ORGANIZATION OF THE chapter 1

HUMAN BODY
 Selected Branches of Anatomy and Physiology

BRANCH OF ANATOMY STUDY OF BRANCH OF PHYSIOLOGY STUDY OF

Embryology The first eight weeks of Neurophysiology

development after Functional properties of nerve cells.
(em!-brē-OL-ō-jē; (NOOR-ō-fiz-ē-ol!-ō-jē;
embry- " embryo; fertilization of a human egg
neuro- " nerve)
-logy " study of)
Endocrinology Hormones (chemical regulators in
Developmental biology The complete development of an (en!-dō-kri-NOL-ō-jē; the blood) and how they control
individual from fertilization to
endo- " within; -crin " secretion) body functions.
death
Cardiovascular physiology Functions of the heart and blood
Cell biology Cellular structure and functions (kar-dē-ō-VAS-kū-lar; vessels.
Histology Microscopic structure of tissues cardi- " heart;
vascular " blood vessels)
(his-TOL-ō -jē; hist- " tissue)
Gross anatomy Structures that can be examined Immunology The body’s defenses against
without a microscope (im!-ū-NOL-ō-jē; disease-causing agents.
immun- " not susceptible)
Systemic anatomy Specific systems of the body
such as the nervous or respiratory Respiratory physiology Functions of the air passageways
systems (RES-pi-ra-tōr- ē; and lungs.
respira- " to breathe)
Regional anatomy Specific regions of the body
such as the head or chest Renal physiology Functions of the kidneys.
Surface markings of the body to (RĒ-nal; ren- " kidney)
Surface anatomy
understand internal anatomy Exercise physiology Changes in cell and organ functions
through visualization and due to muscular activity.
(palpation (gentle touch )
Pathophysiology Functional changes associated
Body structures that can be (Path-ō-fiz-ē-ol!-ō-jē) with disease and aging.
Imaging anatomy
visualized with techniques such
as x-rays, MRI, and CT scans

Pathological anatomy
Structural changes (gross to
microscopic) associated with
(path!-ō-LOJ-i-kal;
disease
path- " disease)

ANATOMY AND PHYSIOLOGY DEFINED

OBJECTIVE • Define anatomy and physiology.
The sciences of anatomy and physiology are the foundation for understanding the structures and functions of the human body.
Anatomy (a-NAT-o¯-me¯; ana- ! up; -tomy ! process of cutting) is the science of structure and the relationships among
structures. Physiology (fiz"-e¯-OL-o¯-je¯; physio- ! nature, -logy ! study of) is the science of body functions, that is, how the
body parts work. Because function can never be separated completely from structure, we can understand the human body best
by studying anatomy and physiology together. We will look at how each structure of the body is designed to carry out a
particular function and how the structure of a part often determines the functions it can perform. The bones of the skull, for
example, are tightly joined to form a rigid case that protects the brain. The bones of the fingers, by contrast, are more loosely
joined, which enables them to perform a variety of movements, such as turning the pages of this book.
ANATOMICAL TERMS
In Figure 1.4, the corresponding anatomical adjective
OBJECTIVES • Describe the anatomical position. for each part of the body appears in parentheses next to the
• Identify the major regions of the body and relate the com-mon name. For example, if you receive a tetanus shot
common names to the corresponding anatomical in your buttock, it is a gluteal injection. The descriptive form
terms for various parts of the body. of a body part is based on a Greek or Latin word or “root”
• Define the directional terms and the anatomical planes for the same part or area.
and sections used to locate parts of the human body. The Latin word for armpit is axilla (ak-SIL-a), for
example, a nd thus one o f the nerves passing within the
The language of anatomy and physiology is very precise.
armpit is named the axillary nerve .
When describing where the wrist is located, is it correct to
say “the wrist is above the fingers”? This description is true if
your arms are at your sides. But if you hold your hands up
above your head, your fingers would be above your wrists. To Directional Terms
prevent this kind of confusion, scientists and health-care pro- To locate various body structures, anatomists use
fessionals refer to one standard anatomical position and use a specific directional terms, words that describe the
special vocabulary for relating body parts to one another. position of one body part relative to another. S veral
In the study of anatomy, descriptions of any part of the directional terms can be grouped in pairs that have opposite
human body assume that the body is in a specific stance meanings, for example, anterior (front) and posterior
called the anatomical position (an!-a-TOM-i-kal). In the (back). Study Exhibit 1.1 and Figure 1.5 to determine,
anatomical position, the subject stands erect facing the ob- among other things, whether your stomach is superior to
server, with the head level and the eyes facing forward. The your lung.
feet are flat on the floor and directed forward, and the arms
are at the sides with the palms turned forward (Figure
1.4 ). In the anatomical position, the body is upright. Two
terms describe a reclining body. If the body is lying face
down, it is in the prone position. If the body is lying face up,
it is in the supine position.

Names of Body Regions

The human body is divided into several major regions that
can be identified externally. These are the head, neck,
trunk, upper limbs, and lower limbs (Figure 1.4). The head
consists of the skull and face. The skull is the part of the
head that encloses and protects the brain, and the face is the
front portion of the head that includes the eyes, nose,
mouth, forehead, cheeks, and chin. The neck supports the
head and attaches it to the trunk. The trunk consists of the
chest, abdomen, and pelvis. Each upper limb is attached to
the trunk and consists of the shoulder, armpit, arm
(portion of the limb from the shoulder to the elbow),
forearm (portion of the limb from the elbow to the
wrist), wrist, and hand. Each lower limb is also attached
to the trunk and consists of the buttock, thigh (portion of
the limb from the hip to the knee), leg (portion of the
limb from the knee to the ankle), ankle, and foot. The
groin is the area on the front surface of the body, marked
by a crease on each side, where the trunk attaches to the
thighs.
 Figure 1.4 The anatomical position. The common names and corresponding anatomical terms (in parentheses)
indicate specific body regions. For example, the head is the cephalic region.
In the anatomical position, the subject stands erect facing the observer with the head level and the eyes facing
ng forwar
forward. The
lower limbs are parallel and the feet are flat on the floor and directed forward, and the upper limbs are at the sides with the
palms facing forward.

Frontal (forehead)
Temporal (temple)
Cranial Orbital or ocular (eye)
(skull)
CEPHALIC Otic (ear)
(HEAD) Facial Buccal (cheek)
(face) CEPHALIC
Nasal (nose) (HEAD)
CERVICAL Occipital
Oral (mouth) (base of skull)
(NECK)
Mental (chin) CERVICAL
Thoracic (NECK)
Axillary Sternal (breastbone)
(chest)
(armpit)
Scapular
Brachial Mammary (breast) (shoulder blade)
(arm)
Umbilical Vertebral
Abdominal (spinal column)
(navel)
Antecubital (abdomen)
TRUNK

(front of elbow) Coxal (hip) Dorsal

Olecranal or (back)
Inguinal
(groin) cubital
Antebrachial UPPER
(back of elbow)
(forearm) LIMB
Pelvic Sacral Lumbar (loin)
Carpal (pelvis) (between
(wrist)
hips)
Pollex
Palmar (thumb)
or volar
(palm) Gluteal
Manual (buttock)
(hand)
Digital or Perineal (region
phalangeal of anus and
(fingers) external genitals)
Femoral Pubic Dorsum
(thigh) (pubis) (back of
hand)
Patellar
Popliteal
(anterior surface of knee) LOWER
(hollow behind knee)
LIMB
Crural
(leg)
Sural
Tarsal (calf)
(ankle)
Pedal
Digital or
(foot)
phalangeal
(toes) Dorsum
(top of foot) Plantar
(sole)
Hallux Calcaneal
(a) Anterior view (great toe) (b) Posterior view (heel)
 Exhibit 1.1 Directional Terms (Figure 1.5)

OBJECTIVE • Define each directional term used to describe the human body.

Most of the directional terms used to describe the human body can be grouped into pairs that have opposite meanings. For example,
superior means toward the upper part of the body, and inferior means toward the lower part of the body. It is important to understand that
directional terms have elative meanings; they only make sense i ii i F
i i i i i i i
i fi i i

DIRECTIONAL TERM DEFINITION EXAMPLE OF USE

Superior (soo’-PĒR-ē-or) Toward the head, or the upper part of a structure. The heart is superior to the liver.
(cephalic or cranial)
Inferior (in-FĒ-rē-or) (caudal) Away from the head, or the lower part of a structure. The stomach is inferior to the lungs.
Anterior (an-TĒR-ē-or) (ventral)* Nearer to or at the front of the body. The sternum (breastbone) is anterior to the heart.
Posterior (pos-TĒR-ē-or) (dorsal) Nearer to or at the back of the body. The esophagus (food tube) is posterior to the trachea
(windpipe).
Medial (MĒ-dē-al) Nearer to the midline (an imaginary vertical line that The ulna is medial to the radius.
divides the body into equal right and left sides).
Lateral (LAT-er-al) Farther from the midline. The lungs are lateral to the heart.
Intermediate (in’-ter-MĒ-dē-at) Between two structures. The transverse colon is intermediate to the ascending
and descending colons.
Ipsilateral (ip-si-LAT-er-al) On the same side of the body as another structure. The gallbladder and ascending colon are ipsilateral.
Contralateral (KON-tra-lat-er-al) On the opposite side of the body from another structure. The ascending and descending colons are contralateral.
Proximal (PROK-si-mal) Nearer to the attachment of a limb to the trunk; nearer to the The humerus (arm bone) is proximal to the radius.
origination of a structure.
Distal (DIS-tal) Farther from the attachment of a limb to the trunk; farther The phalanges (finger bones) are distal to the carpals
from the origination of a structure. (wrist bones).
Superficial (soo’-per-FISH-al) Toward or on the surface of the body. The ribs are superficial to the lungs.
(external)
Deep (Internal) Away from the surface of the body. The ribs are deep to the skin of the chest and back.

*Note that the terms anterior and ventral mean the same thing in humans. However, in four-legged animals ventral refers to the belly side and is therefore
inferior. Similarly, the terms posterior and dorsal mean the same thing in humans, but in four-legged animals dorsal refers to the back side and is therefore
superior.
Figure 1.5 Directional terms.
Directional terms precisely locate various parts of the body in relation to one another.

LATERAL MEDIAL LATERAL

SUPERIOR
Midline

PROXIMAL Esophagus (food tube)

Trachea (windpipe)

Right lung
Rib

Sternum Left lung

(breastbone)

Heart
Humerus
Diaphragm

Stomach

Transverse colon

Liver
Radius Small intestine

Ulna
Descending colon
Gallbladder
Ascending
colon

Urinary bladder
Carpals

Metacarpals

Phalanges

DISTAL INFERIOR
Anterior view of trunk and right upper limb
Planes and Sections all at right angles to one another. An oblique plane, by con-
You will also study parts of the body in four major planes, trast, passes through the body or an organ at an angle be-
that is, imaginary flat surfaces that pass through the body tween the transverse plane and a sagittal plane or between
parts (Figure 1.6): sagittal, frontal, transverse, and oblique. A the transverse plane and the frontal plane.
sagittal plane (SAJ-i-tal; sagitt- ! arrow) is a vertical plane When you study a body region, you will often view it in
that divides the body or an organ into right and left sides. section. A section is a cut of the body or an organ made along
More specifically, when such a plane passes through the mid- one of the planes just described. It is important to know the
line of the body or organ and divides it into equal right and plane of the section so you can understand the anatomical
left sides, it is called a midsagittal plane. If the sagittal plane relationship of one part to another. Figure 1.7 indicates how
does not pass through the midline but instead divides the three different sections—a transverse (cross) section, a frontal
body or an organ into unequal right and left sides, it is called section, and a midsagittal section—provide different views of
a parasagittal plane (para- ! near). A frontal plane or coronal the brain.
plane divides the body or an organ into anterior (front) and
posterior (back) portions. A transverse plane divides the
Figure 1.7 Planes and sections through different parts of the
body or an organ into superior (upper) and inferior (lower) brain. The diagrams (left) show the planes, and the photographs
portions. A transverse plane may also be called a cross-sectional (right) show the resulting sections. (Note: The “View” arrows in the
or horizontal plane. Sagittal, frontal, and transverse planes are diagrams indicate the direction from which each section is viewed.
This aid is used throughout the book to indicate viewing perspective.)
Planes divide the body in various ways to produce sections.

Figure 1.6 Planes through the human body. (a) View

Transverse
Frontal, transverse, sagittal, and oblique planes divide the body plane
in specific ways

Posterior Anterior

Transverse section

(b) Frontal plane

Frontal plane

View
Transverse
plane Frontal section

(c) Midsagittal plane

Midsagittal plane
(through the midline)

Parasagittal
Oblique plane plane

View
Right anterolateral view Midsagittal section
BODY CAVITIES
OBJECTIVES • Describe t e principal b dy cavities and the organs they contain.

• Explain why the abdominopelvic cavity is divided into

regions and quadrants.

Body cavities are spaces within the body that contain, and contains the spinal cord. The major body cavities of the trunk
protect, separate, and support internal organs. Here we are the thoracic and abdominopelvic cavities. The thoracic
discuss several of the larger body cavities (Figure 1.8). cavity (thor-AS-ik; thorac- !chest) is the chest cavity. Within the
The cranial cavity is formed by the cranial (skull) thoracic cavity are three smaller cavities: the pericardial cavity
bones and contains the brain. The vertebral (spinal) (peri = around ; cardial =heart ), a fluid-filled space that surrounds
canal is formed by the bones of the vertebral column
(backbone

Figure 1.8 Body cavities. The dashed lines indicate the border between the abdominal and pelvic cavities.
The major body cavities of the trunk are the thoracic and abdominopelvic cavities.

CAVITY COMMENTS

Cranial cavity Formed by cranial bones and contains brain.

Vertebral canal Formed by vertebral column and contains spinal

Cranial cord and the beginnings of spinal nerves.
cavity

Thoracic cavity* Chest cavity; contains pleural and pericardial

Vertebral cavities and mediastinum.
canal
Pleural cavity Each surrounds a lung; the serous membrane of
each pleural cavity is the pleura.
Thoracic
cavity
Pericardial cavity Surrounds the heart; the serous membrane of the
Diaphragm pericardial cavity is the pericardium.

Abdominopelvic Mediastinum Central portion of thoracic cavity between the

cavity: lungs; extends from sternum to vertebral column
Abdominal and from neck to diaphragm; contains heart,
cavity thymus, esophagus, trachea, and several large
blood vessels.
Pelvic
cavity Abdominopelvic Subdivided into abdominal and pelvic cavities.
cavity

Abdominal cavity Contains stomach, spleen, liver, gallblader,

small intestine, and most of large intestine; the
(a) Right lateral view (b) Anterior view serous membrane of the abdominal cavity is
the peritoneum.

Pelvic cavity i i i i i
i i

* See Figure 1.9 for details of the thoracic cavity.

Figure 1.9 The thoracic cavity. The dashed lines indicate the borders of the mediastinum. Notice that the pericardial cavity surrounds
the heart, and that the pleural cavities surround the lungs.
The mediastinum is the anatomical region medial to the lungs that extends from the sternum to the vertebral column
and from the first rib to the diaphragm.

Mediastinum
Right pleural cavity
Pericardial cavity

Parietal pleura Parietal pericardium

Visceral pericardium
Visceral pleura
Left pleural cavity
Diaphragm

Anterior view

the heart, and two pleural cavities (PLOOR-al; pleur- ! rib or A thin, slippery, double-layered serous membrane
side), each of which surrounds one lung and contains a small covers the viscera within the thoracic and abdominal
amount of fluid (Figure 1.9). The central portion of the thoracic cavities and lines the walls of the thorax and abdomen.
cavity is an anatomical region called the mediastinum. It is The parts of a serous membrane are (1) the parietal layer,
between the lungs, extending from the sternum which lines the walls of the cavities, and (2) the visceral
(breastbone) to the vertebral column (backbone), and from the layer, which covers and adheres to the viscera within the
first rib to the diaphragm (Figure 1.9), and contains all thoracic cavities. A small amount of lubricating fluid between the
organs except the lungs themselves. Among the structures in two layers reduces friction, allowing the viscera to slide
the mediastinum are the heart, esophagus, trachea, and several somewhat during movements, as when the lungs inflate
large blood vessels. The diaphragm is a dome-shaped muscle and deflate during breathing.
that powers breathing and separates the thoracic cavity from the The serous membrane of the pleural cavities is
abdominopelvic..cavity. called the pleura (PLOO-ra). The serous membrane of
.
The abdominopelvic cavity (ab-dom!-i-no-PEL-vic) the pericardial cavity is the pericardium (per!-i-KAR-
extends from the diaphragm to the groin. As the name de¯-um). The peritoneum (per-i-to¯-NE-um) is the
suggests, it is divided into two portions, although no wall serous membrane of the abdominal cavity.
separates them (see Figure 1.8). The upper portion, In addition to those just described, you will also
the abdominal cavity (ab-DOM-i-nal; abdomin- " belly) learn about other body cavities in later chapters.
contains the stomach, spleen, liver, gallbladder, small These include the oral (mouth) cavity, which contains the
intestine, and most of the large intestine. The lower tongue and teeth; the nasal cavity in the nose; the orbital
portion, the pelvic cavity (PEL-vik; pelv- " basin) contains cavities, which contain the eyeballs; the middle ear
the urinary bladder, portions of the large intestine, and cavities, which contain small bones in the middle ear;
internal organs of the reproductive system. Organs inside and synovial cavities, which are found in freely movable
the thoracic and abdominopelvic cavities are called viscera joints and contain synovial fluid.