Answers, BIO 2320, Respiratory

Objectives – 3, BIO 2320, Respiratory SystemAnswers


1.Nasal cavity (passageway & warm, moisturize & filter air) Pharynx, Larynx (passageway & voice), Trachea, Bronchi, Bronchioles & Alveoli in Lungs (exchange in alveoli)

2.Palatine process of maxilla & palatine (=hard palate); Nasal & frontal & ethmoid & sphenoid; Maxillae and Nasal Conchae

3.Vomer & perpendicular plate of ethmoid

4.Hollowed cavity in skull bone that communicates with nasal cavity. Frontal, Maxilla, Ethmoid & Sphenoid bones have a sinus. Sinuses serve to make mucus, lighten the skull and resonate sound

5.Superior, Middle (medial) & Inferior Conchae with Superior, Middle, Inferior Meatuses

6.Nasopharynx is internal nares to soft palate; Oropharynx is soft palate to hyoid; Laryngopharynx is hyoid to larynx.

7.Nasopharynx houses the pharyngeal tonsil = adenoid; while the Oropharynx houses the lingual & palatine tonsils

8.Lymphatic function, trapping microorganisms, making lymphocytes, fighting infection

9.Uvula is also lymphatic tissue hanging from soft palate. Adenoids are the pharyngeal tonsils

10.Eustachian = Auditory tubes are found between nasopharynx and middle ear.

11.2 arytenoids, 2 cuneiforms, 2 corniculates, epiglottis, cricoid, thyroid

12.Prevents choking – closes glottis when swallowing

13.As you exhale, the air vibrates the vocal cords. You have muscles to make the vocal cords tighter (higher tones) or looser (lower tones) and you have resonating chambers in nasal cavity & sinuses as well as tongue and lips for enunciation

14.Incomplete cartilaginous rings

15.Inferior end of trachea

16.As you descend the bronchial tree, the amount of cartilage decreases and amount of smooth muscle increases.

17.Three-right; two-left

18.Membranous tissue surrounding all thoracic organs except lungs.

19.Visceral pleura is shiny covering of lungs, parietal pleura is shiny lining of thoracic cavity & pleural cavity is between the two.

20.Microscopic air sacs in lungs that are where diffusion (exchanges of gases) occurs with blood vessels.

21.One cell layer for each – very thin

22.Alveoli, diffusion

23.Ventilation & gas exchange

24.Given a closed container, the pressure inside is inversely proportional to the size of the container.

25.Ventilation is moving air in and out of airways. Inspiration = inhalation is moving air in and expiration = exhalation is moving air out.

26.Atmospheric pressure is the pressure formed by all of the contributing gases in the air and is 760 mm Hg at sea level. Intrapulmonary pressure is the pressure inside of the lungs & it varies according to Boyle’s law. Intrapleural pressure is a negative (sucking) pressure in the pleural cavity keeping the lungs from collapsing.

27.The diaphragm moves inferiorly, and the ribcage (intercostal muscles) moves up and out. This increases the size of the chest which increases the size of the elastic lungs. This drops the intrapulmonary pressure lower than atmospheric pressure. Air naturally moves along the pressure gradient and into the lungs.

28.Expiration is passive, in that the breathing muscles relax which returns the diaphragm to a more dome shape and the ribcage moves down and in. This decreases the size of the chest which decreases the size of the elastic lungs. This increases intrapulmonary pressure to a level higher than atmospheric pressure. Air naturally moves out along its pressure gradient. Forced expiration is big expiration as in with exercise or a cough. Here, abdominal muscles contract & push viscera upward causing the diaphragm to move even more superiorly.

29.F = P/R; Parasympathetic stimulation decreases size of airways and Sympathetic stimulation increases size of airways.

30.Surface tension arises when like molecules are attracted to each other. If the moisture in the alveoli is attracted to each other the alveolus would collapse.

31.Alveolar cells make a phospholipid called surfactant that decreases surface tension in the alveoli, therefore preventing collapse. During prenatal development, the surfactant is one of the last substances made and therefore is not present in premature babies, making the lungs collapse and breathing extremely difficult.

32.TV is the amount of air in or out in a quiet breathing cycle (500 mls); Respiratory rate is the # of breaths/minute (12 breaths/min); Minute resp vol = TV x RR; IRV is the extra air you could inhale after completing your quiet 500 mls of inhalation. IC = IRV + TV; ERV is the extra air you could possible exhale after your quiet 500 mls of exhalation; RV is the amount of air that you cannot exhale no matter how hard you try (about 1000-1200 mls) & it helps prevent lung collapse; FRC = ERV + RV; VC = TV + ERV + IRV; TLC = VC + RV

33.Dead air volume is the functionally non useable air because it is somewhere besides your alveoli. With a 500 ml breath, only about 350 mls makes it to your alveoli, leaving 150 mls in your nose, trachea….

34.TV-Dead air volume is the amount of air reaching the alveoli. Multiply this by RR if you want a rate. The most efficient means of increasing it is by taking deeper breaths – i.e. increasing tidal volume

35.Just know that they are closely matched. If a section of lung is damaged & has no airflow, then the blood vessels constrict to reroute that blood to functioning areas of the lung

36.Each gas’ contribution to the entire atmospheric pressure. It can be calculated by multiplying the % that gas contributes to the atmosphere by the atmospheric pressure

37.Diffusion! If in the alveolus you have PO2 of 105 mmHg and in the blood you have PO2 of 40, the O2 moves into the blood. If a starving brain cell has a PO2 of 40 and the surrounding blood capillaries have a PO2 of 105, the O2 moves into the brain cell. Same theory for CO2 exchange.


39. PO2 is the main determining factor for whether hemoglobin & oxygen are attached or dissociated. As PO2 increases, more hemoglobin and oxygen are attached, as PO2 decreases (like in the area of an exercising muscle that is starving for O2) then hemoglobin & oxygen dissociate so that the oxygen is available to diffuse into tissues that need it. Acid pH, High PCO2 and High DPG shift the oxygen-hemoglobin dissociation curve to the right. What this means, is that the oxygen and hemoglobin are MORE likely to dissociate in tissues that have these conditions which indicate high metabolism.

40.Some as CO2 in plasma, some attached to hemoglobin, but MOST in the form of bicarbonate ions (HCO3-)

41.CO2 + H2O <—> H2CO3 <—-> H+ and HCO3-

42.Bicarbonate is negatively charged and so are chloride ions. As a negative bicarb moves into a RBC, a negative Cl would move out, keeping the charges balanced.

43.Medullary Rhythmicity (inspiratory)Area in the Medulla is the main control of breathing. It causes inspiration. The only time the expiratory center needs to be active is when you forcefully exhale, because remember, exhalation is normally passive. In the pons are 2 areas. The apneustic area prolongs inspiration and the pneumotaxic area limits inspiration.

44.BIG drops in PO2 increase ventilation

45.PCO2 is the main control of alveolar ventilation because tiny increases in PCO2 increase ventilation

46.Not that sensitive to pH values, but a lower pH increases ventilation

47.Increase RR, TV, dilated airways, Hemoglobin/Dissociation curve shifts to the right due to increased PCO2, decreased pH and increased metabolic byproducts such as DPG, and cardiovascular changes to carry the gases