Learning Objectives By the end of this section, you will be able to: As discussed in Cellular Defenses, major histocompatibility complex (MHC) molecules are expressed on the surface of healthy cells, identifying them as normal and “self” to natural killer (NK) cells. MHC molecules…
Learning Objectives By the end of this section, you will be able to: Clinical Focus Part 1 Olivia, a one-year old infant, is brought to the emergency room by her parents, who report her symptoms: excessive crying, irritability, sensitivity to…
Figure 18.1 Polio was once a common disease with potentially serious consequences, including paralysis. Vaccination has all but eliminated the disease from most countries around the world. An iron-lung ward, such as the one shown in this 1953 photograph, housed patients paralyzed…
Sound Waves Speed of Sound Sound Intensity Normal Modes of a Standing Sound Wave Sources of Musical Sound Beats The Doppler Effect Shock Waves
Learning Objectives By the end of this section, you will be able to: When discussing the Doppler effect of a moving source and a stationary observer, the only cases we considered were cases where the source was moving at speeds…
Learning Objectives By the end of this section, you will be able to: The characteristic sound of a motorcycle buzzing by is an example of the Doppler effect. Specifically, if you are standing on a street corner and observe an ambulance…
Learning Objectives By the end of this section, you will be able to: The study of music provides many examples of the superposition of waves and the constructive and destructive interference that occurs. Very few examples of music being performed…
Learning Objectives By the end of this section, you will be able to: Some musical instruments, such as woodwinds, brass, and pipe organs, can be modeled as tubes with symmetrical boundary conditions, that is, either open at both ends or closed…
Learning Objectives By the end of this section, you will be able to: Interference is the hallmark of waves, all of which exhibit constructive and destructive interference exactly analogous to that seen for water waves. In fact, one way to…
Learning Objectives By the end of this section, you will be able to: In a quiet forest, you can sometimes hear a single leaf fall to the ground. But when a passing motorist has their stereo turned up, you cannot…