-
Chapter 1
Passage 1 Human Body
In this
passage you will learn:
1.
Classification
of
organ
systems2.
Structure
and
function
of
each
organ
system3.
Associated medical terms
To understand the human body it is
necessary to understand how its parts are put
together
and
how
they
function.
The
study
of
the
body's
structure
is
called
anatomy;
the
study
of
the
body's function is known
as physiology. Other studies of human body include
biology, cytology,
embryology,
histology, endocrinology, hematology, immunology,
psychology etc.
了解人体各部分的组成及其功能，对于认识人体是必
需的。研究人体结构的科学叫解
剖学；研究人体功能的科学叫生理学。其他研究人体的科
学包括生物学、细胞学、胚胎学、
组织学、内分泌学、血液学、遗传学、免疫学、心理学
等等。
Anatomists
find
it
useful
to
divide
the
human
body
into
ten
systems,
that
is,
the
skeletal
system, the muscular system, the
circulatory system, the respiratory system, the
digestive system,
the urinary system,
the endocrine system, the nervous system, the
reproductive system and the
skin. The
principal parts of each of these systems are
described in this article.
解剖学家发现把整个人体分
成骨骼、肌肉、循环、呼吸、消化、泌尿、内分泌、神经、
生殖系统以及感觉器官的做法
是很有帮助的。本文描绘并阐述了各系统的主要部分。
The
skeletal system is made of bones, joints between
bones, and cartilage. Its function is to
provide
support
and
protection
for
the
soft
tissues
and
the
organs
of
the
body
and
to
provide
points
of
attachment
for
the
muscles
that
move
the
body.
There
are
206
bones
in
the
human
skeleton. They have
various shapes - long, short, cube - shaped, flat,
and irregular. Many of the
long bones
have an interior space that is filled with bone
marrow, where blood cells are made.
骨骼系
统由骨、关节以及软骨组成。它对软组织及人体器官起到支持和保护作用，并
牵动骨胳肌
，引起各种运动。人体有
206
根骨头。骨形态不一，有长的、
短、立方的、扁
的及不规则的。许多长骨里有一个内层间隙，里面充填着骨髓，
这即是血细胞的制造场所。
A joint
is where bones are joined together. The connection
can be so close that no movement
is
possible, as is the case in the skull. Other kinds
of joints permit
movement: either back
and
forth in one plane - as with the
hinge joint of the elbow - or movement around a
single axis - as
with the pivot joint
that permits the head to rotate. A wide range of
movement is possible when
the ball -
shaped end of one bone fits into a socket at the
end of another bone, as they do in the
shoulder and hip joints.
关节把骨与骨连接起来。颅骨不能
运动，是由于骨与骨之间的连接太紧密。但其它的
关节可允许活动，如一个平面上的前后
屈伸运动，如肘关节；或是绕轴心旋转运动，如枢
轴点允许头部转动。如果一根骨的球形
末端插入另一根骨的臼槽里，大辐度的运动（如肩
关节、髋关节）即成为可能。
Cartilage is a more flexible
material
than bone. It serves as a
protective, cushioning layer
where
bones come together. It also connects the ribs to
the breastbone and provides a structural
base for the nose and the external ear.
An infant's skeleton is made of cartilage that is
gradually
replaced by bone as the
infant grows into an adult.
软骨是一种比一般骨更具
韧性的物质。它是骨连结的保护、缓冲层。它把肋骨与胸骨
连结起来，也是鼻腔与内耳的
结构基础。一个婴儿的骨骼就是由软骨组成，
然后不断生长、
1
骨化，使婴儿长大成人。
The
muscular
system
allows
the
body
to
move,
and
its
contractions
produce
heat,
which
helps maintain a
constant body temperature. Striated muscles can be
consciously controlled. The
ends of
these muscles are attached to different bones by
connective tissue bands so that when the
muscle
contracts,
one
bone moves
in
relation
to
the
other.
This
makes
it
possible
to
move
the
whole
body, as when walking, or to move just one part of
the body, as when bending a finger.
Contractions of the heart and smooth
muscles are not under conscious control. Smooth
muscles
are found in the walls of
organs such as the stomach and the intestines and
serve to move the
contents of these
organs through the body.
肌肉系统使躯体运动，肌肉收缩产
生的热有助于维
持一个恒定的体温。人体能够有意识地控制条纹肌。结缔组织使肌肉末端
附着于不同的骨
面上，所以当肌肉收缩时，两骨彼此靠近而产生运动。这也就使整个人体
可以运动起来，
如走路，
运动躯体某个部位，
< br>如弯曲手指。
心脏收缩和平滑肌收缩就不是被意识所控制的。
器官壁内层的平滑肌，如胃肠壁的平滑肌把胃肠中的物质运送到全身。
The circulatory system. All parts of
the body must have nourishment and oxygen in order
to
function and grow, and their waste
products must be removed before they accumulate
and poison
the body. The circulatory
system distributes needed materials and removes
unneeded ones. It is
made
up
of
the
heart,
blood
vessels,
and
blood,
which
together
make
up
the
cardiovascular
system. The blood is also part of the
body's defense system.
It has
antibodies and white blood
cells that
protect the body against foreign invaders.
循环系统：机体的所有部分需要营养物质
和氧气来使之发挥功能和生长，也需要
在这些器官所产生的废物积聚而危害生命之前将其
排除。循环系统运送有用物质，排泄废
物。心血管系统是循环系统的组成之一；心血管系
统包括心脏、血管及血液。血液也是机
体防御系统的一个部分，血液中有抗体及白细胞来
防止机体受到外来的侵袭。
The heart is a
muscle that is divided into two nearly identical
halves: one half receives blood
from
the lungs and sends it to the rest of the body,
the other half sends blood that has traveled
through the body back to the lungs.
When the heart muscle contracts, the blood is
forced out into
arteries and enters
small capillaries. Blood returns to the heart
through veins.
心脏是一块被分
为几乎对等两
半的肌肉。一半吸收来自肺部的血液，并将血液运送到机体的其余部位，另
一半使流经全
身的血液回流人肺。心脏收缩时，动脉把全身血液输送到毛细血管。静脉输
送血液返回心
脏。
Also
functioning
in
circulation
is
the
lymphatic
system.
Some
of
the
fluid
that
surrounds
cells does not
reenter the blood vessels directly. This fluid,
called lymph, returns to the heart by
way of another system of channels - the
lymph vessels. Lymph nodes along these vessels
filter
the fluid before it reenters the
blood. The spleen is a large lymphatic organ that
filters the blood.
淋巴系统也是循环系统的一个组成部分。一些
细胞周围的体液不是直接回流入血管通道，
这种体液叫淋巴液，它是流经另一个管道系统
——
淋巴管而回流人心脏。沿淋巴管的淋巴
结将淋巴液过滤，过滤后再回流人血液。脾是一个过滤血液的大淋巴器官。
The respiratory system
takes in oxygen from
the air and expels
carbon dioxide and water
vapor.
Air
enters
the
nose and
mouth
and
travels
through
the
larynx,
and
trachea. The
trachea
divides to enter each of the two lungs
and then divides more than 20 times to form a very
large
number of small air spaces.
Oxygen from the air enters the blood through
capillaries in the walls
of these air
spaces, and the blood release carbon dioxide into
the air spaces to be exhaled.
呼吸
2
系统从空气中摄取氧气，并将二氧化碳、水蒸气排出体外。空气经鼻腔、口腔人喉管、气
管。气管分成左右支气管，各连结左右肺，左右支气管再分枝
2
0
多次，在终端形成大量微
小的肺泡。从空气摄取的氧气流经这
些肺泡壁内的毛细血管流入血液，血液再经肺泡把释
放出的二氧化碳排出体外。
The digestive
system consists of a tube extending from the mouth
to the anus. In it, food and
fluids
are
taken
in,
moved
through
the
body,
and
broken
down
into
small
molecules
that
are
absorbed into the
circulatory system. This breakdown, known as
digestion, is both a mechanical
and a
chemical process.
消化系统是一个从口腔直到肛门的管道。
食物和液体在消化道里被吸
收，在肠道里移动时，被分解成小分子物质后
再进入循环系统。这种分解，即消化，是一
个机械过程，也是一个化学过程。
Food enters through
the mouth, where chewing and saliva start to break
it up and make it
easier
to
swallow.
Next,
the
food
travels
down
through
the
esophagus
to
the
stomach.
Contractions of the
stomach's muscular wall continue to break down the
food mechanically, and
chemical
digestion continues when acid and enzymes are
secreted into the stomach cavity.
食物
进入口腔里，咀嚼和唾液开始将食物粉碎，使之便于吞咽。接着，食物经食管人胃。胃肌
壁的收缩继续机械化地分解食物，而当酸和酶分泌入胃腔时，化学性消化开始。
The
liquified
food
gradually
passes
into
the
small
intestine.
In
the
first
part
of
the
small
intestine, called the
duodenum, enzymes from the pancreas are added.
These enzymes complete
the chemical
breakdown of the food. The digestion of fat is
aided by bile, which is made in the
liver and stored in the gall bladder.
The small intestine of an adult is about 21 feet
(6.4 meters)
long.
Most
of
its
length
is
devoted
to
absorbing
the
nutrients
released
during
these
digestive
activities.
液体化食物逐渐进入小肠。小肠的起始部分叫十二指肠，胰腺分泌的酶辅助食物
消化。这些酶完成食物的化学分解。肝脏分泌的胆汁贮存在胆囊内，
胆汁有助于脂肪消
化。
一个成年人的小肠有
21
英尺（<
/p>
6.4
米）长。小肠的大部分肠段用来吸收消化过程中释放的
营养物质。
The liquid remainder of the food enters
the large intestine, or colon, which is about 12
feet
(3.7 meters) long. It is more than
twice as wide as the small intestine. In the large
intestine most
of the fluid is
absorbed, and the relatively dry residues are
expelled.
液状的剩余食物进入大肠，
或结肠，它大
约有
12
英尺（
3.7
米）长。大肠是小肠的两倍多宽。大部分液体在大肠内被
吸收，相对干化的残余
物被排出体外。
The
urinary system maintains normal levels of water
and of certain small molecules such as
sodium
and
potassium
in
the
body.
It
does
this
by
passing
blood
through
the
kidneys,
two
efficient
filtering
organs
that
get
rid
of
any
excess
of
various
molecules
and
conserve
those
molecules that are in short supply.
泌尿系统维持水分及体内某些小分子物质，如钠、钾的正
常水平。身体
是通过让
’
肾过滤血液来做到这一点的。肾是两个有效的过滤器
官，它滤出各
种多余的小分子物质，保留那些供应不足的小分子物质。
< br>
The fluid that leaves
the kidneys, known as urine, travels through a
tube called the ureter to
the bladder.
The bladder holds the urine until it is voided
from the body through another tube, the
urethra.
从肾流出的液体，即尿，通过输尿管人膀胱
。膀胱起贮存尿液的作用，直到尿经膀
胱另一端的管道排出。
The endocrine system. The
two systems that control body activities are the
endocrine system
and the nervous
system. The former exerts its control by means of
chemical messengers called
3
hormones.
Hormones are produced by a variety of endocrine
glands, which release the hormones
directly into the blood stream.
内分泌系统。
内分泌和神经是调控机体活动的两个系统，
前者
依靠其化学信使
——
激素发挥作
用。激素是由各种内分泌腺体制造，并直接被释放入血流
A major gland is the pituitary, which
is located under the brain in the middle of the
head. It
produces at least eight
hormones, which affect growth, kidney function,
and development of the
sex organs.
Because some of the pituitary's hormones stimulate
other glands to produce their own
hormones, the pituitary called the
master gland.
脑垂体是一个主要腺体，它位于头中部脑下
方。它至少分泌八种激素，这些激素对人体生长、肝功能及性器官发育有影响。因为脑垂
体分泌的一些激素促进其他腺体分泌激素，所以脑垂体是主要腺体。
Another gland, the thyroid,
is located between the collar bones. Its hormone
controls the rate
of the body's
metabolism. The sex organs (ovaries end testes)
make the sex cells and also make
hormones that control certain
characteristics of males and females. Located on
top of each kidney
is the adrenal
gland, which produces cortisone and adrenaline.
The pancreas produces not only
digestive
enzymes
but
also
3
insulin
and
glucagon,
which
control
the
body's
use
of
sugar
and
starches.
另一个腺体，甲状腺，位于锁骨之间。甲
状腺激素调控着机体新陈代谢的速度。
性器官（卵巢、睾丸）分泌性细胞和性激素，这些
激素控制着男性和女性的某些特征。每
边肾上方是肾上腺，它分泌可的松和肾上腺激素。
胰腺不仅分泌消化酶，而且分泌胰岛素
和高血糖素，这两种激素控制机体的糖分及淀粉的
消耗。
The nervous
system. The brain, the spinal cord and the nerve -
also controls body activities.
The
lower parts of the brain control basic functions
such as breathing and heart rate as well as
body temperature, hunger, and thirst.
Above these regions are the centers for sight,
sound, touch,
smell, and taste, and the
regions that direct voluntary
muscular
activities of the arms and legs.
Performed
here
are
the
higher
functions
of
integrating
and
processing
information.
神经系统
——
脑、脊髓及神经，也调控机体活动
。脑的偏下部位控制着诸如呼吸、心跳、体温、饥
渴的基本活动。而脑的偏上部位则是视
觉、听觉、触觉、嗅觉及味觉中心，也是指挥臂、
腿随意肌肉运动的区域。神经系统更高
级的功能是整合、处理信息。
The brain receives and sends
information by means of nerves, many of which lie
partly in
the
spinal
cord. The
spinal cord
is
protected
by
the
spinal
column. Nerves
enter
and
leave
the
spinal
cord
at
each
level
of
the
body,
traveling
to
and
from
the
arms,
legs,
and
trunk.
These
nerves
bring
information
from
the
various
sense
organs.
The
information
is
processed
by
the
brain, and then messages are carried
back to muscles and glands through out the body. <
/p>
脑通过神
经收集并传送信息，许多神经部分地分布在脊髓里。脊髓
由脊柱保护。在机体每一级，神
经传人、传出脊髓，往返于臂、腿、躯体。这些神经输送
来自各种感觉器官的信息。信息
经脑处理后输送回全身及腺体
The
reproductive
system
is
constructed
differently
for
males
and
females.
The
male
reproductive system is responsible for
producing, transporting and maintaining viable
sperm (the
male
sex
cell).
It
also
produces
the
male
sex
hormone,
testosterone,
which
regulates
the
development
of
a
beard,
pubic
hair,
a
deep
voice
and
other
bodily
characteristics
of
the
adult
male.
男、女性的生殖系统不同。男性生殖系统产生、输
送、维持能存活的精子（男性性
细胞）
。它也分泌男性激素、睾
酮，以此调节胡须、阴毛、深沉嗓音极其他成年男子身体发
育的特征。
< br>
The female productive
system is responsible for producing and
transporting ova (the female
4
sex cells),
eliminating ova from the body when they are not
fertilized by sperm, nourishing and
providing a place for growth of an
embryo when an ovum is fertilized by sperm, and
nourishing a
newborn child. The female
reproductive system also produces the female sex
hormones, estrogen
and progesterone,
which regulate the development of breasts and
other bodily characteristics of
the
mature female.
女性生殖系统产生、
输送卵子
（女性性细胞）
，
将未受精的卵子排出
体外，
而当精、卵结合时，女性生殖系统培养、提供胚胎生长场所，并孕育新生儿。女性
生殖系
统也分泌女性性激素
——
雌激素
和孕酮，以此调节乳房及其他成熟女性身体发育的特征。
The skin is a complete layer that
protects the inner structures of the body, and it
is the largest
of the body's organs. It
keeps out foreign substances and prevents
excessive water evaporation.
The
nerves
in
the
skin
provide
tactile
information.
The
skin
also
helps
keep
the
body's
temperature
close
to
37
°
C,
heat
is
conserved
by
reducing
blood
flow
through
the
skin
or
is
expended by increasing blood flow and
by evaporation of sweat from the skin. Hair and
nails are
accessory structures of the
skin.
皮肤是保护肌体内层结构的完整层，也是机体的最大器官。
皮肤防御外来侵袭，防止过多水分蒸发。皮肤上的神经提供触觉信息。皮肤也能将体温维
持到
98.6
华氏度（约
37
摄氏度）
。通过皮肤的血流量降低时，热量就被储存起来，通过
皮
肤的血流增加及汗液蒸发时，热量就散发。头发及指甲是皮肤的附属结构。
Cells and
Tissues
细胞与组织
In
this passage, you will learn: body systems as a
whole parts of a cell
kinds of
tissues
Cells
are
organized
into
tissues,
and
tissues
are
arranged
into
organs,
which
in
turn
are
grouped
into systems. Each body system serves its specific
functions. Bear in mind however that
the body functions as a whole----no
system is independent of the others. They work
together to
maintain the body’s state
of internal stability, terme
d
homeostasis. Now
let’s begin our
discussion
with cells, the smallest
unit of living matter that can exist by itself.
细胞构成组织，组织构成器
官，器官又进一步构成系统。人体的每个
系统都有其特定功能，但是，请记住这里
:
机体是
作为一个整体来发挥作用的，没有哪个系统能够独立于其他系统而存在，是整体系统共同
作用保持了机体内部的稳定状态，即体内平衡。现在，我们先讨论细胞
─
能独立存在活性
物质的最小单位。
The body can be studied from its
simplest to its most complex level, beginning with
the cell.
All body functions result
from the activities of billions of the specialized
cells. Some plants and
animals consist
of only a single cell. Others are composed of many
billions of cells.
从细胞开
始，我们能
够从最简单到最复杂的水平来研究机体。所有人体的功能都来自亿万个特定细
胞活动，有
的动植物仅由一个细胞构成，其他生物则由亿万个细胞构成。
Cells exist in a variety of shapes and
sizes. They may, for example, be cube-shaped or
flat.
Scientists who study cells have
determined that a single cell may be as large as a
tennis ball or so
small that thousands
would fit on the point of a needle. The yolk of a
hen’s egg is actually a very
large
cell. By contrast, bacteria----each one of which
is a tiny cell----are among the smallest cells.
Regardless
of
its
shape
or
size,
every
cell
contains
the
“machinery”
needed
to
maintain
life.
While
normally
cells
function
with
great
efficiency,
they
are
subject
to
various
disorders
that
result in disease.
细胞有很多种形状和大小。列如：有可能是立方形或扁形的。科学家的研
究发现单独一个细胞可以像网球一样的大小，或小到几千个细胞才能刚好填满针头。鸡的
5
蛋黄是一个非常大的单细胞。微
小的细菌呢算是最小的细胞。不管是细胞大小或形状的不
同，每个细胞都有
“
需要存活的机制
”
。对每
个正常的细胞，有效力的细胞，都存在许多问
题，能导致疾病。
The size of cells is usually
measured in
microns. A
micron is a millionth of a
meter, and
about 25,000 microns equal one inch.
The smallest bacteria are about 0.2 micron in
diameter. The
average
cell
in
the
human
body----about
ten
microns
in
diameter----is
a
speck
barely
visible
without the aid of a
microscope.
细胞的大小是以
“
< br>微米
”
为长度单位。
微米是一米
的一百万分
之一，
25000
微米等于
一寸。最小的细菌的圆径是
0.2
微米。人体正常细胞的评价圆
径约十
微米，肉眼勉强可以看得到，不需要显微镜的帮助。
The study of cells is the branch of
biology called cytology. The science that deals
with cells
on the smallest structural
and functional level is called molecular biology.
研究关于
“
细胞
”
是生
物学的分支，成为细胞生物学。在最微小水平针对细胞
的结构及功能的研究成为分子生物
学。
All
cells
consist
of
protoplasm,
the
“living
jelly.”
The
protoplasm
of
a
typical
cell
forms
three vital parts----
the cell membrane, the cytoplasm, and the nucleus.
The membrane encloses
the other cell
structures. Much of the chemical work of the cell
is done in the cytoplasm, which
surrounds the nucleus. The nucleus,
enclosed by its own membrane, is the control
center of the
cell. (see Figure 1-1)
所有细胞都是以
“
原生质
< br>”
，
又称
“
生命胶质
”
所形成的。
典型细胞的
原生
质形成了三个重要部分，细胞膜、细胞质和细胞核。细胞膜圈住了细胞的其他结构。
大部
分的化学反应都在细胞核周围，细胞质完成的。被自己的膜包围的细胞核是细胞的控
制中
心。
the cells
Membrane
细胞膜
Cells can survive only in a liquid
medium that brings in food and carries away waste.
For
one-celled organisms this fluid is
an external body of water----the ocean, a lake, or
a stream. For
many-celled plants and
animals, however, the medium is part of the
organism----in plants, the sap;
in
animals, the blood.
细胞只能存活在能供养分又能排除废物的液
体媒介中。对单细胞生物
来说，这就是细胞外的液体，如：大海里、河里或水流中。在对
多细胞生物而言，这种媒
介就是生物体的一部分，植物以汁液的形式，动物以血液的形式
。
The
cell
membrane
is
semipermeable,
or
differentially
permeable----
some
substances
can
pass through it, but others cannot.
This characteristic enables the cell to admit
useful substances
and to reject harmful
substances from
the surrounding fluid
as well as to
force out, or excrete
waste products into the fluid.
< br>细胞膜是半渗透性或区别性的渗透膜，即某些物质能渗透。这
个特殊性使细胞对细
胞周围只吸收了需要的物质而排除掉有害的物质，包括细胞内的废物
通过液体化后排出细
胞外。
The
cell
membrane
is
an
extremely
thin
but
tough
band
of
protein
and
phospholipid
molecules.
Phospholipids
are
chemicals
similar
to
stored
fat.
On
the
evidence
of
electron
micrographs,
biologists
believe
that
it
has
pores
through
which
certain
small
molecules
pass
intact.
Substances
probably
pass
through
the
cell
membrane
in
several
ways.
Small
chambers
located on the cell membrane called
caveolae gather chemical signals and channel them
into the
cells. The caveolae may also
help distribute proteins throughout the cell.
Large molecules enter
the cell by a
process called diffusion, in which they may be
dissolved by substances in the cell
membrane.
They
can
then
through
the
membrane
without
difficulty.
Some
cells
take
in
large
6
molecules
by
means
of
pinocytosis.
In
this
process,
the
cell
membrane
forms
a
pocket
around
large molecules
floating against it. The molecule-and-fluid-filled
pocket then breads loose from
the
membrane to become a bubblelike vacuole, and the
vacuole then drifts into the cytoplasm.
Finally, the vacuole wall breaks up and
the molecules are released into the cytoplasm.
细胞膜是
一种非常薄但确以很坚固的蛋白磷脂膜形成。磷脂是一种类似
于储存的脂肪的蛋白物质。
通过电子显微镜，生物学家相信细胞膜有孔，使较小的物质完
全可以通过。物质可通过多
种方式从细胞膜进入。细胞膜上的结构，称
< br>“
小穴
”
，可接受化学信号再传
到细胞内。小穴
还可能参于细胞蛋白的分配。大的分子可通过
“
渗滤
”
进入细胞内，或被细胞膜内体分
解，
使它们更容易的进入细胞内。有些细胞可通过
“
胞饮
”
方式吞饮较大的物质。这个过程是通
过细胞膜在大物质形成了
“
带
”
把它包围着，将它以泡状的
“
液泡
”
引入细胞质，最后包围解
散，
大物质成功的进入细胞内。
The
cytoplasm
细胞质
The
cytoplasm is mainly water. Its water content
varies from a minimum of about 65 percent
to
a
maximum
of
about
95
percent.
The
solids
in
the
cytoplasm
include
granular
proteins,
carbohydrates, droplets of fat, and
pigments. The cytoplasm is thus a colloidal
system.
细胞质主
要成分是
“
水
”
。水分含量有百分之
65
到最高，百分之
95
。
细胞质内的固体包括蛋白颗粒、
碳水化合物、脂肪小滴和色素。细胞质是胶体性的。
The
cytoplasm
may
be
either
watery
or
syrupy,
depending
on
the
concentration
of
solids
dispersed in the
fluid. When the solid content decreases, these
structures seem to vanish. Changes
in
concentration also produce an apparent steaming of
the cytoplasm from place to place within
the cell. This occurs, for example,
when food molecules enter the cell.
细胞质
可能是水性或糖
浆性，根据散在细胞质内固体的浓度。当固体成分浓度增多，膜状和纤维
状结果在细胞质
显出。而当固体成分浓度减少时，膜状和纤维状的结构就消失。浓度的变
化还可以表现细
胞质内局部流动的变化。食物分子进入时可见。
Most of the cell’s constant work of
keeping alive is performed in the cytoplasm.
Here
food
molecules are
changed into the material needed for energy and
materials for growth or stiffening
of
the cell membrane are manufactures needed by the
rest of the organism. For example, plant
cells
containing
chlorophyll
manufacture
glucose----a
plant
food----from
carbon
dioxide
and
water.
大部分为了细胞存活的工作都在此处（细胞质）
完成的。在此处，食物物质将被转
化成提供细胞能量的材料和提供细胞生长的材料，或细
胞膜的增强剂所生产。多细胞植物
的细胞质还是生产了对其他生物提供食物的物质。列如
：植物叶绿素所产生的葡萄糖，植
物的食物，从水和二氧化碳合成。
One of the cytoplasm’s key energy
transactions occurs in the
sausage
-shaped mitochondria.
Each
mitochondrion
has
an
inner
and
an
outer
membrane.
Like
the
cell
membrane,
the
membranes
of
the
mitochondrion
are
semipermeable.
Food
molecules
that
pass
into
the
cytoplasm are taken into the
mitochondria and oxidized, or burned, for energy.
细胞质能量转换
的要点发生在锥状形的线粒体。每个线粒体都有
内膜和外膜。像细胞膜一样，线粒体的膜
也是半渗透性。进入线粒体的食物分子被氧化提
供出能量。
The
endoplasmic reticulum, a network of membranous
tubes, runs through the cytoplasm.
In
the opinion of some biologists, this network is a
continuous structure that begins at the cell
membrane,
twists
through
the
cytoplasm,
and
ends
at
the
membrane
surrounding
the
nucleus.
Located
along
the
endoplasmic
reticulum
as
well
as
elsewhere
in
the
cytoplasm
are
numerous
7
ribosomes.
These
tiny
granules
consist
in
part
of
ribonucleic
acid
(RNA).
Proteins
are
manufactured
at
the
ribosomes.
The
Golgi
complex,
or
Golgi
apparatus,
is
a
membranous
structure
composed
of
stacks
of
thin
sacs.
Newly
made
proteins
move
from
the
endoplasmic
reticulum to the
Golgi complex, where they are stored for later
secretion.
胞浆网，在细胞质中
由膜所形成管状的
网。有些生物学家认为这是一种连续性结构，始点为细胞膜，在细胞膜
内扭绞，终点为细
胞核的膜。分布于胞浆网包括细胞质中某处的是核糖体。这些小颗粒是
核糖核酸所形成的
。蛋白质是在核糖体合成的。高尔基体是膜状囊包堆成层形成的。新合
成的蛋白从胞浆网
移动到高尔基体储存，为了后来分泌所用。
Vacuoles
drift
through
the
cytoplasm
and
usually
carry
food
molecules
in
solution.
Lysosomes are
structures somewhat similar in appearance to
vacuoles but denser. They appear to
have
a
digestive
function.
Each
lysosome
is
filled
with
digestive
enzymes
and
encased
in
a
membrane.
Lysosomes
are
believed
to
break
down
food
substances
brought
into
the
cell
by
pinocytosis.
It
has
been
suggested
that
the
Golgi
complex
plays
a
part
in
the
formation
of
lysosomes.
在细胞
质内游动的液泡一般是带着食物分子的溶液。溶酶体是一种有点像液泡
的结构，但较稠。
它是用来消化的。每个溶酶体的膜内都是添装着消化酶。我们认为它是
消化通过
“
胞饮
”
方式的大物质
。也认为高尔基体对溶酶体的形成有关系。
The
Nucleus
细胞核
Near the center of the cell is a
roundish or oval-shaped nucleus. The nucleus
controls the
growth and division of the
cell. It also contains the structures that
transmit hereditary traits.
细胞
的中央，圆形或椭圆形的就是细胞核。细胞核控制细胞的生长和分化。也装着遗传信息。
Enclosed by a two-layered membrane, the
nucleus contains a liquid called nucleoplasm as
well as strands of deoxyribonucleic
acid (DNA) covered with a coating of protein. A
strand of
DNA consists of a long series
of genes, which are the units of heredity of
plants and animals.
Genes determine the
characteristics of a cell. They do this by
regulating the production of RNA,
which
in turn controls the manufacture of specific
proteins.
被两层膜圈住着，细胞核内含有称
为
“
核质（浆）
”
的
液体和脱氧核糖核酸的蛋白层。脱氧核糖核酸缕是很长的基因系列所组
成的，它是植物和
动物的遗传信息。基因决定了细胞的特征。它是通过调节核糖核酸，使
核糖核酸产出特异
的蛋白。
Human cells, for example, make only
proteins unique to human beings DNA strands are
usually
too
thinly
strung
out
to
be
seen
with
an
optical
microscope.
Because
the
strands
are
readily stained with dyes, they are
called chromatin. When a cell begins to divide,
however, the
chromatin thickens into
the form of chromosomes.
列如：人的细胞，只产出人独特
拥有的蛋
白。脱氧核糖核酸缕一般都很细小过光学显微镜能观察到。因为脱氧核糖核酸缕
能够染色
后部分被染，称
“
染色质
”
。细胞分化过程中，染色体拾起变厚形成了
“
染色体
”
。
A
nucleus
not
undergoing
division
has
at
least
one
nucleolus.
The
nucleolus
contains
a
concentration of RNA.
Biologists think RNA is made initially in the
nucleus according to a DNA
“blueprint”
and stored there until needed for protein
manufacture.
细胞核分化核仁不会减少，
最少要
有一个核仁。核仁含有丰富的核糖核酸。生物学家认为核糖核酸原本在核仁里，根
据脱氧
核糖核酸的蓝图造出而藏在此处直到有蛋白合成的需要。
the nucleus of animal cells is a
spherical structure called the centrosome, from
which asters
radiate. The centrosome
contains a pair of rodded structure called
centrioles, which usually lie at
right
angles to each other. Although centrioles and
centrosomes have not been seen in plant cells,
8
biologists
believe
that
plant
cells
contain
similar
structures.
靠近动物的细胞核的圆形结构叫
“
中心体
”
，可见
呈放射状散发的星体。中心体内含有一对棍状结构，称为
“
中心
粒
”
，一般
都形成正确固定的角度。无
法在植物细胞发现中心体和中心粒，但生物学家认为植物应该
有存在类似功能的其他结构
。
Tissues
组织
Cells are organized into tissues that
perform specific functions. The four basic tissue
types
are as follows:
多细胞组成了组织，为了特异的功能。四种基本的组织：
Epithelial
tissues----covers
and
protects
body
structures
and
lines
organs,
vessels,
and
cavities.
上皮组织
:
覆盖及保护着身体结构和分清器官、导管和空腔。
Connective
tissues----
supports
and
binds
body
structures.
It
contains
fibers
and
other
nonliving material between the cells;
included are fat tissues, cartilage, bone and
blood.
结缔组
织
:
支柱和联结着身体结构。包括细胞之间的纤维和其它无生物
结构。包括脂肪组织、软
骨、骨头和血液。
Muscle tissues----contracts to produce
movement. The three types
are
：
skeletal or voluntary
muscle
that
moves
the
skeleton;
the
cardiac
muscle
of
the
heart;
and
the
smooth
muscle
that
forms
the
walls
of
the
abdominal
organs.
Cardiac
and
smooth
muscle
can
function
without
conscious control and are thus
described as involuntary
muscle.
肌肉组织
:
通过收拾来产生
动作。分为三种：骨骼肌，作用于一般骨骼移动。心机，心脏的肌肉。
平滑肌，形成胃肠
道壁的肌肉。心机和平滑肌是非意识性，不随意性肌肉。
Nervous
tissue
——
makes up the brain,
spinal cord, and nerves. It coordinates and
controls
body responses by transmitting
electrical impulses.
神经组织
:
组成大脑、脊椎和神经。它是
通过
动作电位来超空身体。
The simplest
tissues are membranes. Mucous membranes secrete
thick fluid called mucus
that protects
underlying tissues. Serous membranes secrete a
thin, watery fluid. They line body
cavities and cover organs.
最
简单的组织就是膜。粘液膜分泌出粘稠的胶液，起得组织保护
作用。粘液组织分泌出较稀
的粘液，起得身体导管的分界和覆盖着各个器官。
Human diseases
In
this
passage
you
will
learn:
e
and
pathology
classification
of
diseases
3.
germs’
invasion
of
the
human
body
4.
the
body’s
defense
against
invasion
5.
the
body’s
immunity to diseases
The
brief
survey
of
the
human
body
in
Chapter
One
has
given
us
a
glimpse
into
two
different studies that are considered
the fundamentals of medical sciences, namely
anatomy and
physiology. However, the
picture is not complete without considering
pathology, the science that
deals
with
the
structural
and
functional
changes
produced
by
the
disease.
In
fact,
the
modern
approach
to
the
study
of
disorder
emphasizes
the
close
relationship
of
the
pathological
and
physiological aspects and the need to
understand the fundamentals of each in treating
any body
diseases.
第一章中，通过对人
体的概论，即解剖学与生理学，我们对两种被认为是医学基
础的不同学科有了一个大致的
印象。然而如果我们不考虑病理学，这门涉及由疾病带来的
结构和功能变化的学科，上述
的人体概论就不是完整的。实际上，现代对疾病的研究方法
强调了病理学与生理学方面的
密切关系，强调了我们在治疗任何人体疾病方面需要了解病
9
理学与生理学基础的重要性。
Then what is a disease? It
may be defined as a condition that impairs the
proper function of
the
body
or
of
one
of
its
parts.
Every
living
thing,
both
plants
and
animals,
can
succumb
to
disease.
People,
for
example,
are
often
infected
by
tiny
bacteria,
but
bacteria,
in
turn,
can
be
infected by even more minute viruses. <
/p>
那么什么是疾病呢？它可能被定义为正常的功能或是
部分功能遭受
损害时的一种状态。每一种生物、植物和动物，都会受制于疾病。例如，人
类常常被微小
的细菌所感染，
但是，反过来说，
细菌又能够被甚至更加微小的
病毒所感染。
Hundreds
of different diseases exist. Each has its own
particular set of symptoms and signs,
clues
that
enable
a
physician
to
diagnose
the
problem.
A
symptom
is
something
a
patient
can
detect, such as fever, bleeding, or
pain. A sign is something a doctor can detect,
such as a swollen
blood vessel or an
enlarged internal body organ.
许多种疾病存在于世
。每一种都有其特定的
症状、征兆和线索，医生能以此诊断疾病之所在。症状是病人自己
就能觉察到的，比如，
高烧、流血，或是疼痛。而征兆则是医生能够观察到的，比如，血
管扩张或是体内器官肿
大。
Diseases can be classified differently.
For instance, an epidemic disease is one that
strikes
many persons in a community.
When it strikes the same region year after year it
is an endemic
disease. An acute disease
has a quick onset and runs a short course. An
acute heart attack, for
example, often
hits without warning and can be quickly fatal. A
chronic disease has a slow onset
and
runs a sometimes years-long course. The gradual
onset and long course of rheumatic fever
makes it a chronic ailment. Between the
acute and chronic, another type is called
subacute.
疾病
可以划分为不同的种类，例如，流行
病是一种在某一社区内侵袭许多人的疾病。当它年复
一年地袭击同一社区，就成了一种地
方病。急性病发作快，但病程短，举个例子来说，急
性心脏病发作常常没有前兆，而且会
很快致命。慢性病发作则慢，但病程有时会长达几年
之久。风湿热正是由于发病慢、病程
长而成为一种慢性失调病（慢性病）
。而介于急性与慢
性之间的
另一种类型，就被称为亚急性。
Diseases
can
also
be
classified
by
their
causative
agents.
For
instance,
an
infectious,
or
communicable,
disease
is
the
one
that
can
be
passed
between
persons
such
as
by
means
of
airborne droplets from a cough or
sneeze. Tiny organisms such as bacteria and fungi
can produce
infectious diseases. So can
viruses. So can tiny worms. Whatever the causative
agent might be, it
survives
in
the
person
it
infects
and
is
passed
on
to
another.
Sometimes,
a
disease-producing
organism
gets into a person who shows no symptoms of the
disease. The asymptomatic carrier
can
then pass the disease on to someone else without
even knowing he has it.
疾病也可以依其
< br>病原体来划分，例如，传染病也叫作可传播的疾病，就是一种通过咳嗽和打喷嚏造成的空
< br>气小粒来传播的疾病。极小的有机体，如，细菌和真菌可导致传染病。病毒和小虫子也不
< br>例外。不论病原体会是什么样，只要它存活于人体内就能够传染给别人。有时，一个致病
< br>的有机体侵人人体后，该人却没有显示带病的症状。于是无症状的病原携带者甚至在自己
< br>也不知情的情况下就把疾病传染给了他人。
Noninfectious
diseases
are
caused
by
malfunctions
of
the
body.
These
include
organ
or
tissue degeneration, erratic cell
growth, and faulty blood formation and flow. Also
included are
disturbances of the
stomach and intestine, the endocrine system, and
the urinary and reproductive
systems.
Some diseases can be caused by diet deficiencies,
lapses in the body's defense system,
or
a poorly operating nervous system.
非传染性
疾病是由身体功能失调引起的。
这包括血管或
10
组织退化、异常细胞生成，以
及异常的血液生成和血液循环。当然其中也包括胃、肠、内
分泌系统和泌尿生殖系统的紊
乱。一些疾病也可能是由饮食不足、身体抵抗力下降、或是
神经系统工作不造成的。
Disability
and
illnesses
can
also
be
provoked
by
psychological
and
social
factors.
These
ailments include drug addiction,
obesity, malnutrition, and pollution-caused health
problems.
心
理因素和社会因素也会引发残废和疾病
，这些病包括吸毒成性、肥胖、营养不良和由污染
造成的健康问题。
Furthermore,
a
thousand or more
inheritable
birth
defects
result
from
alternations
in
gene
patterns.
Since tiny genes are responsible for producing the
many chemicals needed by the body,
missing or improperly operating genes
can seriously impair health. Genetic disorders
that affect
body
chemistry
are
called
inborn
errors
of
metabolism.
Some
forms
of
mental
retardation
are
hereditary.
而且，有上千种乃至为数更多的遗传
性出生缺陷是由于基因变化而造成的。由
于小小的基因负责着生产许多身体所需的化学物
质，它的遗失或是工作状态不良都会严重
损害健康。因基因失调而被影响了的身体化学反
应被称之为先天性代谢失调。一些眢力发
育迟缓就是因遗传而造成的。
< br>
How Germs Invade the
Body
病菌是怎样侵袭身体
Humans
live
in
a
world
where
many
other
living
things
compete
for
food
and
places
to
breed.
The
pathogenic
organisms,
or
pathogens,
often
broadly
called
germs,
that
cause
many
diseases
are
able
to
invade
the
human
body
and
use
its
cells
and
fluids
for
their
own
needs.
Ordinarily, the
body's defense system can ward off these invaders.
人类生活在有一个有许多其
它生物竞争食物和求得繁衍的世界里
。很多致病的有机体或病原体，通常被我们广义地称
为病菌的东西能侵入人体并利用其细
胞和组织液来供它们自身的需求。一般来讲，身体防
御系统能够阻止这些入侵者。
Pathogenic
organisms can enter the body in various ways. Some
- such as these that cause
the
common
cold,
pneumonia,
and
tuberculosis
-
are
breathed
in.
Others
-
such
as
those
that
cause
venereal
diseases
-
enter
through
sexual
contact
of
human
bodies.
Still
others
-
such
as
those
that
cause
hepatitis,
colitis,
cholera,
and
typhoid
fever-get
in
the
body
through
contaminated food, water or utensils. <
/p>
病原有机体能通过多种方式进入身体。
它们的一些是被
呼吸进体内的，比如那些引起普通感冒、肺炎和肺结核的病菌；其它的是通过人体性接触< p>
进入的，比如那些引起花柳病的病原体；还有另外的一些是通过污染了的食物、水或器皿< p>
进入体内的，比如那些引起肝炎、霍乱和伤寒热的病原体。
Insects
can
spread
disease
by
acting
as
vectors,
or
carriers.
Flies
can
carry
germs
from
human waste or other
tainted materials to food and beverages. Germs may
also enter the body
through the bite of
a mosquito, louse, or other insect vector.
< br>昆虫作为媒介动物或是病原携带者
会传播疾病。苍蝇能将病菌从人类的废物或其它
腐烂的材料中带到食物和饮料中去。通过
蚊子、虱子或其它媒介动物的叮咬，病菌也可能
进入体内。
How the
Body Fights
Disease
身体是怎样抵抗疾病的
As a first line of defense,
a healthy body has a number of physical barriers
against infection.
The
skin
and
mucous
membranes
covering
the
body
or
lining
its
openings
offer
considerable
resistance to
invasion by bacteria and other infectious
organisms.
If these physical
barriers are
injured or
burned, infection resistance drops. In minor
cases, only boils or pimples may develop.
In major cases, however, large areas of
the body might become
infected.
作为第一条防线，一个
11
健康的身体有许多屏障来抵御
感染的发生。覆盖在体表或者器官开口处的皮肤和粘膜能在
很大程度上抵抗细菌或其它感
染体的入侵。如果这些屏障遭到了损坏或烧伤，身体对感染
的抵抗力就会下降。在一些病
情较轻的病例中，疥子和小脓胞可能会发生。在病情较重的
病例中，身体的大面积区域则
可能会被感染。
Breathing
passages
are
especially
vulnerable
to
infection.
Fortunately,
they
are
lined
with
mucus-secreting cells
that trap tiny organisms and dust particles. Also,
minute hairs called cilia
line
the
breathing
passages,
wave
like
a
field
of
wheat,
and
gently
sweep
matter
out
of
the
respiratory
tract.
In
addition,
foreign
matter
in
the
breathing
passages
can
often
be
ejected
by
nose
blowing,
coughing,
sneezing,
and
throat
clearing.
Unfortunately,
repeated
infection,
smoking
and
other
causes
can
damage
the
respiratory
passageways
and
make
them
more
susceptible to infectio
n.
呼吸通道尤其容易受到感染，
幸运的是，
< br>呼吸道内覆盖满了能分泌粘
液的细胞，它们能捕捉微小的有机体和尘粒。另外，被
叫做纤毛的细小的毛发也覆盖了呼
吸道，它们象微风下麦田里的小麦一样舞动着，轻轻地
将异物扫出呼吸道。除此之外，呼
吸道内的异物还常常因为擤鼻涕、咳嗽、打喷嚏和清喉
咙而被弹出。不幸的是反复感染、
抽烟或其它别的原因会损坏呼吸道，并且使它们容易受
到感染。
Many potential invaders
cannot stand body temperature (98.6 °
F
or 37 °
C). Even those that
thrive at that temperature may be
destroyed when the body assumes higher, fever
temperatures.
很多潜在的人侵者不能在华氏
9
8.6
度或摄氏
37
度下生存。如果体
温再升高一点，达到高
烧温度，甚至一些在先前温度下能蓬勃繁殖的病菌也可能会因此而
遭到毁灭。
Wax in the
outer ear canals and tears from eye ducts can slow
the growth of some bacteria.
And
stomach acid can destroy certain swallowed germs.<
/p>
外耳道里的蜡质和泪管里的眼泪能减
缓一些细菌的生长速度，而胃
酸也能毁掉某种吞食进去的病菌。
The body's second line of defense is in
the blood and lymph. Certain white blood cells
flock
to
infected
areas
and
try
to
localize
the
infection
by
forming
pus-filled
abscesses.
Unless
the
abscess breaks and
allows the pus to drain, the infection is likely
to spread. When this happens,
the
infection is first blocked by local lymph glands.
For example, an infection in the hand travels
up
the
arm,
producing
red
streaks
and
swollen,
tender
lymph
glands
in
the
armpit.
Unless
the
infection is brought under control, it
will result in blood poisoning.
身体的第二条防
线是在血
液和淋巴里。某些白细胞群聚集在被感染区，并通过形成脓块使感染局部化。如
果脓块不
破裂，里面的脓不排除掉，感染很可能会扩大。当这发生时，感染首先被该区域
的淋巴腺
挡住。例如，手上的感染在向上传到手臂时，手臂上会出现红线条，腋窝处会肿
胀，有触
痛。如果不及时控制住感染的上传，将会导致血液中毒。
Phagocytes
are
located
at
various
sites
to
minimize
infection.
One
type
in
the
spleen
and
liver
keeps
the
blood clean.
Others
in
such high-risk
areas
as
the
walls
of
the
bronchi
and
the
intestines remove certain bacteria and
shattered cells.
吞噬细胞处于身体多种不同的部位而使
得感染的机会变小。位于肝脾内的一类能使身体的血液保持干净。其它的位于像支气管壁< p>
和肠壁这样高危险区的类型能清除某类细茵和已解体的细胞。
How We Become Immune to
Disease
我们是怎样变得对疾病有免疫力的
The body has a special way of handling
infection. It has a system that fends off the
first traces of
an infectious substance
and then, through a
against future
attacks by the same kind of invader.
身体
处理感染有其特殊的方法。
它有一个系
统，能够一开始就阻止感
染性物质的侵袭，然后通过
“
记忆
”<
/p>
，它能给身体
—
个长期的免疫
12
力来抵抗将来由同种入侵者引起的侵袭。
Many substances could harm
the body if they ever entered it. These
substances, or antigens,
range from
bacteria and pollen to a transplanted organ
(viewed by the body as an invader). To
fight them the body makes special
chemicals known as antibodies.
许多物质对身体有害
，
如果它
们一旦进入身体的话。这些物质，或称为抗原，包括从
细菌，花粉到被移植的器官都被身
体视为人侵者。为了抵抗它们身体制造出了特殊的化学
物质，这就是抗体。
Antibodies
are
a
class
of
proteins
called
immunoglobulins.
Each
antibody
is
made
of
a
heavy chain of chemical subunits, or
amino acids, and a light chain of them. The light
chain has
special
sites
where
the
amino
acids
can
link
with
their
complements
on
the
antigen
molecule.
When an antibody
hooks up with an antigen, it often puts the
antigen out of action by inactivating
or
covering
a
key
portion
of
the
harmful
substance.
In
some
cases,
through
the
process
of
opsoni
zation
，
antibodies
the
surface
of
some
antigens
and
make
them
to
phagocytes,
which engulf the antigens. Sometimes an antibody
hooks to a bacterial antigen but
needs
an
intermediate,
or
complement,
to
actually
destroy
the
bacterium.
As
the
antibody-
antigen
complex
circulates
in
the
blood,
the
complex
complement
to
it.
In
turn,
the
complement
causes
powerful
enzymes
to
eat
through
the
bacterial
cell
wall
and
make
the
organism burst.
抗体是一类被称为免疫球蛋白的蛋白质。每一个抗体由一条化学亚单位（即
氨基酸）
的重链和一条轻链所构成。这条轻链上有特别的部位，在那里，氨基酸能使其补
体和抗原
分子相连。当一个抗体与一个抗原粘和上以后，氨基酸常通过使抗原失去活性或
覆盖，它
的关键有害部分来使抗原失去其作用。在某些情况下，通过调理素作用的过程，
抗体在抗
原表面涂抹上一些
“
奶油
”
，让吞噬细胞更喜欢吞噬它们。在另一些情况下，抗体
和一个细菌抗原粘和
上以后，却需要一个中间体，或补体来实施对该细菌的消灭。于是，
当抗体和抗原的结合
体随血液循环时，该结合体会有一个补体附体。结果是补体产生一种
强烈的酶，咬穿了细
菌的细胞壁，细菌有机体就爆开了。
There are several kinds of
immunoglobulins - IgM, the largest; IgG, the most
plentiful and
versatile;
and
IgA,
the
next
most
plentiful
and
specially
adapted
to
work
in
areas
where
body
secretions
could
damage
other
antibodies.
Other
immunoglobulins
are
tied
in
with
allergic
reactions,
IgM
is
made
at
the
first
signs
of
an
antigen,
and
it
is
later
supplanted
by
the
more
effective IgG.
抗体有若干种免疫球蛋白：
体积最大的是
igM
，
数量最多、
用途最多的是
IgG
，
而
IgA
< br>的数量次多，但它特别适合在其它抗体易被身体内分泌物杀死的部位工作，还有其
它的免疫球蛋白专门在过敏物质出现时启动。一有抗原出现，
igM
首先被产生，稍后被更
有效的
IgG
所取代。
When
infection first strikes, the immunity system does
not seem to be working. During the
first
day
or
so,
antibodies
against
the
infection
cannot
be
found
in
the
blood.
But
this
is
only
because the basic cells involved in
antibody production have been triggered by the
presence of
antigen
to
multiply
themselves.
The
antibody
level
starts
to
rise
on
about
the
second
day
of
infection and then zooms
upward. By the fifth day the antibody level has
risen a thousandfold.
当
传染病首次进
攻，免疫系统似乎没有运转起来。在第一天左右，血液中没有发现对付传染
病的抗体。但
是，这只是因为涉及抗体制造的基本细胞已被当前的抗原存在所触发而正准
备开始繁殖。
大约在感染的第二天，抗体水平开始升高，接着直线上升，大约在第五天抗
体水平已升高
了千倍。
The first
antibodies, the large IgM type, are not the best
qualified to fight a wide range of
13
antigens, but
they are particularly effective against bacteria.
The more versatile IgG is circulating
in the blood on about the fourth day of
infection. Its production is stimulated by the
rising level
of
IgM
in
the
blood.
At
this
time,
IgM
production
drops
off
and
the
immunity
systems
concentrates
on
making
IgG
.
The
IgG
type
of
antibody
sticks
well
to
antigens
and
eventually
covers
them
so
that
the
antigens
can
no
longer
stimulate
the
immune
response
and
IgG
production is switched off. This is an
example of negative feedback control.
最
开始出现的抗
体，及大个的
IgM
，不
是对付广谱抗原的最好选择。但它们对付细菌特别有效。而用途广
泛的
< br>IgG
自感染第四天开始在血液中循环，
它的产生是因为
受了血液中
IgM
水平增高的刺
激。至
此，
IgM
的产量下降，免疫系统集中制造
IgG
，
IgG
能很好的与抗原粘
连，甚至能覆
盖抗原，使抗原不能再激发免疫反应，而系统最终停止生产
IgG
。这是消极反馈控制的一
个例子。
Diagnosis
and prognosis
诊断和预后
Diagnosis
诊断
In most clinical encounters, the
patient presents basic questions to the doctor:
what’s wrong
with me? What is causing
my illness? These questions set the stage for
making a diagnosis, i.e.
determine
the
cause
of
an
illness
and
a
diagnosis
is
accomplished
with
history,
physical
examination and laboratory testing.
The process of diagnosing a disease
begins with the person’s health history. The
physician
asks the patient questions on
both present and past illnesses, family history of
disease, habits and
so on. The
following table presents typical contents of a
standard medical history.
诊断在大多数
< br>的就诊过程中，病人会向医生提出一些很基础的问题，例如：
“
< br>我是不是生了病？
”“
我的病
是
什么原因引起的？
”
这些问题促使医生去做出一个诊断，
即确立生病的原因，
而一个完整
的诊断由病人
的病史、
身体检查和实验室检查所组成。
诊断的过程是由采集病人的病史开
始。医生向病人询问当前和过去所患过的疾病、家
庭病史、生活习惯等等。下表展示了一
个标准病史里所包含的典型内容。
Description of
patient
病人的一般情况
Age, gender, race, occupation and
parity (for woman ).
年龄、性别、
民族、职业、生育
情况（女性）
Chief complaint
主诉
Four or five words, preferably quoting
the patient, stating the purpose of the visit and
the
duration of the complaint.
Occasionally the patient states a request instead
of a complaint such as
I need a flu sho
t.
用四到五个字，最好是引用患者的自述，陈述就诊的目的和病痛的持续时
间。偶尔，也可将患者的要求作为主诉，如：
“
我
需要注射流感疫苗
”
。
Other physicians involved in the
patient’s care
患者的其他保健医生续表
Name, address, telephone number, and
relationship to the patient
姓名、地址、电话号码、
与患者的关系
History of the present
illness
现病史
For
each of the major symptom, what, where, when, how
much, chronological course, what
makes
the
symptom
better
or
worse,
past
medical
care,
questions
to
narrow
diagnostic
possibilities.
每一种主要症状，包括什么症状、
发生部位、发生时间、轻重程度、时间经过、症
14
状好转或加重的影响因素、既往诊治情况及可能缩小诊断范围
相关的问题
Past medical
history
既往史
Previous
illnesses
and
hospitalizations,
immunizations,
medications
the
patient
takes,
allergies, and
alcohol, tobacco, and drug habits.
既往所患
疾病及住院治疗情况、
计划免疫、
用
药
情况、过敏史、吸烟、饮酒及有无药物成瘾等
Social
and occupational
history
社会及职业史
Description of a typical day in the
patient’s life and how the present illness affects
it, social
supports ( family, friends,
and colleagues ) available to the patient, and
occupational history.
描述
患者日常生
活中典型的一天以及目前疾病对其的影响；
患者可获得的社会支持
（来自家庭、
朋友或同事）及职业史
Family history
家族史
History
of
genetically
related
diseases
in
the
patient’s
family
and
longevity
and
cause
of
death of
family members.
家族中的遗传病史，家族成员的寿命及死亡原因
Review of
systems
系统回顾
Systematic
review
of
major
organ
systems:
skin,
hematopoietic
system
(
including
lymph
nodes),
head,
eyes,
ears,
nose,
mouth,
throat,
neck,
breasts,
and
respiratory,
cardiovascular,
gastrointestinal,
genitourinary,
musculoskeletal,
nervous,
endocrine,
and
psychiatric
systems.
主要器官系统回顾：皮肤、造血系统（包括淋巴结）
，头、眼、耳、鼻、口、喉、
颈、乳
房及呼吸系统、心血管系统、胃肠道系统、泌尿系统、肌肉骨骼系统、神经系统、内分泌
和精神系统
Asking the
patient’s medical history is followed by the
general physical examination which
includes measuring height and weight,
and taking blood pressure; listening to the heart
and lungs
with
a
stethoscope;
and
examining
eyes,
ears,
and
mouth.
Tests
of
hearing
and
vision
are
sometimes
performed
in
routine
physical
examinations.
Reflex
tests
are
simple
tests
of
nerve
conduction that
involve, among several other tests, tapping with a
rubber hammer in areas such
as
the
knee.
询问病史之后的第二步就是全面的身体检查，其内容包括测量身高和体重、
血
压，对心肺进行听诊，检查眼、耳和口。测试听力和视力有时候在常规身体检查中进行。
反射检查是简单的神经传导检查，其项目有好几项，包括用橡皮锤在一些部位（如膝盖）
的敲打
Since the body
fluids often reveal important information about
the nature of the disorder,
laboratory
testing
plays
an
important
role
in
determining
the
patient’s
disease.
Blood
tests
can
determine whether the person has anemia
---that is,
an insufficient
amount of healthy red blood
cells---
infection,
or
a
blood
disease,
such
as
leukemia.
Blood
analysis
can
also
uncover
nutritional deficiencies and other
disorders. The glucose-tolerance test, which is
used to diagnose
diabetes, measures
insulin activity by monitoring the level of
glucose, or sugar, in the blood.
因
为体液常常揭示了关于疾病的重要信息，所以在确诊病情上，实验室检查
起着非常重要的
作用。血液检查能判断出病人是否贫血，即正常红血细胞不足，
是否有感染或患有血液病，
如白血病。
血液分析
能显示营养不良和其它的疾病。
葡萄糖耐糖实验是用来检查糖尿病的，
< br>它通过检测血液里的糖份水平来测量胰岛素的活性。
Urine is also tested for glucose as
well as for bacteria, protein, and other
materials. Glucose
in
the
urine
is
sometimes
caused
by
diabetes.
Bacteria
in
the
urine
can
indicate
a
kidney
or
bladder infection, and
the presence of protein may result from a kidney
disorder. A stool sample
15
is
tested
for
disease-causing
microorganisms
and
for
blood,
which
is
often
a
symptom
of
intestinal disease.
尿样检验是用来探测小便里是否有葡萄糖、细菌、蛋白质及其它物质的
存在。<
/p>
尿液中的葡萄糖有时是由糖尿病引起的，
尿液中的细菌可以显示肾
脏和膀胱的感染，
尿液中的蛋白质可能起源于肾脏的疾病。粪便样品的检查旨在于找寻便
血和引起疾病的微
生物，这些常常是肠道病的症状
Spinal
fluid
is
examined
for
microorganisms
and
other
unusual
contents
when
a
nervous
system
disorder
is
suspected.
Mucus
from
the
nose
and
throat
can
be
tested
to
identify
the
organisms responsible for respiratory
infections.
当怀疑有神经系统病变时，医生常常通过检
< br>查脊液来发现微生物和其它不正常成分的存在。鼻腔和喉部的粘膜检查常常可确定引起呼
< br>吸道感染的生物。
A sample of
tissue can be taken from an organ or any other
part of the body by a process
called
biopsy.
The
tissue
is
then
sliced
into
very
thin
sections,
stained
with
special
dyes,
and
studied under the microscope to
discover the abnormalities in the cells.
通过活检，
医生可以从人
体的某个器官或其它部位抽取组织样
品，然后把该样品切成非常薄的切片，用特殊的染剂
加以染色，再置于显微镜下观察研究
，以发现细胞组织的病变。
Radiographs, or
x-ray photographs, are used to examine various
parts of the body. A chest x
ray, for
example, can help diagnose tumors, pneumonia, and
tuberculosis. X rays can also show
bone
fractures and other conditions of the
musculoskeletal system.
放射照
片，
x
光照片，被用
来检查身体的多个
部位。比如说，一张胸片有助于诊断肿瘤、肺炎和肺结核。
x
光
照片可
以显示骨折和其它有关于肌肉和骨骼系统的情况。
Radiopaque liquids are injected into
the urinary tract, spinal column, circulatory
system, and
other areas. These
materials do not allow x ray s
to pass
through them. Thus they
allow x ray
examination of soft tissues that would
otherwise be invisible by x ray. Spinal cord
disorders, for
example, often show up
in myelograms after a radiopaque liquid has been
injected into the spinal
canal.
Various
kinds
of
angiograms
show
heart
and
circulatory
disease.
In
these
procedures
a
radiopaque dye is
injected
into a vein or artery, x-ray photographs will then
show if there is a
blockage or an aneur
ysm.
把不能穿透
x
光射线的液体注
射入泌尿道、
脊柱循环系统和其它部
位。由于
< br>x
光不能通过这些物质，因而使
x
光能够检查其它本来
x
光检查不了的软组织。
例如，当不透射线的液体注射人脊髓管后，
x
光脊髓照
片常常揭示脊髓的病变。不同的血
管
x
光片显示
r
心脏和循环系统的疾病，在此过程中，不透射线的染
色液被注入静脉或动
脉，
X
光照片就能
显示血管中是否存在阻塞或有动脉瘤的存在。
x-ray
examination
of
the
esophagus
and
stomach
is
carried
out
by
having
the
patient
swallow a radiopaque
solution to highlight details in the upper
gastrointestinal tract. For x raying
the lower intestinal tract, the patient
is given an enema.
在进行食管和胃部的
X
光检查的时候，
医生常让病人服下不透
X
光射线的流体，目的是让上部胃肠道受检部位特别的显著。而用
X
光检查肠部下端的时候，医生常常给病人施以灌肠。
CT
(
computerized
tomography)
scanners
are
specialized
x
ray
cameras
that
take
highly
detailed images of
hard and soft tissues. By picturing one layer of
the body’s tissues at a time, CT
scanners can detect very small tumors
and other disorders.
计算机断层扫描仪是专业化的
X
光
摄像机，
它能拍下具有
高度细节的软硬组织的照片。
通过一次只拍下身体组织的一个断层，
计算机断层扫描仪能侦察到很微小的肿瘤和其它病变。
Nuclear
magnetic
resonance,
or
magnetic
resonance
imaging,
is
a
hazard-free,
16
non-invasive method that
uses radio waves in the presence of a strong
magnetic field to probe a
patient and
generate visual images of thin slices of the
brain, heart, liver, and other organs. The
high-contrast,
variable-
toned
images
that
result
can
uncover
tumors,
blood-starved
tissues,
and
plaques.
核磁共振
，或核磁共振成像，是一种没有副作用，没有伤害性，在强烈磁场下使
用放射波的探测手
段，它能把大脑、心脏、肝脏和其它人体器官剖析成很薄的片层，并产
生高比较度、具有
不同色泽的照片，能用来探测肿瘤、缺血组织及蚀斑
In
the procedure termed scintigraphy, a small amount
of a radioactive isotope is introduced
into the body. A scintiscan camera, or
gamma camera, measures the uptake and
concentration of
the isotope in certain
tissues, such as the brain, kidney, or thyroid
gland. Metabolic diseases and
other
disorders can be uncovered by this technique.
在一种被称为闪烁显像的方法中，少量的
放射性同位素被导人人体。
一部闪烁或伽玛相机可以测量某些组织中同位素的摄入和浓度，
如大
脑、肾脏或甲状腺。新陈代谢病和其它一些病变可以用这种技术来发现。
Ultrasonography is useful in locating
tumors of the lung and abdominal cavity. It
employs
ultra
high
frequency
sound
waves
to
form
television
images
of
internal
organs.
Because
it
produces no radiation,
ultrasound is sometimes used during pregnancy to
determine the size and
position
of
the
fetus.
肺部和腹腔的肿瘤用超声波检测法是有效的。它使用超高频率的声波
来
形成内部器官的电视图像。由于无放射性，超声波有时被用于妊娠期的妇女，以确定胎
儿
的位置及大小。
Both
the
heart
muscle
and
the
nervous
system
produce
electrical
impulses
that
can
be
measured with special machines. The
electrocardiograph (ECG) is useful for diagnosing
certain
heart conditions. With
electrodes taped t
o a person’s chest,
the electrical activity of the heart can
be recorded while the patient is either
resting or performing some activity, such as
walking on a
treadmill. The
electroencephalogram (EEG) measures the electrical
activity of the brain through
electrodes attached to the head. This
test detects whether there is an area if
irritability in the brain,
such
as
occurs
in
epilepsy.
The
electromyogram
(EMG)
records
the
activity
of
nerves
in
the
muscles.
The
EMG
is
helpful
in
diagnosing
degenerative
nerve
disorders
such
as
multiple
sclerosis.
心肌和神经系统均能产生电流脉冲，可以
用特殊的仪器测量出来。心电图
(
ECG)
< br>对于诊断某些心脏病是有用的。当心电图仪的电极被固定在病人的胸部时，无论病人是在
< br>休息还是在进行某些活动，如在计步器上走动，他心脏的电流活动都可能被记录下来。脑
< br>电图
(
EEG)
则是通过固定
在病人头上的电极来测量他脑部的电流活动。它可探测出癫痫病
人的大脑区是否存在一个
波动很大的区域。
而肌电图
(EMG)
可以记录下肌肉里神经的活动，
对于诊断多发性硬化症这一类的神经退化病变是有效的。
Tests of pulmonary function
measure the breathing capacity of the lungs and
airways. By
exhaling
into
a
tube
connected
to
a
machine
called
a
spirometer,
information
is
obtained
on
respiratory functions.
肺功能测试则
测量肺和呼吸道的呼吸能力。
通过向一根与肺量计相连的
管道呼
气，就能测试出呼吸功能有关的信息。
Fiber
optic
technology
has
allowed
physicians
to
see
parts
of
the
body
that
previously
could be seen only by performing
surgery. Fiber optic tools are essentially hair-
thin glass fibers
that can enter small
areas and can be moved deep into the body
cavities. Fiber optic technology
can be
used to examine the colon and the bronchial tubes
in the lung.
光纤技术使内科医生能看
到一些从前
只能通过手术才能看到的部位。光纤仪器主要是像头发丝一样细的玻璃纤维，
它细得可以
进入很小的区域，能够深深地进入体腔内。光纤技术可以被用来检查结肠和肺
17