Inspiration and Expiration

Last Updated on Fri, 16 Jun 2017 | Human Physiology

Between the bony portions of the rib cage are two layers of intercostal muscles: the external intercostal muscles and the internal intercostal muscles (fig. 16.14). Between the costal cartilages, however, there is only one muscle layer, and its fibers are oriented in a manner similar to those of the internal inter-costals. These muscles are therefore called the interchondral part of the internal intercostals. Another name for them is the parasternal intercostals.

An unforced, or quiet, inspiration results primarily from contraction of the dome-shaped diaphragm, which lowers and flattens when it contracts. This increases thoracic volume in a vertical direction. Inspiration is aided by contraction of the parasternal and external intercostals, which raise the ribs when they contract and increase thoracic volume laterally. Other thoracic muscles become involved in forced (deep) inspiration. The most important of these are the scalenes, followed by the pec-toralis minor, and in extreme cases the sternocleidomastoid muscles. Contraction of these muscles elevates the ribs in an an-teroposterior direction; at the same time, the upper rib cage is stabilized so that the intercostals become more effective. The increase in thoracic volume produced by these muscle contractions decreases intrapulmonary (intra-alveolar) pressure, thereby causing air to flow into the lungs.

Quiet expiration is a passive process. After becoming stretched by contractions of the diaphragm and thoracic muscles, the thorax and lungs recoil as a result of their elastic tension when the respiratory muscles relax. The decrease in lung volume raises the pressure within the alveoli above the atmospheric pressure and pushes the air out. During forced expiration, the internal intercostal muscles (excluding the interchondral part) contract and depress the rib cage. The abdominal muscles also aid expiration because, when they contract, they force abdominal organs up against the diaphragm and further decrease the volume of the thorax. By this means, the intrapulmonary pressure can rise 20 or 30 mmHg above the atmospheric pressure. The events that occur during inspiration

Respiratory Physiology

Muscles of inspiration

Sternocleidomastoid Scalenes

External intercostals

Diaphragm

Muscles of expiration

Muscles of inspiration

Sternocleidomastoid Scalenes

External intercostals

Internal intercostals

External abdominal oblique

Internal abdominal oblique Transversus abdominis Rectus abdominis

Diaphragm

Internal intercostals

External abdominal oblique

Internal abdominal oblique Transversus abdominis Rectus abdominis

■ Figure 16.14 The muscles involved in breathing. The principal muscles of inspiration are shown on the left, and those of expiration are shown on the right.

Table Í6.2	Mechanisms Involved in Normal, Quiet Ventilation and Forced Ventilation
	Inspiration	Expiration
Normal, quiet breathing Contraction of the diaphragm and external intercostal		Relaxation of the diaphragm and external intercostals, plus
	muscles increases the thoracic and lung volume,	elastic recoil of lungs, decreases lung volume and
	decreasing intrapulmonary pressure to about -3 mmHg.	increases intrapulmonary pressure to about +3 mmHg.
Forced ventilation	Inspiration, aided by contraction of accessory muscles	Expiration, aided by contraction of abdominal muscles and
	such as the scalenes and sternocleidomastoid,	internal intercostal muscles, increases intrapulmonary
	decreases intrapulmonary pressure to -20 mmHg or	pressure to +30 mmHg or higher.
	lower.

and expiration are summarized in table 16.2 and shown in figure 16.15.

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Responses

Frederick
Is the transversus thoracis an inspiration muscle?

5 years ago
- Reply
Jodi
What muscles elevate the ribs during forced inspiration?

5 years ago
- Reply
conner
Is transversus thoracis involved with inspiration or expiration?

5 years ago
- Reply
RICHARD
Do scalenes have inspiration or expiration?

5 years ago
- Reply
tuomas
What is the most important muscle of inspiration?

5 years ago
- Reply
Merimac
What are the muscles of inspiration and expiration?

5 years ago
- Reply
Andreas
What thoracic muscles elevate the ribs during forced inspiration?

5 years ago
- Reply
MAIRE
Are the scalenes and the sternocleidomastoids involved in passive inspiration?

5 years ago
- Reply
Janne
How could expiration be aided by thoracic?

5 years ago
- Reply
kerstin
What muscles are involved in deep inspiration?

5 years ago
- Reply
Amparo
What are the steps involved in quiet inspiration and expiration?

5 years ago
- Reply
rowan
What muscles are involved in forced inspiration?

5 years ago
- Reply
Sarah
When the diaphragm and the external intercostals muscles contract intraalveolar pressure?

5 years ago
- Reply
selam
What are the muscles involved in inspiration and expiration?

5 years ago
- Reply
maria teresa
Which muscles increase inspired volume?

5 years ago
- Reply
anna maria
What muscle are involved in forced expiration?

5 years ago
- Reply
alice
Which muscles contract to decrease thoracic volume and raise intrapulmonary pressure?

5 years ago
- Reply
DIANA
What is the increase in thoracic volume in diaphragm?

5 years ago
- Reply
Peter
How is rectus abdominis used in expiration?

5 years ago
- Reply
selam
What muscle contract in forceful exhalation?

5 years ago
- Reply
saba
Does internal lung volume increase or decrease during diaphragm contraction?

5 years ago
- Reply
sofia
Does contraction of internal intercostal muscles increase thoracic volume or pressure?

5 years ago
- Reply
NICOLE
Which muscles provide for normal/quiet expiration?

5 years ago
- Reply
jago
What muscle is involved in normal and forced inspiration?

5 years ago
- Reply
Semhar Kiros
How is the sternocleidomastoid muscle involved in inspiration?

5 years ago
- Reply
Donnie
What respiratory muscles increase thoracic volume?

5 years ago
- Reply
Anja
Is quiet inspiration a passive process?

5 years ago
- Reply
Maria Teresa
What muscle increases thoracic volume?

5 years ago
- Reply
melissa boffin
What muscles contract in quiet expiration?

5 years ago
- Reply
ponto
Are scalenes involved in forced inhalation?

5 years ago
- Reply
dirk
How is inspiration and expiration caused in internal intercostals?

5 years ago
- Reply
ensio
What muscle is involved in increasing thoracic volume?

5 years ago
- Reply
Miranda
Why is the diaphragm and thesternocleidomastoid muscles used on forceful inspiration?

5 years ago
- Reply
Alfrida
How is the sternocleidomastoid muscle involved in forced inspirations?

5 years ago
- Reply
Albano Toscani
How is the ribs a part of inspiration and expiration?

5 years ago
- Reply
immacolata
Why is Inspiration and Expiration so important to humans?

5 years ago
- Reply
KIRSTIN
What is inspiration and expiration in biology?

5 years ago
- Reply
mimosa
Does the internal intercostals increase or decrease the thoracic volume?

5 years ago
- Reply
brigitte fuerst
Which organs are involved in expiration and inspiration?

5 years ago
- Reply
Pupetta
What happens to the intercostal muscles and diaphragm with inspiration and expiration?

5 years ago
- Reply
JULIANE BUSCH
How does the contraction and relaxation of the diaphragm muscle cause inspiration and expiration?

4 years ago
- Reply
cara
What Is forced Inspiration and Expiration?

4 years ago
- Reply
bucca
What muscle is used for forcable inspiration?

4 years ago
- Reply
stefan
Is intrapulmonary volume increase the 3 rd step of inspiration?

4 years ago
- Reply
zula
What muscle of the thorax is contracted during forced expiration.?

4 years ago
- Reply
rihanna
How does the diaphragm affect inspiration and expiration?

4 years ago
- Reply
Iiro
How is forced inspiration produced?

4 years ago
- Reply
settimio
What about forsed inspiration and expiration?

4 years ago
- Reply
philipp
How does diaphragmcontribute to inspiration and expiration?

4 years ago
- Reply
Niko
Which muscle elevates the ribs during forced inspiration, as during strenuous exercise?

4 years ago
- Reply
ibrahim
Which muscle contracts during forced expiration?

4 years ago
- Reply
viljo
How insoiration and expiration works in human?

4 years ago
- Reply
sharon
What muscles contract during forced expiration?

3 years ago
- Reply
Mathias
Why is expiration a passive process?

3 years ago
- Reply
heike
What intercostals increase or decrease alveolar pressur and expiration?

3 years ago
- Reply
Mimosa
Which muscles are involved with respiratory volumes and capacity?

2 years ago
- Reply
isaia
Do scalenes increase or decrease thoracic volume?

2 years ago
- Reply
albano
Which muscles contact to decrease thoracic volume and raise intrapulmonary pressure?

2 years ago
- Reply
John
Which muscle contract to increase thoracic volume and decrease intrapulmonary pressure quizlet?

2 years ago
- Reply
tommy hyypi
Which muscles decrease thoracic volume and raise intrapulmonarypressure?

2 years ago
- Reply
hamilcar
Why is inspiration a muscular effort and expiration a passive process?

2 years ago
- Reply
James Wilson
What two muscles are primarily engaged in inspiration?

2 years ago
- Reply
Tiina
When the ribs elevate dores presure increase or decraesre?

2 years ago
- Reply
Johanna
Do external intercostals contract during expiration?

2 years ago
- Reply
basilio
Which muscle contracts during forced expiration quizlet?

2 years ago
- Reply
Michael Maxson
Which muscles contract to decrease thoracic volume and raise intapilmonary pressure?

1 year ago
- Reply
abrha
Does expiration and inspiration last the same time in a normal person?

1 year ago
- Reply
Bryn
When the muscles of inspiration contract w, what happens to the pressure?

1 year ago
- Reply
zula
Is external abdominal can cause insprtion?

1 year ago
- Reply
MELINDA
Can scalenes increaseor decreasethoracicvolume?

1 year ago
- Reply
Harry
What are the three steps of inhalation thoracic volume?

1 year ago
- Reply
venla
Which muscles contract to decreases thoracic volume and raise intrapulmonary pressure?

1 year ago
- Reply
tuula taipale
What muscles are involved during forced expiration?

1 year ago
- Reply
Mylie
What are are the muscles used in forced expiration and forced inspiration?

1 year ago
- Reply
PATRICIA
What two muscles are primarly engaged in inspiration which is the process o breathing in?

1 year ago
- Reply
jan
What muscles increase the volume of the thorax during a normal inhalation?

1 year ago
- Reply
connie
Which muscle contract to decrease thoracic volume and raise intrapulmonary pressure?

1 year ago
- Reply
cornelio sal
How is intrapulmonary pressure during forced inspiration?

1 year ago
- Reply
teresa
When the diaphram and external intercostal muscles contract, _____ quizlet?

1 year ago
- Reply
Matthew
How is inspiration and expiration alike?

1 year ago
- Reply
pamphila took-took
Does the thoracic volume increase or decrease during inhalation?

1 year ago
- Reply
Landolfo
What are the elements that would stimulate inspiration and expiration?

1 year ago
- Reply
medhane girma
What two muscles engage in inspiration?

1 year ago
- Reply
cathryn
How Ventilation Muscles Cause Inspiration and Expiration?

12 months ago
- Reply
J
When the diaphragm and external intercostal muscles contract,?

11 months ago
- Reply
nick
Which muscles are normally contracted during quiet expiration in respiration?

10 months ago
- Reply
niamh
Which muscles are normally contrated during expiration in respiration?

10 months ago
- Reply
ky
How does inspiration and expiration occur in humans?

10 months ago
- Reply
Aamu
Why inspiration and expiration happened at the same time?

10 months ago
- Reply
Marko
Is inspiration or expiration is deeper?

10 months ago
- Reply
manuela k
When the diaphragm and external intercostal muscles contract quizlet?

9 months ago
- Reply
rudibert
Do internal intercoastal muscles contract during forced expiration?

8 months ago
- Reply
benito
Which muscles contract to decrease thorasic volume and raise the interpulmonary pressure?

8 months ago
- Reply
pasquale buccho
Does intrapulmonary pressure increase or decrease during inspiration?

7 months ago
- Reply
hugo h
Does the scalenes contraction increase thoraci volume?

7 months ago
- Reply
theodore
What happned to.internal intercoastal muscle in expiration?

7 months ago
- Reply
Tranquillino
Does internal incoastal muscle relax or contract during inspiration?

5 months ago
- Reply
christopher
Which muscles contract during quiet relaxed inspiration?

5 months ago
- Reply
belinda
What muscles contract during quiet inspiration during forced inspiration and expiration?

4 months ago
- Reply
Allan
WHICH MUSCLE INCREASE INSPIRED VOLUME?

3 months ago
- Reply
hildifons
What are the muscles involved in normal inspiration and forced inspiration?

3 months ago
- Reply
jamie stevenson
Which muscles are primarily responsible for quiet (normal, relaxed) inspiration?

3 months ago
- Reply
Maria Rosa
When muscle contracts what does intrapulmonary pressure do?

3 months ago
- Reply
futsum
When do internal intercostal muscles contract intrapulmonary pressure?

2 months ago
- Reply
giosu
What occurs during force expiration?

2 months ago
- Reply
ky
Does the diaphragm decrease thoracic volume?

2 months ago
- Reply
marco
What Muscle Are Used For Inhalation Forceful Expiration?

2 months ago
- Reply
mewael semere
Is the diaphragm involved in inspiration or expiration?

1 month ago
- Reply
Jamila
Which situation involve active expiration?

21 days ago
- Reply
Matthias
What increases with inspiration and decreases with expiration in the lungs?

19 days ago
- Reply

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