The Respiratory System

Biology 12

THE RESPIRATORY SYSTEM ASSIGNMENT

1. Label the diagram of the respiratory system with the following structures:

a.        Larynx                        b.        Pharynx

c.        Trachea                d.        Bronchus

e.        Bronchioles                f.        Alveoli

g.        Diaphragm                h.        Pleural membranes

i.        Lungs                        j.        Thoracic Cavity

1. Ribs

[pic 1]

Give the function and special structural characteristics of each part.

1. List 4 ways alveoli structure lends itself to their function?

grape cluster- increase surface area for maximum diffusion

thin walls- maximum diffusion rate

moist walls- facilitates diffusion

stretch receptors- prevents overfilling

pulmonary surfactant- reduces surface tension

dense with capillaries- allows for maximum gas exchange

1. Where would you find cilia and/or mucus in the respiratory tract?  What is each of their functions?

nasal cavity, trachea, bronchi, bronchioles

mucus traps debris, dust, bacteria, etc

cilia sweeps the mucus and debris out of the respiratory tract

1. Explain what occurs during INSPIRATION and EXPIRATION to the rib cage, the diaphragm and the pressure in the lungs.  Use terms such as partial vacuum and negative pressure.

intercostal muscles and diaphragm contract, increases the volume of the thoracic cavity, lowers the pressure creating “-“ pressure (partial vacuum).  Air from outside rushes in to equalize the low pressure as a result

1. Explain how the respiratory center of the medulla oblongata is involved in inspiration and expiration (identify the afferent – to the brain, and efferent – away from the brain, nerves).

carotid and aortic bodies detect CO2, pH, and O2 and send their message to the medulla via the glossopharyngeal and aortic nerves, respectively.  The medulla also detects CO2 and pH as well.  The medulla sends messages to the intercostals and diaphragm through the thoracic and phrenic nerves, respectively.  Afferent nerves go towards medulla and efferent go towards the lungs

1. What is the role CO2 and H+ ions play in breathing?  Explain where their concentrations are detected and the effect rising concentrations have on breathing.

aortic and carotid bodies…the central chemoreceptor is the medulla

The medulla detects CO2 because it is a product of cellular respiration.  It detects H+ because the majority of CO2 transport (85%) is as bicarbonate.  H+ is a byproduct of bicarbonate production

1. What is the role the pleural membranes play in breathing?

They cover the inside of the ribs and the outside of the lungs.  Pleural fluid between the layers reduces friction when the lungs rub past the ribs during breathing

1. Define the following:

reduced hemoglobin; carbaminohemoglobin; oxyhemoglobin; bicarbonate ion; carbonic anhydrase

Reduced hemoglobin- H+ ion joins to Hb and kicks off oxygen

Carbaminohemoglobin- CO2 joined to Hb

Oxyhemoglobin- O2 molecules joined to Hb

Bicarbonate- major form that CO2 travels as

Carbonate anhydrase- an enzyme that catalyzes the reaction of CO2 and water into carbonic acid and the opposite

1. Discuss the events of external respiration.  Include 4 pertinent equations in your discussion.

Hb + O2 → HbO2

HBCO2→ Hb + CO2

HHb→ Hb + H+

HCO3- + H+ → H2CO3 → CO2 + H2O

last step uses carbonic anhydrase

1. What 4 equations pertain to the exchange of gases during internal respiration?

HbO2→ Hb + O2  

Hb + CO2→ HBCO2

Hb + H+→ HHb

CO2 + H2O→ H2CO3→ HCO3- + H+

        First step uses carbonic anhydrase