Respiratory System Pt.1

Upper Respiratory Tract

• Nose

• Nasal cavity

• Pharynx

Lower Respiratory Tract

• Larynx

• Trachea

• Bronchi

• Bronchioles

• Alveolar ducts

• Alveoli

Conducting Zone

• Transport/conducting air

• Nose → terminal bronchioles

Respiratory Zone

• Gas exchange with blood

• Respiratory bronchioles, alveolar ducts, alveoli

Epithelium

• Progressively thinner from nasal cavity to alveoli

• Pseudostratified ciliated columnar → Simple ciliated columnar → simple cuboidal → simple squamous

Nose

• Paired nasal bones

• Hyaline cartilage

  • One pair of lateral cartilage

  • Two pairs of alar (lower lateral) cartilage

• Nostrils consists of dense irregular connective

• Warm, moistens & filter air before reaching the lungs

Nasal Conchae

• Bony projections along lateral wall of nasal cavity

• Increase amount of contact between inhaled air and mucous membranes

Paranasal Sinuses

• Spaces within skull bones that connected to the nasal cavity by ducts

• Lined by pseudostratified columnar epithelium with mucosa

• Swept mucus and foreign particles into nasal cavity and then into pharynx

Nasopharynx

• Only air pass through

• Auditory tubes that connect it to the middle ear. Equalize pressure between ear and atmosphere

• Pseudostratified columnar epithelium

Oropharynx & Laryngopharynx

• Stratified squamous epithelium

• Passageway for food & air

Thyroid

• Component of larynx

• Consist of hyaline cartilage, and is the largest cartilage

• Forms the anterior & lateral walls of larynx

Epiglottis

• Component of larynx

• Consist of elastic cartilage (everything else of larynx is made up of hyaline)

• Closes over laryngeal inlet during swallowing

Intrinsic Ligaments

• Vocal ligaments made up of elastic CT that form the true vocal ford

• Function in voice production and help close larynx when swallowing

Extrinsic Muscles

Stabilize the larynx and move it during swallowing

Sound Produced

• Vocal folds vibrate

• The intrinsic laryngeal muscles narrow opening of rima glottis and air is forced past the vocal cords during expiration

Tracheal

• 15-20C shaped rings of hyaline cartilage

• Rigidity ensures that trachea remains open

• Flexibility allows distension when swallowing food and expulsion of air during coughing

Lungs

Right lung

• 3 lobes that are larger and wider

Left lung

• 2 lobes and it has cardiac notch

Pleural Cavity

• Space between visceral and parietal membranes

• Contains serous fluid to decrease friction between the membranes during breathing

Bronchi

• Incomplete rings of hyaline cartilage that support the walls of the main bronchi

• Ensure the walls remain open

• Support lessens as diameter decreases

Terminal Bronchioles

• No cartilage in the walls, but have thicker layer of smooth muscle than bronchi

• Bronchoconstriction: contraction of smooth muscle to narrow the diameter of the bronchiole that leads to decreasing air flow (asthma)

• Bronchodilation: relaxation of smooth muscle to increases diameter of bronchiole that leads to increasing air flow

Alveolar Cells

• Alveolar Type I cell: create moist inner surface of alveoli so it prones to collapse

• Alveolar Type II cell: produce pulmonary surfactant (oily fluid) to prevent collapse of alveolus

Respiratory Membrane

• Consists of alveolar epithelium and capillary endothelium

• Oxygen diffuses across respiratory membrane into pulmonary capillary

• CO₂ diffuses from blood through membrane into alveolus

Alveoli

Simple squamous

Primary Bronchi

1 on the left

1 on the right

Secondary Bronchi

3 on the right

2 on the left