{"id":4456,"date":"2017-03-29T16:08:55","date_gmt":"2017-03-29T16:08:55","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=4456"},"modified":"2024-04-26T02:19:57","modified_gmt":"2024-04-26T02:19:57","slug":"sound-and-reception","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/sound-and-reception\/","title":{"raw":"Sound and Reception","rendered":"Sound and Reception"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Describe the relationship of amplitude and frequency of a sound wave to attributes of sound<\/li>\r\n \t<li>Trace the path of sound through the auditory system<\/li>\r\n<\/ul>\r\n<\/div>\r\nAuditory stimuli are sound waves, which are mechanical, pressure waves that move through a medium, such as air or water. There are no sound waves in a vacuum since there are no air molecules to move in waves. The speed of sound waves differs, based on altitude, temperature, and medium, but at sea level and a temperature of 20\u00ba C (68\u00ba F), sound waves travel in the air at about 343 meters per second.\r\n\r\nAs is true for all waves, there are four main characteristics of a sound wave: frequency, wavelength, period, and amplitude. Frequency is the number of waves per unit of time, and in sound is heard as pitch. High-frequency (\u226515.000Hz) sounds are higher-pitched (short wavelength) than low-frequency (long wavelengths; \u2264100Hz) sounds. Frequency is measured in cycles per second, and for sound, the most commonly used unit is hertz (Hz), or cycles per second. Most humans can perceive sounds with frequencies between 30 and 20,000 Hz. Women are typically better at hearing high frequencies, but everyone\u2019s ability to hear high frequencies decreases with age. Dogs detect up to about 40,000 Hz; cats, 60,000 Hz; bats, 100,000 Hz; and dolphins 150,000 Hz, and American shad (<em class=\"emphasis\" data-effect=\"italics\">Alosa sapidissima<\/em>), a fish, can hear 180,000 Hz. Those frequencies above the human range are called <b>ultrasound<\/b>.\r\n\r\nAmplitude, or the dimension of a wave from peak to trough, in sound is heard as volume and is illustrated in Figure\u00a01. The sound waves of louder sounds have greater amplitude than those of softer sounds. For sound, volume is measured in decibels (dB). The softest sound that a human can hear is the zero point. Humans speak normally at 60 decibels.\r\n\r\n[caption id=\"attachment_2714\" align=\"aligncenter\" width=\"544\"]<img class=\"size-full wp-image-2714\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/07215102\/Figure_36_04_01.jpg\" alt=\"A graph shows a regularly repeating sine wave that goes gradually up, then down, then up again. The distance between two crests is the wavelength. The amplitude is the height of the wave. On the graph, two waves with different wavelengths but the same amplitude are superimposed on one another.\" width=\"544\" height=\"372\" \/> Figure\u00a01.\u00a0For sound waves, wavelength corresponds to pitch. Amplitude of the wave corresponds to volume. The sound wave shown with a dashed line is softer in volume than the sound wave shown with a solid line. (credit: NIH)[\/caption]\r\n<h2>Reception of Sound<\/h2>\r\nIn mammals, sound waves are collected by the external, cartilaginous part of the ear called the <b>pinna<\/b>, then travel through the auditory canal and cause vibration of the thin diaphragm called the <b>tympanum<\/b> or ear drum, the innermost part of the <b>outer ear<\/b> (illustrated in\u00a0Figure\u00a02). Interior to the tympanum is the <b>middle ear<\/b>. The middle ear holds three small bones called the <b>ossicles<\/b>, which transfer energy from the moving tympanum to the inner ear. The three ossicles are the <b>malleus<\/b> (also known as the hammer), the <b>incus<\/b> (the anvil), and <b>stapes<\/b> (the stirrup). The aptly named stapes looks very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in hearing. The malleus attaches at three points to the interior surface of the tympanic membrane. The incus attaches the malleus to the stapes. In humans, the stapes is not long enough to reach the tympanum. If we did not have the malleus and the incus, then the vibrations of the tympanum would never reach the inner ear. These bones also function to collect force and amplify sounds. The ear ossicles are homologous to bones in a fish mouth: the bones that support gills in fish are thought to be adapted for use in the vertebrate ear over evolutionary time. Many animals (frogs, reptiles, and birds, for example) use the stapes of the middle ear to transmit vibrations to the middle ear.\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"660\"]<img id=\"4\" class=\"\" src=\"https:\/\/openstax.org\/resources\/487050861455b4b7c74f1fc8d24f6b5c53513433\" alt=\"This image shows the structure of the ear with the major parts labeled. The external ear contains the auricle, ear canal, and tympanic membrane. The middle ear contains the ossicles and is connected to the pharynx by the Eustachian tube. The inner ear contains the cochlea and vestibule, which are responsible for audition and equilibrium, respectively.\" width=\"660\" height=\"418\" data-media-type=\"image\/png\" \/> Figure 2. Sound travels through the outer ear to the middle ear, which is bounded on its exterior by the tympanic membrane. The middle ear contains three bones called ossicles that transfer the sound wave to the oval window, the exterior boundary of the inner ear. The organ of Corti, which is the organ of sound transduction, lies inside the cochlea.[\/caption]\r\n\r\n&nbsp;\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/10652c97-38af-4cc8-9816-20c7f43cec4c\r\nhttps:\/\/assess.lumenlearning.com\/practice\/5ab76dd1-faa6-444c-a7bf-3f64efadb0bb\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Describe the relationship of amplitude and frequency of a sound wave to attributes of sound<\/li>\n<li>Trace the path of sound through the auditory system<\/li>\n<\/ul>\n<\/div>\n<p>Auditory stimuli are sound waves, which are mechanical, pressure waves that move through a medium, such as air or water. There are no sound waves in a vacuum since there are no air molecules to move in waves. The speed of sound waves differs, based on altitude, temperature, and medium, but at sea level and a temperature of 20\u00ba C (68\u00ba F), sound waves travel in the air at about 343 meters per second.<\/p>\n<p>As is true for all waves, there are four main characteristics of a sound wave: frequency, wavelength, period, and amplitude. Frequency is the number of waves per unit of time, and in sound is heard as pitch. High-frequency (\u226515.000Hz) sounds are higher-pitched (short wavelength) than low-frequency (long wavelengths; \u2264100Hz) sounds. Frequency is measured in cycles per second, and for sound, the most commonly used unit is hertz (Hz), or cycles per second. Most humans can perceive sounds with frequencies between 30 and 20,000 Hz. Women are typically better at hearing high frequencies, but everyone\u2019s ability to hear high frequencies decreases with age. Dogs detect up to about 40,000 Hz; cats, 60,000 Hz; bats, 100,000 Hz; and dolphins 150,000 Hz, and American shad (<em class=\"emphasis\" data-effect=\"italics\">Alosa sapidissima<\/em>), a fish, can hear 180,000 Hz. Those frequencies above the human range are called <b>ultrasound<\/b>.<\/p>\n<p>Amplitude, or the dimension of a wave from peak to trough, in sound is heard as volume and is illustrated in Figure\u00a01. The sound waves of louder sounds have greater amplitude than those of softer sounds. For sound, volume is measured in decibels (dB). The softest sound that a human can hear is the zero point. Humans speak normally at 60 decibels.<\/p>\n<div id=\"attachment_2714\" style=\"width: 554px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-2714\" class=\"size-full wp-image-2714\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/07215102\/Figure_36_04_01.jpg\" alt=\"A graph shows a regularly repeating sine wave that goes gradually up, then down, then up again. The distance between two crests is the wavelength. The amplitude is the height of the wave. On the graph, two waves with different wavelengths but the same amplitude are superimposed on one another.\" width=\"544\" height=\"372\" \/><\/p>\n<p id=\"caption-attachment-2714\" class=\"wp-caption-text\">Figure\u00a01.\u00a0For sound waves, wavelength corresponds to pitch. Amplitude of the wave corresponds to volume. The sound wave shown with a dashed line is softer in volume than the sound wave shown with a solid line. (credit: NIH)<\/p>\n<\/div>\n<h2>Reception of Sound<\/h2>\n<p>In mammals, sound waves are collected by the external, cartilaginous part of the ear called the <b>pinna<\/b>, then travel through the auditory canal and cause vibration of the thin diaphragm called the <b>tympanum<\/b> or ear drum, the innermost part of the <b>outer ear<\/b> (illustrated in\u00a0Figure\u00a02). Interior to the tympanum is the <b>middle ear<\/b>. The middle ear holds three small bones called the <b>ossicles<\/b>, which transfer energy from the moving tympanum to the inner ear. The three ossicles are the <b>malleus<\/b> (also known as the hammer), the <b>incus<\/b> (the anvil), and <b>stapes<\/b> (the stirrup). The aptly named stapes looks very much like a stirrup. The three ossicles are unique to mammals, and each plays a role in hearing. The malleus attaches at three points to the interior surface of the tympanic membrane. The incus attaches the malleus to the stapes. In humans, the stapes is not long enough to reach the tympanum. If we did not have the malleus and the incus, then the vibrations of the tympanum would never reach the inner ear. These bones also function to collect force and amplify sounds. The ear ossicles are homologous to bones in a fish mouth: the bones that support gills in fish are thought to be adapted for use in the vertebrate ear over evolutionary time. Many animals (frogs, reptiles, and birds, for example) use the stapes of the middle ear to transmit vibrations to the middle ear.<\/p>\n<div style=\"width: 670px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" id=\"4\" class=\"\" src=\"https:\/\/openstax.org\/resources\/487050861455b4b7c74f1fc8d24f6b5c53513433\" alt=\"This image shows the structure of the ear with the major parts labeled. The external ear contains the auricle, ear canal, and tympanic membrane. The middle ear contains the ossicles and is connected to the pharynx by the Eustachian tube. The inner ear contains the cochlea and vestibule, which are responsible for audition and equilibrium, respectively.\" width=\"660\" height=\"418\" data-media-type=\"image\/png\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 2. Sound travels through the outer ear to the middle ear, which is bounded on its exterior by the tympanic membrane. The middle ear contains three bones called ossicles that transfer the sound wave to the oval window, the exterior boundary of the inner ear. The organ of Corti, which is the organ of sound transduction, lies inside the cochlea.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_10652c97-38af-4cc8-9816-20c7f43cec4c\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/10652c97-38af-4cc8-9816-20c7f43cec4c?iframe_resize_id=assessment_practice_id_10652c97-38af-4cc8-9816-20c7f43cec4c\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe><br \/>\n\t<iframe id=\"assessment_practice_5ab76dd1-faa6-444c-a7bf-3f64efadb0bb\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/5ab76dd1-faa6-444c-a7bf-3f64efadb0bb?iframe_resize_id=assessment_practice_id_5ab76dd1-faa6-444c-a7bf-3f64efadb0bb\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-4456\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology 2e. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":14,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology 2e\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction\"}]","CANDELA_OUTCOMES_GUID":"ea02f74b-3448-41b0-9031-3fe737eafeeb, 6aecc298-578c-4236-873c-744d0ec13332, 2eddf582-e7a8-4c8b-96e8-f70308084c69","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-4456","chapter","type-chapter","status-publish","hentry"],"part":3798,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4456","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":10,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4456\/revisions"}],"predecessor-version":[{"id":8591,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4456\/revisions\/8591"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/parts\/3798"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/4456\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=4456"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=4456"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=4456"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=4456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}