This topic contains a solution. Click here to go to the answer

Author Question: As ventilatory muscles, the sternocleidomastoids do which of the following? a. They elevate the ... (Read 54 times)

Ebrown

  • Hero Member
  • *****
  • Posts: 567
As ventilatory muscles, the sternocleidomastoid s do which of the following?
 
  a. They elevate the upper chest, increasing chest anteroposterior diameter.
  b. They elevate the ribs and decrease chest anteroposterior diameter.
  c. They increase lateral chest movement dur-ing inspiration.
  d. They lower the sternum, thus increasing chest anteroposterior diameter.

Question 2

Which accessory muscles of ventilation work to pull the ribs closer together?
 
  a. External intercostals
  b. Internal intercostals
  c. Scalenes
  d. Sternocleidomastoid s



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

ApricotDream

  • Sr. Member
  • ****
  • Posts: 336
Answer to Question 1

ANS: A
The sternocleidomastoid muscles can function to lift the upper chest. They receive nerve impulses from branches of the accessory nerves (cranial nerve XI) and cervical nerves C1 and C2. These muscles are active during forceful inspiration and become visible as thick bands on either side of the neck during the inspiratory phase in an individual who is in respiratory distress. This motion increases the anteroposterior diameter of the chest.

Answer to Question 2

ANS: B
The internal intercostal muscles (Figure 9-22) lie between the ribs and just behind the external intercostal muscles. They originate along the inferior border of the upper ribs and insert into the superior border of the lower ribs. The muscle fibers of the internal intercostal muscles run down-ward and less obliquely than the external intercostal muscle fibers. This orientation causes these muscles to pull the ribs together, which results in compression of the thoracic cavity.




Ebrown

  • Member
  • Posts: 567
Reply 2 on: Jul 16, 2018
Excellent


Perkypinki

  • Member
  • Posts: 339
Reply 3 on: Yesterday
Great answer, keep it coming :)

 

Did you know?

Though the United States has largely rejected the metric system, it is used for currency, as in 100 pennies = 1 dollar. Previously, the British currency system was used, with measurements such as 12 pence to the shilling, and 20 shillings to the pound.

Did you know?

A serious new warning has been established for pregnant women against taking ACE inhibitors during pregnancy. In the study, the risk of major birth defects in children whose mothers took ACE inhibitors during the first trimester was nearly three times higher than in children whose mothers didn't take ACE inhibitors. Physicians can prescribe alternative medications for pregnant women who have symptoms of high blood pressure.

Did you know?

Urine turns bright yellow if larger than normal amounts of certain substances are consumed; one of these substances is asparagus.

Did you know?

Fewer than 10% of babies are born on their exact due dates, 50% are born within 1 week of the due date, and 90% are born within 2 weeks of the date.

Did you know?

Adult head lice are gray, about ? inch long, and often have a tiny dot on their backs. A female can lay between 50 and 150 eggs within the several weeks that she is alive. They feed on human blood.

For a complete list of videos, visit our video library