Mader: Understanding ② The McG ysiology, Fifth Edition gure 1.1 Levels of organization of the human body. Each level is more complex than the previous leveL. Atom Tissue 1.1 The human bod can in turn join to form macromolecules. For example, mol- ecules called amino acids join to form a macromolecule Anatomy and physiology is the study of the human body. called protein, which makes up the bulk of our muscles Anatomy is concerned with the structure of a part.For Macromolecules are found in all cells, the basic units of example, the stomach is a J-shaped, pouchlike organ all living things Within cells are organelles, tiny structures (Fig. 1. 1). The stomach wall has thick folds, which disappear that perform cellular functions. For example, the organelle as the stomach expands to increase its capacity. Physiology is called the nucleus is especially concerned with cell reproduc concerned with the function of a part. For example, the stom- tion; another organelle, called the mitochondrion, supplies ach temporarily stores food, secretes digestive juices, and the cell with passes on partially digested food to the small intestine. Tissues are the next level of organization. A tissue is com- Anatomy and physiology are closely connected in that the posed of similar types of cells and performs a specific fune structure of an organ suits its function. For example, the stom- tion. An organ is composed of several types of tissues and per ach's pouchlike shape and ability to expand are suitable to its forms a particular function within an organ system. For function of storing food. In addition, the microscopic struc- example, the stomach is an organ that is a part of the digestive ire of the stomach wall is suitable to its secretion of digestive system. It has a specific role in this system, whose overall func- juices, as we shall see in Chapter 15 tion is to supply the body with the nutrients needed growth and repair. The other systems of the body(see page Organization of Body Parts 13)also have specific functions. All of the body systems together make up the organism- The structure of the body can be studied at different levels of such as, a human being. Human beings are complex animals, organization(Fig. 1. 1). First, all substances, including body but this complexity can be broken down and studied at ever parts, are composed of chemicals made up of submicroscopic simpler levels. Each simpler level is organized and constructed particles called atoms. Atoms join to form molecules, which in a particular way Part I Human Organization
Mader: Understanding Human Anatomy & Physiology, Fifth Edition I. Human Organization 1. Organization of the Body © The McGraw−Hill Companies, 2004 1.1 The Human Body Anatomy and physiology is the study of the human body. Anatomy is concerned with the structure of a part. For example, the stomach is a J-shaped, pouchlike organ (Fig. 1.1). The stomach wall has thick folds, which disappear as the stomach expands to increase its capacity. Physiology is concerned with the function of a part. For example, the stomach temporarily stores food, secretes digestive juices, and passes on partially digested food to the small intestine. Anatomy and physiology are closely connected in that the structure of an organ suits its function. For example, the stomach’s pouchlike shape and ability to expand are suitable to its function of storing food. In addition, the microscopic structure of the stomach wall is suitable to its secretion of digestive juices, as we shall see in Chapter 15. Organization of Body Parts The structure of the body can be studied at different levels of organization (Fig. 1.1). First, all substances, including body parts, are composed of chemicals made up of submicroscopic particles called atoms. Atoms join to form molecules, which can in turn join to form macromolecules. For example, molecules called amino acids join to form a macromolecule called protein, which makes up the bulk of our muscles. Macromolecules are found in all cells, the basic units of all living things. Within cells are organelles, tiny structures that perform cellular functions. For example, the organelle called the nucleus is especially concerned with cell reproduction; another organelle, called the mitochondrion, supplies the cell with energy. Tissues are the next level of organization. A tissue is composed of similar types of cells and performs a specific function. An organ is composed of several types of tissues and performs a particular function within an organ system. For example, the stomach is an organ that is a part of the digestive system. It has a specific role in this system, whose overall function is to supply the body with the nutrients needed for growth and repair. The other systems of the body (see page 13) also have specific functions. All of the body systems together make up the organism— such as, a human being. Human beings are complex animals, but this complexity can be broken down and studied at ever simpler levels. Each simpler level is organized and constructed in a particular way. 2 Part I Human Organization Atom Molecule Macromolecule Organelle Cell Tissue Organ Organism Organ system Figure 1.1 Levels of organization of the human body. Each level is more complex than the previous level
Mader: Understanding ② The McG ysiology, Fifth Edition Figure 1.2 Directional terms. Directional terms tell us where body parts are located with reference to the body in anatomical position. proximal ventra (dorsal) 1.2 Anatomical terms Inferior means that a body part is below another part, or toward the feet. The navel is inferior to the chin Certain terms are used to describe the location of body parts, Medial means that a body part is nearer than another part to regions of the body, and imaginary planes by which the body an imaginary midline of the body. The bridge of the can be sectioned. You should become familiar with these lose is medial to the eyes. terms before your study of anatomy and physiology begins. Lateral means that a body part is farther away from the Anatomical terms are useful only if everyone has in mind the midline. The eyes are lateral to the nose. ame position of the body and is using the same reference Proximal means that a body part is closer to the point of points. Therefore, we will assume that the body is in the ttachment or closer to the trunk. The elbow is proximal anatomical position: standing erect, with face forward, arms at to the hand the sides, and palms and toes directed forward, as illustrated Distal means that a body part is farther from the point of Fi attachment or farther from the trunk or torso The hand is distal to the elbow Directional Terms Superficial (external) means that a body part is located near the surface. The skin is superficial to the muscles Directional terms are used to describe the location of one Deep (internal) means that the body part is located away body part in relation to another( Fig. 1. 2) from the surface. The intestines are deep to the spine. Anterior(ventral) means that a body part is located toward Central means that a body part is situated at the center of he front. The windpipe(trachea) is anterior to the the body or an organ. The central nervous system is esophagus. located along the main axis of the body the back. The heart is posterior to the rib cage toward Posterior(dorsal)means that a body part is located eripheral means that a body part is situated away from the enter of the body or an organ. The peripheral nervous uperior means that a body part is located above another system is located outside the central nervous system part, or toward the head. The face is superior to the neck. Chapter1 Organization of the Body 3
Mader: Understanding Human Anatomy & Physiology, Fifth Edition I. Human Organization 1. Organization of the Body © The McGraw−Hill Companies, 2004 1.2 Anatomical Terms Certain terms are used to describe the location of body parts, regions of the body, and imaginary planes by which the body can be sectioned. You should become familiar with these terms before your study of anatomy and physiology begins. Anatomical terms are useful only if everyone has in mind the same position of the body and is using the same reference points. Therefore, we will assume that the body is in the anatomical position: standing erect, with face forward, arms at the sides, and palms and toes directed forward, as illustrated in Figure 1.1. Directional Terms Directional terms are used to describe the location of one body part in relation to another (Fig. 1.2): Anterior (ventral) means that a body part is located toward the front. The windpipe (trachea) is anterior to the esophagus. Posterior (dorsal) means that a body part is located toward the back. The heart is posterior to the rib cage. Superior means that a body part is located above another part, or toward the head. The face is superior to the neck. Inferior means that a body part is below another part, or toward the feet. The navel is inferior to the chin. Medial means that a body part is nearer than another part to an imaginary midline of the body. The bridge of the nose is medial to the eyes. Lateral means that a body part is farther away from the midline. The eyes are lateral to the nose. Proximal means that a body part is closer to the point of attachment or closer to the trunk. The elbow is proximal to the hand. Distal means that a body part is farther from the point of attachment or farther from the trunk or torso. The hand is distal to the elbow. Superficial (external) means that a body part is located near the surface. The skin is superficial to the muscles. Deep (internal) means that the body part is located away from the surface. The intestines are deep to the spine. Central means that a body part is situated at the center of the body or an organ. The central nervous system is located along the main axis of the body. Peripheral means that a body part is situated away from the center of the body or an organ. The peripheral nervous system is located outside the central nervous system. Chapter 1 Organization of the Body 3 superior inferior medial lateral proximal distal superficial deep posterior (dorsal) anterior (ventral) Figure 1.2 Directional terms. Directional terms tell us where body parts are located with reference to the body in anatomical position
Mader: Understanding ② The McG Human Anatomy ysiology, Fifth Edition gure 1. 3 Terms for body parts and areas. a. Anterior b Posterior nasal (nose) oral(mouth) buccal (cheek) cervical (neck) mental(chin) sternal (point of shoulder) oint of shoulde axillary(armpit mammary(breast) brachial brachial(arm) cubital (elbow) sacral(between hips) (forearm) carpal (wrist) digital (finger) femoral( thigh) reproductive organs popliteal(back of knee) (front of knee) crural(leg)- tarsal (instep) pedal( foot) plantar( sole) Regions of the body common name for that region. For example, the cephalic re- n is commonly called the head The human body can be divided into axial and appendicular Notice that the upper arm includes among other parts the The trunk can be divided into the thorax, abdomen, and pelvis. and the lower limb includes among other parts the femoral region(thigh) and the crural region (leg). In other words, appendicular portion of the human body includes the contrary to common usage, the terms arm and leg refer to only a part of the upper limb and lower limb, respectively The human body is further divided as shown in Figure Most likely, it will take practice to learn the terms in Fig 1.3.The labels in Figure 1.3 do not include the word"region. ure 1.3. One way to practice might be to point to various re It is understood that you will supply the word region in each gions of your own body and see if you can give the scientific The scientific name for each region is followed by the name for that region. Check your answer against the figure. Part I Human Organization
Mader: Understanding Human Anatomy & Physiology, Fifth Edition I. Human Organization 1. Organization of the Body © The McGraw−Hill Companies, 2004 Regions of the Body The human body can be divided into axial and appendicular portions. The axial portion includes the head, neck, and trunk. The trunk can be divided into the thorax, abdomen, and pelvis. The pelvis is that part of the trunk associated with the hips. The appendicular portion of the human body includes the limbs—that is, the upper limbs and the lower limbs. The human body is further divided as shown in Figure 1.3. The labels in Figure 1.3 do not include the word “region.” It is understood that you will supply the word region in each case. The scientific name for each region is followed by the common name for that region. For example, the cephalic region is commonly called the head. Notice that the upper arm includes among other parts the brachial region (arm) and the antebrachial region (forearm), and the lower limb includes among other parts the femoral region (thigh) and the crural region (leg). In other words, contrary to common usage, the terms arm and leg refer to only a part of the upper limb and lower limb, respectively. Most likely, it will take practice to learn the terms in Figure 1.3. One way to practice might be to point to various regions of your own body and see if you can give the scientific name for that region. Check your answer against the figure. 4 Part I Human Organization otic (ear) cervical (neck) acromial (point of shoulder) mammary (breast) brachial (arm) antecubital (front of elbow) antebrachial (forearm) genital (reproductive organs) crural (leg) cephalic (head) orbital (eye cavity) mental (chin) sternal pectoral (chest) inguinal (groin) coxal (hip) umbilical (navel) pedal (foot) occipital (back of head) acromial (point of shoulder) brachial (arm) dorsum (back) cubital (elbow) gluteal (buttocks) perineal femoral (thigh) popliteal (back of knee) crural (leg) plantar (sole) a. b. patellar (front of knee) vertebral (spinal column) sacral (between hips) lumbar (lower back) abdominal (abdomen) carpal (wrist) palmar (palm) digital (finger) nasal (nose) oral (mouth) frontal (forehead) buccal (cheek) tarsal (instep) axillary (armpit) Figure 1.3 Terms for body parts and areas. a. Anterior. b. Posterior
Mader: Understanding ② The McG ysiology, Fifth Edition Figure 1.4 Body planes and sections. The planes shown in(a),(b), and (c) are typically used as sites for sectioning the body as shown in (d),(e), and a Sagittal (median) plane b Frontal(coronal) plane d. Sagittal section of e Frontal section of f Transverse section of thoracic cavity head at eye level Planes and Sections of the Body A frontal (coronal) plane also extends lengthwise, but it is perpendicular to a sagittal plane and divides the body or To observe the structure of an internal body part, it is custom- ary to section (cut) the body along a plane. A plane an organ into anterior and posterior portions. The thoracic organs are often illustrated in frontal section( Fig. 1.4 imaginary flat surface passing through the body. The body is A transverse(horizontal)plane is perpendicular to the body customarily sectioned along the following planes( Fig. 1. 4) long axis and therefore divides the body horizontally to A sagittal(median) plane extends lengthwise and divides roduce a cross section. a transverse cut divides the body the body into right and left portions. A midsagittal plane or an organ into superior and inferior portions. Figure 1. 4f passes exactly through the midline of the body. The is a transverse section of the head at the level of the eyes pelvic organs are often shown in midsagittal section (Fig. 1. 4d). Sagittal cuts that are not along the midline The terms longitudinal section and cross section are often applied are called parasagittal sections. to body parts that have been removed and cut either length wise or straight across, respectively Chapter 1 Organization of the Body5
Mader: Understanding Human Anatomy & Physiology, Fifth Edition I. Human Organization 1. Organization of the Body © The McGraw−Hill Companies, 2004 Planes and Sections of the Body To observe the structure of an internal body part, it is customary to section (cut) the body along a plane. A plane is an imaginary flat surface passing through the body. The body is customarily sectioned along the following planes (Fig. 1.4): A sagittal (median) plane extends lengthwise and divides the body into right and left portions. A midsagittal plane passes exactly through the midline of the body. The pelvic organs are often shown in midsagittal section (Fig. 1.4d). Sagittal cuts that are not along the midline are called parasagittal sections. A frontal (coronal) plane also extends lengthwise, but it is perpendicular to a sagittal plane and divides the body or an organ into anterior and posterior portions. The thoracic organs are often illustrated in frontal section (Fig. 1.4e). A transverse (horizontal) plane is perpendicular to the body’s long axis and therefore divides the body horizontally to produce a cross section. A transverse cut divides the body or an organ into superior and inferior portions. Figure 1.4f is a transverse section of the head at the level of the eyes. The terms longitudinal section and cross section are often applied to body parts that have been removed and cut either lengthwise or straight across, respectively. Chapter 1 Organization of the Body 5 a. Sagittal (median) plane b. Frontal (coronal) plane c. Transverse (horizontal) plane f. Transverse section of head at eye level e. Frontal section of thoracic cavity d. Sagittal section of pelvic cavity Figure 1.4 Body planes and sections. The planes shown in (a), (b), and (c) are typically used as sites for sectioning the body as shown in (d), (e), and (f)
Mader: Understanding ② The McG ysiology, Fifth Edition gure 1.5 The two major body cavities and their subdivisions. a Left lateral view b. Frontal view mediastinum vertebral canal thoracic spinal cord pleural cavity thoracic cavity abdominal cavity anterior(ventral)abdominal cavity body cavity abdominopelvic pelvic cavity 1.3 Body Cavities and Membranes blood Serous fluid between the smooth serous membranes reduces friction as the viscera rub against each other or against During embryonic development, the body is first divided into the body wall two internal cavities: the posterior(dorsal) body cavity and To understand the relationship between serous mem- the anterior(ventral) body cavity. Each of these major cavities branes and an organ, imagine a ball that is pushed in on one is then subdivided into smaller cavities. The cavities, as well as side by your fist. Your fist would be covered by one membrane the organs in the cavities(called the viscera), are lined by (called a visceral membrane), and there would be a small membrane space between this inner membrane and the outer membrane (called a parietal membrane Posterior(Dorsal Body Cavity The posterior body cavity is subdivided into two parts: (1) The cranial cavity, enclosed by the bony cranium, contains the brain. (2)The vertebral canal, enclosed by vertebrae, con tains the spinal cord(Fig. 1.5a) The posterior body cavity is lined by three membranous I parietal serous membrane ers called the meninges. The most inner of the meninges is tightly bound to the surface of the brain and the spinal cord. The space between this layer and the next layer is filled with cere- brospinal fluid Spinal meningitis, a serious condition, is an in- cavity flammation of the meninges usually caused by an infection. Anterior (VentraL Body Cavity The large anterior body cavity is subdivided into the superior thoracic cavity and the inferior abdominopelvic cavity(Fig. Thoracic Cavity 1.5a). A muscular partition called the diaphragm separates the The thoracic cavity is enclosed by the rib cage, and has three wo cavities. Membranes that line these cavities are called portions: the left, right, and medial portions. The medial por serous membranes because they secrete a fluid that has just tion, called the mediastinum, contains the heart, thymus about the same composition as serum, a component of gland, trachea, esophagus, and other structures( Fig. 1.5b) 6 I Human Organization
Mader: Understanding Human Anatomy & Physiology, Fifth Edition I. Human Organization 1. Organization of the Body © The McGraw−Hill Companies, 2004 1.3 Body Cavities and Membranes During embryonic development, the body is first divided into two internal cavities: the posterior (dorsal) body cavity and the anterior (ventral) body cavity. Each of these major cavities is then subdivided into smaller cavities. The cavities, as well as the organs in the cavities (called the viscera), are lined by membranes. Posterior (Dorsal) Body Cavity The posterior body cavity is subdivided into two parts: (1) The cranial cavity, enclosed by the bony cranium, contains the brain. (2) The vertebral canal, enclosed by vertebrae, contains the spinal cord (Fig. 1.5a) The posterior body cavity is lined by three membranous layers called the meninges. The most inner of the meninges is tightly bound to the surface of the brain and the spinal cord. The space between this layer and the next layer is filled with cerebrospinal fluid. Spinal meningitis, a serious condition, is an in- flammation of the meninges usually caused by an infection. Anterior (Ventral) Body Cavity The large anterior body cavity is subdivided into the superior thoracic cavity and the inferior abdominopelvic cavity (Fig. 1.5a). A muscular partition called the diaphragm separates the two cavities. Membranes that line these cavities are called serous membranes because they secrete a fluid that has just about the same composition as serum, a component of blood. Serous fluid between the smooth serous membranes reduces friction as the viscera rub against each other or against the body wall. To understand the relationship between serous membranes and an organ, imagine a ball that is pushed in on one side by your fist. Your fist would be covered by one membrane (called a visceral membrane), and there would be a small space between this inner membrane and the outer membrane (called a parietal membrane): Thoracic Cavity The thoracic cavity is enclosed by the rib cage, and has three portions: the left, right, and medial portions. The medial portion, called the mediastinum, contains the heart, thymus gland, trachea, esophagus, and other structures (Fig. 1.5b). 6 Part I Human Organization cranial cavity vertebral canal spinal cord thoracic cavity diaphragm abdominal cavity abdominopelvic cavity abdominopelvic cavity anterior (ventral) body cavity posterior (dorsal) body cavity pelvic cavity mediastinum diaphragm pleural cavity pericardial cavity thoracic cavity abdominal cavity pelvic cavity a. b. Figure 1.5 The two major body cavities and their subdivisions. a. Left lateral view b. Frontal view. outer balloon wall (parietal serous membrane) inner balloon wall (visceral serous membrane) cavity fist