Additional text

1. Read the text carefully. Be ready to fulfil the tasks that follow.

The brain

Evolutionarily, the vast majority of organisms above the level of the primitive invertebrate phyla have evolved sense organs in the anterior portion (front end) of their bodies that respond to the high concentration of incoming information there. The most anterior ganglion, or enlarged, organized, integrative mass of nervous tissue, is called the brain. It is the brain that is responsible for processing most of the incoming information.

In many species of invertebrates, the brain is not much larger than the other ganglia located along the rest of the longitudinal nerve cords. The brain of an invertebrate usually has considerably less dominance over the rest of the nervous system, and therefore the body, than is true for a vertebrate` brain in the same size category. The brain in most lower vertebrates is not capable of significantly more complex tasks than most invertebrate brains. But the early vertebrate brains reflect evolutionary trends that led to many of the brain developments that have helped distinguish the vertebrates from other groups of organisms.

In the higher invertebrates as well as in the vertebrates, the brain functions in coordination with, or in place of, the many localized, segmented ganglia that are usually little more than a stimulus-and-response apparatus. This large accumulation of nervous tissue receives and transmits sufficiently large amounts of data to give it considerable control over the rest of the organism. The brain also makes it possible for many of these organisms to learn.

2. POST-READING TASKS.

1. Define what the brain is and enumerate its functions.

2. Name the differences between the brain of an invertebrate and a vertebrate.

3. Sum up what you have learned about the brain and write an essay about it.

UNIT 5

1. PRE-READING AND READING TASKS.

1.Study the vocabulary which is intended to aid your comprehension of the text:

contract (v)	[kqn'trxkt]	сокращать(ся)
enclose (v)	[In'klqVz]	окружать
excite (v)	[Ik'saIt]	возбуждать
inhibit (v)	[In'hIbIt]	задерживать
link up (v)	['lINkAp]	связывать
process (v)	['prqVses]	обрабатывать
release (v)	[rI'li:s]	освобождать
Arm	[Q:m]	ветвь, отросток
Axon	['xksPn]	аксон,нейрит
Dendrites	['dendraIt] ?????	дендрит
end-plate	['endpleIt]	концевая пластинка
Fiber	['faIbq]	нить, волокно
Gap	[gxp]	разрыв
Injury	['IndZqrI]	рана, ушиб
Junction	['dZANkS(q)n]	место соединения
Myelin	['maIqlIn]	миелин
Network	['netwE:k]	сеть
Passing	['pQ:sIN]	прохождение
Sensation	[sen'seIS(q)n]	чувство,ощущение
spinal column	['spaInl 'kPlqm]	позвоночный столб
Strand	[strxnd]	нить (ДНК, белка)
synapse	['saInxps]	синапс
Digestive	[d(a)I'dZestIv]	пищеварительный

2. Make sure you can supply an adequate translation for each of the following word combinations:

throughout one’s body	smooth muscles
to speed up the conduction	reflex action
sensory nerves	somatic system
motor neurons	peripheral system
muscle fiber	parasympathetic system
voluntary control	cardiac muscles

2. Read and translate the text.