum. it ends by dividing the two main bronchi at mid thorax. trachea wall consists of several layers that are common to many tubular body organs–the mucosa, submucosa, and adventitia–plus a layer of hyaline cartilage.
discuss the mucosa layer of the trachea
the mucosa has the same goblet cell containing psuedostratified epithelium that occurs throughout most of the respiratory tract. its cilia continually propel debris-ladden mucus toward the pharynx.
discuss the submucosa layer of the trachea
the submucosa layer of the trachea is a connective tissue layer deep to the mucosa that contains seromucous glands that help produce the mucus “sheets” within the trachea. The submucosa is supported by 16-0 c shaped rings of hyaline catilage encased by the adventitia, the outermost layer of connective tissue.
trachea continued
the trachea’s elastic elements make it flexible enough to stretch and move inferiorly during inspiration and recoil during expiration, but the cartilage rings prevent it from collapsing and keep the airway patent (open) despite the pressure changes that occur during breathing. The open posterior parts of the cartilage rings, which abut the esophagus, are connected by smooth muscle fibers of the trachealis muscle and by soft connective tissue.
define carina
the carina is the last trachea cartilage. it is expanded and projects posteriorly from its inner face, marking the point where the trachea branches into the two main bronchi. The mucosa of the carina is highly sensitive and violent coughing is triggered when a foreign object makes contact with it.
define the bronchial or respiratory tree
the branching pattern of the airwaves. the site where conducting zone structures give way to respiratory zone structures.
describe bronchi
the trachea divides to form the righ and left main (primary) bronchi approximately at the level of T7 in an erect person. Each bronchus runs obliquely in the mediastinum before plunging into the medial depression of the lung on its own side. The right main bronchus is wider, shorter, and more vertical than the left. Therefore, it is the more common site for an inhaled foreign object to become lodged.
once inside the lungs, each main bronchi subdivides into lobar (secondary) bronchi–three on the right and two on the left–each supplying one lung lobe.
the lobar bronchi branch into third-order segmental (tertiary) bronchi, which divide repeatedly into smaller and smaller bronchi.
describe bronchioles
passages smaller than 1 mm in diameter are called bronchioles, and the tiniest of these, the terminal bronchioles are less than 0.5 mm in diameter.
more about bronchi and bronchioles
the tissues of the walls of the main bronchi mimics that of the trachea, but as the conducting tubes become smaller, the following structural changes occure:
- the cartilage rings are replaced by irregular plates of cartilage, and by the time teh bronchioles are reached, supportive cartilage is no longer present in the tube walls. However, elastic fibers are found in the tube walls throughout the bronchial tree.
- the mucosal epithelium thins as it changes from pseudostratified columnar to columnar and then to cuboidal in the terminal bronchioles. Cilia are sparse, and mucus-producing cells are absent in the bronchioles.
- the relative amount of smooth muscle in the tube walls increases as the pasageways become smaller. A complete layer of circular smooth muscle in the bronchioles and the lack of supporting cartilage allows the bronchioles to provide substantial resistance to air pasage under certain conditions.
function and structure of conducting zone of the lungs
the conducting zone of the lungs is made up of the trachea, windpipe, which branches off into the main (primary) bronchi. The bronchi further subdivides into the lobar bronchi which splits further into segmental (tertiary) bronchi. These tertiary divide repeatedly into smaller and smaller bronchi until they are small enough to be called bronchioles…(if smaller than 1 mm in diameter)
The purpose of the trachea as an air passageway is to clean, warm, and moisten incoming air.
the bronchial tree is also an airpasage connecting the trachea with alevoli; cleans warms, and moistens incoming air.
function and structure of the respiratory zone of the lungs
the respiratory zone begins as the terminal bronchioles feed into respiratory bronchioles within the lung. Present are thin-walled air sacs called alveoli. These air sacs are where gas exchange occurs.
the respiratory bronchioles have scattered alveoli in their walls which lead into alveolar ducts, which are completely lined by alveoli. These ducts end in clusters of alveoli called alveolar sacs. The alveolar sacs look much like a bunch of grapes with the alveoli being a single grape.
gas exchange occurs in the alveoli across the respiratory membrane. this occurs through simple diffusion—O2 passes from the alveolus into the blood, and CO2 leaves the blood to enter the gas-filled alveolus.
list and define the three types of cells present in the alveoli
- the walls of the alveoli are composed primarily of a single layer of squamous epithelial cells, called type 1 cells, surrounded by a flimsy basement membrane.
The external surfaces of the alveoli are densely covered with a “cobweb” of pulmonary capillaries. Together the alveolar and capillary walls and their fused basement membranes form the respiratory membrane.
- cuboidal type 2 cells are spread amongst the type 1. These cells secrete a fluid containing a detergent-like substance called surfactant that coats the gas exposed alveolar surfaces.
- the alveoli also contain aleolar macrophages that crawls freely along the internal surfaces.
define parietal pleura
the parietal pleura covers the thoracic wall and superior face of the diaphragm. It continues around the heart and between the lungs, forming the lateral walls of the mediastinal enclosure and snugly enclosing the lung root.
define visceral pleura
the layer of the pleura that covers the external lung surface, dipping into and linning its fissures.
define pleural cavity
the slit-like cavity between the parietal and visceral pleurae.
this cavity is filled with pleural fluid and the lubricating secretion allows the lungs to glide easily over the thorax wall during breathing movements.
the pleura also help divide the thoracic cavity into three chambers–the central medistinum and the two lateral pleural compartments, each containing a lung.