chapter 23, part 1
TRANSCRIPT
Chapter 23 – Respiratory Anatomy!
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Chapter 23, Part 1!Respiratory Anatomy!
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SECTION 23-1!The respiratory system, organized into an upper respiratory system and a lower respiratory system, has several basic functions!
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Functions!
1. Surface area for gas exchange between air and blood!
2. Moving air in and out of lung exchange area (pulmonary ventilation)!
3. Protection for respiratory surfaces!E.g. from dehydration, temp. changes, pathogens!
4. Sound production!5. Location for olfactory epithelium!6. Conversion of angiotensin I to angiotensin II!
Has blood volume and pressure effects!
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Respiratory System Components Figure 23-1!
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Organizational Schemes!A. Upper respiratory tract!• Nose, nasal cavity, paranasal sinuses, pharynx!
ü Warm, filter, humidify incoming air!ü Cool, dehumidify outgoing air!
B. Lower respiratory tract!• Larynx, trachea, bronchi, bronchioles, alveoli!
OR !A. Conducting portion - No gas exchange occurs!• External nares to terminal bronchioles!
B. Respiratory portion - Gas exchange occurs!• Respiratory bronchioles to alveoli!
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Respiratory Mucosa!
The respiratory mucosa is a mucous membrane.!a. Epithelium (type depends upon location)!
Upper respiratory tract!• Pseudostratified ciliated columnar EPI!
Lower respiratory tract!• Becomes simple squamous EPI in
alveoli!b. Lamina propria!
Areolar CT!Mucous glands!
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Respiratory Defense System!
• Mucus traps particles, pathogens!• Cilia move particles to throat where they are
swallowed (“mucus escalator”)!• Alveolar macrophages ingest particles that
arrive there!• Hairs in nose!
• Coughing!
• Sneezing!
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SECTION 23-2!Located outside the thoracic cavity, the upper respiratory system consists of the nose, nasal cavity, paranasal sinuses, and pharynx!
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Nose and Nasal Cavity!Anatomy!
A. External portion = nose (Learn something new every day!)!• Bone, cartilage, skin, muscle, mucous
membranes!• Nostrils = external nares!
B. Internal portion = nasal cavity!• Opens into nasopharynx via internal nares!• Walls = maxilla, nasal, frontal, ethmoid,
sphenoid bones!
Discussed in lab or later in notes!
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Nasal Cavity – 2!
Cavity communicates with nasolacrimal ducts!Nasal septum!• Cartilage and bone (vomer, perpendicular
plate of ethmoid)!Nasal conchae (turbinates)!• Inferior, middle and superior!• Stir up air!• Increase area for filtration, warming, olfaction!
Discussed in lab or later in notes!
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Nasal Cavity Functions!
1. Warms and moistens inspired air!a) Rich blood supply!b) Drainage from nasolacrimal duct!c) Secretions from paranasal sinuses!d) Water in inspired air tends to condense on
turbinates (nasal conchae)!2. Filters inspired air!
a) Hairs!b) Respiratory epithelium!• Mucus traps particles!• Cilia move mucus and particles!
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The Respiratory Epithelium Figure 23-2!
Discussed in lab or later in notes!
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Nasal Cavity Functions – 2; Pharynx!
3. Olfaction (Chapter 17)!4. Modifies speech sounds (resonance)!!!Pharynx (throat)!• Passageway for air and food!• Extends from internal nares to junction of
esophagus and larynx!• Nasopharynx, oropharynx, laryngopharynx!
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Nose, Nasal Cavity, and Pharynx Figure 23-3c!
Nasopharynx
Oropharynx
Laryngopharynx
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1. Nasopharynx!
Respiration only!Pseudostratified ciliated columnar EPI!Above soft palate!Openings:!• Internal nares (2 – in)!• Auditory (Eustachian) tubes (2)!• Oropharynx (1 – out)!
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2. Oropharynx; 3. Laryngopharynx!
Respiration and digestion!• Stratified squamous EPI!• One opening = fauces = “throat” = opening
from mouth!• Contains palatine and lingual tonsils!• Extends to level of hyoid bone!
3. Laryngopharynx!Respiration and digestion!• Stratified squamous EPI!• Extends to junction of esophagus and larynx!
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SECTION 23-3!Composed of cartilages, ligaments, and muscles, the larynx produces sound!
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Larynx!
Connects laryngopharynx with trachea!Formed by 9 pieces of cartilage!• Singles: thyroid, epiglottic, cricoid!• Pairs: arytenoid, cuneiform, corniculate!
Epithelium!• Vocal folds (cords) and above: stratified squamous
EPI!• Inferior to vocal folds: pseudostratified!
Epiglottis!• Elastic cartilage plate!• Closes off glottis !
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The Anatomy of the Larynx Figure 23-4!
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Sound Production - Anatomy!
Vestibular folds = false vocal cords = superior!• Close off glottis during breath holding, lifting,
etc.!Vocal folds = true vocal cords = inferior!• Folds of mucous membrane of larynx!• Vibrate to produce speech sounds!
o Fold attached anteriorly to thyroid cartilage!o Fold attached posteriorly to arytenoid
cartilage!o Folds contain elastic fibers!
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The Glottis Figure 23-5!
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Voice Production Physiology!
Laryngeal muscles!1. Rotate arytenoid cartilage medially or laterally to
abduct or adduct vocal folds!2. Adjust tension on folds!
Voice pitch!• Proportional to tension on and thickness of
folds• Higher tension ➙ higher pitch• Thinner folds (females) ➙ higher pitch
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Voice Production Physiology – 2!Loudness (volume)!• Proportional to air pressure!
Whispering!• Only posterior part of rima glottidis open!• Vocal folds do not vibrate ➙ no pitch!
Speech!• Also requires resonating chambers!
Pharynx, mouth, nasal cavity, paranasal sinuses!
• Muscles of tongue, face, lips!
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Conducting airways!• Trachea to terminal bronchioles!• a.k.a. bronchial tree!• No gas exchange here!
SECTION 23-4!The trachea and primary bronchi convey air to and from the lungs!
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Trachea (“rough”)!
Short (5”) tube from larynx to carina (junction of primary bronchi)!
1. Mucosa!• Pseudostratified EPI!• Lamina propria with elastic and reticular
fibers!2. Submucosa!• Areolar CT!• Seromucous glands and ducts!• Hyaline cartilage C-shaped rings!
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Trachea – 2!
Tracheal rings:!• Prevent collapse during inspiration!• Allow expansion of esophagus during
swallowing!• Trachealis muscle adjusts opening!
3. Adventitia!• Areolar CT!
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The Anatomy of the Trachea Figure 23-6!
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SECTION 23-5!Enclosed by a pleural membrane, the lungs are paired organs containing alveoli, which permit gaseous exchange!
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Lungs!
Sit on diaphragm!Each surrounded by pleural membrane = a
serous membrane!1. Parietal pleura - lines thoracic wall!2. Visceral pleura - covers lungs!3. Pleural cavity!
A “potential space” containing pleural fluid!• Reduces friction between layers!• Causes layers to adhere to one another!
Prevents collapse of lungs!
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The Gross Anatomy of the Lungs Figure 23-7!
Note apex, base, number of lobes (R. vs. L.), cardiac notch
Discussed in lab or later in notes!
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The Gross Anatomy of the Lungs Figure 23-7!
Note apex, base, hilus, primary bronchus, and blood vessels and their colors in this diagram
Discussed in lab or later in notes!
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Lung Lobes/Lobules, Bronchi/Bronchioles!
Each lung receives a primary bronchus!Each lobe receives a secondary bronchus!Each tertiary bronchus supplies a
bronchopulmonary segment containing lung lobules!
• Lobules wrapped in elastic CT!• Contain terminal bronchioles which lead to
respiratory bronchioles!Pathway: Terminal bronchiole → respiratory
bronchiole → alveolar ducts → alveolar sacs → alveoli!
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Bronchi and Lobules of the Lung Figure 23-9b!
About 23 “generations” of
branches.!Ie., bronchi
divide 23 times to form alveoli!
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Bronchi and Lobules of the Lung Figure 23-9c!
Lung!lobule!
Note: alveoli!are not shaped!like bubbles!!
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Changes From Trachea to Terminal Bronchioles!
Comprise “anatomical dead space” (discussed later)!Pattern of changes!1. Pseudostratified → simple columnar/cuboidal EPI!2. Incomplete cartilage large rings → cartilage plates
→ no cartilage!3. Relative amount of smooth muscle increases!• Asthma → smooth muscle constricts small bronchi
and bronchioles!• No cartilage to keep airway open!
4. Decreasing mucus production (↓ goblet cells)!5. Decreasing cilia (macrophages do cleanup)!
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Lung Histology Figure 23-9,10!
Do these alveoli look like spheres?
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Alveoli - Alveolar Cell Types!
1. Type I alveolar cells!• Simple squamous EPI!• Make up most of wall!• Site of gas exchange!
2. Type II alveolar (septal) cells!• Cuboidal epithelial cells!• Have microvilli!• Secrete surfactant (discussed later)!
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Alveolar Cell Types!
3. Alveolar macrophages (dust cells)!• Fixed macrophages!• Remove particulate matter!
4. Fibroblasts!• In basement membrane!• Produce elastic and reticular fibers!
Important for elastic recoil of lungs!Help keep alveoli open
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Alveolar Organization Figure 23-10c!
Alveoli are not spherical!
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The Respiratory Membrane Figure 23-10d!
Respiratory membrane!• Site of gas exchange!• Blood on one side, air on
the other side!1. Capillary (endothelial) wall!2. Fused basement membranes!
a) Epithelial (alveolar)!b) Capillary !
3. Alveolar epithelium!