1. Organization of the Human Body – Body Cavities and Membranes
Chapter 1
Organization of the Human Body – Body Cavities and Membranes

2. Major Parts of Human Body
The human body consists of three major parts:
Cavities
Membranes
Organ Systems

3. Major Divisions of the Human Body
The human body can be separated into:
Axial portion
Includes the head, neck, and trunk
Appendicular portion
Includes the upper and lower limbs

4. Cavities of the Axial Portion
Cranial cavity
Houses the brain

5. Cavities of the Axial Portion
Vertebral canal
Contains the spinal cord surrounded by portions of the backbone (vertebrae)

6. Cavities of the Axial Portion
Thoracic cavity
Contains organs called viscera:
Lungs, heart, esophagus, trachea, and thymus gland
The wall of the thoracic cavity consists of skin, skeletal muscles, and bones.
The region between the left and the right lungs is called the mediastinum.
The mediastinum contains the heart, esophagus, trachea, and thymus gland
Separates the thorax into two compartments (one containing the right lung and one containing the left lung).

7. Cavities of the Axial Portion
Abdomino-pelvic cavity
Includes an upper abdominal portion and a lower pelvic portion
Contains organs called viscera
The viscera within the abdominal cavity include the stomach, liver, spleen, gallbladder, and the small and large intestines
The pelvic cavity (which is the area enclosed by the pelvic bones) contains the terminal end of the large intestine, the urinary bladder, and the internal reproductive organs
The wall of the abdomino-pelvic cavity primarily consists of skin, skeletal muscles, and bones
Separated from the thoracic cavity by the diaphragm
The diaphragm is a broad thin muscle that curves upward into the thorax like a dome when it is at rest and presses down on the abdominal viscera when it contracts during inhalation

8. Cavities of the Axial Portion
Smaller cavities within the head:
Oral cavity
Contains the teeth and tongue
Nasal cavity
Located within the nose
Divided into right and left portion by a nasal septum
Several air-filled sinuses (including sphenoidal and frontal sinuses) are connected to the nasal cavity.
Orbital cavities
Contain the eyes and associated muscles and nerves
Middle ear cavities
Contain the middle ear bones

9. Cavities of the Axial Portion

10. Cavities of the Axial Portion

11. Cavities of the Axial Portion

12. Thoracic and Abdominopelvic Membranes
Serous membranes
Thin membranes that line the walls of the thoracic and abdominal cavities
Fold back to cover organs within both cavities
Secrete a slippery serous fluid that separates the layer lining the wall (called the parietal layer) from the layer covering the organ (called the visceral layer)

13. Thoracic and Abdominopelvic Membranes
Thoracic membranes
Parietal pleura – serous membrane that lines the right and left thoracic compartments, which contain the lungs
Visceral pleura – part of the parietal pleura that folds back to cover the lungs
A thin film of serous fluid separates the parietal and visceral pleural membranes.
Pleural cavity
The potential space between the membranes

14. Thoracic and Abdominopelvic Membranes
Pericardial membranes
Surround the heart (which is located in the broadest portion of the mediastinum)
Visceral pericardium
Cover’s the surface of the heart
Parietal pericardium
Layer that covers the visceral pericardium but that is separated from the visceral pericardium by a small amount of serous fluid.
The potential space between the two membranes is called the pericardial cavity
Fibrous pericardium
Much thicker layer that covers the parietal pericardium

15. Thoracic and Abdominopelvic Membranes

16. Thoracic and Abdominopelvic Membranes
Peritoneal membranes
Parietal peritoneum
Lines the wall
Visceral peritoneum
Covers each organ in the abdominal cavity
Peritoneal cavity
The potential space between the parietal peritoneum and the visceral peritoneum

17. Thoracic and Abdominopelvic Membranes