diaphragm

Examples of diaphragm in the following topics:

• Barrier Methods

  • The spring in the rim of the diaphragm forms a seal against the vaginal walls.
  • The diaphragm, like the cervical cap, is typically used with a spermicide.
  • The rim of a diaphragm is squeezed into an oval or arc shape for insertion.
  • Diaphragms come in different sizes.
  • A too-large diaphragm may also rub a sore on the vaginal wall.

• Injuries to the Phrenic Nerves

  • The phrenic nerve provides motor innervation and receives sensory information from the diaphragm.
  • It is important for breathing, as it passes motor information to the diaphragm and receives sensory information from it.
  • These nerves provide the only motor supply to the diaphragm as well as sensation to the central tendon.
  • A hiccough is a spasmodic contraction of the diaphragm, which pulls air against the closed folds of the larynx.
  • Severing the phrenic nerve, or a phrenectomy, will paralyze that half of the diaphragm.

• Aging and the Respiratory System

  • In mammals, breathing in is due to a flattening of the diaphragm and lung expansion.
  • In mammals, breathing (inhaling) occurs during the contraction and flattening of the diaphragm—a domed muscle separating the thorax and abdomen.
  • When the diaphragm relaxes air leaves largely by elasticity of the lung.
  • Increased abdominal pressure then tilts the diaphragm and ribcage upwards, increasing volume and air entry.
  • Note the barrel-shaped chest and flat diaphragm.

• Inspiration

  • Inspiration begins with the contraction of the diaphragm, which results in expansion of the thoracic cavity and the pleural cavity.
  • The diaphragm is the primary muscle involved in breathing, however several other muscles play a role in certain circumstances.
  • They provide a mechanism for inspiration when the diaphragm is injured and can't contract normally.
  • The accessory muscles assist breathing by expanding the thoracic cavity in a similar way to the diaphragm.
  • However, they expand a much smaller part of the thoracic cavity compared to diaphragm.

• Abdominal Aorta

  • It begins at the level of the diaphragm, crossing it via the aortic hiatus, a hole in the diaphragm that allows the passage of the great vessels, at the vertebral level of T12.
  • The aorta, highlighted in red, includes the abdominal aorta which begins at the diaphragm and ends as it branches into the common iliac arteries.

• Thoracic Aorta

  • Contained within the posterior mediastinal cavity it begins at the lower border of the fourth thoracic vertebra where it is continuous with the aortic arch, and ends in front of the lower border of the twelfth thoracic vertebra at the aortic hiatus in the diaphragm.
  • The thoracic aorta's relation, from above downward, is as follows: anteriorly with the root of the left lung, the pericardium, the esophagus and the diaphragm; posteriorly with the vertebral column; on the right side with the hemiazygos veins and thoracic duct; and on the left side with the left pleura and lung.
  • The esophagus lies on the right side of the aorta for most of its length, but at the lower part of the thorax is placed in front of the aorta and close to the diaphragm, situated on its left side.
  • The aorta, highlighted in red, includes the thoracic aorta, the section of the aorta which runs from the lower border of the fourth thoracic vertebra to the diaphragm.

• Neural Mechanisms (Cortex)

  • The processes that drive its functions aren't fully understood, but it works by sending signals to the spinal cord, which sends signals to the muscles it controls, such as the diaphragm and the accessory muscles for respiration.
  • The center for diaphragm control is posterior to the location of thoracic control (within the superior portion of the primary motor cortex).
  • The phrenic nerves: The nerves that stimulate the activity of the diaphragm.
  • The vagus nerve: Innervates the diaphragm as well as movements in the larynx and pharynx.
  • Damage to any of these three respiratory nerves can cause severe problems, such as diaphragm paralysis if the phrenic nerves are damaged.

• Perineum

  • The perineum is the region of the body inferior to the pelvic diaphragm and between the legs.
  • The region of the perineum can be considered a distinct pelvic area with the two regions separated by the pelvic diaphragm.
  • It is bounded laterally by obturator internus muscle, medially by pelvic diaphragm and the anal canal.

• Expiration

  • Expiration is typically a passive process that happens from the relaxation of the diaphragm muscle (that contracted during inspiration).
  • Just as the plueral cavity's increased negative pressure leads to air uptake during inhalation, the pleural cavity will contract during the exhalation (due to relaxation of the diaphragm),which exerts pressure on the lungs and causes the pressure inside the cavity to be less negative.
  • Abdominal Muscles: Any number of muscles in the abdomen that exert pressure on the diaphragm from below to expand it, which in turn contracts the thoracic cavity, causing forced exhalation.
  • As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air.
  • As the diaphragm relaxes, the pleural cavity contracts, which exerts pressure on the lungs, which reduces the volume of the lungs as air is passively pushed out of the lungs.

• Lungs

  • The base is curved inward to allow it to rest on the diaphragm.
  • The diaphragm, a sheet of skeletal muscle that lies beneath the lungs, plays an important role in inhalation.
  • Breathing is largely driven by the muscular diaphragm at the bottom of the thorax.
  • Contraction of the diaphragm pulls the bottom of the cavity in which the lung is enclosed downward, increasing volume and thus decreasing pressure, causing air to flow into the airways and into the lungs.
  • During normal breathing, expiration is passive— no muscles are contracted—and the diaphragm relaxes from its contracted state.