Anatomy and Physiology Answer Key

B spirometry can be used to measure the extent of

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Unformatted text preview: r 6 L 6. (a) During strenuous exercise, PV increases markedly. (b) Increased PV is achieved as a result of an increase in both breathing rate and tidal volume. 7. (a) There is 90X more CO2 in exhaled air than in inhaled air (3.6 ÷ 0.04). Biozone International 2009 Photocopying Prohibited Control of Breathing (page 167) 1. The basic rhythm of breathing is controlled by the respiratory center in the medulla which sends rhythmic impulses to the intercostal muscles and diaphragm to bring about normal breathing. 2. (a) Phrenic nerve: Innervates the diaphragm (which contracts and moves down in inspiration). (b) Intercostal nerves: Innervate the intercostal muscles (internal and external intercostal nerves and muscles) to bring about ribcage movements. (c) Vagus nerve: Sensory portion carries impulses from stretch receptors in the bronchioles to the respiratory center to inhibit inspiration. (d) Inflation reflex (also known as the Hering-Breuer reflex): The inhibition of the inspiratory center to end the breath in. Note: Sensory impulses from the stretch receptors in the bronchioles travel (via the vagus) to inhibit the inspiratory center and expiration follows. When the lungs deflate, the stretch receptors are not stimulated and the inhibition of the inspiratory center stops. Anatomy and Physiology (a) Oxygen is high in the lung alveoli and in the capillaries leaving the lung. (b) Carbon dioxide is high in the capillaries leaving the tissues and in the cells of the body tissues. Surfactant reduces the surface tension of the lung tissue and counteracts the tendency of the alveoli to recoil inward and stick together after each expiration. 4. 1. 2. 3. 28 3. (a) Low blood pH increases rate and depth of breathing. (b) Sensory information from aortic and carotid chemoreceptors is sent to the respiratory center, which mediates the increase in breathing rate. Note: Sensory impulses are sent from the carotid bodies (chemoreceptors) via the carotid sinus nerve and then the glossopharyngeal nerve. Sensory impulses from the aortic bodies (chem...
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This document was uploaded on 01/28/2014.

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