Lecture 20: Respiratory System Overview

Question 1

What are the functions of the respiratory system?

Answer 1

1. Provide the body with oxygen.
2. Take away carbon dioxide from the body.
3. Sense of smell
4. Vocalization

Question 2

What happens when the breathing rate does not sufficiently eliminate CO2?

Answer 2

The body becomes more acidic which can cause protein denaturation.

Question 3

What is pulmonary ventilation?

Answer 3

Breathing: Air is moved into the lungs during inspiration and out of the lugs during expiration.

Question 4

What is external respiration?

Answer 4

It is where gas exchange occurs when oxygen diffuses into the blood and CO2 diffuses out of the blood.

Question 5

What is transport of respiratory gases?

Answer 5

Oxygen is transported to the left side of the heart and through the systemic circuit. Whereas, CO2 is transported from the tissues to the right side of the heart.

Question 6

What is internal respiration?

Answer 6

Gas exchange occurring in capillary beds within body tissues.

Question 7

Which type of cells are trachea and bronchi made up from?

Answer 7

They are made up from pseudostratified ciliated columnar epithelium. This helps to trap dust and bacteria from entering the lungs.

Question 8

What are the structures to the external nose and nasal cavity?

Answer 8

External nose: Consists of bone, cartilage and mucous membranes.
Nasal cavity: Posterior to the external nose. Divided into 2 nostrils by the nasal septum. Conchae are folds in the lateral walls of the nasal cavity which connect posteriorly to pharynx.

Question 9

What are some functions of the nasal cavity?

Answer 9

1. Passageway for air to flow through.
2. Warms, moistens and filters air.
3. Houses olfactory receptors.
4. Resonating chamber for voice.

Question 10

What are the three distinct regions of pharynx?

Answer 10

1. Nasopharynx
2. Oropharynx
3. Laryngopharynx

Question 11

What are some important structures of pharynx?
(Hint: Tonsils and tubes)

Answer 11

1. From superior to inferior: Pharyngeal, palatine and lingual tonsils. (Macrophages and lymphocytes reside in the tonsils)
2. Eustachian tubes (Open in nasopharynx and helps with maintaining middle ear pressure with atmospheric pressure).

Question 12

What are the functions of the larynx?

Answer 12

1. Air passageway
2. Epiglottis acts as a switching mechanism to route air and food into proper channels.
3. Voice production

Question 13

What is trachea supported by?

Answer 13

Trachea is supported by the cartilage rings which prevent the trachea from collapsing with changes in air pressure during breathing.

Question 14

What is the relation to smooth muscle and cartilage as you travel deeper through the tree?

Answer 14

Smooth muscle increases and cartilage decreases as you travel down the tree.

Question 15

What causes asthma attack?

Answer 15

Smooth muscles in the bronchioles constrict and further decrease air flow to the airways by inflammation and excess mucus secretion.

Question 16

Which cells are alveoli walls composed of?

Answer 16

Composed of a single layer of squamous epithelium with a thin basement membrane.

Question 17

What are the three types of alveolar cells?

Answer 17

1. Type I alveolar (squamous pulmonary epithelial) cells.
2. Type II alveolar (septal) cells
3. Alveolar macrophages (dust cells)

Question 18

What are type II alveolar (septal) cells?

Answer 18

Secrete surfactant which lowers surface tension of alveolar fluid and prevents the collapse of alveoli with each expiration.
Also secrete antimicrobial proteins.

Question 19

What is respiratory distress syndrome?

Answer 19

It is a disorder of premature infants in which the alveoli do not have sufficient surfactant to remain open.

Question 20

What is the function of alveolar macrophages?

Answer 20

Creep over the alveolar membrane and phagocytize ay microbes encountered as well as dust or cellular debris.

Question 21

What are the four layers of membrane to cross during external respiration?

Answer 21

1. Alveolar epithelium
2. Alveolar basement membrane
3. Capillary basement membrane
4. Capillary endothelium

Question 22

What are the parietal and visceral pleura and serous fluid?

Answer 22

Parietal Pleura: Adheres to the wall of thoracic cavity.
Visceral Pleura: Adheres to the surface of each lung.
Serous fluid: Secreted into the pleural cavity.

Question 23

What is the difference between left and right lung?

Answer 23

Left lung is smaller, separated into two lobes and has the cardiac notch giving space for the heart.
Right lung has three lobes.
Apex: Superior aspect of each lung.
Base: Inferior aspect of each lung which rests on the diaphragm.

Question 24

What are bronchopulmonary segments?

Answer 24

Each segment is served by its own artery and vein and receives air from an individual segmental (tertiary) bronchus.