Anatomy Of The Respiratory Tract

Question 1

What are the main functions of the respiratory system?

Answer 1

• Provides oxygen to all body tissues
• Removes carbon dioxide
• Regulates blood pH
• Defence against pathogens
• Produces sound
• Olfaction (sense of smell)

Question 2

List the structures included in the upper respiratory tract.

Answer 2

• Nose
• Pharynx
• Paranasal sinuses
• Larynx

Question 3

List the structures included in the lower respiratory tract.

Answer 3

• Trachea
• Bronchi
• Bronchioles
• Alveoli

Question 4

What are the functions of the upper respiratory tract?

Answer 4

• protects lower tract
• Warms and moistens air
• Filters air
• Olfaction (smell)
• Production and resonation of sound

Question 5

What are vibrissae?

Answer 5

Hairs at the entrance to the nose that trap large dust particles

Question 6

What is the role of conchae in the nasal cavity?

Answer 6

Projections from lateral wall that produce turbulence to allow more time to warm and moisten the air

Question 7

What type of epithelium lines the nasal cavity?

Answer 7

Pseudostratified ciliated columnar epithelium with goblet cells

Question 8

What do goblet cells produce?

Answer 8

Mucous to trap particles

Question 9

What is the role of the rich capillary network under the mucosa in the nose?

Answer 9

Blood warms the air

Question 10

What is the function of seromucous glands in the nasal cavity?

Answer 10

Secretions moisten the air

Question 11

Where is the olfactory mucosa located?

Answer 11

In the upper aspect of the nose, above the superior conchae
Contain receptors for smell

Question 12

What are paranasal sinuses?

Answer 12

Air-filled spaces in bones around the nose that lighten the skull and resonate sound
Secretions for the sinuses drain into nasal cavity

Question 13

What are the three regions of the pharynx?

Answer 13

• Nasopharynx - posterior to the nose
• Oropharynx - posterior to the mouth
• Laryngopharynx - posterior to the larynx

Question 14

What are the main functions of the larynx?

Answer 14

• Maintains an open airway
• Prevents food and drink from entering the lower respiratory tract
• Sound production

Also involved in coughing and defecation

Question 15

What is the glottis?

Answer 15

• The space between the vocal cords
• Usually open to allow air flow
• Closed during swallowing to prevent aspiration
• Air vibrated over the vocal cords to produce sound

Question 16

What is the anatomical structure of the trachea?

Answer 16

• A tough, flexible tube, 4.5 cm long and 2.5 cm in diameter
• Extends from larynx to the carina (where trachea ends)
• Lies anterior to the oesophagus
• Contains 15-20 horseshoe shaped cartilages which keep airway open

Question 17

What is the role of the trachealis muscle?

Answer 17

Joins posterior ends of cartilage and constricts during coughing to increase pressure

Question 18

What type of epithelium lines the trachea?

Answer 18

Pseudostratified ciliated columnar epithelium with goblet cells

Acts as a muscociliary escalator

Question 19

What is the bronchial tree?

Answer 19

A branching network of air tubes including primary, secondary, tertiary bronchi and bronchioles, terminal bronchioles and respiratory bronchioles

Question 20

What structural changes occur in the bronchial tree?

Answer 20

• Amount of cartilage decreases
• Amount of smooth muscle increases
• Height of epithelial cells decreases

Question 21

What type of epithelium lines the bronchioles?

Answer 21

Simple columnar epithelium with cilia

Question 22

What are Clara cells and their function?

Answer 22

Cells in bronchioles that produce surfactant

Question 23

What is the primary function of alveoli?

Answer 23

Site of gas exchange

Provide an extensive surface area for gas exchange

Question 24

How many alveoli are typically present in one lung?

Answer 24

150-250 million

surrounded by a network of capillaries

Question 25

What is the structure of an alveolus?

Answer 25

- Type I alveolar cell (simple squamous epithelium) forms wall of alveolus - Type II alveolar cell (secretes surfactant) reduces surface tension to allow lungs to expand - Macrophage (phagocytoses small inhaled particles and bacteria) can go to blood or is coughed up and swallowed - respiratory membrane (air has to go across this to get to capillary) very thin for fast diffusion

Question 26

What comprises the respiratory membrane?

Answer 26

* Epithelium of type I cell * Basement membrane of type I cell * Endothelium of capillary * Basement membrane of capillary The two basement membranes tend to be fused together (so very thin!)

Question 27

What does the conductive portion of the respiratory tract include?

Answer 27

Passageway & preparation of air * Nasal cavity & paranasal sinuses * Pharynx * Larynx * Trachea * Primary bronchi * Secondary bronchi * Tertiary bronchi * Bronchioles * Terminal bronchioles (end of conduction)

Question 28

What does the respiratory portion of the respiratory tract include?

Answer 28

Gas exchange here * Respiratory bronchioles * Alveolar ducts * Alveolar sacs * Alveoli

Question 29

What do cilia do in the nose?

Answer 29

Waft the trapped particles to the pharynx where they can be swallowed

Question 30

What is the pharynx?

Answer 30

Fibromuscular tube - forms a communal passageway for respiratory and gastrointestinal (food) systems The close proximity of gastrointestinal and respiratory systems can lead to swallowing difficulties and aspiration of food & fluid

Question 31

What does the larynx consist of?

Answer 31

- a cartilaginous skeleton - a lining made of membranes - vocal cords - muscles which move the vocal cords

Question 32

Describe the structure of primary bronchi

Answer 32

- 2 of them = right and left - supply each lung - 2-3 cm long - right is wider and more vertical than left (as goes to the heart) - C- shaped cartilages

Question 33

Describe the structure of secondary bronchi (lobar)

Answer 33

- supply lobes of the lungs (3 on right and 2 on left) - plates of cartilage

Question 34

Describe the structure of tertiary bronchi (segmental)

Answer 34

- supply segments of the lung (10 on right and 8 on left) - plates of cartilage

Question 35

What type of epithelial cells line the bronchus?

Answer 35

Pseudostratified ciliated columnar epithelium with goblet cells

Question 36

Describe the structure of bronchioles

Answer 36

- no cartilage - simple columnar epithelium with cilia - few goblet cells - smooth muscle SO can constrict and dilate (to reduce/ increase flow) - each gives rise to 50-80 terminal bronchioles

Question 37

Describe the structure of terminal bronchioles

Answer 37

- simple columnar epithelium with cilia - no goblet cells or mucous glands - Clara cells = produce surfactant (reduces surface tension) - each gives rise to 2 or more respiratory bronchioles

Question 38

Describe the structure of respiratory bronchioles

Answer 38

- simple cuboidal epithelia - no cilia - Clara cells = produce surfactant - alveoli extend from the lumen SO gas exchange occurs here

Question 39

Describe alveoli

Answer 39

- scattered alveoli on respiratory bronchioles - respiratory bronchioles —> alveolar ducts - alveolar ducts = elongated airways with walls made of alveoli —> alveolar sacs - alveolar sacs = spaces surrounded by clusters of alveoli

Question 40

What is the conductive portion of the respiratory tract?

Answer 40

Concerned with filtering, warming and moistening the air and conducting the air into the lungs

Question 41

What is the respiratory portion of the respiratory tract?

Answer 41

Includes all parts of the tract where gas exchange occurs