Q: If a person has a tidal volume ($$TV) of 500 mL$$, a respiratory rate ($$RR) of 16 $$breaths per minute, and an anatomic dead space ($$V_0) of 150 mL$$, what is their alveolar ventilation ($$V_A) $$per minute?

Alveolar ventilation is calculated as $$V_A = RR \times (TV - V_0$). $$Thus, $$V_A = 16 \times (500 - 150) = 16 \times 350 = 5600 mL/$$min.

Question 1

Which of the following best describes the function of surfactant produced by type II pneumocytes in the alveoli?

Accepted Answer

Surfactant reduces surface tension, preventing alveolar collapse during exhalation.

Question 2

A patient with cystic fibrosis experiences frequent respiratory infections. Which aspect of respiratory defense is most directly impaired in this condition?

Accepted Answer

The mucociliary escalator mechanism due to thick, sticky mucus.

Question 3

During forceful exhalation, which muscles are primarily responsible for depressing the ribs and compressing the abdomen?

Accepted Answer

Internal intercostal muscles and abdominal muscles.

Question 4

If a person has a tidal volume ($$TV) of 500 mL$$, a respiratory rate ($$RR) of 16 $$breaths per minute, and an anatomic dead space ($$V_0) of 150 mL$$, what is their alveolar ventilation ($$V_A) $$per minute?

Accepted Answer

Alveolar ventilation is calculated as $$V_A = RR 	imes (TV - V_0$). $$Thus, $$V_A = 16 	imes (500 - 150) = 16 	imes 350 = 5600 mL/$$min.

Question 5

Which factor would most effectively increase the efficiency of gas exchange in the lungs?

Accepted Answer

Increasing the total surface area of alveoli.

Question 6

A patient is exposed to carbon monoxide (CO). What is the primary danger of CO exposure regarding oxygen transport?

Accepted Answer

CO binds to hemoglobin with greater affinity than oxygen, preventing oxygen transport.

Question 7

Which equation correctly represents the conversion of carbon dioxide to bicarbonate ions in red blood cells?

Accepted Answer

$$CO_2 + H_2O$$ \xrightarrow{carbonic\ anhydrase} H_2CO_3 \rightarrow H^+ + $$HCO_3$$^-$$

Question 8

During exercise, the pH of active muscle tissue decreases. How does this affect the oxygen-hemoglobin saturation curve?

Accepted Answer

The curve shifts to the right, and hemoglobin releases oxygen more readily.

Question 9

Which respiratory center is primarily responsible for establishing the basic rhythm and depth of breathing?

Accepted Answer

Dorsal respiratory group (DRG) in the medulla oblongata.

Question 10

A person is hyperventilating, leading to hypocapnia. What is the expected response of the chemoreceptors and respiratory rate?

Accepted Answer

Chemoreceptor activity decreases, causing respiratory rate to fall.

Question 11

Which of the following is NOT a function of the digestive system?

Accepted Answer

Gas exchange between air and blood.

Question 12

Which salivary gland produces a serous secretion rich in salivary amylase and is located inferior to the zygomatic arch?

Accepted Answer

Parotid gland.

Question 13

During the pharyngeal phase of swallowing, which event prevents food from entering the respiratory tract?

Accepted Answer

The epiglottis closes the glottis.

Question 14

Which hormone is released when lipids and carbohydrates enter the small intestine and promotes insulin release while inhibiting gastric activity?

Accepted Answer

Gastric inhibitory peptide (GIP).

Question 15

Which hormone stimulates the contraction of the gallbladder and relaxation of the hepatopancreatic sphincter, facilitating the release of bile and pancreatic juice into the duodenum?

Accepted Answer

Cholecystokinin (CCK).

Question 16

Which reflex is triggered by stretch receptors in the rectum and results in relaxation of the internal anal sphincter and peristaltic contractions in the sigmoid colon?

Accepted Answer

Intrinsic myenteric defecation reflex.

Question 17

What is the primary purpose of bile salts in the digestive process?

Accepted Answer

Bile salts break lipid droplets apart, increasing surface area for pancreatic lipase.

Question 18

Which metabolic function of the liver is responsible for converting ammonia, a byproduct of amino acid deamination, into a less toxic compound?

Accepted Answer

Urea synthesis.

Question 19

A patient has a tidal volume ($$TV) of 450 mL$$, a respiratory rate ($$RR) of 14 $$breaths per minute, and an anatomic dead space ($$V_0) of 150 mL. $$What is their respiratory minute volume and alveolar ventilation per minute?

Accepted Answer

Respiratory minute volume: $$14 	imes 450 = 6300 mL/$$min; Alveolar ventilation: $$14 	imes (450 - 150) = 14 	imes 300 = 4200 mL/$$min.

Question 20

Which of the following best describes the effect of increased temperature on the oxygen-hemoglobin saturation curve?

Accepted Answer

The curve shifts to the right, and hemoglobin releases oxygen more readily.

Study Notes: The Respiratory and Digestive Systems

Study Guide - Practice Questions

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