Intro to the Respiratory System

Question 1

What is the primary function of the respiratory system?

Answer 1

Delivery of O2 to lungs for gas exchange, and removal of CO2 produced by tissues out of the lungs.

Question 2

What is external respiration?

Answer 2

Exchange of gases between atmospheric air and blood.

Question 3

List additional important functions of the respiratory system.

Answer 3

• Acid-base balance
• Immunity
• Thermoregulation
• Site of metabolism/activation
• Vocalisation/communication

Question 4

What structures comprise the upper respiratory tract?

Answer 4

• Nasal cavity
• Pharynx
• Larynx

Question 5

What structures comprise the lower respiratory tract?

Answer 5

• Trachea
• Bronchi
• Bronchioles
• Alveolar ducts
• Alveoli

Question 6

How is air delivered to the upper respiratory tract?

Answer 6

Air enters via nose (sometimes mouth).

Question 7

What divides the left and right nasal cavities?

Answer 7

Nasal septum.

Question 8

What are conchae?

Answer 8

Mucosa lined bone scrolls in the nasal cavity.

Question 9

What are meatuses?

Answer 9

Openings/canals in the nasal cavity.

Question 10

What type of epithelium mostly lines the nasal cavity?

Answer 10

Respiratory epithelium.

Question 11

What is the function of the epiglottis?

Answer 11

Protects airway during swallowing.

Question 12

What are paranasal sinuses?

Answer 12

Diverticula of the nasal cavity within the skull.

Question 13

List the functions of the paranasal sinuses.

Answer 13

• Thermal protection
• Mechanical protection
• Lighten head

Question 14

What is the pharynx?

Answer 14

The common cavity through which air and ingesta pass.

Question 15

What does the pharynx connect?

Answer 15

Oral cavity to oesophagus and nasal cavity to larynx.

Question 16

What are the anatomical borders of the pharynx?

Answer 16

• Dorsally - base of skull and C1-C2
• Ventrally - larynx and mandible
• Laterally - pterygoid muscles and suspensory part of hyoid apparatus
• Rostrally - soft palate separates rostral pharynx into dorsal and ventral (nasopharynx and oropharynx)

Question 17

What is the larynx?

Answer 17

Musculocartilaginous organ that connects pharynx to trachea.

Question 18

What are the functions of the larynx?

Answer 18

• Protect trachea from aspiration
• Vocalisation
• Pressure build-up (glottis closure)

Question 19

What type of epithelium lines the larynx?

Answer 19

Stratified squamous epithelium near pharynx, respiratory epithelium elsewhere.

Question 20

What is the innervation of the larynx?

Answer 20

Innervated by branches of vagus nerve (cranial laryngeal n., caudal (recurrent) laryngeal n.).

Question 21

What does the recurrent laryngeal nerve supply?

Answer 21

All intrinsic muscles except cricothyroideus.

Question 22

What is the structure of the trachea?

Answer 22

Extends from larynx to bifurcation at base of heart, C-shaped hyaline cartilages connected by fibroelastic tissue.

Question 23

What type of epithelium lines the trachea?

Answer 23

Respiratory epithelium (ciliated, pseudostratified columnar epithelium).

Question 24

What is the difference between bronchi and bronchioles?

Answer 24

Bronchi are lined by ciliated, pseudostratified columnar epithelium and supported by cartilage; bronchioles are smaller, lack cartilage, and are lined by variably ciliated or non-ciliated columnar epithelium.

Question 25

What are conducting airways?

Answer 25

All airways up until bronchioles, where there is no gas exchange.

Question 26

What are respiratory airways?

Answer 26

Respiratory bronchioles to alveoli, where gas exchange occurs.

Question 27

What is an acinus?

Answer 27

The functional unit consisting of terminal bronchiole and its distal structures.

Question 28

What type of epithelium is found in respiratory bronchioles?

Answer 28

Cuboidal epithelium (club cells) ## Footnote Club cells produce secretions and are a source of new cells.

Question 29

What is the function of the flattened squamous epithelium (type 1 pneumocytes) in the alveoli?

Answer 29

Gas exchange

Question 30

What are the main functions of type II pneumocytes in the alveoli?

Answer 30

Secrete fluid (surfactant) to prevent alveolar collapse (atelectasis) ## Footnote Surfactant reduces surface tension in the alveoli.

Question 31

What are the gaps in the septum of alveoli called?

Answer 31

Pores of Kohn ## Footnote These connect alveoli for efficient movement of air.

Question 32

List the components of the blood-gas interface.

Answer 32

* Surfactant * Alveolar epithelial cell (pneumocyte) * Epithelial basement membrane * Connective tissue * Capillary basement membrane * Capillary endothelial cell * Blood plasma * Red blood cell

Question 33

What two main components make up the lungs?

Answer 33

* Parenchyma (functional tissue) * Interstitium (soft tissue, nerves, glands, blood and lymph vessels)

Question 34

What is the role of the pleura in the lungs?

Answer 34

Encloses potential space and small amount of fluid ## Footnote The pleura consists of parietal and visceral layers.

Question 35

How many lobes does the left lung have?

Answer 35

2 lobes: Cranial and Caudal ## Footnote The left lung is smaller to accommodate the heart.

Question 36

What are the lobes of the right lung?

Answer 36

* Cranial * Middle * Caudal * Accessory

Question 37

What does the visceral pleura cover?

Answer 37

Surface of the lung including fissures ## Footnote Contains abundant elastic fibers.

Question 38

What are the three parts of the parietal pleura?

Answer 38

* Costal pleura * Diaphragmatic pleura * Mediastinal pleura

Question 39

What is the diaphragm?

Answer 39

Musculotendinous sheet separating thoracic and abdominal cavity ## Footnote It has openings for structures like the esophagus and aorta.

Question 40

What is the function of the diaphragm in respiration?

Answer 40

Drives volume change of thorax and therefore negative pressure for breathing.

Question 41

What is contained within the mediastinum?

Answer 41

* Heart in pericardiac sac * Trachea * Esophagus * Thymus * Mediastinal lymph nodes * Great vessels * Nerves including vagosympathetic trunk

Question 42

True or False: The mediastinum contains the lungs.

Answer 42

False ## Footnote The mediastinum does not contain the lungs, caudal vena cava, or right phrenic nerve.

Question 43

What is the pathway of non-oxygenated blood in pulmonary circulation?

Answer 43

RV -> lungs -> LA

Question 44

What type of blood exchange occurs in pulmonary circulation?

Answer 44

Gas exchange

Question 45

Describe the pressure and volume characteristics of pulmonary circulation.

Answer 45

Large volume, low pressure

Question 46

How do pulmonary arteries and veins differ in relation to bronchi?

Answer 46

Pulmonary arteries follow bronchi, veins do not always

Question 47

What is the source of blood for bronchiole circulation?

Answer 47

From aorta

Question 48

What is the pressure and volume characteristic of bronchiole circulation?

Answer 48

Low volume, high pressure

Question 49

What is the pathway of oxygenated blood in bronchiole circulation?

Answer 49

LV -> lungs -> RA (via azygous v.)

Question 50

What do anastomoses between bronchial and pulmonary circulations help preserve?

Answer 50

Lung tissue

Question 51

What physiological response occurs in hypoxic vasoconstriction?

Answer 51

Reflex vascular smooth muscle contraction

Question 52

What happens to areas that receive little alveolar oxygen in terms of blood flow?

Answer 52

Reduced flow from the pulmonary artery

Question 53

How does hypoxic vasoconstriction affect ventilation and perfusion?

Answer 53

Maximizes oxygen exchange

Question 54

What is angiogenesis in the context of bronchopulmonary circulation?

Answer 54

New bronchopulmonary arterial anastomoses

Question 55

Fill in the blank: The common capillary network helps preserve lung tissue if the pulmonary supply becomes _______.

Answer 55

compromised

Question 56

What effect does vasodilation of bronchial arteries have on blood flow?

Answer 56

Increases flow

Question 57

What is the primary function of the common capillary network between bronchial and pulmonary circulations?

Answer 57

By-pass the obstructed pulmonary artery