Chapter 11 Part 4

Question 1

What is the primary respiratory muscle in mammals?

Answer 1

Diaphragm

Question 2

Diaphragm

Answer 2

o Separates thorax from abdomen
o lies anterior to the liver and acts directly on the pleural cavities in which the lungs reside

Question 3

What other muscles help with inspiration for inhalation?

Answer 3

▪ Upon inhalation: external intercostal muscles contract to rotate the adjacent ribs and medial sternum forward
▪ Rotation includes an outward as well as a forward swing of each arched rib
▪ The result is to expand the space that the rib cage encloses around the lungs
▪ Contraction of the dome-shaped diaphragm causes it to flatten, further enlarging the thoracic cavity

Question 4

What other muscles help with inspiration in exhalation with mammals?

Answer 4

▪ Active exhalation: internal intercostal muscles slant in the opposite direction of the relaxed external intercostals and pull the ribs back
▪ Relaxation of the diaphragm causes it to recoil and resume its arched, dome shape

Question 5

Respiratory tree

Answer 5

The respiratory tree: from trachea to terminal bronchioles
o conduction of air deeper into the lungs (no gas exchange)

Question 6

bronchioles

Answer 6

separate into partitions of alveoli/alveolus(singular)

Question 7

Terminal bronchiole

Answer 7

The smallest bronchioles that do not contain alveoli; they mark the end of the conducting zone of the respiratory system.

Question 8

Respiratory bronchiole

Answer 8

Bronchioles that have scattered alveoli along their walls, marking the transition between the conducting zone and the respiratory zone

Question 9

Alveolar duct

Answer 9

small ducts that connect the respiratory bronchioles to the alveolar sacs, lined with numerous alveoli

Question 10

Alveolar sac

Answer 10

Clusters of alveoli at the end of alveolar ducts where gas exchange occurs

Question 11

Alveolus

Answer 11

Tiny, balloon-like structures within the lungs where the primary gas exchange of oxygen and carbon dioxide takes place.

Question 12

Who takes part in positive vs. negative pressure?

Answer 12

Positive pressure(buccal pump): amphibians

Negative pressure(aspiration pump):
- Mammals – muscular diaphragm and intercostals
- Birds – intercostals and air sacs
- Crocodilians – diaphragmaticus muscle
- Turtles – internal muscles and a membrane
- Squamates – intercostal muscles