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The lungs are surrounded by the diaphragm and intercostal muscles

Riesenauswahl an Markenqualität. Folge Deiner Leidenschaft bei eBay! Kostenloser Versand verfügbar. Kauf auf eBay. eBay-Garantie Mehr als 200.000 Maschinen sofort verfügbar. Bis zu 90 % sparen! Keine Zeit verlieren: Angebote entdecken und ohne Anmeldung sofort beim Händler anfragen In addition to the lungs, your respiratory system includes the trachea (windpipe), muscles of the chest wall and diaphragm, blood vessels, and tissues that make breathing and gas exchange possible Mammalian lungs are located in the thoracic cavity where they are surrounded and protected by the rib cage, intercostal muscles, and bound by the chest wall. The bottom of the lungs is contained by the diaphragm, a skeletal muscle that facilitates breathing

The lungs are surrounded by the diaphragm and intercostal muscles-this allows the lungs room to contract and relax to draw oxygen in and let CO2 out How the diaphragm and intercostal muscles cause inspiratio The diaphragm: Located below the lungs, the diaphragm is the main muscle needed to breathe. It separates the chest and abdominal cavities and contracts to help inflate the lungs. Intercostal muscles: Located between the ribs, these muscles give the lungs room to breathe by expanding and contracting the chest cavity

Große Auswahl an ‪Diaphragm - Diaphragm

The respiratory diaphragm is a large complex muscle and thus its blood supply comes from various arteries. The costal portion of the diaphragm is supplied by the subcostal arteries and the five most inferior pairs of intercostal arteries. Inferior phrenic arteries are closely related to the diaphragm and give off a few branches to supply it Muscles surrounding the lungs, such as the diaphragm, intercostal muscles, and abdominal muscles, expand and contract to change the volume of the thoracic cavity. Muscles expand the thoracic cavity and decrease the pressure inside the alveoli to draw atmospheric air into the lungs The diaphragm and intercostals muscles relax. As a result, the ribs are pulled down and back, reducing the volume of the chest cavity. This increases the volume of the lungs as the thoracic cavity expands and pulls them out. Because there is a bigger volume, pressure therefore decreases

The lungs have no skeletal muscles of their own. The work of breathing is done by the diaphragm, the muscles between the ribs (intercostal muscles), the muscles in the neck, and the abdominal muscles d. the lungs collapse. e. the volume of the lungs decreases. 2)If plasma pH in capillaries goes from 7.40 to 7.3, hemoglobin's affinity for oxygen will _____ so _____ oxygen; Question: Please help 1) When the diaphragm and external intercostal muscles contract, a. expiration occurs b. the volume of the thorax increases. c

Diaphragma gebraucht - Maschinensucher

The muscles of respiration are those muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity.The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing.The elasticity of these muscles is crucial to the health of the respiratory system and to maximize its functional capabilities The diaphragm is a dome-shaped muscle that sits underneath the lungs and separates the thoracic cavity from the abdominal cavity. It is innervated by the phrenic nerve, which originates in the medullary respiratory centre in the medulla of the brain The intercostal muscles are located in the ribcage The diaphragm is the main muscle of respiration and functions in breathing. During inhalation, the diaphragm contracts and moves in the inferior direction, enlarging the volume of the thoracic cavity and reducing intra-thoracic pressure (the external intercostal muscles also participate in this enlargement), forcing the lungs to expand Mammalian lungs are located in the thoracic cavity where they are surrounded and protected by the rib cage, intercostal muscles, and bound by the chest wall. The bottom of the lungs is contained by the diaphragm, a skeletal muscle that facilitates breathing. Breathing requires the coordination of the lungs, the chest wall, and most importantly.

The Respiratory System

The functional anatomy of the respiratory muscles has been reviewed. The diaphragm has been emphasized, since this is the most important inspiratory muscle, but the view has been presented that the intercostal, scaleni, and other accessory inspiratory muscles become increasingly important as airflow obstruction leads to hyperinflation The lungs are pyramid-shaped, paired organs that are connected to the trachea by the right and left bronchi; on the inferior surface, the lungs are bordered by the diaphragm. The diaphragm is the flat, dome-shaped muscle located at the base of the lungs and thoracic cavity. The lungs are enclosed by the pleurae, which are attached to the. To exhale air, the diaphragm and external intercostal muscles relax while the internal intercostal muscles contract to reduce the volume of the thorax and increase the pressure within the thoracic cavity. The pressure gradient is now reversed, resulting in the exhalation of air until the pressures inside the lungs and outside of the body are equal Respiratory zone: respiratory bronchioles, alveoli. Breathing cycle. Inspiration - diaphragm contracts and pulls down, intercostal muscles contract and expand the rib cage -> air enters the lungs. Expiration - diaphragm relaxes and goes up, intercostal muscles relax and rib cage collapses -> air exits the lungs

Transcribed image text: 0/1 pts Incorrect Question 4 The fact that the lungs expand and contract as the breathing muscles expand and contract the chest wall is due to the cohesive connection between the external intercouches and the ribe SUCCS the diaphragm and the external intercostal muscles Das the soldier Cones 23 GO Incorrect Question 5 0/1 pts Asthma reduces air flow to and from the. Muscle of inspiration: When breathing in, this muscle contracts, pulling the central tendon down. This elevates negative pressure inside the chest cavity, which draws air in, and the diaphragm flattens while the external intercostal muscles raise the front of the chest as the lungs expand

Intercostal, Clavicular, Diaphragm muscle Breathing Exercise . Equal Breathing Exercise Intercostal Breathing Exercise. Clavicular Breathing Exercise Abdominal Breathing Exercise. Any person on an average utilizes only one-third of his /her lung capacity during the act of breathing.Whereas nature has designed our lung capacity proportional to the oxygen requirement for optimally performing all. Breathing in. When you inhale: the internal intercostal muscles relax and the external intercostal muscles contract, pulling the ribcage upwards and outwards. the diaphragm contracts, pulling downwards. lung volume increases and the air pressure inside decreases. Click to see full answer Here is the answer for the question - During a breathing cycle, as the diaphragm and intercostal muscles _____, the volume of the pleural cavity _____ and air moves _____ the lungs..You'll find the correct answer belo

How the Lungs Work NHLBI, NI

  1. During inhalation, a person s diaphragm and intercostal muscles contract, expanding the chest cavity and lowering the internal air pressure below ambient so that air flows in through the mouth and.
  2. The diaphragm is a huge dome-shaped muscle located in the lower part of the rib cage. the intercostal muscles, it lowers the pressure in the chest cavity and this allows air to enter the lungs.
  3. The Lungs. Most mammalian lungs have the same basic structure.The Trachea (windpipe) leads from the mouth and nose and splits into the Bronchi which in turn split into the Bronchioles which lead to the Alveoli (air sacs) where gaseous exchange occurs.. These form a pair of inflatable structures, the Lungs, supported by the ribs and the Diaphragm which allow the animal to Inspire and Expire
  4. When you inhale, the diaphragm and external intercostals contract and lower the thorax, expanding the lungs. This causes the pressure inside the lungs to decrease, facilitating the flow of air into the lungs. Upon exhalation, the external intercostal muscles relax, allowing the thorax to return to its original position, forcing the air out
  5. ant muscle Sternocleidomastoid and trapezius = accessory muscles. o Used during exercise or when there is pulmonary compromise Right lung has 3 lobes Left has 2 lobes Trachea = 10-11 cm long and 2cm in diameter R bronchus= wider, shorter and more vertical= more susceptible to aspiration of foreign bodies
  6. namely, the scaleni muscles, the intercostal muscles raise the 2nd to the 12th ribs toward the first rib, as in inspiration. If, conversely, the 12th rib is fixed by the quadratus lumborum muscle and the oblique muscles of the abdomen, the 1st to the 11th ribs will be lowered by the contraction of the intercostal muscles, as in expiration
  7. al cavity (the word diaphragm is derived from the Greek 'diáphragma', meaning partition).; Undergoes contraction and relaxation, altering the volume of the thoracic cavity and the lungs, producing.

Breathing Biology I - Lumen Learnin

The muscle of the diaphragm and external intercostal muscles are principal muscles of inspiration. Movement of fresh air into the lungs By the above mechanism the volume of thoracic cavity increases, as a result, there is a decrease of air pressure in the lungs Pressure and volume changes produced by the intercostal muscles and the diaphragm during isolated and combined contraction with the airway occluded and open. Intercostal Muscles Diaphragm Intercostal Muscles + Diaphragm; Airway occluded ΔPao, cmH 2 O: −11.1±1.5: −12.4±2.0: −23.7±1.7 ΔPab, cmH 2 O: −5.6±0.7 +4.3±0.4 +1.9±0. The lungs are inflated by action of the diaphragm and the intercostal muscles. The diaphragm, a large dome-shaped muscle, forms the bottom of the thoracic cage. As it contracts it flattens, increasing the diameter of the thorax and elevating the lower ribs. Both of these actions increase the space for expansion of the lungs

Lungs and gas exchange Questions and Study Guide Quizlet

How the Lungs Work Lung Center Temple Healt

  1. The muscles responsible for moving the lungs can be divided into two groups: muscles of inhalation and muscles of exhalation. The chief muscle of inhalation is the diaphragm. Responsible for sixty to eighty percent of inhalation, the diaphragm receives more attention than any other breathing muscle. It is
  2. By comparison with the intercostal muscles, the diaphragm has a very low density of muscle spindles and is poorly innervated by the γ-motoneurons. Reflex excitation of the diaphragm, however, can be achieved via proprioceptive excitation within the intercostal system ( Decima and von Euler, 1969 )
  3. Muscles of Breathing The diaphragm is the main muscle of quiet breathing. Howeves, the external intercostal mandes aid in the process as wynergists. When these muscles contract, they move the ribs up and out, increasing the volume of the pleural cavity. Other muscles can be recruited to expand the pleural cavity even more when forced.
  4. • Quiet expiration is a passive process, in which the diaphragm and the external intercostal muscles relax, and the elastic lungs and thoracic wall recoil inward. • This decreases the volume and therefore increases the pressure in the thoracic cavity. • As the diaphragm relaxes, it moves superiorly
  5. The effect of this is that air moves into the lungs because the molecules tend to move from where there is a high pressure of the gas to where there is a low pressure of the gas. The opposite process happens when exhalation occurs. In this situation, the muscular diaphragm and external intercostal muscles relax. The lungs also become smaller in.
  6. The diaphragm and external intercostal muscles contract, applying force to the bottom and sides of the lungs. The innermost intercostal muscles now contract, while the external intercostal muscles relax. This causes the chest cavity to contract as a whole, forcing the air out of your lungs. The internal intercostal muscles, or middle layer of.
  7. is. d. External obliques and pectoralis major. ANS: A The major muscle of respiration is the diaphragm. The intercostal muscles lift the sternum and elevate the ribs during inspiration, increasing the anteroposterior diameter. Expiration is primarily passive

C. The posterior intercostal arteries of the lower nine spaces are branches of the thoracic aorta. D. Throughout an intercostal space, the intercostal nerves and blood vessels lie close to the upper border of the lower rib. E. The intercostal nerves and blood vessels run be-tween the internal and the innermost intercostal muscles Intercostal muscles - Located between the ribs and expand and contract as the lungs fill or deflate. They keep the ribs in place too. They keep the ribs in place too. Trachea - Lined with C shaped (or U shaped, depends how you think of it) rings of cartilage, these protect it from being crushed • Muscles involved in quiet breathing in During relaxed inspiration, the muscles that increase the thoracic cavity volume are the diaphragm and the external intercostal muscles. When the diaphragm contracts, it moves down, thus increasing the thoracic volume. The external intercostal muscles are located between the ribs, and their contraction causes the ribs to move upward and outward, which.

Breathing Biology for Majors II - Lumen Learnin

Anatomy - Thorax Thoracic cavity surrounded by thoracic wall contains the thymus, heart, lungs, distal part of trachea, most of esophagus. Skeleton of thoracic wall forms osteocartilaginous thoracic cage. Contains 12 thoracic vertebrae and intervertebral discs, 12 pairs of ribs, and sternum. Thoracic vertebrae have costal facets on bodies for articulation with heads of ribs [joint of head of. The muscles of respiration are those muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity.The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing.Additional 'accessory muscles of respiration' are typically only used under conditions of high metabolic demand (e.g. exercise) or.

week 4: the respiratory system Flashcards Quizle

Transcribed image text: Incorrect Question 4 0 / 1 pts The fact that the lungs expand and contract as the breathing muscles expand and contract the chest wall is due to the cohesive connection between the external intercostal muscles and the ribs the diaphragm and the external intercostal muscles the alveoli and respiratory muscles the pleura and the alveoli the two layers of the pleur The lungs and airways bring in fresh, oxygen-enriched air and get rid of waste carbon dioxide made by your cells. They also help in regulating the concentration of hydrogen ion (pH) in your blood. When you inhale, the diaphragm and intercostal muscles (those are the muscles between your ribs) contract and expand the chest cavity. HowStuffWorks.

The intercostal muscles and the diaphragm can work together or independently to ventilate the lungs. This means that when we are doing 'quiet breathing' there may be no noticeable chest movement as the lungs are ventilated mainly by changes in the shape of the diaphragm. When we need to increase the rate of gas exchange (for example during. the external intercostal muscles relax and the internal intercostal muscles contract, pulling the ribcage downwards and inwards the diaphragm relaxes, moving back upwards lung volume decreases and. The diaphragm is attached to the base of the sternum, the lower parts of the rib cage, and the spine. As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs. The intercostal muscles help move the rib cage and thus assist in breathing The diaphragm: the respiratory muscle. The intercostals muscles: two groups of internal and external chest muscles that move the ribs. During inhalation: The internal muscles between the ribs contract, moving them up. The diaphragm muscle below the lungs contracts. The chest cavity increases. The internal pressure of air inside the lungs is. The muscles around your lungs will increase in strength due to the continued use of them. These muscles include the intercostal muscles and diaphragm. When muscles grow and get stronger it is called hypertrophy. That is exactly what happens here over a sustained period of exercise

Exchange and Transport Ep 5 - Gas Exchange in Humans - Zoë02 Gas Exchange - Emma L Nason

Respiratory system structure and function - Respiratory

10M.1.SL.TZ2.29: What happens to the external and internal intercostal muscles and diaphragm when inhaling? 10M.2.SL.TZ2.4b: Describe the need for a ventilation system in humans. 09N.1.SL.TZ0.27: What change occurs to the pressure and volume of the lungs when the external intercostal.. The external intercostal muscles also help bring about this enlargement of the thoracic cavity. This enlargement thus creates a negative pressure which leads to a suction force and drawing of air into the lungs. After inhalation, when the diaphragm relaxes, air is exhaled due to the elastic recoil of the lungs and the tissues lining the. 10) The lungs expend in inspiration / inhalation because? a) Diaphragm contracts upward b) The volume of thoracic cavity increases c) External intercostal muscles relax d) Diaphragm relaxes. 11) The process of exhalation / expiration is begun mainly due to? a) The contraction of external intercostal muscles b) The contraction of the diaphragm The diaphragm is controlled by the phrenic nerve that exits the spinal cord at levels C3, C4 and C5. An injury at these levels will affect diaphragm control of breathing. A second set of muscles, the intercostal muscles, assist in causing air to enter the lungs. The intercostal muscles are in between each rib BREATHING is the process of inspiration (air flows into the lung) and exhalation (air flows out of the lung). Inspiration begins when the diaphragm and the intercostal muscles of the chest wall contract in response to neural impulses from the brain stem (Fig. 3). Contraction of the diaphragm causes it t

Biology 109 > Foley > Flashcards > Respiratory System

The breathing process is aided by a large dome-shaped muscle under the lungs called the diaphragm. When you breathe in, the diaphragm and intercostal muscles (those are the muscles between your ribs) contract and expand the chest cavity, causing an expansion of the lungs and results in a rush of fresh air into the lungs The diaphragm, a dome-shaped sheet of muscle that separates the chest cavity from the abdomen, is the most important muscle used for breathing in (called inhalation or inspiration). The diaphragm is attached to the base of the sternum, the lower parts of the rib cage, and the spine. As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs The ratio between the ΔP ao obtained during combined diaphragm-intercostal contraction and the sum of the ΔP ao produced by their separate contraction was also found to vary as a function of lung volume; this ratio was 1.0 when transrespiratory pressure before muscle contraction was set at −10 cmH 2 O, and it gradually increased to 1.9 when. primarily due to the fact that the intercostal muscles reduce shortening of the diaphragm. When the lung is maintained at functional residual capacity, however, the synergism is obscured because the greater stiffness of the rib cage during diaphragm contraction enhances the Pao produced by the isolated diaphragm and reduces the Pao produced by.

Respiratory System: How We Breathe - ThoughtC

Drag and drop the pins to their correct place on the image.. trachea, bronchi, bronchioles, Alveoli, Heart, Diaphragm , Rib, Intercostal Muscle When you inhale, the diaphragm and intercostal muscles (the muscles between your ribs) contract and expand the chest cavity. This expansion lowers the pressure in the chest cavity below the outside air pressure. Air then flows in through the trachea and bronchi and inflates the lungs

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The Lungs - Position - Structure - TeachMeAnatom

The diaphragm is the main ventilatory muscle, when it contracts it pulls itself downward creating negative pressure in the chest which causes air to rush into the lungs. When it relaxes, it is pulled upwards by the lungs natural recoil (springlike nature) which causes air to rush out of the lungs like a collapsing balloon People also ask, what is the role of the diaphragm and intercostal muscles in breathing? The diaphragm is attached to the base of the sternum, the lower parts of the rib cage, and the spine. As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs. The intercostal muscles help move the rib cage and thus assist in breathing Categories Chapter 10 Tags During a breathing cycle, as the diaphragm and intercostal muscles _____, the volume of the pleural cavity _____ and air moves _____ the lungs. Leave a comment Search for Colleg When the diaphragm contracts, it moves inferiorly toward the abdominal cavity, creating a larger thoracic cavity and more space for the lungs.Contraction of the external intercostal muscles moves the ribs upward and outward, causing the rib cage to expand, which increases the volume of the thoracic cavity

The diaphragm is a large muscle sheath (pictured below and in video, right) that stretches across the bottom of the rib-cage, nearly cutting the body in half, separating the lower organs from the heart and lungs. During normal breathing, the diaphragm naturally flexes (or flattens) and contracts drawing air in and out of the lungs Abdominal pressure during combined contraction was invariably lower than during isolated diaphragm contraction. It is concluded, therefore, that the canine diaphragm and intercostal muscles act synergistically during lung expansion and that this synergism is primarily due to the fact that the intercostal muscles reduce shortening of the diaphragm

Respiratory System: A Brief Anatomy - Passionate in Knowledg

The diaphragm is the primary muscle of inspiration. It is a thin, dome-shaped sheet of muscle that inserts into the lower ribs. However, during exercise, expiration becomes an active process-- the abdominal muscles contract to raise abdominal pressure, which pushes the diaphragm upward and forces air out of the lungs The intercostal muscles run between each rib. When a person needs to breathe in, these muscles contract and pull the ribs upward. This creates more room inside the chest for the lungs to fill. When a person is resting, the about 30% to 40% of their ability to breathe comes from the intercostal muscles. The intercostal muscles are controlled by. The diaphragm lowers with contraction and the external intercostal muscles raise the rib cage. With the increasing volume of the thorax, the volume of the lungs also increase and inhalation occurs When the internal intercostal muscles contract and diaphragm relax, the ribs move downward and inward and diaphragm becomes, convex (dome shaped), thus decreasing the volume of thoracic cavity and increasing the pressure inside as compared to the atmospheric pressure outside. This will cause the air to move out (expiration) The muscles in the respiratory is called diaphragm, ribcage muscle, external intercostal, and the abdominal muscles. There is many more muscles but let's keep this short and sweet. The mechanism of breathing is gases travel from high pressure to low pressure. The respiratory tract is the nose, throat, larynx, bronchi, trachea, and lungs

Respiratory system

The Process of Breathing - Anatomy and Physiolog

The internal intercostal muscles are used when exhaling with force. The muscles contract and shorten which bring the ribs closer together as the lungs decrease in size. The innermost intercostal. Inspiration occurs when the inspiratory muscles—that is, the diaphragm and the external intercostal muscles—contract. Contraction of the diaphragm (the skeletal muscle below the lungs) causes an increase in the size of the thoracic cavity, while contraction of the external intercostal muscles elevates the ribs and sternum HOW BREATHING WORKS. To inhale, the intercostal muscles contract, and the diaphragm moves down, making the chest expand. Air is sucked into the lungs, because the pressure in the airways is less than it is outside. When the intercostal muscles and diaphragm relax, we exhale. The ribs fall downward and inward, and the diaphragm springs back into.

Midterm #3 - Anatomy 040 with Speer at Los Medanos CollegeGas Exchange at Harvard University - StudyBlue

Diaphragm: Location, anatomy, innervation and function

external, internal, intercostal, contract, relax, volume, pressure Read the following statement about the diaphragm. For each one, put a tick ( ) if it is correct, or a cross ( ) if it is not correct. Statement or The diaphragm is a sheet of muscle. When the diaphragm contracts, it moves down. When the diaphragm relaxes, it moves down Your Diaphragm and intercostal muscles are essential for breathing but their health and conditioning is so often overlooked in preventative healthcare. The Live, Love, Breathe Intercostal and Diaphragm Trainer/Exerciser helps you focus on building strength in these two critical muscle groups, allowing easier breathing and oxygenation The diaphragm in the thorax is called the thoracic diaphragm and serves as an important anatomical landmark that separates the thorax, or chest, from the abdomen. It functions during breathing when it contracts to enlarge the thoracic cavity and reduce the intrathoracic pressure so that lungs may expand and fill their alveoli with air. It is a dome-shaped muscle and tendon that functions as. When the diaphragm and external intercostal muscles contract, a. Intrapulmonary pressure decreases b. Intrapulmonary pressure increases There are about 200,000 new cases of lung cancer every. When the diaphragm and external intercostal muscles contract, which of the following actions does NOT occur? A. Air moves into lungs B. The diaphragm moves inferiorly C. The intrapulmonary pressure decreases D. The intrapleural pressure increases

Lungs - Innerbod

intercostal definition: 1. between the ribs (= bones around the chest): 2. one of the muscles between the ribs (= bones. Learn more cavity and the lungs. Page 5. Quiet Expiration: Muscle Relaxation • Quiet expiration is a passive process, in which the diaphragm and the external intercostal muscles relax, and the elastic lungs and thoracic wall recoil inward. • This decreases the volume and therefore increases the pressure in the thoracic cavity The diaphragm is a 2-4mm thin, dome-shaped flat muscle and tendinous structure that separates the thoracic cavity (chest) from the abdominal (belly) cavity. It is located below the lungs and the heart and above the liver. It only allows passing for the two important blood vessels (the vena cava and the aorta) and the oesophagus Inspiration is a process of entering air into the lungs. It is an active process. When the external intercostal muscles contract the diaphragm becomes flat and space inside increases thoracic cavity. At the same time, high pressure outside air flows into the lungs. Expiration is a process of expelling air from the lungs The Payoff: Stretches the intercostal muscles (which lie between the ribs), relaxes the shoulders, engages the diaphragm and pelvic floor, and helps balance breathing between the left and right lungs

What happens to the intercostal muscles during exercise

The muscles of respiration (Respiratory muscle) are those skeletal muscles that contribute to inhalation and exhalation, by aiding in the expansion and contraction of the thoracic cavity.The diaphragm and, to a lesser extent, the intercostal muscles drive respiration during quiet breathing.The elasticity of these muscles is crucial to the health of the respiratory system and to maximize its. Thoracic cavity, also called chest cavity, the second largest hollow space of the body.It is enclosed by the ribs, the vertebral column, and the sternum, or breastbone, and is separated from the abdominal cavity (the body's largest hollow space) by a muscular and membranous partition, the diaphragm.It contains the lungs, the middle and lower airways—the tracheobronchial tree—the heart. The external intercostal muscles originate on the inferior surfaces of the proximal parts of the ribs and insert on the superior and distal parts of the next lower rib. These are innervated by intercostal nerves originating in thoracic segments of the spinal cord. Contraction of these muscles raises the rib cage upward and outward, thereby contributing to the expansion of the thoracic cavity. Diaphragm and external intercostal muscles contracts. 2. Diaphragm and internal intercostal muscles relax. 3. Intra Pleural pressure is less than atmospheric pressure. 4. Both A and C. Q 93: 82 % From NCERT