Exam 3: BIOS255 BIOS 255 Latest

Exam 3: BIOS255 / BIOS 255 (Latest

Update 2025 / 2026) Anatomy and Physiology III with Lab | Questions & Answers | 100% Correct | Grade A - Chamberlain

Question:

how do O2 and CO2 move across the alveolar membrane?

Answer:

simple diffusion

Question:

what variables affect alveolar gas exchange?

Answer:

pressure gradient, membrane area, membrane thickness, solubility of gases

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Question:

how much oxygen is delivered to the tissues?

Answer:

22%

Question:

hemoglobin affinity

Answer:

drop in pH causes hemoglobin to have decreased affinity to O2

increase in o2 delivery or unloading from hemoglobin

Question:

what factors affect hemoglobin affinity?

Answer:

ambient PO2, temperature, ambient pH, diphosphoglycerate (BPG)

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Question:

ventral respiratory group (VRG)

Answer:

• primary generator or respiratory rhythm responsible for

-inspiratory and expiratory processes

Question:

where does the VRG relay signals?

Answer:

to the diaphragm by phrenic nerves & to the external intercostal muscles by intercostal nerves -located in medulla

Question:

dorsal respiratory group (DRG)

Answer:

• primarily responsible for the initiation of inspiration
• modifies respiratory rhythm depending on signals from chemoreceptors in

medulla & arteries stretch in receptors in airway & higher brainstem functions -located in medulla

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Question:

pontine respiratory group (PRG)

Answer:

• interacts w/ both VRG & DRG
• reg. & control breathing

-located in pons region of brainstem

Question:

central chemoreceptors

Answer:

brainstem neurons that respond to changes in pH

Question:

peripheral chemoreceptors

Answer:

carotid & aortic bodies

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