Lecture 18: The Respiratory System

Question 1

What is the function of the respiratory system?

Answer 1

• Gas Exchange (CO2 AND O2)
• Regulate blood pH
• Receptors for sense of smell
• Filters, warms and moistens inspired air
• Produces sounds

Question 2

Structurally classify the components of the respiratory system?

Answer 2

• Upper respiratory system

→ Nose

→ Nasal Cavity

→ Pharynx

→ Larynx (above vocal chords)

• Lower respiratory system:

→ Larynx (below vocal)

→ Trachea

→ Brochi

→ Lungs

Question 3

Functionally classify the respiratory system:

Answer 3

Conductive portion: Collection and conditioning of air via tubes carrying into the lungs.

Respiratory portion: Site of gas exchange; bronchioles, alveolar ducts and sacs

Question 4

What is the role of the mucous membrane?

Answer 4

• Lines body cavity that opens to the exterior
• Lubrication of body cavity/tissues and protection from foreign particles

PRODUCED MORE ON COLD DAYS

Question 5

Where is the respiratory epithelium located and what are its specializations?

Answer 5

• Located in most of the conductive portion of respiratory system (Nasal cavity → Bronchi)
• Specializations: Goblet cells (mucous), brush (microvilli endings), Basal cells, cilli

Question 6

Describe the anatomy of the nose:

Answer 6

External: Nasal bones which form bridge, Opening nostrils (external nares), nasal vestibule divided by septum contains vibrissae (hairs).

Internal: Nasal Cavity (divided by septum), Conchae (superior, middle and inferior), internal nares (choanae)

Question 7

Where is the olfactory epithelium located and what is its function:

Answer 7

Located in the superior nasal conchae

Contains chemoreceptors for the sense of smell

• Sustentacular Cells (support)
• Basal Cells
• Olfactory cells
  
  • Olfactory Bowman’s gland (mucous secretion)

Question 8

Where is the pharynx?

Answer 8

Tube connecting the nasal and oral cavities and the larynx (oesophagus)

Skeletal muscle lined with mucous membrane acts as a passageway for food and air.

Question 9

What are the 3 components of the pharynx

Answer 9

1. Nasopharynx- Choane to soft palate, openings for eustachian tubes and lined with respiratory epithelium
2. Oropharynx- Soft palate to hyoid bone, tonsils, lined with non keratinised stratified squamous epithelium
3. Laryngopharynx- Hyoid Bone to Trachea, Respiration and Digestion, non keratinised stratified squamous epithelium

Question 10

What is the function of the Larynx and identify any key features

Answer 10

Connects the laryngopharynx to the trachea; midline of the neck anterior to oesophagus

Made up of 9 pieces of cartilage:

Thyroid - Anterior wall connected to the hyoid

Epiglottis- Leaf life structure posterior to thyroid: closes glottis when food is swallowed

Cricoid- Circular cartilage inferior to thyroid

Cuneiform- Bumps on cartilage where vocal chords attach (2)

Corniculate- Apex of arytenoid cartilage (2)

Arytenoid- Prong like structures attached to cricoid cartilage (2)

Question 11

What is your vocal chords made out of?

Answer 11

1. Ventricular folds (false) → Will close of to form pressure when lifting heavy object
2. Vocal Folds (true) → contains elastic ligament which can be altered to form sounds through tension

Question 12

What are the main function of the vocal chords?

Answer 12

Control airflow and allow the production of sound

Question 13

Describe the anatomy of the trachea

Answer 13

Anterior to the oesophagus from larynx

Wall:

• Mucosa: Respiratory Epithelium
• Submucosa: Areolar Tissue
• Media: 16-20 C-shaped rings of hyaline cartilage unified by fibrocartilage (trachealis muscle)
• Adventitia: Areolar tissue joins trachea with surrounding tissues.

Question 14

Outline the Structural classification of the bronchi as it enters the lung:

Answer 14

Primary (main) Bronchi

• L + R main bronchus
• Right is more vertical than left (means food can be more easily transported to R)

Secondary (lobar) bronchi

• L + R lobar bronchus 3 RIGHT AND 2 LEFT (match number of lobes of lung)

Tertiary (Segmental) Bronchi

• 10 in each lung and they will divide into bronchioles

Question 15

How does epithelium change throughout the bronchiole tree?

Answer 15

pseudostratified ciliated columnar epithelium (bronchi) → Simple non ciliated cuboidal (terminal bronchioles)

Question 16

How does cartilage change throughout the bronchiole tree?

Answer 16

Incomplete rings of cartilage gradually gets replaced with smooth muscle.

Question 17

How do cell specialisations change throughout the bronchiole tree

Answer 17

Goblet cells gradually decrease until zero at terminal bronchioles where it is replaced with Clara cells- produce surfactant

Question 18

Anatomically describe the lungs

Answer 18

• Paired organs within thoracic cavity - Surrounded by visceral pleura
• APEX- projects superiorly to the clavicle
• Anterior base, mediastinal base, diaphragmatic base
  
  • Left lung slightly smaller and has a cardiac notch for the heart

Question 19

Describe the anatomy of the right lung

Answer 19

• 3 lobes
• Horizontal fissure and Oblique fissure
• Superior lobe = Most superior lobar bronchus
• Middle lobe = middle superior lobar bronchus
• Inferior lobe = Most inferior lobar bronchus

Question 20

Describe the anatomy of the left lung:

Answer 20

Only oblique fissure

Superior lobe = superior lobar bronchus

Inferior lobe = inferior lobar bronchus

Question 21

What is after the terminal bronchioles

Answer 21

Respiratory Bronchi → Alveolar Ducts → Alveolar sacs → Alveolus

Question 22

What is the function of the alveolus and identify its histological cells features:

Answer 22

Sites of gas exchange where it is surrounded by networks of capillaries

Made of 2 types of cells:

1. Simple squamous epithelium where gas exchange occurs.
2. conciliated simple cuboidal, synthesize and secrete surfactant

Question 23

Identify the full bronchiole tree

Answer 23

Main Bronchi → Lobar Bronchi → Segmental bronchi → Terminal bronchi → respiratory bronchioles → Alveolar ducts → Alveolar Sacs → alveoli