Terminology
Cranial- towards the head
Caudal- towards the tail
Medial towards the middle of the animal
Lateral- towards the side of the animal
Ventral- towards the belly of the animal
Rostral- towards the nose
Distal- furthest from the body of the animal
Proximal- nearest to the body of the animal
Dorsal- towards the back
Body cavity
The body can be divided into compartments.
Thorax- heart/lungs
Abdomen- spleen/liver/kidney/stomach
Pelvic cavity- rectum//bladder/colon/anus
Mediastinum- heart
Coelom (birds & reptiles)- thorax and abdominal organs
Cavity lining
They are all linned with a serious membrane which secretes a small amount of serous fluid.
This acts as a lubricant between the surfaces of the cavity and the organ structure within it.
Serous membranes are composed of simple squamous epithelium.
Serious membrane
Each part of the serious membrane is a continuous layer, named according to its postion within the cavity.
Parietal- describes the serous membranes that lines the boundaries or sides
Visceral-
Thorax cavity
Lined by a serious membrane known as the pleura which is forms the pleura cavity.
Divided left/right by a double layer called the mediastinum
The space between theses layers contains the heart and other structures
The pleura covering the lungs can also be called the pulmonary or visceral pleura.
Negative pressure
Between the lungs and the parietal pleura is the pleura space.
This has negative pressure in relation to the atmospheric pressure
This then allows the lungs to inflate.
Pleura fluid moves freely to allow organs to move.
Abdominal cavity
The serious membrane is reffered to as the peritoneum and forms the peritoneal cavity
The membrane consists of a single layer of cells which produce peritoneal fluids. (small amount)
Pelvic cavity
Is not physical seperated and so is used as an anatomic term
Covers the cranial surface within the cavity including the bladder, uterus.
The remainder is filled with organs, muscles, connective tissue which is not linned.
Mediastinum
