Chapter 23 - Respiratory System
Terms
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- Respiration
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includes four components;
ventilation, the movement of air into and out of the lungs;
gas exchange between the air in the lungs and the blood;
transport of oxygen and carbon dioxide in the blood;
gas exchange between the blood and the tissues - List five functions of the respiratory system.
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1) Gas exchange
2) Regulation of blood pH
3) Voice production
4) Olfaction
5) Protection - Upper respiratory tract
- refers to the nose, pharynx, and associated structures
- Lower respiratory tract
- refers to the larynx, trachea, bronchi, and lungs
- Nose (nasus)
- consists of the external nose and the nasal cavity
- External nose
- the visible structure that forms a prominent feature of the face
- Nasal cavity
- part of the nose that extends from the nares to the choanae
- Nares
- the external openings of the nasal cavity
- Choanae
- the openings of the nasal cavity into the pharynx
- Vestibule
- the anterior part of the nasal cavity, just inside each naris
- Hard palate
- a bony plate covered by a mucous membrane that forms the floor of the nasal cavity; separates the nasal cavity from the oral cavity
- Nasal septum
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a partition dividing the nasal cavity into right and left parts;
anterior part is made of cartilage and the posterior part is composed of the vomer bone and the perpendicular plate of the ethmoid bone - Conchae
- bony ridges that modify the lateral walls of the nasal cavity, beneath each lies a meatus
- Meatus
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passageways that lie beneath each conchus;
openings from the paranasal sinuses open into the superior and middle meatus;
openings from the nasolacrimal duct open into the the inferior meatus - List the main funcitons of the nasal cavity.
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exists as a passageway for air that's open even when the mouth is full of food;
cleans the air, the vestibule is lined with hairs that trap large particles of dust;
humidifies and warms the air;
the olfactory epithelium is located in the most superior part of the nasal cavity;
the nasal cavity and paranasal sinuses are resonating chambers for speech - Pharynx
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the common opening of both the digestive and respiratory tracts;
divided into three regions, the nasopharynx, the oropharynx, and the laryngopharynx - Nasopharynx
- located posterior to the choanaeand superior to the soft palate
- Soft palate
- an incomplete muscle and and connective tissue partition separating the nasopharynx from the oropharynx; prevents swallowed materials from entering the nasopharynx and nasal cavity
- Uvula
- the posterior extension of the soft palate
- Oropharynx
- region of the pharynx that extends from the soft palate to the epiglottis
- Fauces
- the opening from the oral cavity into the oropharynx
- Laryngopharynx
- region of the pharynx that extends from the tip of the epiglottis to the esophagus and passes posterior to the larynx
- Larynx
- located in the anterior part of the throat; connected by membranes and/or muscles superiorly to the hyoid bone and inferiorly to the trachea; consists of an outer casing of nine cartilages that are connected to one another by muscles and ligaments
- Name the three unpaired cartilages and six paired cartilages that form the larynx.
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Unpaired:
thyroid, cricoid, and epiglottis
Paired:
arytenoid, corniculate, and cuneiform - Glottis
- the vocal folds and the opening between them
- Vestibular folds (false vocal cords)
- these come together to prevent food and liquids from entering the larynx during swallowing and prevent air from leaving the lungs, as when a person holds their breath
- Vocal folds (true vocal cords)
- a mucous membrane the covers the inferior laryngeal ligaments and makes noise as air is forced through the glottis
- List the three important functions of the larynx.
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the thyroid and cricoid cartilages maintain an open passageway for air movement;
the epiglottis and vestibular folds prevent swallowed material from moving into the larynx;
the vocal folds are the primary source of sound production - Trachea
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also known as the windpipe;
a membranous tube that consists of dense regular connective tissue and smooth muscle reinforced with 15-20 C-shaped pieces of cartilage that support the trachea and maintain an open airway - Trachealis muscle
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bundles of smooth muscle that lie on the non-cartilagenous side of the trachea and when contracted, can decrease the diameter of the trachea;
contracted when coughing to try and expel particles through the quicker movement of air through the smaller opening - Carina
- a ridge that separates the openings into the main bronchi; formed by the most inferior tracheal cartilage
- Primary bronchi
- two smaller tubes into which the trachea divides, each of which extends to a lung
- Tracheobronchial tree
- all the respiratory passageways from the trachea onward; can be divided into the conducting and the respiratory zone based on function
- Conducting zone
- extends from the trachea to the terminal bronchioles; about 16 generations of branching occur; funcitons as a passageway for air movement and contains epithelial tissue (pseudostratiried ciliated columnar epithelium) that helps to remove debris from the air and to move it out of the tracheobroncial tree
- Lobar (secondary) bronchi
- primary bronchi give rise to secondary bronchi; two secondary bronchi in the left lung, three in the right lung
- Segmented (tertiary) bronchi
- secondary bronchi give rise to numerous tertiary bronchi, which gives rise to bronchioles
- Bronchiole
- one of the finer subdivisions of the bronchial tubes, less than 1mm in diameter; has no cartilage in its wall, but does have relatively more smooth muscle and elastic fibers
- Respiratory zone
- extends from the termainl bronchioles to the alveoli; contains about 7 generations of branching; sites of gas exchnage between the air and lungs
- Alveolar duct
- part of the respiratory passages beyond the respiratory bronchioles; from it arise alveolar sacs and alveoli
- Alveolar sac
- two or more alveoli that share a common opening
- Passageway of air from outside the body to the blood
- Mouth - trachea - main bronchi - lobar bronchi - segmented bronchi - bronchiole - terminal bronchiole - respiratory bronchiole - alveolar duct - alveolar sac/alveoli
- Type I pneumocytes
- one of two types of cells that form the alveolar walls; thin, squamous epithelial cells that form 90% of the alveolar surface; cells through which most gas exchange occurs
- Type II pneumocytes
- one of two types of cells that form the alveolar walls; round or cube-shaped secretory cells that produce surfactant, which makes it easier for alveoli to expand during inspiration
- Respiratory membrane
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the location in the lungs where gas exchange occurs; primarily formed by alveolar walls and surroudning pulmonary capillaries; it contains:
1. a thin layer of fluid lining the alveolus
2. alveolar epithelium composed of simple squamous epithelium
3. basement membrane of the alveolar epithelium
4. a thin interstitial space
5. the basement membrane of the capillary endothelium
6. capillary endothelium composed of simple squamous epithelium - Lungs
- principle organs of respiration; among the largest organs of the body
- Hilium
- a region on the medial surface of the lung, where structures, such as the main bronchus, blood vessels, nerves, and lymphatic vessels, enter or exit the lung; area also referred to as "the root of the lung"
- Lobes
- right lung has three lobes, the left lung has two; lobes are separated by deep, prominent fissures on the surface of the lung; and each is supplied by a lobar bronchus
- Bronchopulmonary segments
- lobar subdivisions which are supplied by the segmental bronchi; nine are present in the left lung, ten in the right lung
- Lobules
- Bronchopulmonary segments are divided into lobules by incomplete connective tissue walls