By H. Ramirez. Belhaven College.
Lateral commissure Lateral junction of the upper and lower eyelids Sclera Outer fibrous layer of the eyeball; the “white” Lacrimal caruncle Fleshy purchase 400 mg hoodia with mastercard, pinkish elevation at the medial commissure order hoodia 400 mg fast delivery. Eyebrows protect against potentially damaging sunlight and contraction of these muscles may eventually cause permanent mechanical blows; eyelids reflexly close to protect against ob- crease lines in the skin. Optometry and ophthalmology are con- materials and prevent the surface of the eyeball from drying. Dentistry is entirely Many of the surface features of the ocular region are shown in devoted to the health and functional and cosmetic problems of the figure 10. The auricular region includes the visible surface structures and internal organs that function in hearing and maintaining The ocular region includes the eyeball and associated struc- equilibrium. Most of the surface features of the ocular region protect the the middle ear, called the external acoustic canal, are the only Van De Graaff: Human IV. Surface and Regional © The McGraw−Hill Anatomy, Sixth Edition Anatomy Companies, 2001 Chapter 10 Surface and Regional Anatomy 303 TABLE 10. External acoustic canal Earlobe Fleshy inferior portion of the auricle Antitragus Tragus Small projection of the auricle, just anterior to the external acoustic canal. Earlobe Antitragus Small, cartilaginous anterior projection opposite the tragus Antihelix Semicircular ridge anterior to the greater portion of the helix Concha Depressed hollow of the auricle. External acoustic canal Slightly S-shaped tube extending inward FIGURE 10. Triangular fossa Triangular depression in the superior part of the antihelix observable surface features of the auricular region. The rim of the auricle, shaped and supported by elastic cartilage, is called the helix; the inferior portion is referred to as the earlobe. The earlobe is composed primarily of connective and fatty tissue, bones unite. For this reason, it is some- firm,narrow part between the eyes is the bridge (dorsum nasi) of times used when obtaining blood for a blood count.
FIGURE: Understanding the actions of muscles is possible only through knowing their precise points of attachment generic hoodia 400 mg line. Muscular System © The McGraw−Hill Anatomy purchase 400mg hoodia visa, Sixth Edition Companies, 2001 234 Unit 4 Support and Movement 3. The skeletal system provides a INTRODUCTION framework for the body, but skeletal muscles maintain pos- TO THE MUSCULAR SYSTEM ture, stabilize the flexible joints, and support the viscera. Certain muscles are active postural muscles whose primary Skeletal muscles are adapted to contract in order to carry out the function is to work in opposition to gravity. Some postural functions of generating body movement, producing heat, and sup- muscles are working even when you think you are relaxed. As you are sitting, for example, the weight of your head is Objective 1 Define the term myology and describe the balanced at the atlanto-occipital joint through the efforts three principal functions of muscles. If you start to get sleepy, your head will suddenly nod forward as the Objective 2 Explain how muscles are described according postural muscles relax and the weight (resistance) over- to their anatomical location and cooperative function. Muscle tissue in the body is of three types: smooth, cardiac, Myology is the study of muscles. Although these three types differ in make up the muscular system, and technically each one is an structure and function, and the muscular system refers only to organ—it is composed of skeletal muscle tissue, connective tissue, the skeletal muscles composed of skeletal tissue, the following and nervous tissue. Each muscle also has a particular function, such basic properties characterize all muscle tissue: as moving a finger or blinking an eyelid. Collectively, the skeletal muscles account for approximately 40% of the body weight. Muscle tissue is sensitive to stimuli from nerve Muscle cells (fibers) contract when stimulated by nerve impulses. Muscle tissue responds to stimuli by con- cause a noticeable effect, but isolated fiber contractions are im- tracting lengthwise, or shortening. Once a stimulus has subsided and the fibers cient number of skeletal muscle fibers are activated, the muscle within muscle tissue are relaxed, they may be stretched contracts and causes body movement. The fibers are then prepared for another (2) heat production, and (3) body support and maintenance of contraction. The most obvious function performed by dency to recoil to their original resting length. A histological description of each of the three muscle types Even the eyeball and the auditory ossicles have associated was presented in chapter 4 and should be reviewed at this skeletal muscles that are responsible for various move- time.
Define bipedal locomotion and discuss the “certain peculiarities of the right little (d) the greater sciatic notch adaptations of the pelvic girdle and lower finger suggest that he may have played (e) the linea aspera extremities that allow for this type of the harpsichord buy hoodia 400 mg online, piano buy hoodia 400 mg amex, or a stringed movement. Explain how the female pelvis is adapted bones can serve as a storehouse of line would involve to the needs of pregnancy and childbirth. Explain the significance of the limb buds, technology, what other types of (b) the femur. What is meant by a congenital skeletal adaptation of the hand or adaptation of pelvis malformation? Speculate as to why a single bone is (b) is narrower at the pelvic outlet. What are the differences between thigh, whereas the antebrachium and leg (d) has a shallower symphysis pubis. Clubfoot is a congenital foot deformity that Give some examples of traumatic 4. Compare the tibia and fibula with respect is clinically referred to as fractures. Why is it important that the fracture be of the tibia or a compound fracture of the (c) pes planus. Contrast the structure of the pectoral and Smithsonian Institution, died in 1829 at pelvic girdles. Articulations © The McGraw−Hill Anatomy, Sixth Edition Companies, 2001 Articulations 8 Classification of Joints 197 Fibrous Joints 197 Cartilaginous Joints 199 Synovial Joints 200 Developmental Exposition: The Synovial Joints 206 Movements at Synovial Joints 207 Specific Joints of the Body 214 CLINICAL CONSIDERATIONS 224 Clinical Case Study Answer 229 Important Clinical Terminology 230 Chapter Summary 230 Review Activities 231 Clinical Case Study A 20-year-old college football player sustained injury to his right knee during the opening game of the season. Because of rapid swelling and intense pain, he was taken to the emergency room of the local hospital. When the attending physician asked him to describe how the injury oc- curred, the athlete responded, “I was carrying the ball on an end run left on third down and two. As I planted my right foot just before I was going to make my cut, I was hit in the knee from the side. I felt my knee give way, and then I felt a stabbing pain on the inside of my knee. The doctor determined that valgus stress (an inward bowing stress on the knee) caused the medial aspect of the joint to “open.
