The Respiratory System

Question 1

Nares

Answer 1

external parts of the nose through which air enters the respiratory tract

Question 2

Passageway of air from outside to lungs

Answer 2

Nares/nasal cavity –> pharynx –> larynx –> Trachea –> bronchi –> bronchioles –> alveoli

Question 3

Pleurae

Answer 3

Membranes which surround each lung: forms a closed sac against which the lung expands

Question 4

Visceral pleura vs. parietal pleura

Answer 4

Surface adjacent to the lung is visceral pleura, outer part is parietal pleura.

Question 5

Negative-pressure breathing

Answer 5

Lungs expand into intrapleural space, and pressure in lungs drop.
Air is then sucked in from a higher-pressure environment to the relatively lower pressure inside.

Question 6

External vs. internal intercostal muscles

Answer 6

External intercostal muscles –> expand thoracic cavity, i.e. in inhalation.
Internal intercostal muscles –> Decreases volume of thoracic cavity, i.e. in exhalation

Question 7

Spirometer

Answer 7

An instrument used to measure lung capacities and volumes

Question 8

Total lung capacity (TLC)

Answer 8

Maximum volume of air in the lungs when one inhales completely; usually around 6-7 liters

Question 9

Residual volume (RV)

Answer 9

Volume of air remaining in the lungs when one exhales completely

Question 10

Vital Capacity (VC)

Answer 10

Difference between min and max volume of air in lungs (TLC - RV)

Question 11

Tidal Volume (TV)

Answer 11

Volume of air inhaled or exhaled in a normal breath

Question 12

Expiratory reserve volume (ERV)

Answer 12

Volume of additional air that can be forcibly exhaled after a normal exhalation

Question 13

Inspiratory reserve volume (IRV)

Answer 13

Volume of additional air that can be forcibly inhaled after a normal inhalation.

Question 14

Ventilation center

Answer 14

A collection of neurons in the medulla oblongata that fire rhythmically to cause regular contraction of respiratory muscles. These neurons contain chemoreceptors that are primarily sensitive to CO2 concentration.

Question 15

Direction of gas exchange between alveoli and heart

Answer 15

Capillaries around alveolus bring deoxygenated blood from the pulmonary arteries, which originate from the right ventricle of the heart.
Oxygenated blood returns to left atrium of heart via pulmonary veins.

Question 16

What is the driving force of gas exchange in the lungs

Answer 16

Pressure differential of gases:
Blood arriving at alveoli has relatively low partial pressure of oxygen and relatively high partial pressure of carbon dioxide, facilitating transfer of each down its respective concentration gradient.

Question 17

Lysozyme

Answer 17

An enzyme in the nasal cavity: also found in tears and saliva, and is able to attack the peptidoglycan walls of gram-positive bacteria.

Question 18

Mucociliary escalator

Answer 18

Underlying cilia in the internal airways propel mucus up the respiratory tract to the oral cavity, where it can be expelled or swallowed.

Question 19

Bicarbonate buffer system

Answer 19

Co2 (g) + H2O (l) –> H2CO3 (aq) –> H+ (aq) + HCO3- (aq)