biol_119_lecture_11_9-28-09

biol_119_lecture_11_9-28-09 - Lecture 11, 9-28-2009 End of...

Info iconThis preview shows pages 1–7. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Lecture 11, 9-28-2009 End of 42 and then on to chapter 43 Review today at 3:30 in Newton 201 G. Mammalian Respiratory Systems: A Closer Look The lungs of mammals have a spongy texture and are honeycombed with a moist epithelium. A system of branching ducts conveys air to the lungs. Branch from the pulmonary vein (oxygen-rich blood) Terminal bronchiole Branch from the pulmonary artery (oxygen-poor blood) Alveoli Colorized SEM SEM 50 m 50 m Heart Left lung Nasal cavity Pharynx Larynx Diaphragm Bronchiole Bronchus Right lung Trachea Esophagus Figure 42.24 In mammals, air inhaled through the nostrils Air enters through the nostrils and is then filtered by hairs, warmed and humidified, and sampled for odors as it flows through the nasal cavity. The nasal cavity leads to the pharynx, and when the glottis is open , air enters the larynx , the upper part of the respiratory tract . In most mammals, the larynx is adapted as a voicebox in which vibrations of a pair of vocal cords produce sounds. From the larynx, air passes into the trachea , or windpipe, whose shape is maintained by rings of cartilage. The trachea forks into two bronchi , one leading into each lung. Within the lung, each bronchus branches repeatedly into finer and finer tubes, called bronchioles . The epithelium lining the major branches of the respiratory tree is covered by cilia and a thin film of mucus. The mucus traps dust, pollen, and other particulate contaminants, and the beating cilia move the mucus upward to the pharynx, where it is swallowed. Countercurrent exchange in a fish _____. A. speeds up the flow of water through the gills B. maintains a high p throughout the gills which enhances the rate of 0 2 diffusion C. enables blood oxygenation in fish regardless of the direction of water flow relative to blood flow D. means that blood and water flow in the same direction E. decreases the distance over which diffusion occurs Review question C.c.42.5 Why is the position of lung tissues within the body an advantage for terrestrial animals? The interior position helps them stay moist. If the respiratory surfaces of lungs extended out into the terrestrial environment, they would quickly dry out and diffusion of oxygen and carbon dioxide across these surfaces would stop. After a heavy rain, earthworms come to the surface. How would you explain this behavior in terms of an earthworms requirements for gas exchange? Concept 42.6: Breathing ventilates the lungs The process that ventilates the lungs is breathing; the alternate inhalation and exhalation of air A. How a amphibian breathes: such as a frog ventilates its lungs by positive pressure breathing, which forces air down the trachea B. How a mammal breathes: ventilate their lungs by negative pressure breathing, which pulls air into the lungs Air inhaled Air exhaled INHALATION Diaphragm contracts (moves down) EXHALATION Diaphragm relaxes (moves up) Diaphragm Lung Rib cage expands as...
View Full Document

Page1 / 101

biol_119_lecture_11_9-28-09 - Lecture 11, 9-28-2009 End of...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online