Respiratory system

Question 1

Into what to portions can the respiratory system be divided?

Answer 1

Into conducting and respiratory portions.

Question 2

What are the functions of the conducting portion?

Answer 2

To warm, moisten, and filter air, and transport it towards the respiratory portion.

Question 3

What are the two parts of the conducting portion?

Answer 3

Extrapulmonary and intrapulmonary

Question 4

Of which organs is the extrapulmonary part of the conducting portion comprised of?

Answer 4

Nasal cavity, pharynx, and larynx.

Question 5

Of which organs is the intrapulmonary part of the conducting portion comprised of?

Answer 5

Trachea, bronchi, bronchioles.

Question 6

What happens in the respiratory portion?

Answer 6

Gaseous exchange between the blood and air.

Question 7

Of what is the respiratory portion composed of?

Answer 7

Alveolar ducts and alveolar sacs. Alveolar sacs are groups of alveoli.

Question 8

What are the functions of the respiratory system?

Answer 8

• Mechanical ventilation
• Defence
• Olfaction
• Phonation: larynx in mammals and syrinx in birds

Question 9

What is the general histological structure of the respiratory system?

Answer 9

• Epithelium
• Lamina propria
• Smooth muscle
• Submucosa
• Cartilage
• Adventitia

Question 10

What kind of epithelium is found from the respiratory system?

Answer 10

Pseudostratified columnar ciliated or simple columnar or cuboidal epithelium.

Question 11

What is the general structure of nasal cavity as a whole?

Answer 11

Bone and cartilage covered by connective tissue and epithelium.

Question 12

What are the parts of the nasal cavity as a whole?

Answer 12

• Nasal vestibule
• Nasal cavity
• Olfactory region

Question 13

What is the nasal vestibule?

Answer 13

The most external part of the nasal cavity (kirsu).

Question 14

Explain the composition of the nasal vestibule.

Answer 14

• Epithelium:
• variable
• transition to pseudostratified columnar non-ciliated epithelium
• Lamina propria:
• dense connective tissue
• defense cells
• serous glands
• vessels.

-Hyaline cartilage

Question 15

Explain the composition of the nasal cavity.

Answer 15

• Respiratory epithelium:
• basal cells
• Goblet cells
• columnated ciliated cells
• Lamina propria:
• seromucous glands
• defense cells
• vessels
• Hyaline cartilage and bone
• Turbinates (bone)

Question 16

What is the composition of the olfactory region?

Answer 16

• Specialized respiratory epithelium:
• Olfactory cells: bipolar neurones.
• Columnar cells with microvilli.
• Basal cells
• Lamina propria
• serous glands
• Vomeronasal organ:
• pheromones

Question 17

What are the paranasal sinuses?

Answer 17

Empty cavities near the nasal cavity. They are lined with respiratory epithelium.

Question 18

What is the nasopharynx and where it is located?

Answer 18

It is the uppermost part of the throat and it is located caudally to the nasal cavity.

Question 19

Why is the nasopharynx called a mixed region?

Answer 19

Because it has a mix of two different kinds of epithelia. It is partially a caudal continuation of the nasal cavity and contains respiratory epithelium, and partially it is a continuation of the hard palate and contains non-keratinised stratified epithelium.

Question 20

What is larynx histologically?

Answer 20

Larynx (kurkunpää) is formed of cartilages covered by mucosa.

Question 21

What type of cartilage is there in the larynx?

Answer 21

Epiglottis and parts of arytenoids are elastic. Rest (cricoid, thyroid) are formed of hyaline cartilage.

Question 22

What type of epithelium is found in the larynx?

Answer 22

Epiglottis:non-keratinised stratified flat epithelium.
Rest: respiratory epithelium.

Question 23

What is found in the lamina propria of the larynx?

Answer 23

Mucous glands and defence cells.

Question 24

What are vocal cords histologically?

Answer 24

Folds of the tissue.

Question 25

What type of muscle is found in the larynx?

Answer 25

Smooth: Extrinsic laryngeal muscles join larynx to hyoid. Intrinsic laryngeal muscles control sound production and are found around thyroid and cricoid cartilage.

Question 26

What type of mucosa does the trachea have?

Answer 26

Mucosa with respiratory epithelium: columnar ciliated epithelia, goblet cells and basal cells.

Question 27

What is special about tracheal submucosa?

Answer 27

Submucosa and lamina propria are continuous (not separate layers) loose connective tissue with elastic fibres. It includes seromucous tracheal glands, diffuse lymphoid tissue or lymphoid follicles, nerve ganglia responsible for coughing reflex.

Question 28

Describe the tracheal cartilage:

Answer 28

C-shaped hyaline cartilage "rings" and perichondrium. | The "rings" are linked by connective tissue.

Question 29

Describe the tracheal muscle:

Answer 29

Smooth muscle which joins dorsally each ring. Muscle is attached to the connective tissue of perichondrium either externally (in carnivores) or internally (in other mammals).

Question 30

What is the tunica adventitia of the trachea formed of?

Answer 30

Of dense connective tissue.

Question 31

To what portions can the lungs be divided to?

Answer 31

Conducting portion: bronchi and bronchioles | Respiratory portion: alveolar ducts and sacs and alveoli.

Question 32

What is found next to each airway?

Answer 32

A corresponding vessel.

Question 33

What are the types of bronchi from biggest to smallest?

Answer 33

Primary bronchi, secondary bronchi, and tertiary/segmentary bronchi.

Question 34

What does happen to the cartilage, submucosa and muscle when the bronchial tree divides?

Answer 34

Cartilage and submucosal glands decrease progressively while smooth muscle increases progressively.

Question 35

What is the general histological structure of bronchi?

Answer 35

Mucosa: - Ciliated respiratory epithelia (because mucus needs to be moved) - lamina propria with elastic fibres Submucosa: -submucosal glands (amount decreases the more the airways divide, as no mucous is wanted down in the lungs). Smooth muscle: -concentric Hyaline cartilage: -composed of random cartilaginous plates around the airway Tunica adventitia: -loose connective tissue with elastic fibres.

Question 36

How can you distinguish a blood vessel from an airway?

Answer 36

Look if there are blood cells inside or random plates of hyaline cartilage around.

Question 37

How can you distinguish a bronchiole from bronchi?

Answer 37

In bronchioles, the epithelia are cuboidal to columnar, there are no goblet cells nor submucosal glands and the lamina propria and submucosa are scarce. There is no cartilage around but instead, muscle is abundant.

Question 38

Name the histological structures characteristical to alveolar ducts:

Answer 38

Cuboidal epithelium and smooth muscle in the alveolar openings.

Question 39

What are alveolar sacs and how are they divided?

Answer 39

Groups of alveoli divided with the intra-alveolar septa. The septa are composed of connective tissue and capillaries around the alveoli.

Question 40

What are alveoli?

Answer 40

Air space limited by alveolar epithelium, supportive tissue and capillaries which form a plexum around the alveoli. Alveoli are composed of pneumocytes type I (thin and responsible for gaseous exchange) and type II (cuboidal, secrete surfactant="lubricant").