medullary cavity

Examples of medullary cavity in the following topics:

• Supply of Blood and Nerves to Bone

  • The nutrient arteries divide into ascending and descending branches in the medullary cavity.

• Gross Anatomy

  • The interior part of the long bone is called the medullary cavity; the inner core of the bone cavity is composed of marrow.

• Development of the Skeleton

  • This creates cavities within the bone.
  • Blood vessels forming the periosteal bud invade the cavity left by the chondrocytes and branch in opposite directions along the length of the shaft.
  • The blood vessels carry hemopoietic cells, osteoprogenitor cells and other cells inside the cavity.
  • Osteoblasts, differentiated from the osteoprogenitor cells that entered the cavity via the periosteal bud, use the calcified matrix as a scaffold and begin to secrete osteoid, which forms the bone trabecula.
  • Osteoclasts, formed from macrophages, break down spongy bone to form the medullary (bone marrow) cavity.

• Cerebrospinal Fluid and Its Circulation

  • This diagram indicates the (1) posterior medullary velum (2) choroid plexus (3) cisterna cerebellomedullaris of subarachnoid cavity (4) central canal (5) corpora quadrigemina (6) cerebral peduncle (7) anterior medullary velum (8) ependymal lining of ventricle (9) cisterna pontis of subarachnoid cavity
  • Diagrammatic representation of a section across the top of the skull, showing the membranes of the brain with the subarachnoid cavity visible on the left.

• Body Cavities

  • Blood vessels are not considered cavities but may be held within cavities.
  • The dorsal cavity is a continuous cavity located on the dorsal side of the body.
  • The abdominoplevic cavity is the posterior ventral body cavity found beneath the thoracic cavity and diaphragm.
  • Humans have multiple body cavities, including the cranial cavity, the vertebral cavity, the thoracic cavity (containing the pericardial cavity and the pleural cavity), the abdominal cavity, and the pelvic cavity.
  • In mammals, the diaphragm separates the thoracic cavity from the abdominal cavity.

• Epithalamus and Pineal Gland

  • It includes the habenula and their interconnecting fibers (the habenular commissure), the stria medullaris, and the pineal gland.
  • The stria medullaris, also known as stria medullaris thalami, is a fiber bundle containing afferent fibers from the septal nuclei, lateral preoptic hypothalamic region, and anterior thalamic nuclei to the habenula.

• Serous Membranes

  • The pericardial cavity (surrounding the heart), pleural cavity (surrounding the lungs), and peritoneal cavity (surrounding most organs of the abdomen) are the three serous cavities within the human body.
  • Serous membranes line and enclose several body cavities, known as serous cavities, where they secrete a lubricating fluid which reduces friction from muscle movement.
  • The pericardial cavity (surrounding the heart), pleural cavity (surrounding the lungs) , and peritoneal cavity (surrounding most organs of the abdomen) are the three serous cavities within the human body .
  • While serous membranes have a lubricative role to play in all three cavities, in the pleural cavity it plays a greater role in the function of breathing.
  • Describe the function of the serous membranes in the pericardial, pleural, and peritoneal cavities

• Serosa

  • Serous membranes line and enclose several body cavities, known as serous cavities, where they secrete a lubricating fluid that reduces friction from muscle movement.
  • The pericardial cavity (surrounding the heart), pleural cavity (surrounding the lungs) and peritoneal cavity (surrounding most organs of the abdomen) are the three serous cavities within the human body.
  • While serous membranes have a lubricative role to play in all three cavities, in the pleural cavity it has a greater role to play in the function of breathing.
  • Early in embryonic life, visceral organs develop adjacent to a cavity and invaginate into the bag-like coelom.
  • Therefore each organ becomes surrounded by serous membrane - they do not lie within the serous cavity.

• Bilaminar Embryonic Disc Development

  • The floor of the amniotic cavity is formed by the embryonic disc.
  • The floor of the amniotic cavity is formed by the embryonic disc, which is composed of a layer of prismatic cells and the embryonic ectoderm.
  • As the embryo progresses in implantation, a small space appears in the embryoblast and forms the amniotic cavity.
  • The epiblast forms the floor of the amniotic cavity and is continuous with the amnion.
  • The hypoblast forms the roof of the exocoelomic cavity and is continuous with the thin exocoelomic membrane.

• Inspiration

  • Inspiration begins with the contraction of the diaphragm, which results in expansion of the thoracic cavity and the pleural cavity.
  • As the volume of air inside the lung increases, the lung pushes back against the expanded pleural cavity as a result of the drop in intrapleural pressure (pressure inside the pleural cavity).
  • External intercostal muscles: muscles located in between the ribs that help the thoracic cavity (and thus pleural cavity) to expand during quiet and forced inspiration.
  • 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.