chapter 2 For Review Only Not for Duplication or Classroom Use Body Regions and Major Body Cavities I. Body Regions Introduction

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1 Body Regions and Major Body Cavities JJ Introduction In the first lab activity you were introduced to various generic terms that indicate locations on and in the body. These terms are applicable to any animal. In this exercise you will learn terms to indicate specific regions of the human body, and you will learn about the major cavities within the human body, where many of the vital internal organs are housed. I. Body Regions Objective 1: Identify the specific regions of the body listed on the following page. If someone asked you to point to your shoulder, you could certainly fulfill this request. Could you comply with the request to point to your popliteal region? Sometimes common terms are properly used in A&P. Often you need to learn new terms in place of the more common terms. 11

2 ACTIVITY 1 Look at Figure 2-1. For each of the body regions below provide a description of the region in your own words in Table 2-1. The first one has been done for you. A Oral Cervical Deltoid Axillary Brachial Antecubital Abdominal Digital Pubic Femoral Digital Orbital Buccal Sternal Pectoral Umbilical Inguinal Patellar Hayden-McNeil, LLC B Figure 2-1. Body regions. Occipital Deltoid Lumbar Sacral Popliteal Plantar 12

3 Body Regions and Major Body Cavities Table 2-1. Body region descriptions. 1. occipital the back of the head 12. sternal 2. orbital 13. abdominal 3. oral 14. umbilical 4. buccal 15. lumbar 5. cervical 16. sacral 6. deltoid 17. inguinal 7. pectoral 18. pubic 8. axillary 19. femoral 9. brachial 20. patellar 10. antecubital 21. popliteal 11. digital 22. plantar 13

4 QUESTION 1. Although we have not yet studied the skeletal system, can you identify three of the body regions with names that match bones in those locations? II. Major Body Cavities Objective 2: Describe the major body cavities and identify various organs found in each. If you have ever cleaned a fish or dissected an animal in science class, you may recall that when you cut into the abdomen you open a space that contains various organs, such as the stomach. Cracking open the skull reveals the cavity that contains the brain. Before embarking upon studies of the major organ systems, we will learn the names and locations of the cavities in which some of the organs reside. There are two major cavities within the human body: the dorsal body cavity and the ventral body cavity. The dorsal body cavity lies within the skull and within the spine. Although it is one continuous space, we can divide the dorsal body cavity into two parts: the space inside the skull is the cranial cavity, and the space inside the spine is the vertebral cavity. The brain occupies the cranial cavity, and the spinal cord occupies the vertebral cavity. The ventral body cavity is much larger than the dorsal body cavity, and it contains more organs. The superior portion of the ventral body cavity is separated from the inferior portion by the diaphragm. The entire superior portion is called the thoracic cavity, and it is further subdivided into a medial portion, called the mediastinum, and two lateral portions, called the pleural cavity. The mediastinum contains the trachea and the esophagus. It also contains yet another cavity, called the pericardial cavity, which contains the heart. Each of the two pleural cavities contains one of the lungs. The inferior portion of the ventral body cavity is called the abdominopelvic cavity. This cavity also is further subdivided: the superior portion is the abdominal cavity, and the inferior portion is the pelvic cavity. The abdominal cavity contains many organs, including the stomach, liver, spleen, pancreas, and intestines. The pelvic cavity contains the urinary bladder, the rectum, and some reproductive organs. 14

5 Body Regions and Major Body Cavities ACTIVITY 2 Label the diagrams in Figure 2-2 with the names of the appropriate body cavities. A. Body cavities lateral view B. Body cavities anterior view Hayden-McNeil, LLC Figure 2-2. Dorsal and ventral body cavities. 15

6 Fill in the blanks to complete an organizational outline of the major body cavities. I. Dorsal body cavity A. The cavity encloses the brain. B. The cavity encloses the spinal cord. II. Ventral body cavity A. The cavity is superior to the diaphragm. 1. The contains the esophagus, the trachea, and the pericardial cavity. 2. The cavity contains the heart. 3 The cavity contains the lungs. B. The cavity is inferior to the diaphragm. 1. The cavity contains the stomach and intestines. 2. The cavity contains the urinary bladder and the rectum. III. Membranes That Line the Major Body Cavities Objective 3: Identify the membranes that line the major body cavities. Organs in the dorsal body cavity are wrapped in membranes called the meninges. You will study these membranes in more detail when you study the nervous system later in the semester. Organs in the ventral body cavity are wrapped in two-layered membranes called serous membranes. Each organ is wrapped in a thin layer of membrane referred to as the visceral serosa. The inside of the body cavity wall is lined in a thin layer of membrane referred to as the parietal serosa. Between the visceral serosa and the parietal serosa is serous fluid, which lubricates the membranes. The serous membranes are given specific names according to the specific parts of the ventral body cavity in which they are found. The membranes in the pericardial cavity are the visceral pericardium and parietal pericardium. The membranes in the pleural cavities are the visceral pleura and the parietal pleura. The membranes in the abdominopelvic cavity are the visceral peritoneum and the parietal peritoneum. Additional membranes, called mesenteries, hold the organs of the abdominopelvic cavity in place, attaching them to each other and to the inside of the body wall. 16

7 Body Regions and Major Body Cavities ACTIVITY 3 Obtain a roll of clear tape and a bean. Imagine the shaded area below represents a portion of the inside of the abdominal cavity wall, and imagine the bean represents the stomach. Tear a piece of tape about three or four inches long. Fold the middle section of the tape around the bean, stick the tape together for about half an inch, then stick the free ends of the tape to the shaded area on the page. Your instructor should demonstrate this for you. QUESTIONS 2. Refer to Activity 3, and be as specific as possible with your answers. What does the tape attached to the shaded portion of the page represent? What does the tape that surrounds the bean represent? What does the section of the tape stuck together between the page and the bean represent? 3. Pleurisy is a condition in which the serous membranes associated with the lungs become inflamed. Inflamed serous membranes typically produce less serous fluid than normal, and breathing becomes painful when a person has pleurisy. Briefly explain why serous fluid is particularly important for the lungs. 17

8 4. Why are mesenteries not necessary in the pleural or pericardial cavities? CLEAN UP Return rolls of tape and unused beans to their proper places. Throw away all trash. Leave your tables clean (wipe them down if necessary) and push in your stools before leaving. 18