CHAPTER 1 Introduction to the Human body Pleurisy is an inflammation of the pleural membranes associated with a lung. The infection generally confined to just one of the pleural cavities. Trauma to a pleural cavity(such as from a crushed rib cage or a bullet or knife wound) may permit air to enter the pleural cavity--a condi tion known as a pneumothorax. Blood in a pleural cavity is known as a hemothorax. a pneumoth- orax causes the lung on the affected side to collapse. The compartmentalization of thoracic organs, however, ensures that one of the lungs will remain functional 1. 26 Define peritoneal cavity and explain what is meant by a retroperitoneal organ. The parietal peritoneum is a thin membrane attached to the inside of the abdominal wall. It is continuous around the intestinal viscera as the visceral peritoneum. The peritoneal cavity is the space between the parietal and visceral portions of the peritoneum. Retroperitoneal organs, such as the kidneys, adrenal glands, and a portion of the pancreas, are positioned behind the parieal peritoneum but are still within the abdominopelvic cavity. Peritonitis is an inflammation of the peritoneal membrane. The infection is confined to the peri toneal cavity. Normally, this cavity is aseptic, but it can become contaminated by trauma, rupture of a visceral organ(e.g, a ruptured appendix), an ectopic pregnancy(abnormal pregnancy site) or postoperative complications. Peritonitis is usually extremely painful and life threatening Treatment usually involves the injection of massive doses of antibiotics and perhaps peritoneal intubation to permit drainage 1.27 State the function of the mesenteries The mesenteries are double-layered membranes that support the abdominopelvic viscera in a pendent fashion so that intestinal peristalsis(rhythmic waves of muscular contraction) will not be impeded. The mesenteries also support the vessels and nerves that serve the viscera Objective K To become familiar with the descriptive and directional terms that are applied to anatomical Descriptive and directional terms are used to communicate the position of structures, surfaces, and regions of the body with respect to anatomical position 1. 28 Define the important descriptive and directional terms and illustrate their usage Some of the more commonly used descriptive and directional terms are listed in table 1.2 TABLE 1. 2 Commonly Used Descriptive and Directional Terms TERM DEFINITION EXAMPLE Superior(cranial) Toward the top: toward the head The thorax is superior to the abdomen Inferior(caudal) Away from the head; toward the bottom The legs are inferior to the trunk Toward the front The navel is on the anterior side of the body. Posterior(dorsal) The kidneys are posterior to the intestines. Toward the midline of the body The heart is medial to the lung Lateral Toward the side of the body The ears are lateral to the head Internal(deep) Away from the surface of the bod The brain is internal to the External(superficial) Toward the surface of the body The skin is external to the muscles Toward the main mass of the body The knee is proximal to the foot Away from the main mass of the body The hand is distal to the elbow Related to internal organs The lungs are covered by a thin membrane called the visceral pleura. Parietal Related to the body walls The parietal pleura is the inside lining of the thoracic cavity.Pleurisy is an inflammation of the pleural membranes associated with a lung. The infection is generally confined to just one of the pleural cavities. Trauma to a pleural cavity (such as from a crushed rib cage or a bullet or knife wound) may permit air to enter the pleural cavity—a condi￾tion known as a pneumothorax. Blood in a pleural cavity is known as a hemothorax. A pneumoth￾orax causes the lung on the affected side to collapse. The compartmentalization of thoracic organs, however, ensures that one of the lungs will remain functional. 1.26 Define peritoneal cavity and explain what is meant by a retroperitoneal organ. The parietal peritoneum is a thin membrane attached to the inside of the abdominal wall. It is continuous around the intestinal viscera as the visceral peritoneum. The peritoneal cavity is the space between the parietal and visceral portions of the peritoneum. Retroperitoneal organs, such as the kidneys, adrenal glands, and a portion of the pancreas, are positioned behind the parieal peritoneum but are still within the abdominopelvic cavity. Peritonitis is an inflammation of the peritoneal membrane. The infection is confined to the peri￾toneal cavity. Normally, this cavity is aseptic, but it can become contaminated by trauma, rupture of a visceral organ (e.g., a ruptured appendix), an ectopic pregnancy (abnormal pregnancy site), or postoperative complications. Peritonitis is usually extremely painful and life threatening. Treatment usually involves the injection of massive doses of antibiotics and perhaps peritoneal intubation to permit drainage. 1.27 State the function of the mesenteries. The mesenteries are double-layered membranes that support the abdominopelvic viscera in a pendent fashion so that intestinal peristalsis (rhythmic waves of muscular contraction) will not be impeded. The mesenteries also support the vessels and nerves that serve the viscera. Objective K To become familiar with the descriptive and directional terms that are applied to anatomical structures. Descriptive and directional terms are used to communicate the position of structures, surfaces, and regions of the body with respect to anatomical position. 1.28 Define the important descriptive and directional terms and illustrate their usage. Some of the more commonly used descriptive and directional terms are listed in table 1.2. 12 CHAPTER 1 Introduction to the Human Body Survey TABLE 1.2 Commonly Used Descriptive and Directional Terms TERM DEFINITION EXAMPLE Superior (cranial) Toward the top; toward the head The thorax is superior to the abdomen. Inferior (caudal) Away from the head; toward the bottom The legs are inferior to the trunk. Anterior (ventral) Toward the front The navel is on the anterior side of the body. Posterior (dorsal) Toward the back The kidneys are posterior to the intestines. Medial Toward the midline of the body The heart is medial to the lungs. Lateral Toward the side of the body The ears are lateral to the head. Internal (deep) Away from the surface of the body The brain is internal to the cranium. External (superficial) Toward the surface of the body The skin is external to the muscles. Proximal Toward the main mass of the body The knee is proximal to the foot. Distal Away from the main mass of the body The hand is distal to the elbow. Visceral Related to internal organs The lungs are covered by a thin membrane called the visceral pleura. Parietal Related to the body walls The parietal pleura is the inside lining of the thoracic cavity