Respiratory System

Question 1

What is respiration?

Answer 1

Ventilation: the movement of air in and out of the lungs
External respiration: the gas exchange between the lungs and blood.
Transport of respiratory gases.
Internal respiration: the gas exchange between the blood and tissues.

Question 2

What are the functions of the respiratory system?

Answer 2

Regulation of blood pH.
Voice production
Smell
Protection

Question 3

What is the structural classification of the respiratory system?

Answer 3

Upper respiratory tract: nasal cavity, pharynx (throat), larynx.
Lower respiratory tract: trachea, bronchi, lungs.

Question 4

What is the functional classification of the respiratory system?

Answer 4

Conducting zone: passages where air travels from nose to bronchi (cleanses, humidifies and warms air).
Respiratory zone: in the lungs (exchange of gages: includes bronchioles, alveoli, alveolian ducts).

Question 5

What are the structural components of the nasal cavity?

Answer 5

Vestibule: entry to nasal cavity lined with stratified squamous, sweat and sebaceous glands and hair follicles.
Hard palate: floor of cavity, bone.
Septum: separated the nasal cavity into left and right parts.
Concha (bony ridges): superior, middle or inferior concha and meatus (increase surface area and filters through turbulent pathway). Epithelium of concha is pseudostratified ciliated columnar.

Question 6

What is the structure of the nasopharynx?

Answer 6

Posterior to the nasal cavity. Pseudostratified ciliated columnar epithelium. Houses openings of Eustachian tubes. The posterior surface of nasopharynx has the pharyngeal tonsils.

Question 7

What is the structure of the oropharynx?

Answer 7

Posterior to the oral cavity. Stratified squamous epithelium. Palantine and lingual tonsils.

Question 8

What is the structure of the laryngopharynx?

Answer 8

Lies posterior to the epiglottis. Stratified squamous epithelium.

Question 9

What is the structure of the larynx?

Answer 9

Made up of 9 cartilage.
6 paired: arytenoid, corniculate, cuneiform.
3 unpaired: thyroid, cricoid, epiglottis.

Question 10

What is the function of the larynx?

Answer 10

Maintains an open passageway for air movement. Directs food into oesophagus away from the respiratory tract. Sound production. Traps debris - prevents entering the lungs.

Question 11

What is the structure of the trachea?

Answer 11

Descends from the larynx and sits anterior to the oesophagus. 15-20 C-shaped hyaline cartilage rings for support. Dense connective tissue and smooth muscle in between cartilage rings. Tracheal lumen lined with pseudostratified ciliated columnar epithelium with goblet cells.

Question 12

What is the structure of the tracheobronchial tree?

Answer 12

Consists of:

• carina: last piece of cartilage of trachea branches into 2
• primary bronchus
• lobar (secondary) bronchus [3 in right, 2 in left]
• segmental (tertiary) bronchus
• bronchiole
• terminal bronchioles.

Question 13

What changes moving from the trachea to terminal bronchioles?

Answer 13

Increase in smooth muscles.
Decrease in cartilage.
Change in epithelium in lumen from pseudostratified ciliated columnar -> simple ciliated columnar -> simple ciliated cuboidal.

Question 14

What is the order of airflow from the trachea to alveoli?

Answer 14

1. Terminal bronchiole
2. Respiratory bronchioles
3. Alveolar duct
4. Alveolar sac
5. Alveoli.

Question 15

What is the structure of the alveolus side of the respiratory membrane?

Answer 15

Simple squamous epithelium

• Type 1 pneumocyte (allows for gas exchange and simple diffusion).
• Type 2 pneumocytes: cuboidal cell, secretes a surfactant to reduce surface tension.

Question 16

What is the structure of the capillary side of the respiratory membrane?

Answer 16

Basement membrane
Capillary enaothelium (simple squamous).
Red blood cells.

Question 17

What is the structure of the lungs?

Answer 17

Left lung has 2 lobes and a cardiac notch.
Right lung has 3 lobes.
Lobes are separated by fissures.
Hilum on the medial surface - the entry point for blood and nervous supply, lymphatic vessels and bronchi.
Hilum
Bronchopulmonary segments.

Question 18

What are factors that affect gas exchange through the respiratory membrane?

Answer 18

1. The thickness of the respiratory membrane
2. Surface area
3. Diffusion coefficient (how easily a gas can diffuse in and out of a liquid or tissue).
4. Partial pressure (pressure exerted by each gas in a mixture of gases) [gas often moves from the side with a high PP to the lower PP].

Question 19

How is oxygen transported?

Answer 19

98. 5% is transported in the red blood cells.

1. 5% is dissolved in the blood plasma.

Question 20

How is carbon dioxide transported?

Answer 20

HCO^3 is dissolved in plasma (70%).
CO2 is dissolved in plasma (7%).
Bound to haemoglobin (23%).

Question 21

What is the process of inspiration?

Answer 21

Lungs: volume increases as it fills with air.
Diaphragm: moves inferiorly and flattens.
Rib cage: elevated.
Sternum: elevated.
Intercostal muscles: contracts.

Question 22

What is the process of expiration?

Answer 22

Lungs: volume decreases as air leaves.
Diaphragm: moves superiorly as it relaxes.
Rib cage: depresses
Sternum: depresses
Intercostal muscles: relaxes.

Question 23

What is the process of airflow in and out of the alveoli?

Answer 23

Air moves from areas of high pressure to areas of low pressure.
Barometric air pressure (P^B) - atmosphere air pressure outside the body.
Intra-alveolar pressure (P^ALV) - pressure inside the alveoli.