畜牧兽医专业英语十篇课文翻译

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.骨骼关节需要上油，以减少磨损。倘骨头满足，它们覆盖软骨它作为一个减振器，并提供了一个耐磨的外表与一包。超过产生的流体润滑关节软骨是一种膜。Movement

in

joints

is

caused

by

the

contraction

and

expansion

of

muscles

associated

with

that

joint.在关节中的运动是由与该关节相关联的肌肉的收缩和膨胀。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.肌肉细胞，如神经元，浓度被激发化学，电和机械地产生沿其细胞膜上的动作电位被发送。它们包含收缩蛋白和不同于神经元，它们有一个收缩的机制被激活的动作电位。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.肌肉一般分为3种类型，骨骼肌，心肌，光滑，虽然不是一个均一的单category.Skeletal肌肉包括躯体肌肉组织带来了大量的平滑肌。它有兴旺的交叉条纹，一般不会在紧张刺激的情况下，缺乏单个肌纤维的解剖和功能之间的连接，一般在自愿的控制〔1〕。心脏肌肉也有横条纹，但它是功能合胞在有节奏的性格和合同在没有外部支配，因为在心肌起搏细胞放电自发的存在。平滑肌缺乏交叉条纹。最空腔脏器中发现的类型是在性质和功能合胞体，不规那么的心脏起搏器放电。发现的眼睛，在其他一些地方的类型是不自发活动的，类似于骨骼肌。有类似的那些肌肉在许多其他细胞中的收缩蛋白，它出现这些蛋白是负责细胞的运动性，有丝分裂和细胞内的各种组件的移动。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.对动物有机体的碳水化合物，蛋白质和脂肪的氧化，生产主要CO2，H2O，和必要的能量，对生命processes.CO2，H2O和能量也烧以外的body.However食物时，在体内产生，氧化是不一个一步，semiexplosive的反响，而是一个复杂的，缓慢的，渐进的过程叫分解代谢，释放出的能量小，可用金额。能量可以被存储在身体在从特别富含能量的磷酸盐化合物和从更简单的分子合成的蛋白质，脂肪，和复杂的碳水化合物的形式形成这些物质的进程所占用，而不是解放的能量被称为合成代谢。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双重功能：生产的生殖细胞〔配子〕和性激素分泌。雄激素是性激素在他们的行动是男性化的，雌激素是那些女性化。激素这两种类型，通常在两个sexes.The睾丸分泌大量的雄激素，主要是睾酮分泌的，但它们也分泌少量雌激素，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，可能是在男女两性的肾上腺皮质分泌的。的卵巢也分泌progesterons的，一种类固醇，具有特殊funtctions在准备怀孕的子宫。在怀孕期间，卵巢分泌的肽类激素松弛，耻骨联合韧带放松和软化宫颈，促进胎儿的交付。

，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都取决于垂体前叶促性腺激素，FSH和LH的分泌。抑制促性腺激素分泌的性激素和抑制饲料。在男性，促性腺激素分泌非循环但在postpuberal女性分泌的促性腺激素一个有序的，连续的动情周期，妊娠和哺乳期的发生是必要的。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).胃肠道系统的门户网站，通过它的营养物质，维生素，矿物质和流体进入的body.Proteins，脂肪和复杂的碳水化合物被分解成可吸收的单位〔消化〕，主要是在消化的的小intestine.The产品和维生素，矿物质，和水穿过粘膜和输入淋巴或血液〔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个有序的过程，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的行动被发现的腔膜和该行的辅助酶的的小intestine.The行动由盐酸，由胃和由肝脏分泌的胆汁分泌的细胞的细胞质中。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.在小肠的粘膜细胞有无数的微绒毛衬他们的心尖surface.This边界由刷子边界是富含enzymes.It

islined丰富的中性糖和氨基糖，糖萼〔1层是由在其管腔侧〕。粘膜细胞的膜含有糖蛋白的酶水解的碳水化合物和肽，糖萼在肠腔中〔2〕延伸到这些糖蛋白的碳水化合物局部的一局部。往下的刷状缘和蛋白质复合物是100或400υm搅拌的水层〔UWL〕类似UWL其他生物membranes.Solutes的必须通过UWL黏膜细胞扩散。粘膜的外衣上覆的细胞也构成了重大障碍扩散。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.

物质传递从淋巴结的胃肠道的细胞外液，并从那里通过扩散的淋巴结和血液，促进扩散，溶剂拖动，主动运输，次级主动运输〔加上运输〕，和endocytosis.Most物质必须通过从肠腔黏膜细胞，然后黏膜细胞的细胞外液，并负责整个管腔细胞膜的运动的过程往往是完全不同的运动整个根底和lsteral的细胞膜，细胞外液的负责。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.呼吸系统的气体交换的器官〔肺和呼吸道〕和，通风的lungs.The的泵的泵由胸壁，呼吸肌，从而增加和减少的胸腔的大小;中心在大脑中控制肌肉和的大片和神经连接大脑到肌肉。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，作为一般使用的术语，包括2个过程：外呼吸，吸收02脱除CO2的身体作为一个整体和INTERAL的呼吸，利用O2和CO2生产的细胞之间的气体交换的细胞和它们的流体介质。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.从外观到肺泡，导致呼吸道移动加湿和降温或升温，甚至极热或极冷的空气吸入空气，使体温到达或接近的时候，它作为气体导管〔1〕。到达肺泡〔2〕支气管分泌物中含有分泌型免疫球蛋白〔IGA〕和其他物质，以帮助抵抗感染，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.肺泡巨噬细胞〔PAMS〕，尘细胞的重要组成局部的肺防御，mechanisms.Like的其他巨噬细胞，这些细胞来最初是从骨髓中，他们都在积极吞噬，和摄取吸入的细菌和小颗粒。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.除了气体交换和国防，肺部有一些的代谢functions.They制造adjiusts外表张力的外表活性剂，呼吸过程中，有助于防止肺水肿和艾滋病的婴儿呼吸。它们还包含一个纤溶系统，溶解接近的的肺vessels.In肺部，一些生物活性物质从血液中去除，但一些合成和释放进入血液，肺也可以激活一种激素，醛固酮刺激的升压，八肽的生理活性的十肽血管紧张素ⅰ转换血管紧张素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).流体，类似于等离子在肾脏过滤通过肾小球滤过进入肾小管，肾小球毛细血管。由于这肾小球滤液通过肾小管，它的体积减少和结构改变的过程肾小管重吸收〔去除水和溶质从管状的流体〕的尿液进入肾pelvis.A等离子体的组合物，比拟和一个平均的尿液样本的一些这些变化〔表1〕示出的幅值和amphasizes废物被消除的方式在其中而水和重要的电解质和代谢物是保守的〔1〕。此外，尿中的组合物，可以是多种多样的，和许多稳态的调控机制减少或防止通过改变水和各种特定溶质的量的变化的组合物中的ECFurine.From肾盂，尿液传递到膀胱排尿过程中，或排尿被排出到外部。肾脏，前列腺素和激肽，并且它们也是内分泌器官，分泌肾素和肾的促红细胞生成因子和形成1,25

-二羟基〔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).传入和传出的神经元中的轴突的和肌肉中产生的inpulses是“全或无〞在character.On另一方面，有3路口或junctionlike的区域在反射弧响应分级。有受体传入神经传入和传出的神经元之间的突触，神经元的区域，和的的myoneural

junction.At每个这些点，nonpropagated潜在需求量比例传入刺激的幅度的大小〔2〕产生的梯度电位用于electrotonically去极化相邻的神经或肌肉膜，并设置高达全部或没有responses.The的动作电位的传入神经是在感官的刺激的大小成比例，也有一个粗糙的相关betwnnm的的巨大的刺激和传入和传出neurous通常是在中枢神经系统中，并在反射弧活性改性聚光上的传出神经元〔3〕的多个输入。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.最简单的反射弧是一个单一的传入和传出的神经元之间的突触之一。这样的弧是单突触反射，和发生在他们是单突触反射。反射弧传入和传出的神经元之间的其中一个或多个的interneurons

polysynapitc，在圆弧的突触的数量从2变化到这两种类型，但特别是在多突触反射弧许多hundreds.In，活动空间和改性时间的便利，闭塞，的影响潜意识弗林斯，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