Anatomical Variability
Anatomical Variability
Humans differ externally and internally.
90 % of all structures present in the body match the description in the textbook.
Body Cavities
The two sets of internal of internal body cavities called the dorsal and ventral body cavities are closed to the outside and provide different degrees of protection to the organs within them.
Dorsal body cavity
The -------- protects the fragile nervous system organs, has two subdivisions. It has two subdivisions the cranial and vertebral cavity.
Cranial cavity
The ---------, in the skull, encases the brain
Vertebral or spinal
The ------- cavity, which runs within the bony vertebral column, encloses the delicate spinal cord.
Ventral Body Cavity
The more anterior and larger of the closed body cavities is --------. It has two major subdivisions, the thoracic cavity and the abdominopelvic cavity.
Viscera
The ventral body cavity houses internal organs collectively called the ------ (viscus = an organ in a body cavity), or visceral organs.
Thoracic cavity
The superior subdivision, the ---------- is surrounded by the ribs and muscles of the chest.
Medial Mediastinum
The thoracic cavity is further subdivided into lateral pleural cavities each enveloping a lung, and the ----------- -------.
Pericardial Cavity
The mediastinum contains the --------, which encloses the heart, and it also surrounds the remaining thoracic organs (esophagus, trachea, and others).
Abdominopelvic Cavity
The thoracic cavity is separated from the more inferior ---------- by the diaphragm, a dome-shaped muscle important in breathing.
The abdominopelvic cavity, as its name suggests, has two parts. However these regions are not --------- separated by a muscular or membrane wall.
Psychically
Its superior portion, the -------- ----, contains the stomach, intestine, spleen, liver, and other organs.
Abdominal cavity
Pelvic Cavity
The inferior part, the ------, lies in the bony pelvis and contains the urinary bladder, some reproductive organs, and the rectum.
Membranes in the Ventral Body Cavity
Membranes in the Ventral Body Cavity
Serosa or serous membrane.
The walls of the ventral body cavity and the outer surfaces of the organ it contains are covered by a thin, double-layered membrane, the ------- ------.
Parietal Serosa
The part of the membrane lining the cavity walls is called the ---------. It folds in on itself to form the visceral serosa, covering the organs in the cavity.
In the body, the serous membrane are separated not by air but by a thin layer of lubricating fluid, called --------, which is secreted by both membranes.
Serous Fluid
Slippery
The ------- serous fluids allows the organs to slide without friction across the cavity walls and one another as they carry out their routine functions.
The serous membranes are named for the specific cavity and organs in which they are associated pg. 18
Pericardium = Heart
Pleurae = Lungs
Peritoneum = Abdominopelvic cavity
Abdominopelvic Regions and Quadrants
Because the abdominopelvic cavity is large and contains several organs, it helps to divide it into smaller areas for study.
Medical personnel usually use a simple scheme to locate the abdominopelvic cavity organs. In this scheme, a transverse and a median plane pass through the umbilicus at right angles.
The four resulting quadrants are named according to their positions from the subject's point of view: the right upper quadrant (RUQ), left upper quadrant (LUQ), right lower quadrant (RLQ), and left lower quadrant (LLQ).
Another division method, used primarily by anatomists, uses two transverse and two parasagittal planes. These planes, positioned like a tic-tac-toe grid on the abdomen, divide the cavity into nine regions:
Another division method, used primarily by anatomists, uses two transverse and two parasagittal planes. These planes, positioned like a tic-tac-toe grid on the abdomen, divide the cavity into nine regions:
Umbilical
The ------- region is the centermost region deep to and surrounding the umbilicus (navel).
Epigastric
The ------- region is located superior to the umbilical region (epi = upon, above; gastri = belly).
Hypogastric
The -------- (pubic) region is located inferior to the umbilical region (hypo=below).
Right and Left
The ------- iliac, or inguinal, regions are located lateral to the hypogastric region ( iliac=superior part of the hip bone)
lumbar
The right and left ----- regions lie lateral to the umbilical region (lumbus = loin).
hypochondria
The right and left ------ regions lie lateral to the epigastric region and deep to the ribs (chondro = cartilage)
Other Body Cavities
In addition to the large close body cavities, there are several smaller body cavities. Most of these are in the head and most open to the body exterior.
Other Body Cavities
Exposed to environment
Oral and digestive
-------- cavities the oral cavity, commonly called the mouth contains the teeth and tongue.
Oral and digestive
------ is part of and continuous with the cavity of the digestive organs, which opens to the body exterior at the anus.
Nasal Cavity
------- located within and posterior to the nose, the nasal cavity is part of the respiratory system passageways.
Middle Ear Cavities
------- the middle ear cavities in the skull lie just medial to the eardrums.
Middle Ear
------- cavities contain tiny bones that transmit sound vibrations to the hearing receptors in the inner ears.
Synovial Cavities
-------- are joint cavities. They are enclosed within fibrous capsules that surround freely movable joints of the body (such as the elbow and knee joints).
friction
Like the serous membranes, membranes lining synovial cavities secrete a lubricating fluid that reduces ------- as the bones move across one another.