{"id":1508,"date":"2014-10-07T05:11:21","date_gmt":"2014-10-07T05:11:21","guid":{"rendered":"https:\/\/courses.candelalearning.com\/apvccs\/?post_type=chapter&#038;p=1508"},"modified":"2019-08-22T19:24:08","modified_gmt":"2019-08-22T19:24:08","slug":"structural-organization-of-the-human-body","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/chapter\/structural-organization-of-the-human-body\/","title":{"raw":"Structural Organization of the Human Body","rendered":"Structural Organization of the Human Body"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n\r\n&nbsp;\r\n\r\n<\/div>\r\nBefore you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity: subatomic particles, atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms and biosphere (Figure\u00a01).\r\n\r\n[caption id=\"attachment_4223\" align=\"alignnone\" width=\"1242\"]<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/4583\/2014\/10\/04140608\/LevelsOfOrg1.png\"><img class=\"size-full wp-image-4223\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/4583\/2014\/10\/04140608\/LevelsOfOrg1.png\" alt=\"\" width=\"1242\" height=\"1645\" \/><\/a> <strong>Figure 1. Levels of Structural Organization of the Human Body.<\/strong> The organization of the body often is discussed in terms of six distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.[\/caption]\r\n<h2>The Chemical level<\/h2>\r\nTo study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules. All matter in the universe is composed of one or more unique pure substances called elements, familiar examples of which are hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of any of these pure substances (elements) is an <strong>atom<\/strong>. Atoms are made up of subatomic particles such as the proton, electron and neutron. Two or more atoms combine to form a <strong>molecule<\/strong>, such as the water molecules, proteins, and sugars found in living things. Molecules are the chemical building blocks of all body structures.\r\n<h2>Cells<\/h2>\r\nA\u00a0<strong>cell<\/strong>\u00a0is the smallest independently functioning unit of a living organism. Even bacteria, which are extremely small, independently-living organisms, have a cellular structure. Each bacterium is a single cell. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells.\r\n\r\nA human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid together with a variety of tiny functioning units called\u00a0<strong>organelles<\/strong>. In humans, as in all organisms, cells perform all functions of life.\r\n<h2>Tissues<\/h2>\r\nIn the body's organizational hierarchy, tissues occupy a place between cells and organs. That is, a <strong>tissue<\/strong> is a group of cells with a similar shape and function. In turn, organs (which make up the body) are comprised of various tissues.\r\n\r\nThe component cells of a tissue are a specific cell type. A tissue\u2019s cells may be identical, but are not necessarily so. Broadly speaking there are four types of tissues.\r\n<ul>\r\n \t<li>Muscle tissue (in turn divided into skeletal, smooth and cardiac) is contractile. It allows locomotion of the body. It also allows necessary contractions of various organs such as the heart and of respiratory and digestive systems.<\/li>\r\n \t<li>Nerve tissue comprises the body\u2019s wiring system. It conducts signals between the nervous system and various organs.<\/li>\r\n \t<li>Connective tissue holds the body together. It is found in most organs, anchoring them to the skeleton and other organs. Types of connective tissue include fibrous tissue, fatty tissue, loose tissue and cartilage. Connective tissue also includes bone, blood and lymph.<\/li>\r\n \t<li>Epithelial tissue is the body\u2019s protection against the outside environment. Skin tissue helps to maintain homeostasis. It helps monitor and control temperature, and resists abrasion, foreign bodies and damaging chemicals. Internally, epithelial tissue lines most internal cavities, secreting or absorbing nutrients.<\/li>\r\n<\/ul>\r\n<img class=\"aligncenter wp-image-2966\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/229\/2016\/06\/07223225\/L_M5_1.jpg\" alt=\"diagrams of the four different tissue types\" width=\"500\" height=\"374\" \/>\r\n\r\nTissues form during development. Stem cells in the embryo differentiate into various cell types. The necessary genes in the cells turn on or off, resulting in the production of proteins that characterize a cell\u2019s structure and function. Early in embryonic growth, the cells migrate to the appropriate location in the body. Once there, they proliferate so that the tissue can perform its needed function.\r\n\r\nDifferent tissues arise from the source cells in each of the three primary germ cell layers. For example, the epithelium is derived from the ectoderm and endoderm. Connective tissue arises largely from the mesoderm. Gastrointestinal and respiratory tissues arise mostly from the endoderm. Programmed cell death, or apoptosis, may take place to eliminate transitory tissues in the embryo, such as the pronephros, a simple excretory organ that is later replaced by the kidney.\r\n\r\n[embed width=\"948\" height=\"500\"]https:\/\/oea.herokuapp.com\/assessments\/load?src_url=https:\/\/s3-us-west-2.amazonaws.com\/qtiquiz\/olianp\/_u2_m3_tissues_inline.xml&amp;eid=_u2_m3_tissues_inline&amp;results_end_point=https:\/\/oea.herokuapp.com\/api&amp;assessment_id=_u2_m3_tissues_inline&amp;confidence_levels=true[\/embed]\r\n\r\n[embed width=\"948\" height=\"500\"]https:\/\/oea.herokuapp.com\/assessments\/load?src_url=https:\/\/s3-us-west-2.amazonaws.com\/qtiquiz\/olianp\/_u2_m3_tissues_digt_inline.xml&amp;eid=_u2_m3_tissues_digt_inline&amp;results_end_point=https:\/\/oea.herokuapp.com\/api&amp;assessment_id=_u2_m3_tissues_digt_inline&amp;confidence_levels=true[\/embed]\r\n<h2>Organs<\/h2>\r\nThe organ level of organization in the body may be the most familiar to us from our everyday experiences. Many of the common ailments we hear about\u2014an upset stomach, a broken bone, lung disease, skin cancer\u2014are named for the organs they affect.\r\n\r\nAn organ is made up two or more tissues that work together to perform a specific function for the body as a whole.\u00a0 For example, the contractile cells of skeletal muscle are bundled together to make muscle fiber tissue. In turn, connective tissue wraps around bundles of muscle fibers, like a tortilla around the filling of a burrito. Several of these bundles are\u00a0 are in turn wrapped by another tissue, perimysium. Finally, bundles of these are surrounded by a sheath of yet another tissue, epimysium, which covers the outside of the whole muscle. Yet more tissue is necessary for the muscle to function in the body. Connective tissue comprising ligaments attaches the muscle to the skeleton, and nerve tissue conducts impulses from the nervous system to signal the muscle to contract.\u00a0Groups of organs that perform related functions are organized into organ systems, which perform more general functions. Table 1 describes the structures and functions of some common organs.\r\n<table>\r\n<thead>\r\n<tr>\r\n<th colspan=\"4\">Table 1. Structure and Function of Organs<\/th>\r\n<\/tr>\r\n<tr>\r\n<th>Organ<\/th>\r\n<th>Primary function(s)<\/th>\r\n<th>Tissues it contains<\/th>\r\n<th>Organ system(s) it is a part of<\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>brain<\/td>\r\n<td>control of body systems and behavior; cognition<\/td>\r\n<td>nervous, connective, epithelial<\/td>\r\n<td>nervous system; endocrine system<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>skin<\/td>\r\n<td>protection; support and containment; temperature and fluid regulation<\/td>\r\n<td>epithelial, nervous, connective, muscular<\/td>\r\n<td>integumentary system<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>stomach<\/td>\r\n<td>chemical and mechanical digestion of food<\/td>\r\n<td>epithelial, connective, muscular, nervous<\/td>\r\n<td>digestive system<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>sternum (breastbone)<\/td>\r\n<td>support; protection; blood cell production<\/td>\r\n<td>epithelial, connective, nervous<\/td>\r\n<td>skeletal system; immune system; cardiovascular system<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>kidney<\/td>\r\n<td>waste removal; fluid regulation<\/td>\r\n<td>epithelial, connective, nervous<\/td>\r\n<td>urinary system<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<h2>Organ Systems, The Whole Body, and Populations<\/h2>\r\nOrgan systems are made up of organs that work together to perform a specific function for the body as a whole. Table 2 describes the organ systems and their primary organs and physiological functions.\r\n<table>\r\n<thead>\r\n<tr>\r\n<th colspan=\"3\">Table 2.\u00a0Organ Systems<\/th>\r\n<\/tr>\r\n<tr>\r\n<th>Organ system<\/th>\r\n<th>Key Organ(s)<\/th>\r\n<th>Primary function(s)<\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>integumentary<\/td>\r\n<td>skin<\/td>\r\n<td>support; protection; regulation of fluid levels<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>skeletal<\/td>\r\n<td>bones, cartilage<\/td>\r\n<td>support; protection; movement; blood cell production<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>muscular<\/td>\r\n<td>muscles, tendons<\/td>\r\n<td>support; movement<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>urinary<\/td>\r\n<td>kidneys, bladder, urethra<\/td>\r\n<td>waste removal; regulation of fluid levels<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>digestive<\/td>\r\n<td>tongue, esophagus, stomach, small intestine, large intestine, gallbladder, rectum<\/td>\r\n<td>digestion of food; waste removal<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>respiratory<\/td>\r\n<td>trachea, lungs<\/td>\r\n<td>gas exchange; regulation of temperature<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>cardiovascular<\/td>\r\n<td>heart, blood vessels<\/td>\r\n<td>transport of materials through the body; regulation of temperature<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>nervous<\/td>\r\n<td>brain, spinal cord<\/td>\r\n<td>control of behavior and body systems; cognition<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>endocrine<\/td>\r\n<td>glands<\/td>\r\n<td>control of the body systems and development<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>immune<\/td>\r\n<td>thymus, tonsils, spleen<\/td>\r\n<td>defense agains infection<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>lymphatic<\/td>\r\n<td>lymph nodes, lymphatic vessels<\/td>\r\n<td>immunity; regulating fluid balance<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>reproductive<\/td>\r\n<td>penis, testes, prostate (male); uterus, ovaries, vagina (female)<\/td>\r\n<td>reproduction<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\n<h3>The Whole Body<\/h3>\r\nThe organ systems of the body all work together to maintain proper physiological functions. Many times in the arena of anatomy and physiology, including in this course, we closely examine the molecules, cells, tissues and organs of the body to learn their forms and functions. However, it is important to consider that every molecule works as part of the entire system. Endocrine disorders such as diabetes affect glucose levels in the body. Altered blood glucose levels can affect many organ systems. For example, the immune system may not heal as well, the urinary system may experience kidney damage, and the cardiovascular system can experience vascular damage, even to the point of causing blindness. In the body, everything is interconnected.\r\n<h3>Populations<\/h3>\r\nBeyond the body, populations and environment can impact physiology and health. Some diseases and disorders are common to certain populations, most likely because of genetic connections. Also, environmental conditions can impact health. Particulates in the air can impact respiratory function. We are also affected by foods, exercise, sun exposure and other environmental conditions.\r\n\r\nA\u00a0<strong>tissue<\/strong>\u00a0is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function. An\u00a0<strong>organ<\/strong>\u00a0is an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions. <strong>An\u00a0organ system<\/strong>\u00a0is a group of organs that work together to perform major functions or meet physiological needs of the body.\r\n\r\nThis book covers eleven distinct organ systems in the human body (Figure 2\u00a0and\u00a0Figure 3). Assigning organs to organ systems can be imprecise since organs that \u201cbelong\u201d to one system can also have functions integral to another system. In fact, most organs contribute to more than one system.\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"800\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082339\/102_Organ_Systems_of_BodyPage1.jpg\" alt=\"This illustration shows eight silhouettes of a human female, each showing the components of a different organ system. The integumentary system encloses internal body structures and is the site of many sensory receptors. The integumentary system includes the hair, skin, and nails. The skeletal system supports the body and, along with the muscular system, enables movement. The skeletal system includes cartilage, such as that at the tip of the nose, as well as the bones and joints. The muscular system enables movement, along with the skeletal system, but also helps to maintain body temperature. The muscular system includes skeletal muscles, as well as tendons that connect skeletal muscles to bones. The nervous system detects and processes sensory information and activates bodily responses. The nervous system includes the brain, spinal cord, and peripheral nerves, such as those located in the limbs. The endocrine system secretes hormones and regulates bodily processes. The endocrine system includes the pituitary gland in the brain, the thyroid gland in the throat, the pancreas in the abdomen, the adrenal glands on top of the kidneys, and the testes in the scrotum of males as well as the ovaries in the pelvic region of females. The cardiovascular system delivers oxygen and nutrients to the tissues as well as equalizes temperature in the body. The cardiovascular system includes the heart and blood vessels.\" width=\"800\" \/> <strong>Figure 2.\u00a0Organ Systems of the Human Body.\u00a0<\/strong>Organs that work together are grouped into organ systems.[\/caption]\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"800\"]<img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082341\/102_Organ_Systems_of_BodyPage2.jpg\" alt=\"The lymphatic system returns fluid to the blood and defends against pathogens. The lymphatic system includes the thymus in the chest, the spleen in the abdomen, the lymphatic vessels that spread throughout the body, and the lymph nodes distributed along the lymphatic vessels. The respiratory system removes carbon dioxide from the body and delivers oxygen to the blood. The respiratory system includes the nasal passages, the trachea, and the lungs. The digestive system processes food for use by the body and removes wastes from undigested food. The digestive system includes the stomach, the liver, the gall bladder (connected to the liver), the large intestine, and the small intestine. The urinary system controls water balance in the body and removes and excretes waste from the blood. The urinary system includes the kidneys and the urinary bladder. The reproductive system of males and females produce sex hormones and gametes. The male reproductive system is specialized to deliver gametes to the female while the female reproductive system is specialized to support the embryo and fetus until birth and produce milk for the infant after birth. The male reproductive system includes the two testes within the scrotum as well as the epididymis which wraps around each testis. The female reproductive system includes the mammary glands within the breasts and the ovaries and uterus within the pelvic cavity.\" width=\"800\" \/> <strong>Figure 3.\u00a0Organ Systems of the Human Body (continued).\u00a0<\/strong>Organs that work together are grouped into organ systems.\u00a0The organism level is the highest level of organization. An\u00a0<strong>organism<\/strong>\u00a0is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In multicellular organisms, including humans, all cells, tissues, organs, and organ systems of the body work together to maintain the life and health of the organism.[\/caption]","rendered":"<div class=\"textbox learning-objectives\">\n<p>&nbsp;<\/p>\n<\/div>\n<p>Before you begin to study the different structures and functions of the human body, it is helpful to consider its basic architecture; that is, how its smallest parts are assembled into larger structures. It is convenient to consider the structures of the body in terms of fundamental levels of organization that increase in complexity: subatomic particles, atoms, molecules, organelles, cells, tissues, organs, organ systems, organisms and biosphere (Figure\u00a01).<\/p>\n<div id=\"attachment_4223\" style=\"width: 1252px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/4583\/2014\/10\/04140608\/LevelsOfOrg1.png\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-4223\" class=\"size-full wp-image-4223\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/4583\/2014\/10\/04140608\/LevelsOfOrg1.png\" alt=\"\" width=\"1242\" height=\"1645\" \/><\/a><\/p>\n<p id=\"caption-attachment-4223\" class=\"wp-caption-text\"><strong>Figure 1. Levels of Structural Organization of the Human Body.<\/strong> The organization of the body often is discussed in terms of six distinct levels of increasing complexity, from the smallest chemical building blocks to a unique human organism.<\/p>\n<\/div>\n<h2>The Chemical level<\/h2>\n<p>To study the chemical level of organization, scientists consider the simplest building blocks of matter: subatomic particles, atoms and molecules. All matter in the universe is composed of one or more unique pure substances called elements, familiar examples of which are hydrogen, oxygen, carbon, nitrogen, calcium, and iron. The smallest unit of any of these pure substances (elements) is an <strong>atom<\/strong>. Atoms are made up of subatomic particles such as the proton, electron and neutron. Two or more atoms combine to form a <strong>molecule<\/strong>, such as the water molecules, proteins, and sugars found in living things. Molecules are the chemical building blocks of all body structures.<\/p>\n<h2>Cells<\/h2>\n<p>A\u00a0<strong>cell<\/strong>\u00a0is the smallest independently functioning unit of a living organism. Even bacteria, which are extremely small, independently-living organisms, have a cellular structure. Each bacterium is a single cell. All living structures of human anatomy contain cells, and almost all functions of human physiology are performed in cells or are initiated by cells.<\/p>\n<p>A human cell typically consists of flexible membranes that enclose cytoplasm, a water-based cellular fluid together with a variety of tiny functioning units called\u00a0<strong>organelles<\/strong>. In humans, as in all organisms, cells perform all functions of life.<\/p>\n<h2>Tissues<\/h2>\n<p>In the body&#8217;s organizational hierarchy, tissues occupy a place between cells and organs. That is, a <strong>tissue<\/strong> is a group of cells with a similar shape and function. In turn, organs (which make up the body) are comprised of various tissues.<\/p>\n<p>The component cells of a tissue are a specific cell type. A tissue\u2019s cells may be identical, but are not necessarily so. Broadly speaking there are four types of tissues.<\/p>\n<ul>\n<li>Muscle tissue (in turn divided into skeletal, smooth and cardiac) is contractile. It allows locomotion of the body. It also allows necessary contractions of various organs such as the heart and of respiratory and digestive systems.<\/li>\n<li>Nerve tissue comprises the body\u2019s wiring system. It conducts signals between the nervous system and various organs.<\/li>\n<li>Connective tissue holds the body together. It is found in most organs, anchoring them to the skeleton and other organs. Types of connective tissue include fibrous tissue, fatty tissue, loose tissue and cartilage. Connective tissue also includes bone, blood and lymph.<\/li>\n<li>Epithelial tissue is the body\u2019s protection against the outside environment. Skin tissue helps to maintain homeostasis. It helps monitor and control temperature, and resists abrasion, foreign bodies and damaging chemicals. Internally, epithelial tissue lines most internal cavities, secreting or absorbing nutrients.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-2966\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/229\/2016\/06\/07223225\/L_M5_1.jpg\" alt=\"diagrams of the four different tissue types\" width=\"500\" height=\"374\" \/><\/p>\n<p>Tissues form during development. Stem cells in the embryo differentiate into various cell types. The necessary genes in the cells turn on or off, resulting in the production of proteins that characterize a cell\u2019s structure and function. Early in embryonic growth, the cells migrate to the appropriate location in the body. Once there, they proliferate so that the tissue can perform its needed function.<\/p>\n<p>Different tissues arise from the source cells in each of the three primary germ cell layers. For example, the epithelium is derived from the ectoderm and endoderm. Connective tissue arises largely from the mesoderm. Gastrointestinal and respiratory tissues arise mostly from the endoderm. Programmed cell death, or apoptosis, may take place to eliminate transitory tissues in the embryo, such as the pronephros, a simple excretory organ that is later replaced by the kidney.<\/p>\n<p><iframe loading=\"lazy\" class=\"resizable\" src=\"https:\/\/oea.herokuapp.com\/assessments\/load?src_url=https:\/\/s3-us-west-2.amazonaws.com\/qtiquiz\/olianp\/_u2_m3_tissues_inline.xml&amp;eid=_u2_m3_tissues_inline&amp;results_end_point=https:\/\/oea.herokuapp.com\/api&amp;assessment_id=_u2_m3_tissues_inline&amp;confidence_levels=true\" frameborder=\"0\" width=\"948\" height=\"500\"><\/iframe><\/p>\n<p><iframe loading=\"lazy\" class=\"resizable\" src=\"https:\/\/oea.herokuapp.com\/assessments\/load?src_url=https:\/\/s3-us-west-2.amazonaws.com\/qtiquiz\/olianp\/_u2_m3_tissues_digt_inline.xml&amp;eid=_u2_m3_tissues_digt_inline&amp;results_end_point=https:\/\/oea.herokuapp.com\/api&amp;assessment_id=_u2_m3_tissues_digt_inline&amp;confidence_levels=true\" frameborder=\"0\" width=\"948\" height=\"500\"><\/iframe><\/p>\n<h2>Organs<\/h2>\n<p>The organ level of organization in the body may be the most familiar to us from our everyday experiences. Many of the common ailments we hear about\u2014an upset stomach, a broken bone, lung disease, skin cancer\u2014are named for the organs they affect.<\/p>\n<p>An organ is made up two or more tissues that work together to perform a specific function for the body as a whole.\u00a0 For example, the contractile cells of skeletal muscle are bundled together to make muscle fiber tissue. In turn, connective tissue wraps around bundles of muscle fibers, like a tortilla around the filling of a burrito. Several of these bundles are\u00a0 are in turn wrapped by another tissue, perimysium. Finally, bundles of these are surrounded by a sheath of yet another tissue, epimysium, which covers the outside of the whole muscle. Yet more tissue is necessary for the muscle to function in the body. Connective tissue comprising ligaments attaches the muscle to the skeleton, and nerve tissue conducts impulses from the nervous system to signal the muscle to contract.\u00a0Groups of organs that perform related functions are organized into organ systems, which perform more general functions. Table 1 describes the structures and functions of some common organs.<\/p>\n<table>\n<thead>\n<tr>\n<th colspan=\"4\">Table 1. Structure and Function of Organs<\/th>\n<\/tr>\n<tr>\n<th>Organ<\/th>\n<th>Primary function(s)<\/th>\n<th>Tissues it contains<\/th>\n<th>Organ system(s) it is a part of<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>brain<\/td>\n<td>control of body systems and behavior; cognition<\/td>\n<td>nervous, connective, epithelial<\/td>\n<td>nervous system; endocrine system<\/td>\n<\/tr>\n<tr>\n<td>skin<\/td>\n<td>protection; support and containment; temperature and fluid regulation<\/td>\n<td>epithelial, nervous, connective, muscular<\/td>\n<td>integumentary system<\/td>\n<\/tr>\n<tr>\n<td>stomach<\/td>\n<td>chemical and mechanical digestion of food<\/td>\n<td>epithelial, connective, muscular, nervous<\/td>\n<td>digestive system<\/td>\n<\/tr>\n<tr>\n<td>sternum (breastbone)<\/td>\n<td>support; protection; blood cell production<\/td>\n<td>epithelial, connective, nervous<\/td>\n<td>skeletal system; immune system; cardiovascular system<\/td>\n<\/tr>\n<tr>\n<td>kidney<\/td>\n<td>waste removal; fluid regulation<\/td>\n<td>epithelial, connective, nervous<\/td>\n<td>urinary system<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Organ Systems, The Whole Body, and Populations<\/h2>\n<p>Organ systems are made up of organs that work together to perform a specific function for the body as a whole. Table 2 describes the organ systems and their primary organs and physiological functions.<\/p>\n<table>\n<thead>\n<tr>\n<th colspan=\"3\">Table 2.\u00a0Organ Systems<\/th>\n<\/tr>\n<tr>\n<th>Organ system<\/th>\n<th>Key Organ(s)<\/th>\n<th>Primary function(s)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>integumentary<\/td>\n<td>skin<\/td>\n<td>support; protection; regulation of fluid levels<\/td>\n<\/tr>\n<tr>\n<td>skeletal<\/td>\n<td>bones, cartilage<\/td>\n<td>support; protection; movement; blood cell production<\/td>\n<\/tr>\n<tr>\n<td>muscular<\/td>\n<td>muscles, tendons<\/td>\n<td>support; movement<\/td>\n<\/tr>\n<tr>\n<td>urinary<\/td>\n<td>kidneys, bladder, urethra<\/td>\n<td>waste removal; regulation of fluid levels<\/td>\n<\/tr>\n<tr>\n<td>digestive<\/td>\n<td>tongue, esophagus, stomach, small intestine, large intestine, gallbladder, rectum<\/td>\n<td>digestion of food; waste removal<\/td>\n<\/tr>\n<tr>\n<td>respiratory<\/td>\n<td>trachea, lungs<\/td>\n<td>gas exchange; regulation of temperature<\/td>\n<\/tr>\n<tr>\n<td>cardiovascular<\/td>\n<td>heart, blood vessels<\/td>\n<td>transport of materials through the body; regulation of temperature<\/td>\n<\/tr>\n<tr>\n<td>nervous<\/td>\n<td>brain, spinal cord<\/td>\n<td>control of behavior and body systems; cognition<\/td>\n<\/tr>\n<tr>\n<td>endocrine<\/td>\n<td>glands<\/td>\n<td>control of the body systems and development<\/td>\n<\/tr>\n<tr>\n<td>immune<\/td>\n<td>thymus, tonsils, spleen<\/td>\n<td>defense agains infection<\/td>\n<\/tr>\n<tr>\n<td>lymphatic<\/td>\n<td>lymph nodes, lymphatic vessels<\/td>\n<td>immunity; regulating fluid balance<\/td>\n<\/tr>\n<tr>\n<td>reproductive<\/td>\n<td>penis, testes, prostate (male); uterus, ovaries, vagina (female)<\/td>\n<td>reproduction<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>The Whole Body<\/h3>\n<p>The organ systems of the body all work together to maintain proper physiological functions. Many times in the arena of anatomy and physiology, including in this course, we closely examine the molecules, cells, tissues and organs of the body to learn their forms and functions. However, it is important to consider that every molecule works as part of the entire system. Endocrine disorders such as diabetes affect glucose levels in the body. Altered blood glucose levels can affect many organ systems. For example, the immune system may not heal as well, the urinary system may experience kidney damage, and the cardiovascular system can experience vascular damage, even to the point of causing blindness. In the body, everything is interconnected.<\/p>\n<h3>Populations<\/h3>\n<p>Beyond the body, populations and environment can impact physiology and health. Some diseases and disorders are common to certain populations, most likely because of genetic connections. Also, environmental conditions can impact health. Particulates in the air can impact respiratory function. We are also affected by foods, exercise, sun exposure and other environmental conditions.<\/p>\n<p>A\u00a0<strong>tissue<\/strong>\u00a0is a group of many similar cells (though sometimes composed of a few related types) that work together to perform a specific function. An\u00a0<strong>organ<\/strong>\u00a0is an anatomically distinct structure of the body composed of two or more tissue types. Each organ performs one or more specific physiological functions. <strong>An\u00a0organ system<\/strong>\u00a0is a group of organs that work together to perform major functions or meet physiological needs of the body.<\/p>\n<p>This book covers eleven distinct organ systems in the human body (Figure 2\u00a0and\u00a0Figure 3). Assigning organs to organ systems can be imprecise since organs that \u201cbelong\u201d to one system can also have functions integral to another system. In fact, most organs contribute to more than one system.<\/p>\n<div style=\"width: 810px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082339\/102_Organ_Systems_of_BodyPage1.jpg\" alt=\"This illustration shows eight silhouettes of a human female, each showing the components of a different organ system. The integumentary system encloses internal body structures and is the site of many sensory receptors. The integumentary system includes the hair, skin, and nails. The skeletal system supports the body and, along with the muscular system, enables movement. The skeletal system includes cartilage, such as that at the tip of the nose, as well as the bones and joints. The muscular system enables movement, along with the skeletal system, but also helps to maintain body temperature. The muscular system includes skeletal muscles, as well as tendons that connect skeletal muscles to bones. The nervous system detects and processes sensory information and activates bodily responses. The nervous system includes the brain, spinal cord, and peripheral nerves, such as those located in the limbs. The endocrine system secretes hormones and regulates bodily processes. The endocrine system includes the pituitary gland in the brain, the thyroid gland in the throat, the pancreas in the abdomen, the adrenal glands on top of the kidneys, and the testes in the scrotum of males as well as the ovaries in the pelvic region of females. The cardiovascular system delivers oxygen and nutrients to the tissues as well as equalizes temperature in the body. The cardiovascular system includes the heart and blood vessels.\" width=\"800\" \/><\/p>\n<p class=\"wp-caption-text\"><strong>Figure 2.\u00a0Organ Systems of the Human Body.\u00a0<\/strong>Organs that work together are grouped into organ systems.<\/p>\n<\/div>\n<div style=\"width: 810px\" class=\"wp-caption aligncenter\"><img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/198\/2014\/10\/20082341\/102_Organ_Systems_of_BodyPage2.jpg\" alt=\"The lymphatic system returns fluid to the blood and defends against pathogens. The lymphatic system includes the thymus in the chest, the spleen in the abdomen, the lymphatic vessels that spread throughout the body, and the lymph nodes distributed along the lymphatic vessels. The respiratory system removes carbon dioxide from the body and delivers oxygen to the blood. The respiratory system includes the nasal passages, the trachea, and the lungs. The digestive system processes food for use by the body and removes wastes from undigested food. The digestive system includes the stomach, the liver, the gall bladder (connected to the liver), the large intestine, and the small intestine. The urinary system controls water balance in the body and removes and excretes waste from the blood. The urinary system includes the kidneys and the urinary bladder. The reproductive system of males and females produce sex hormones and gametes. The male reproductive system is specialized to deliver gametes to the female while the female reproductive system is specialized to support the embryo and fetus until birth and produce milk for the infant after birth. The male reproductive system includes the two testes within the scrotum as well as the epididymis which wraps around each testis. The female reproductive system includes the mammary glands within the breasts and the ovaries and uterus within the pelvic cavity.\" width=\"800\" \/><\/p>\n<p class=\"wp-caption-text\"><strong>Figure 3.\u00a0Organ Systems of the Human Body (continued).\u00a0<\/strong>Organs that work together are grouped into organ systems.\u00a0The organism level is the highest level of organization. An\u00a0<strong>organism<\/strong>\u00a0is a living being that has a cellular structure and that can independently perform all physiologic functions necessary for life. In multicellular organisms, including humans, all cells, tissues, organs, and organ systems of the body work together to maintain the life and health of the organism.<\/p>\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-1508\">\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>Anatomy &amp; Physiology. <strong>Authored by<\/strong>: OpenStax College. <strong>Provided by<\/strong>: Rice University. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@9.1\">http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@9.1<\/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>: http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@9.1<\/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":74,"menu_order":3,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Anatomy & Physiology\",\"author\":\"OpenStax College\",\"organization\":\"Rice University\",\"url\":\"http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@9.1\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"http:\/\/cnx.org\/contents\/14fb4ad7-39a1-4eee-ab6e-3ef2482e3e22@9.1\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-1508","chapter","type-chapter","status-publish","hentry"],"part":35,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/chapters\/1508","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/wp\/v2\/users\/74"}],"version-history":[{"count":18,"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/chapters\/1508\/revisions"}],"predecessor-version":[{"id":4642,"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/chapters\/1508\/revisions\/4642"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/parts\/35"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/chapters\/1508\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/wp\/v2\/media?parent=1508"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/pressbooks\/v2\/chapter-type?post=1508"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/wp\/v2\/contributor?post=1508"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/suny-dutchess-anatomy-physiology\/wp-json\/wp\/v2\/license?post=1508"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}