Lecture 6: The Respiratory System Flashcards
what is respiration
-exchange of gases (O2 and CO2) between the atmosphere, blood, and cells
-closely couples with CVS, which transports gases
-breakdown of CHO in the presence of O2 by the body-> cellular respiration
-O2 from lungs transported to tissues to break CHO to yield energy
what is the formula for cellular respiration
C6H12O6 + 6O2 → 6CO2 + 6H2O + energy
what are the 4 processes of respiration
- Pulmonary ventilation (breathing)
- External respiration
- Transport of respiratory gases
- Internal respiration
what is pulmonary ventilation
also known as breathing
-ventilation consists of inspiration and expiration
-inspiration: mves are into the lungs from the atmosphere
-expiration: moves air out of the lungs into the atmosphere
what are the structural components (2) of the respiration system
- upper respiratory system
- lower repiratory system
what are the functional components (2) of the respiration system
components of the respiratory system are divided into two zones:
1. conducting zone: nasal cavity to larger bronchioles
2. respiratory zone: smallest bronchiols and alveoli
what are the structural components of the upper respiratory system
nose, nasal cavity, sinuses, and pharynx
what are the structural components of the lower respiratory system
larynx, trachea, bronchus, lungs, bronchioles, alveoli
significance of nose and functions in respiratory system
the onlny external portion of the respiratory system
-functions:
-provides an airway for respiration
-moistens and waarms entering air
-filters nad cleans inspired auir
-serves as resonating chamber for speech
-houses olfactory receptors
-is didvided into two regions: external nose and nasal cavity
what is the external nose
formed by:
- nasal & frontal bones superiorly- form bridge & root, respectively
-maxillary bones laterally
-plates of hyaline cartilage inferiorly
-areas include: root (area between eyebrows); bridge, dorsum nasi (anterior margin -> ;ength of nose), and apex (tip of nose)
-nostrils (nares): bounded laterally by alae
areas of external nose
-areas include: root (area between eyebrows); bridge, dorsum nasi (anterior margin -> ;ength of nose), and apex (tip of nose)
-nostrils (nares): bounded laterally by alae
what is the nasal cavity
-within and posterior to external nose
-divided by midline nasal septum, formed: anertiorly by the septal cartilage and posteriorly by the vomer bone and perpendicular plate of ethmoid bone
what is the posterior nasal apertures (choncae) (nasal cavity)
opening where nasal cavity turns into nasopharynx
-roof: formed by ethmoid and sphenoid bones
-floor: formed by hard palate (bone) and soft palate (muscle)
what is the nasal vestibule (nasal cavity)
nasal cavity superior to nostrils
-lined with vibrissae (hairs) that filter coarse particles from inspired air
-rest of nasal cavity lined with mucous membranes
what is the olfactory mucosa
lines superior region of nasal cavity and contains olfactory epithelium
what is the respiratory mucosa
pseudostratified ciliated columnar epithelium, contains goblet cells and rests on lamina propria that contains many seromucous nasal glands
what is the nasal conchae
-medial projections from each lateral wall of nasal cavity]-3 sections: superior, middle, and inferior conchae
-groove inferior to each conchae -> nasal meatus
-shape of conchae help to: increase mucosal area; enhance air turbulence
what are the functions of conchae
during inhilation, conchae and nasal mucosa: filter, heat, and moisten are
during exhalatin these structures: reclaim heat and moisture
what are the paranasal sinuses
-form the right around nasal cavities
-located in frontal, sphenoid, ethmoid, and maxillary bones
what are the functions of the paranasal sinuses
lighten skull, secrete mucus, help to warm and moisten air
what is the pharynx
-funnel-shpaed muscular tube that runs from base of skill to vertebra C6
-connects nasal cavity and mouth to larynx and esophagus
-composed of skeletal musclew
what are the three regoins of the pharynx
- nasopharynx: air passageway; pseudostratified columnar epithelium, uvula, soft palate
- oropharynx: soft palate to epiglottis; air & food; statified squamous epithelium
- laryngopharynx: posterior to epiglottis; air & food; startified squamous epithelium
what is in the lower repiratory system
larynx, trachea, bronchi, and lungs
-broken into two zones: respiratory and conducting
what is the respiratory zone of the lower respiratory system
-site of gas exchange
-consists of microscopic structures such as repsiratory bronchioles, alveolar ducts, amd alveoli
what is the conducting zone of the lower respiratory system
-conduits that transport gas to and from gas exchange sites
-includea all other respiratory structures
-cleanses, warms, and humidifies air
what are the functions of the larynx
- provides patent airway
- routes air and food into proper channels
- voice production-> houses vocal folds
what are the caartillage of the larynx
framework consists of nin hyline cartilages (except for epiglottis), connected by membranes and ligaments
1. thyroid cartilage: large cartilage that resembles an upright open bood; “spine” of book-> laryngeal prominence (adam’s apple)
2.cricoid cartilage: righ-shaped
3. paired arytenoid cartilages
4. paired cuniform cartilages
5. paired corniculate
6. epiglottis
what is the epiglottis
elastic cartilage
-covers laryngeal inlet during swallowing
-covered in taste buds containing mucosa
what are the vocal folds
-vocal ligaments: form core of vocal folds (true vocal cords)
-ligaments lie underneath laryngeal mucosa and connects arytenoid and thyroid cartilages
-contain elastic fibers, appear whitish becasue of lack of blood vessels
what is the glottis
opening between vocal folds
-folds vibrate to produce sound as air rushes up from lungs
what are the vestibular folds
also known as false vocal cords
-superior to vocal folds
-help to close glottis during swallowing
-no part in sound production
what are the epithelium of the larynx
-superior portion: stratified squamous epithelium
-inferior to vocal fold: pseudostratified ciliated columnar epithelium
explain voice production
speech: intermittent release of expired air during opening and closing of glottis
-pitch: determined by length and tension of vocal cords
-loudness:depnds upon force of air
-chambers of pharynx and oral, nasal, and sinus cavities amplify and enhance sound quality
-sounds is “shaped” into language by muscles of pharynx, tongue, soft palate, and lips
what are the sphincter functions of the larynx
vocal folds may act as sphincters to prevent air passage
-valsalva’s manuever: glottis closes to prevent exhalation, abdominal muscles contrct, intra-abdominal pressure rises, helps to empty rectum or stabilizes truck during heavy lifting
explain valsalva’s manuever
glottis closes to prevent exhalation, abdominal muscles contrct, intra-abdominal pressure rises, helps to empty rectum or stabilizes truck during heavy lifting
what is the trachea
also known as the windpipe
- extends from larynx into mediatsinum, and divides into two main branches
what are the walls of the trachea
- mucosa: ciliated pseudostratified epithelium with goblet cells
- submucosa: CT with seromucous grlands supported by 16-20 C-shaped cartilage rings that prevent collapse of trachea
- adventitia: outermost layer made of CT
what is the trachealis
-consists of smooth muscle fibers; connects posterior parts of cartilage rings
-contracts during coughing to expel mucus
what is the carina
-last tracheal cartilage that is expanded and found at point where trachea branches into two main bronchi
-highly sensitive mucosa
-violent coughing will be tirggered if any foreign object makes contact with it
what are the bronchi
air passages undergo 23 orders of branching-> bronchial tree
-from tips of bronchial tree: conducting zone structures give rise to respiratory zone structures
what are the conducting zone strutures in the bronchi
-trachea divides to form right and left main (primary) bronchi, the right main bronchus is wider/ shorter/ more vertical than left
-each main bronchus enters hilum of one lung
-main bronchus then branches into lobar (secondary) bronchi-> 3 on right & 2 on left
-each lobar bronchus supplies one lobe
-each lobar bronchus-> segmental (tertiary) bronchi-> divide repeatedly
-branches become smaller and smaller
what are the bronchioles
small bronchi
-less than 1 mm in diameter
what are the terminal bronchioles
smallest of all branches <0.5 mm in diameter
what are the changes in conducting zone of the bronchi
bronchi to bronchioles
-changes in support structure: cartilage rings become irregular plates, in bronchioles the elastic fibers completely replace cartilage
-epithelium type changes: pseudostratified columnar gives way to cuboidal, cilia and goblet cells become more sparse
-amount of smooth muscle increases: allows bronchioles to provide substantial resistance to air passage
what are the respiratory zone structures of the bronchi
-begins where terminal bronchioles feed into repiratory bronchioles-> alveolar ducts-> alveolar sacs (saccules)
-alveolar sacs contain clusters of alveoli, ~300 milliom alveoli make up most of lung volume, sites of actual gas exchange
explain the alveoli
-blood-air barrier that consts of alveolar and capillary walls along witht heir fused basement membranes, very thin (~0.5 um); allows gas exchange across membrane by simple diffusion
what do the alveolar walls consist of
-single layer of squamous epithelium (type I alveolar cells)
-scattered cuboidal type II alveolar cells secrete surfactant and antimicrobial proteins
what are some significant features of the alveoli
- surrounded by fine elastic fibers and pulmonary capillaries
- alveolar pores connect adjacent alveoli, equalize air pressure throughout the lung, provide alternate routes in case of blockages
3.alveolar macrophages keep alveolar surfaces sterile, 2 million dead macrophages per hour carried by cilia to throat and swallowed
what do the lungs occupy (regions)
lungs occupy all of the thoracuc cavity except for mediastinum
what is the roof of the lungs
site of vascular and bronchial attachment to mediastinum
what is the costal surface of the lungs
the anterior, lateral, and posterior surfaces
what is the apex of the lungs
superior tip, deep to claviclew
what is the base of the lungs
inferior surface that rests on diaphragm
what is the hilum of the lungs
on mediastinal surface, sire for entry/exit of blood vessels, bronchi, lymphatic vessels, and nerves
what is each lobe of the lung firther divided into
bronchopulmonary segments
how many bronchopulmonary segments are there in the lungs
-10 on right, 8-10 on left that are all seperated bu conective tissue septa
-each segment is served by its own artery, vein, and bronchus
-if one segment is diseased, it can be individually removed
what are the lobules of the lungs
smallest subdivisions visible to maked eye; hexogonal segments served by bronchioles and their branches
-lungs are mostly composed of alveolu; the rest consists of stroma, elastic connective tissue-> makes lungs very elastic and spongy
what are the two blood supplies of the lungs
lungs are perfused by two tunctionally different circulations:
1. pulmonary circulation
2. broncial circulation
explain pulmonary circulation of the lungs
-pulmonary arteries: systemic venous blood from heart to lungs for oxygenations, bronach profusely to feed into pulmonary capillary networks
-pulmonary veins: oxygenated blood from respiratory zones back to heart, low pressure/ high-volume system, lung capillary endothelium contains many enzymes that act on different substances in blood (ex. angiostensin-converting enzyme (ACE) activates blood pressure hormone)
explain bronchial circulation of the lungs
-bronchial arteries: provide oxygenated blood to lung tissue, arise from aorta and enter lungs at hilum, part of the systemic circulation so high pressure and low volume, supply all lung tissue except alveoli
-broncial veins: anastomoses (interconnections) with pulmonary veins, pulmonary veins carry most venous blood back to heart
