LO 16 Flashcards
List the respiratory organs
- Nose
- Pharynx
- Larynx
- Trachea
- Bronchi
- Lungs
- Alveoli
What are the functions of the respiratory system?
- Air distributor
- Gas exchanger
- Homeostatic mechanism
- Filters, warms, and humidifies air for breathing
- Speech and sound production
- Olfaction
What are the organs of the upper respiratory tract?
- Nose
- Pharynx
- Larynx
Think head cold
What are the organs of the lower respiratory tract?
- Trachea
- Bronchial tree
- Lungs
Think chest cold
Describe respiratory mucosa
- Specialized membrane that lines the air distribution tubes of the respiratory system
- Covered with mucus—“mucus blanket”
- More than 125 ml of mucus produced each day
- Air purification/filtration – traps inspired irritants
Describe cilia
- On mucosal cells
- ‘beat’ in one direction to ‘propel’ mucus and trapped irritants toward the pharynx for expulsion
- Note: cigarette smoke ‘paralyses’ cilia
Describe the structures of the nose
- Nostrils (external nares) = entrance for air
- Nasal septum separates interior into R & L cavities lined with respiratory mucosa
- Paranasal sinuses (frontal, maxillary, sphenoidal, ethmoidal) and lacrimal sacs drain into nose
- Conchae (superior, middle, inferior) are ‘fold-like’ structures that increase surface area in nasal cavity
Describe the function of the nose
- Warms and moistens inhaled air as it flows over the conchae
- Contains sense organs of smell (olfactory receptors) in the nasal mucosa
Describe the structure of the pharynx
- 12.5 cm (5 inches) long
- Three segments - Nasopharynx, Oropharynx, Laryngopharynx
- Two sinuses, mouth, esophagus, larynx, and auditory (eustachian) tubes all have openings into pharynx
- Pharyngeal tonsils in nasopharynx; palantine tonsils in oropharynx
Describe the eustachian/auditory tubes of the pharynx
- Open into/connect middle ears with nasopharynx, allowing equalization of air pressure between the middle and exterior ear
- Lining of tubes is continuous with that of the nasopharynx and middle ear, so a sinus infection can develop from a cold where the nasal mucosa is inflamed and an ear infection can develop from inflammation of the nasal pharynx
Describe the functions of the pharynx
- The pharynx has both digestive & respiratory system functions:
- Passageway for food & liquids to the esophagus
- Passageway for air to the respiratory tree
Describe the structure of the larynx
- Just below pharynx
- Framework = several pieces of cartilage
- Thyroid cartilage (Adam’s apple) is largest
- Epiglottis partially covers opening into larynx – closes off the larynx when we swallow to prevent food from entering trachea
- Mucous lining
- Vocal cords consist of 2 fibrous bands that stretch across the interior of the larynx (looks like a vagina)
Describe the function of the larynx
- Air distribution; passageway for air to move to and from lungs
- Voice production via muscles attached to the larynx cartilage that pull on the vocal cords
- when cords are tense 🡪 high-pitched sound
- when cords are relaxed 🡪 low-pitched sound)
Describe the structure of the trachea
- ‘windpipe’
- 11 cm (4.5 inches) long tube
- from larynx to bronchi
- held open by C-shaped rings of cartilage
- mucous lining
- ciliated epithelium
Describe the Bronchi, Bronchioles & Alveoli Structure
- Trachea branches into right & left bronchi (primary bronchi) which lead into right and left lungs
- In lung, each primary bronchi branches into increasingly smaller secondary bronchi which eventually lead to bronchioles
- Walls of bronchioles = smooth muscle (no rings of cartilage)
- Bronchioles divide into microscopic tubes called alveolar ducts (look like the stem of a bunch of grapes)
- Alveolar ducts end in clusters of microscopic alveolar sacs (look like clusters of grapes)
- Walls of alveolar sacs are made of alveoli - Millions of alveoli per lung
Describe the function of the trachea
- Passageway for air to move to and from lungs
- Ciliated mucosal lining traps airborne irritants
- Complete occlusion of the airway causes death in minutes
- 4000+ deaths annually in the United States due to tracheal obstruction
- Heimlich maneuver is a lifesaving technique used in cases of tracheal obstruction
What is the function of bronchi and bronchioles?
Passage way for air to move to & from alveoli
What is the function of alveoli?
- Site of exchange of O2 and CO2 between blood in lung capillaries and air in alveoli
- Thin-walled – single layer of cells
- Direct contact with blood capillary
Describe the alveoli and respiratory membrane
- thin membrane that lies between the blood in the capillaries and the air in each alveolus
- covered with surfactant – a substance that reduces surface tension to prevent collapse of alveoli as air moves in & out