Chapter 22 Check Your Understanding

Where is angiotensin converting enzyme found and why is this a good location for this enzyme? name the BP-INCREASING HORMONE cascade to which this enzyme belongs.

Angiotensin converting enzyme is found in the palsma membrane of lung capillary endothelial cells. This is a good location for it bc all of the blood in the body passes through the lung capillaries about once every minute. Angiotensin converting enzyme is part of the renin-angiotensin aldosterone hormone cascade, which increases blood pressure.

An injured soccer player arrives by ambulance in the ER. She is in obviou distress, breathing rapidly. Her blood Pco2, is 26 mmHg and pH is 7.5. Is she suffering from hyperventilation or hyperpnea? Explain.

Her pco2 is low, normal pco2 is 40mmHg. The low pco2 reveals that this is hyperventilation and not hyperpnea which is not accompanied by changes in blood Co2 levels.

What is the difference between respiratory volumes and respiratory capacities?

Respiratory capacities are combinations of 2 or more respiratory volumes

Name the two types of mucous membrane found in the nasal cavity

Respiratory mucosa nd olfactory mucosa

A 3yr old boy is brought to the ED after aspirating a peanut. Bronchoscopy confirms the suspicion that the peanut is lodges in a bronchus and then it is successfully extracted. Which main bronchus was the peanut most likely to be in. Why?

Right right because it is straighter and wider than the left.

Suppose a patient is receiving o2 by mask. Are the arterioles leading into the O2-enriched alveoli dilated or constricted? What is the advantage of this response?

The arterioles leading into the O2 enriched alveoli would be dilated. This response allows matching of blood flow to availability of oxygen.

What causes the partial vacuum (negative pressure) inside the pleural cavity? What happens to a lung if air enters the pleural cavity? what is the clinical name for this condition?

The partial vacuum (negative pressure) inside the pleural cavity is caused by the opposing force acting on the visceral and parietal pleurae. The visceral pleurae are pulled inward by the lungs' natural tendency to recoil and the surface tension of the alveolar fluid. The parietal pleurae are pulled outward by the elasticity of the chest wall. if air enters the pleural cavity, the lung on that side will collapse. This condition is called pneumothorax.

What is the relationship between Co2 and ph in the blood? explain.

as blood co2 increases , blood pH decreases. this is bc co2 combines with water to form carbonic acid. However, the change in pH in blood for given increase in CO2 is minimized by other buffer systems

Explain why slow, deep breaths ventilate the alveoli more effectively than do rapid, shallow breaths

it is more effective because a smaller fraction of the tidal volume of each breath is spent moving air into and out of the dead space.

Air moving from nose to the larynx passes by a number of structures. List (in order) as many of these structures as you can.

nasal cavities (nares, nasal vestibule, nasal conchae); nasopharynx, oropharynx, and laryngopharynx

The lungs are perfused by two different circulations. Name these circulations and indicate their roles in the lungs.

pulmonary circulation which delivers deoxygenated blood to the lungs for oxygenation and returns oxygenated blood to the heart; and the bronchial circulation; which provides systemic (oxygenated) blood to lung tissue

What is the driving force for pulmonary ventilation?

the driving force for pulmonary ventilation is a pressure gradient created by changes in the thoracic volume.

What distinguishes the obstruction in asthma from that in chronic bronchitis?

the obstruction in asthma is reversible, and acute exacerbations are typically followed by symptom-free periods. Obstruction in chornic bronchitis is generally not reversible.

The dotted lines in the 2 graphs below represent a shift in the ozygen-hemoglobin dissociation curve. Which shift would allow more oxygen delivery to the tissues?

the shift shown in graph b would allow more oxygen delivery to tissues. Conditions that would cause the curve to shift this way are increased temp, increased PCo2, decreased PH , or an increase in BPG levels

Which brain stem respiratory area is thought to generate the respiratory rhythm?

the ventral rsepiratory group of the medulla VRG is thought to be the rhythm generating area

Which chemical factor in blood normally provides the most powerful stimulus to breathe? Which chemoreceptors are most important for this response?

co2 in blood normally provides the most powerful stimulus to breathe. Central chemoreceptors are most important in this response.

List the 3 ways CO2 is transported in the blood?

70% of co2 is transported as bicarbonate ion in plasma. Over 20% is transported boun to hemoglobin in the rbcs, and 7-10% is dissolved in plasma

Premature infants often lack adequate surfactant. How does this affect their ability to breathe.

A lack of surfactant increases surface tension in the alveoli and causes them to collapse between breaths.

Which structure seals the larynx when we swallow?

Epiglottis

Suppose you are given a sealed container of water and air. The PCo2, and Po2, in the water? Which gas has more molecules dissolved in the water? Why?

In a sealed container, the air and water would be at equilibrium. Therefore, the partial pressures of co2 and o2 (Pco2 and po2) will be the same in the water as in the air: 100 mm Hg each. more Co2 than o2 molucules will be dissolved in the water, bc Co1 is more soluble than o2 in water.

What long term adjustments does the body make when living at high altitude?

Long term adjustments to altitude include an increase in erythropoiesis, resulting in a higher hematocrit; an increase in BPG, which decreases Hb affinity for oxygen; and an increase in minute respiratory volume.

Create a summary table of the pharynx and the 3 parts.

Nasopharynx conducts air, has pseudostrastified ciliated columnar epithelium; oropharynx conducts air and food has stratifiedsquamous; and laryngopharynx conducts air and food and has stratified squamous

Po2 in the alveoli is about 56mmHg lower than in the inspired air. Explain the difference

The difference in Po2 between inspired air and alveolar air can be explained by 1. the gas exchange occuring in the lungs (02 continuously diffuses out of the alveoli into the blood); 2. the humidifcation of inspired air (which adds water moleucles that dilute the o2 molecules) and 3. the mixing of newly inspired air with gases already present in the alveoli

Which structural features of the trachea allow it to expand and contract, yet keep it from collapsing?

The incomplete, C shaped cartilage rings of the trachea allow it to expand and contract and yet keep it from collapsing.

What features of the alveoli and their respiratory membranes suit them to their function of exchanging gases by diffusion?

They have a large surface area when they are bunched together. Along with the thinness of their respiratory membranes make it best for gas exchange.

Your patient has COPD. As a result, his pulmonary alveoli are poorly ventilated. Would you expect his pulmonary alveoli are poorly ventilated. Would you expect his pulmonary arterial BP TO BE HIGHER OR LOWER THAN normal? Explain. Over the long term, this change in BP may cause him to develop hear failure. which side of the heart will fail? Edema is one sign of heart failure. Where would youexpect to see edema in the pt?

because his alveoli are poorly ventilated, the local Po2 around those alveoli would be low. This low Po2 would cause the pulmonary arterioles to constrict due to ventilation-perfusion coupling, increasing resistance and thereby increasing pulmonary blood pressure. In the long term, pulmonary hypertension can cause right heart failure. Right heart failure would result in peripheral edema, noticeable in the extremities such as feet and ankles.