-
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
< br>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、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，
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
< br>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
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
20<
/p>
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
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.
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
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. <
/p>
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
homeostas
is. 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
“<
/p>
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
< br>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<
/p>
”
，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.
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,
biologistsbelieve 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 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 breadsloose
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
“
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
“<
/p>
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。
< br>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。<
/p>
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
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，<
/p>
在细胞膜内
扭绞，
终点为细胞核的膜。<
/p>
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<
/p>
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,
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。<
/p>
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
: <
/p>
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<
/p>
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、
< br>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。
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.
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进<
/p>
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
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，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，<
/p>
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
98.6
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.
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，<
/p>
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
burs
t.
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
Ig
G.
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
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
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
，<
/p>
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
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 ques
tions 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.
T
he 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
多数的就诊过程中，病人会向医生提出一些很基础的问题，例
如：
“
我是不是生了病？
”“
我
的病是什么原因引起的？
”
< br>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 shot.
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
”
。<
/p>
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、
< br>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，<
/p>
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