chapter 22 - respiratory system

functions of the respiratory system

1. transports air

2. exchanges O2 and CO2 with the blood stream

3. produces sound through the larynx

conducting zone

• external nares (nostrils) → terminal bronchioles

• filter, humidify, and warm incoming air

respiratory zone

• respiratory bronchioles + alveoli

• site of gas exchange

upper vs lower respiratory tract

divided by larynx (apart of upper)

functions of the nose

1. provides an airway for respiration

2. moistens and warms air

3. filters inhaled air

4. resonating chamber for speech

5. houses olfactory receptors

nasal cavity mucous membranes

1. olfactory mucosa - roof of nasal cavity, olfactory receptors

2. respiratory mucosa - lines nasal cavity, pseudostratified cilliated columnar epithelium

nasal conchae

• superior, middle, and inferior

• during inhalation - filter, heat, and moisten incoming air

• during exhalation - moisture and heat are reclaimed

paranasal sinuses

1. frontal bone

2. maxillary bone

3. sphenoid bone

4. ethmoid bone

pharynx

• connects nasal cavity and mouth

• nasopharynx + oropharynx + laryngopharynx

nasopharynx

• AIR passageway

• closed off during swallowing by uvula

• contains opening to auditory tube

• pharyngeal tonsil - collects and kills bacteria

• pseudostratified ciliated columnar epithelium

oropharynx

• FOOD + AIR

• stratified squamous epithelium

• palatine tonsils + lingual tonsils

laryngopharynx

• FOOD + AIR

• stratified squamous epithelium

larynx functions

1. voice production

2. open airway

3. routes and air and food into proper channels

larynx cartilage

• thyroid cartilage + adam’s apple

• cricoid cartilage

• epiglottis (elastic cartilage, cover glottis during swallowing)

larynx

• stratified squamous AND pseudostratified cilliated columnar epithelium

• vocal folds (produce pitch) + vestibular folds

trachea

• apart of mediastinum

• hyaline cartilage

• carina at very end

• pseudostratified cilliated columnar epithelium

• trachealis muscle constricts trachea allowing air to be expelled with more force (coughing)

bronchi

left and right primary → 2 left and 3 right secondary → tertiary

• pseudostratified cilliated columanar epithelium

→ bronchioles

• simple columnar epithelium

→ terminal bronchioles

• simple cuboidal epithelium

respiratory bronchioles

• simple cuboidal epithelium

• off of terminal bronchioles

• lead to alveoli

alveoli

• site of gas exchange!

• type I alveolar cells

  • simple squamous epithelium

• type II alveolar cells

  • cuboidal epithelium

  • secrete surfactant (reduce surface tension → keep alveoli open)

• alveolar macrophages - last line of defense

right vs left lung anatomy

left → 2 lobes

right → 3 lobes

hilum contents

• pulmonary arteries - oxygen-poor blood

• pulmonary veins - oxygen-rich blood

• bronchi - air

lung innervation

• parasympathetic constriction

• sympathetic dilation

*medulla oblongata!

inspiration

• conscious

• driven by diaphragm and external intercostals

• Boyle’s law

• secondary muscles - scalenes, stenocleidomastoid, pectoralis minor, erector spinae

expiration

• passive

• muscles relax

• forced expiration

  • active process

  • obliques + transversus abdominis + internal intercostals

chemoreceptors

• monitor O2 levels

• located in carotid sinus + bodies

bronchial asthma

• allergic inflammation

• difficulty with expiration

• spasming smooth muscle

• diagnosis: <80% FEV1 test

• treatment: steroids + albuterol

cystic fibrosis

• thick mucus production (exocrine glands)

• treatment: airway clearance techniques

• inherited

chronic obstructive pulmonary disease (COPD)

• common in smokers

• difficult expiration

• obstructive emphysema