Chapter Summary

1. Our scientific name, Homo sapiens, means "man the intelligent," and our intelligence is our most distinguishing feature.
2. Humans belong to the phylum Chordata because of the presence of a notochord, a dorsal hollow nerve cord, and pharyngeal pouches during the embryonic stage of human development.
3. Humans are mammals, and as such have mammalian characteristics. These include hair, mammary glands, three auditory ossicles, heterodontia, a placenta, a muscular diaphragm, and a four-chambered heart with a left aortic arch.
4. Humans are also classified within the order Primates. Primates have prehensile hands, digits modified for grasping, and well-developed brains.
5. Humans are the sole members of the family Hominidae.
6. Some of the characteristics of humans are a large, well-developed brain; bipedal locomotion; an opposable thumb; well-developed vocal structures; and stereoscopic vision.

Body Organization

1. Cells are the fundamental structural and functional components of life.
2. Tissues are aggregations of similar cells that perform specific functions.
3. An organ is a structure consisting of two or more tissues that performs a specific function.
4. A body system is composed of a group of organs that function together.

Anatomical Nomenclature

1. Most anatomical terms are derived from Greek or Latin words that provide clues to the meaning of the terms.
2. Familiarity with the basic prefixes and suffixes facilitates learning and remembering anatomical terminology.
3. Anatomy is a foundation science for all of the medical and paramedical fields.

Planes of Reference and Descriptive Terminology

1. The body or organs of the body may be sectioned according to planes of reference. These include a midsagittal plane that runs vertically through a structure, dividing it into right and left halves; a sagittal plane that runs vertically through a structure, dividing it into right and left portions; a coronal (frontal) plane that runs vertically through a structure, dividing it into anterior (front) and posterior (back) portions; and a transverse (cross-sectional) plane that runs horizontally through a structure, dividing it into upper and lower portions.
2. In the anatomical position, the subject is standing with feet parallel, eyes directed forward, and arms at the sides of the body with palms turned forward and fingers pointing downward.
3. Directional terms are used to describe the location of one body part with respect to another part in anatomical position.
4. Clinical procedures include observation (visual inspection), palpation (feeling with firm pressure), percussion (detecting resonating vibrations), auscultation (listening to organ sounds), and reflex-response testing (determining involuntary movements).

Body Regions

1. The head is divided into a facial region, which includes the eyes, nose, and mouth, and a cranial region, which covers and supports the brain.
2. The neck is called the cervical region and functions to support the head and permit movement.
3. The front of the thorax is subdivided into two mammary regions and one sternal region.
4. On either side of the thorax is an axillary fossa and a lateral pectoral region.
5. The abdomen may be divided into nine anatomical regions or four quadrants.
6. Regional names pertaining to the upper extremity include the shoulder, brachium, antebrachium, and manus.
7. Regional names pertaining to the lower extremity include the hip, thigh, leg, and foot.

Body Cavities and Membranes

1. The posterior cavity, which encompasses the cranial and spinal cavities, encloses and protects the brain and spinal cord, "the central nervous system."
2. The anterior cavity, which encompasses the thoracic and abdominopelvic cavities, contains the visceral organs.
3. Other body cavities include the oral, nasal, and middle-ear cavities.
4. The body has two principal types of membranes: mucous membranes, which secrete protective mucus, and serous membranes, which line the ventral cavities and cover visceral organs. Serous membranes secrete a lubricating serous fluid.
5. Serous membranes may be categorized as pleural membranes (associated with the lungs), pericardial membranes (associated with the heart), or peritoneal membranes (associated with the abdominal viscera).