畜牧獸醫(yī)專業(yè)英語十篇課文翻譯

The

joints

of

the

skeleton

need

oiling

to

reduce

wear.

Where

the

bones

meet,they

are

covered

with

a

pack

of

cartilage

which

acts

as

a

shock

absorber

and

provides

a

wear-resistant

surface.

Over

the

cartilage

is

a

membrane

which

produces

a

fluid

to

lubricate

the

joint.骨骼關(guān)節(jié)需要上油，以減少磨損。倘骨頭滿足，它們覆蓋軟骨它作為一個減振器，并提供了一個耐磨的外表與一包。超過產(chǎn)生的流體潤滑關(guān)節(jié)軟骨是一種膜。Movement

in

joints

is

caused

by

the

contraction

and

expansion

of

muscles

associated

with

that

joint.在關(guān)節(jié)中的運動是由與該關(guān)節(jié)相關(guān)聯(lián)的肌肉的收縮和膨脹。Lesson

2

muscle

Muscle

cells,like

neurons,con

be

excited

chemically,electrically,and

mechanically

to

produce

an

action

potential

that

is

transmitted

along

their

cell

membrane.

They

contain

contraction

proteins

and,unlike

neurons,

they

have

a

contractile

mechanism

that

is

activated

by

the

action

potential.肌肉細胞，如神經(jīng)元，濃度被激發(fā)化學，電和機械地產(chǎn)生沿其細胞膜上的動作電位被發(fā)送。它們包含收縮蛋白和不同于神經(jīng)元，它們有一個收縮的機制被激活的動作電位。Muscle

is

generally

divided

into

3

types,

skeletal,cardiac,and

smooth,although

smooth

muscle

is

not

a

homogeneous

single

category.Skeletal

muscle

comprises

the

great

mass

of

the

somatic

musculature.

It

has

well-developed

cross-striations,does

not

normally

in

the

absence

of

nervous

stimulation,lacks

anatomic

and

functional

connections

between

individual

muscle

fibers,and

is

generally

under

voluntary

control(1).Cardiac

muscle

also

has

cross-striations,but

it

is

functionally

syncytial

in

character

and

contracts

rhythmically

in

the

absence

of

external

innervation

owing

to

the

presence

in

the

myocardium

of

pacemaker

cells

that

discharge

spontaneously.

Smooth

muscle

lacks

cross-striations.

The

type

found

in

most

hollow

viscera

is

functionally

syncytial

in

character

and

contains

pacemakers

that

discharge

irregularly.

The

type

found

in

the

eye

and

in

some

other

locations

is

not

spontaneously

active

and

resembles

skeletal

muscle.

There

are

contractile

proteins

similar

to

those

in

muscle

in

many

other

cells,and

it

appears

that

these

proteins

are

responsible

for

cell

motility,mitosis,and

the

movement

of

various

components

within

cell.肌肉一般分為3種類型，骨骼肌，心肌，光滑，雖然不是一個均一的單category.Skeletal肌肉包括軀體肌肉組織帶來了大量的平滑肌。它有興旺的交叉條紋，一般不會在緊張刺激的情況下，缺乏單個肌纖維的解剖和功能之間的連接，一般在自愿的控制〔1〕。心臟肌肉也有橫條紋，但它是功能合胞在有節(jié)奏的性格和合同在沒有外部支配，因為在心肌起搏細胞放電自發(fā)的存在。平滑肌缺乏交叉條紋。最空腔臟器中發(fā)現(xiàn)的類型是在性質(zhì)和功能合胞體，不規(guī)那么的心臟起搏器放電。發(fā)現(xiàn)的眼睛，在其他一些地方的類型是不自發(fā)活動的，類似于骨骼肌。有類似的那些肌肉在許多其他細胞中的收縮蛋白，它出現(xiàn)這些蛋白是負責細胞的運動性，有絲分裂和細胞內(nèi)的各種組件的移動。Lesson

3

The

circulatory

system

is

the

transport

system

that

supplies

O？

and

substances

absorbed

from

the

gastrointestinal

tract

to

the

tissues,returns

CO2

to

the

lungs

and

other

products

of

metabolism

to

the

kidneys,functions

in

the

regulation

of

body

temperature,and

distributes

hormones

and

other

agents

that

regulate

cell

function.

The

blood,

the

carrier

of

these

substances,is

pumped

through

a

closed

system

of

blood

vessels

by

the

heart,which

in

mammals

is

really

2

pumps

in

series

with

each

other(1).From

the

left

ventricle

,blood

is

pumped

through

the

arteries

and

arterioles

to

the

capillaries,where

the

blood

equilibrates

with

the

interstitial

fluid.The

capillaries

drain

throuth

venules

into

the

veine

and

back

to

the

right

atrium.This

is

the

major(systemic)

circulation.

From

the

right

atrium,

blood

folws

to

the

right

ventricle

,

which

pumps

it

through

the

vessels

of

the

lungs---the

lesser(pulmonary)

cirulation---and

the

left

atrium

to

the

left

ventricle(2).In

the

pulmonary

capillaries,the

blood

another

system

of

closed

vessels,the

O2

and

CO2

in

the

alveolar

air.Some

tissue

fluids

enother

system

of

closed

vessels,the

lymphatics,which

drain

lymph

via

the

thoracic

duct

and

the

right

lymphatic

duct

into

the

venous

system(the

lymphatic

circulation).The

cirulation

is

controlled

by

multiple

regulatory

systems

that

function

in

general

to

maintain

adequate

capillary

blood

flow---when

possible,in

all

organs,

but

particularly

in

the

heart

and

brain.

Lesson

4

metabolism

The

endocrine

system,like

the

nervous

system,adjusts

and

correlates

the

activities

of

the

various

body

systems,making

them

appropriate

to

the

changing

demands

of

the

external

body

systems,making

them

appropriate

to

the

external

and

internal

environment(1).

Endocrine

integration

is

brought

about

by

hormones,chemical

messengers

produced

by

ductless

glands

than

are

transported

in

the

circulation

to

target

cells,where

they

regulate

the

metabolic

processes(2).

The

term

metabolism

,meaning

literally

'

change

',is

used

to

refer

to

all

the

chemical

and

energy

transformations

that

occur

in

the

body.The

animal

organism

oxidizes

carbohydrates,proteins,and

fats,producing

principally

CO2,H2O,and

the

energy

necessary

for

life

processes.CO2,H2O

and

energy

are

also

produced

when

food

is

burned

outside

the

body.However

,in

the

body,oxidation

is

not

a

onestep

,semiexplosive

reaction

but

a

complex

,

slow,stepwise

process

called

catabolism,

which

liberates

energy

in

small,

usable

amounts.

Energy

can

be

stored

in

the

body

in

the

from

of

special

energy-rich

phosphate

compounds

and

in

the

form

of

proteins,fats,and

complex

carbohydrates

synthesized

from

simpler

molecules

.formation

of

these

substances

by

processes

that

take

up

rather

than

liberate

energy

is

called

anabolism.對動物有機體的碳水化合物，蛋白質(zhì)和脂肪的氧化，生產(chǎn)主要CO2，H2O，和必要的能量，對生命processes.CO2，H2O和能量也燒以外的body.However食物時，在體內(nèi)產(chǎn)生，氧化是不一個一步，semiexplosive的反響，而是一個復(fù)雜的，緩慢的，漸進的過程叫分解代謝，釋放出的能量小，可用金額。能量可以被存儲在身體在從特別富含能量的磷酸鹽化合物和從更簡單的分子合成的蛋白質(zhì)，脂肪，和復(fù)雜的碳水化合物的形式形成這些物質(zhì)的進程所占用，而不是解放的能量被稱為合成代謝。Lesson

5

the

gonadsModern

genetics

and

experimental

embryology

make

it

clear

that,in

many

species,the

multiple

difference

between

the

male

and

the

female

depend

primarily

on

a

single

chromosome

(the

Y

chromosome)

and

a

single

pair

of

endocrine

structures

the

testes

in

the

male

and

the

ovaries

in

the

female.

The

differentiation

of

the

primitive

gonads

into

testes

or

ovaries

in

utero

is

genetically

determined

in

domestic

animals,but

the

formation

of

male

genitalia

depends

upon

the

presence

of

a

functional

,secreting

testis.there

is

evidence

that

male

sexual

behavior

and,in

some

species,the

male

pattern

of

gonadotropin

secretion

are

due

to

the

action

of

male

hormones

on

the

brain

in

early

development.

After

birth,

the

gonads

remain

quiescent

until

puberty,when

they

are

activated

by

gonadotropins

from

the

anterior

pituitary.

Hormones

secreted

by

the

gonads

at

this

time

cause

the

appearance

of

features

typical

of

the

adult

male

or

female

and

the

onset

of

the

sexual

cycle

in

the

female.in

males,the

gonads

remain

more

or

less

active

from

puberty

onward.In

both

sexes,the

gonads

have

a

dual

function:the

production

of

germ

cells(gametogenesis)

and

the

secretion

of

sex

hormones.

The

androgens

are

the

steroid

sex

hormones

that

are

masculinizing

in

their

action;the

estrogens

are

those

that

are

feminizing.

Both

types

of

hormones

are

normally

secreted

in

both

sexes.The

testes

secrete

large

amounts

of

androgens,

principally

testosterone

,but

they

also

secrete

small

amounts

of

estrogens.

The

ovaries

secrete

large

amounts

of

estrogens

and

small

amounts

of

androgens

.

Androgens

and,

probably

,small

amounts

of

estrogens

are

secreted

from

the

adrenal

cortex

in

both

sexes.

The

ovaries

also

secrete

progesterons,a

steroid

that

has

special

funtctions

in

preparing

the

uterus

for

pregnancy.

During

pregnancy,the

ovaries

secrete

the

peptide

hormone

relaxin,which

loosens

the

ligaments

of

the

pubic

symphysis

and

softens

the

cervix

,

facilitating

delivery

of

the

fetus.

In

both

sexes,the

gonads

also

secrete

inhibin

,

a

polypeptide

that

inhibin

FSH

secretion.男性和女性的性腺具有雙重功能：生產(chǎn)的生殖細胞〔配子〕和性激素分泌。雄激素是性激素在他們的行動是男性化的，雌激素是那些女性化。激素這兩種類型，通常在兩個sexes.The睪丸分泌大量的雄激素，主要是睪酮分泌的，但它們也分泌少量雌激素，孕激素。卵巢分泌大量的雌激素和雄激素的少量。雄激素，少量的雌激素，可能是在男女兩性的腎上腺皮質(zhì)分泌的。的卵巢也分泌progesterons的，一種類固醇，具有特殊funtctions在準備懷孕的子宮。在懷孕期間，卵巢分泌的肽類激素松弛，恥骨聯(lián)合韌帶放松和軟化宮頸，促進胎兒的交付。

，男性和女性的性腺分泌抑制素，抑制FSH分泌的多肽。

The

secretory

and

gametogenic

functions

of

the

gonads

are

both

dependent

upon

the

secretion

of

the

anterior

pituitary

gonadotropins,FSH,and

LH.

The

sex

hormones

and

inhibin

feed

back

to

inhibit

gonadotropin

secretion.

In

males,gonadotropin

secretion

is

noncyclic;

but

in

postpuberal

females

an

orderly,sequential

secretion

of

gonadotropins

is

necessary

for

the

occurrence

of

estrous

cycle,

pregnancy

,

and

lactation.性腺功能的分泌和gametogenic都取決于垂體前葉促性腺激素，F(xiàn)SH和LH的分泌。抑制促性腺激素分泌的性激素和抑制飼料。在男性，促性腺激素分泌非循環(huán)但在postpuberal女性分泌的促性腺激素一個有序的，連續(xù)的動情周期，妊娠和哺乳期的發(fā)生是必要的。lesson

6The

gastrointestinal

system

is

the

portal

through

which

nutritive

substances,vitamins,minerals

and

fluids

enter

the

body.Proteins,fats,and

complex

carbohydrates

are

broken

down

into

absorbable

units(digested),principally

in

the

small

intestine.The

products

of

digestion

and

the

vitamins,minerals

,and

water

cross

the

mucosa

and

enter

the

lymph

or

the

blood(absorption).胃腸道系統(tǒng)的門戶網(wǎng)站，通過它的營養(yǎng)物質(zhì)，維生素，礦物質(zhì)和流體進入的body.Proteins，脂肪和復(fù)雜的碳水化合物被分解成可吸收的單位〔消化〕，主要是在消化的的小intestine.The產(chǎn)品和維生素，礦物質(zhì)，和水穿過粘膜和輸入淋巴或血液〔吸收〕。Digestion

of

the

major

foodstuffs

is

an

orderly

process

involving

the

action

large

number

of

digestive

enzymes.Some

of

there

enzymes

are

found

in

the

secrtions

of

the

salivary

glands,the

stomach,and

the

exocrine

portion

of

the

pancreas.Other

enzymes

are

found

in

the

luminal

membranes

and

the

cytoplasm

of

the

cells

that

line

the

small

intestine.The

action

of

the

enzymes

is

aided

by

the

hydrochloric

acid

secreted

by

the

stomach

and

the

bile

secreted

by

the

liver.消化的主要食品是一個有序的過程，涉及大量的有酶存在于唾液腺，胃，和外分泌部的pancreas.Other酶的secrtions的的消化enzymes.Some的行動被發(fā)現(xiàn)的腔膜和該行的輔助酶的的小intestine.The行動由鹽酸，由胃和由肝臟分泌的膽汁分泌的細胞的細胞質(zhì)中。The

mucosal

cells

in

the

small

intestine

have

a

brush

border

made

up

of

numerous

microvilli

lining

their

apical

surface.This

border

is

rich

in

enzymes.It

islined

on

its

luminal

side

by

a

layer

that

is

rich

in

neutral

and

amino

sugars,the

glycocalyx(1).The

membranes

of

the

mucosal

cells

contain

glycoprotein

enzymes

that

hydrolyze

carbohydrates

and

peptides,and

the

glycocalyx

is

made

up

in

part

of

the

carbohydrate

portions

of

these

glycoproteins

that

extend

into

the

intestinal

lumen(2).Next

to

the

brush

border

and

glycocalyx

is

a

100

or

400υm

unstirred

water

layer(UWL)

similar

to

the

UWL

to

other

biologic

membranes.Solutes

must

diffuse

across

the

UWL

to

mucosal

cells.

The

mucous

coat

overlying

the

cells

also

constitutes

a

significant

barrier

to

diffusion.在小腸的粘膜細胞有無數(shù)的微絨毛襯他們的心尖surface.This邊界由刷子邊界是富含enzymes.It

islined豐富的中性糖和氨基糖，糖萼〔1層是由在其管腔側(cè)〕。粘膜細胞的膜含有糖蛋白的酶水解的碳水化合物和肽，糖萼在腸腔中〔2〕延伸到這些糖蛋白的碳水化合物局部的一局部。往下的刷狀緣和蛋白質(zhì)復(fù)合物是100或400υm攪拌的水層〔UWL〕類似UWL其他生物membranes.Solutes的必須通過UWL黏膜細胞擴散。粘膜的外衣上覆的細胞也構(gòu)成了重大障礙擴散。Substances

pass

from

the

lymph

of

the

gastrointestinal

to

the

extracellular

fluid

and

thence

to

the

lymph

and

blood

by

diffusion,

facilitated

diffusion,

solvent

drag,active

transport,secondary

active

transport(coupled

transport),and

endocytosis.Most

substances

must

pass

from

the

intestinal

lumen

into

the

mucosal

cells

and

then

out

of

the

mucosal

cells

to

the

extracellular

fluid,and

the

processes

responsible

for

movement

across

the

luminal

cell

membrane

are

often

quite

different

from

those

responsible

for

movement

across

the

basal

and

lsteral

cell

membranes

to

the

extracellular

fluid.

物質(zhì)傳遞從淋巴結(jié)的胃腸道的細胞外液，并從那里通過擴散的淋巴結(jié)和血液，促進擴散，溶劑拖動，主動運輸，次級主動運輸〔加上運輸〕，和endocytosis.Most物質(zhì)必須通過從腸腔黏膜細胞，然后黏膜細胞的細胞外液，并負責整個管腔細胞膜的運動的過程往往是完全不同的運動整個根底和lsteral的細胞膜，細胞外液的負責。lesson

7The

respiratory

system

is

made

up

of

the

gas-exchanging

organs(the

lungs

and

respiratory

passages)

and

a

pump

that

ventilates

the

lungs.The

pump

consists

of

the

chest

wall,the

respiratory

muscles,which

increase

and

decrease

the

size

of

the

thoracic

cavity;the

centers

in

the

brain

that

control

the

muscles

;and

the

tracts

and

nerves

that

connect

the

brain

to

the

muscles.呼吸系統(tǒng)的氣體交換的器官〔肺和呼吸道〕和，通風的lungs.The的泵的泵由胸壁，呼吸肌，從而增加和減少的胸腔的大小;中心在大腦中控制肌肉和的大片和神經(jīng)連接大腦到肌肉。Respiration,as

the

term

is

generally

used,includes

2

processes:External

respiration,

the

absorption

of

02

and

removal

of

CO2

from

the

body

as

a

whole

;and

interal

respiration,the

utilization

of

O2

and

production

of

CO2

by

cells

and

the

gaseous

exchanges

between

the

cells

and

their

fluid

medium.呼吸，作為一般使用的術(shù)語，包括2個過程：外呼吸，吸收02脫除CO2的身體作為一個整體和INTERAL的呼吸，利用O2和CO2生產(chǎn)的細胞之間的氣體交換的細胞和它們的流體介質(zhì)。The

respiratory

passages

that

lead

from

the

exterior

to

the

alveoli

do

move

than

serve

as

gas

conduits(1).They

humidify

and

cool

or

warm

the

inspired

air

so

that

even

very

hot

or

very

cold

air

is

at

or

near

body

temperature

by

the

time

it

reaches

the

alveoli(2).Bronchial

secretions

contain

secretory

immunoglobulins

(IGA)

and

other

substances

that

help

to

resist

infections

and

maintain

the

integrity

of

the

mucosa.從外觀到肺泡，導(dǎo)致呼吸道移動加濕和降溫或升溫，甚至極熱或極冷的空氣吸入空氣，使體溫到達或接近的時候，它作為氣體導(dǎo)管〔1〕。到達肺泡〔2〕支氣管分泌物中含有分泌型免疫球蛋白〔IGA〕和其他物質(zhì)，以幫助抵抗感染，保持粘膜的完整性。The

pulmonary

alveolar

macrophages

(PAMS),the

dust

cells,are

important

components

of

the

pulmonary

defence

,mechanisms.Like

other

macrophages,these

cells

come

originally

from

the

bone

marrow

.They

are

actively

phagocytic

and

ingest

inhaled

bacteria

and

small

particles.肺泡巨噬細胞〔PAMS〕，塵細胞的重要組成局部的肺防御，mechanisms.Like的其他巨噬細胞，這些細胞來最初是從骨髓中，他們都在積極吞噬，和攝取吸入的細菌和小顆粒。In

addition

to

the

gas

exchange

and

defence,the

lungs

have

a

number

of

metabolic

functions.They

manufacture

surfactant

which

adjiusts

surface

tension

during

breathing,helps

to

prevent

pulmonary

edema

and

aids

to

the

infant

respiration

.They

also

contain

a

fibrinolytic

system

that

lyses

close

in

the

pulmonary

vessels.In

lungs,

some

biologically

active

substances

are

removed

from

the

blood,but

some

are

synthesized

and

released

into

the

blood,The

lungs

also

activate

one

hormone;the

physiologically

inactive

decapeptide

angiotensin

Ⅰ

is

converted

to

the

pressor

,aldosterone-stimulating

octapeptide

angiotesin

Ⅱ.除了氣體交換和國防，肺部有一些的代謝functions.They制造adjiusts外表張力的外表活性劑，呼吸過程中，有助于防止肺水腫和艾滋病的嬰兒呼吸。它們還包含一個纖溶系統(tǒng)，溶解接近的的肺vessels.In肺部，一些生物活性物質(zhì)從血液中去除，但一些合成和釋放進入血液，肺也可以激活一種激素，醛固酮刺激的升壓，八肽的生理活性的十肽血管緊張素ⅰ轉(zhuǎn)換血管緊張素ⅱ。lesson

8

In

the

kidneys,a

fluid

that

resembles

plasma

is

filtered

through

the

glomerular

capillaries

into

the

renal

tubules(glomerular

filtration).As

this

glomerular

filtrate

passes

down

the

tubules,its

volume

is

reduced

and

its

composition

altered

by

the

processes

of

tubular

reabsorption(removal

of

water

and

solutes

from

the

tubular

fluid)to

the

urine

that

enters

the

renal

pelvis.A

comparison

of

the

composition

of

the

plasma

and

an

average

urine

specimen

illustrates

the

magnitude

of

some

of

theses

changes(table1)

and

amphasizes

the

manner

in

which

wastes

are

eliminated

while

water

and

important

electrolytes

and

metabolites

are

conserved(1).Furthermore,the

composition

of

the

urine

can

be

varied,and

many

homeostatic

regulatory

mechanisms

minimize

or

prevent

changes

in

the

composition

of

the

ECF

by

changing

the

amount

of

water

and

various

specific

solutes

in

the

urine.From

the

renal

pelvis,the

urine

passes

to

the

bladder

and

is

expelled

to

the

exterior

by

the

process

of

urination,or

micturition.

The

kidneys

make

prostaglandins

and

kinins,

and

they

are

also

endocrine

organs,secreting

renin

and

renal

erythropoietic

factor

and

forming

1,25-dihydroxycholecalciferol(2).流體，類似于等離子在腎臟過濾通過腎小球濾過進入腎小管，腎小球毛細血管。由于這腎小球濾液通過腎小管，它的體積減少和結(jié)構(gòu)改變的過程腎小管重吸收〔去除水和溶質(zhì)從管狀的流體〕的尿液進入腎pelvis.A等離子體的組合物，比擬和一個平均的尿液樣本的一些這些變化〔表1〕示出的幅值和amphasizes廢物被消除的方式在其中而水和重要的電解質(zhì)和代謝物是保守的〔1〕。此外，尿中的組合物，可以是多種多樣的，和許多穩(wěn)態(tài)的調(diào)控機制減少或防止通過改變水和各種特定溶質(zhì)的量的變化的組合物中的ECFurine.From腎盂，尿液傳遞到膀胱排尿過程中，或排尿被排出到外部。腎臟，前列腺素和激肽，并且它們也是內(nèi)分泌器官，分泌腎素和腎的促紅細胞生成因子和形成1,25

-二羥基〔2〕的。lesson

9

The

basic

unit

of

integrated

neural

activity

is

the

reflex

arc.

This

arc

consists

of

a

sense

organ,an

afferent

neuron,one

or

more

synapses

in

a

central

integrating

station

or

sympathetic

ganglion,an

efferent

neuron

,and

an

effector.Inmammals,the

connection

between

afferent

and

efferent

somatic

neurons

is

generally

in

the

brain

or

spinal

cord

.The

afferent

neurons

enter

via

the

dorsal

roots

or

cranial

nerves

and

have

their

cell

bodies

in

the

dorsal

root

gantlia

or

in

the

homologous

ganglia

on

the

cranial

nerves.The

efferent

fibers

leave

via

the

ventral

roots

or

corresponding

motor

cranial

nerves.The

principle

that

in

the

spinal

cord

the

dorsal

roots

are

sensory

and

the

ventral

roots

are

motor

is

known

as

the

Bell-Magendie

low(1)Inpulses

generated

in

the

axons

of

the

afferent

and

efferent

neurons

and

in

muscle

are

“all

or

none〞in

character.On

the

other

hand,there

are

3

junctions

or

junctionlike

areas

in

the

reflex

arc

where

responses

are

graded

.There

are

the

receptor-afferent

neuron

region,the

synapse

between

the

afferent

and

efferent

neurons,and

the

myoneural

junction.At

each

of

these

points,

a

nonpropagated

potential

proportionating

in

size

to

the

magnitude

of

the

incoming

stimulus

is

generated(2).The

graded

potentials

serve

to

electrotonically

depolarize

the

adjacent

nerve

or

muscle

membrane

and

set

up

all

or

none

responses.The

number

of

action

potentials

in

the

afferent

nerve

is

proportionate

to

the

magnitude

of

the

applied

stimulus

at

the

sense

organ,there

is

also

a

rough

correlation

betwnnm

the

magnitude

of

the

stimulus

and

the

afferent

and

efferent

neurous

is

usually

in

the

central

nervous

system,and

activity

in

the

reflex

arc

is

modified

by

the

multiple

inputs

converging

on

the

efferent

neurons(3).傳入和傳出的神經(jīng)元中的軸突的和肌肉中產(chǎn)生的inpulses是“全或無〞在character.On另一方面，有3路口或junctionlike的區(qū)域在反射弧響應(yīng)分級。有受體傳入神經(jīng)傳入和傳出的神經(jīng)元之間的突觸，神經(jīng)元的區(qū)域，和的的myoneural

junction.At每個這些點，nonpropagated潛在需求量比例傳入刺激的幅度的大小〔2〕產(chǎn)生的梯度電位用于electrotonically去極化相鄰的神經(jīng)或肌肉膜，并設(shè)置高達全部或沒有responses.The的動作電位的傳入神經(jīng)是在感官的刺激的大小成比例，也有一個粗糙的相關(guān)betwnnm的的巨大的刺激和傳入和傳出neurous通常是在中樞神經(jīng)系統(tǒng)中，并在反射弧活性改性聚光上的傳出神經(jīng)元〔3〕的多個輸入。The

simplest

reflex

arc

is

one

with

a

single

synapse

between

the

afferent

and

efferent

neurons.

Such

arcs

are

monosynaptic,

and

reflexes

occurring

in

them

are

monosynaptic

reflexes.

Reflex

arcs

in

which

one

or

more

interneurons

are

interposed

between

the

afferent

and

efferent

neurons

are

polysynapitc,the

number

of

synapses

in

the

arcs

varying

from

2

to

many

hundreds.In

both

types,but

especially

in

polysynaptic

reflex

arcs,activity

is

modified

by

spatial

and

temporal

facilitation,

occlusion,subliminal

frings

effects,and

other

effects.最簡單的反射弧是一個單一的傳入和傳出的神經(jīng)元之間的突觸之一。這樣的弧是單突觸反射，和發(fā)生在他們是單突觸反射。反射弧傳入和傳出的神經(jīng)元之間的其中一個或多個的interneurons

polysynapitc，在圓弧的突觸的數(shù)量從2變化到這兩種類型，但特別是在多突觸反射弧許多hundreds.In，活動空間和改性時間的便利，閉塞，的影響潛意識弗林斯，和其他效果。lesson

10The

chemical

moiety

on

or

in

the

target

cell

that

provides

recognition

of

the

chemical

messenger

is

presumed

to

be

the

same

as

the

binding

site

for

the

chemical

messenger

and

is

the

minimal

unit

referred

to

as

“receptor〞(1).Not

only

must

the

chemical

messenger

be

recognized,but

the

combination

of

it

with

receptor

must

initiate

the

series

of

biochemical

events

that

resulr

ultimately

in

a

biological

event.Thus,the

concept

of

receptor

implies

that

the

same

molecule

that

has

the

binding

or

recognition

site

can

participate

normally

in

the

initiating

event

in

cell

activation

(2).This

part

of

the

molecule

may

be

referred

to

as“effector〞.In

all

likelihood,the

same

molecule

contains

both