ADDITIONAL TEXT. 1. Read the text carefully to fulfil the tasks that follow.

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

BLOOD

Like muscle, bone, cartilage, and nerves, blood is a type of tissue, a collection of similar types of cells and the associated intercellular substances that surround them. Tissues are categorized into four main types: 1) epithelium, 2) muscle, 3) nervous, and 4) connective. Connective tissue includes blood, lymph, bone, and cartilage. In the case of blood and lymph, the base substance, or matrix, is a liquid. What differentiates these two from other tissue types is that they are not stationary. Blood is a fluid flowing through blood vessels throughout the body (lymph runs through the lymph vessels).

Blood accounts for about 8 percent of a human’s total body weight, amounting to an average of four to six liters per adult (over a gallon), depending on individual size. Blood is thicker (more viscous) and slightly heavier than water. And, depending on the organism, blood is usually slightly warmer than the animal’s body temperature. While the core body temperature of most humans is 37^oC (98.6^oF), their blood is about 38^oC (100.4^oF). Blood pH is slightly alkaline, ranging from about 7.35 to 7.45. Its salt (NaCl) concentration normally varies from about 85 to 90 ppt (parts per thousand), or two to three times the concentration of sea water.

Plasma is the fluid portion of both blood and lymph. Fifty to sixty percent of the blood volume consists of plasma. When the proteins involved in clotting are removed from blood plasma, the remaining liquid is called serum. The plasma, which is over 90 percent water, carries a variety of ions and molecules. In addition to salts and proteins, there are many nutrients such as amino acids, fats, and glucose. There are also dissolved gases such as carbon dioxide, as well as antibodies, hormones, enzymes, and certain waste products such as urea and uric acid. The relative amount of plasma in the blood depends upon the species, the sex, the organism’s health when being examined, and on a host of other variables. The remaining 40 to 50 percent of the blood volume is composed of cells and cell fragments that can be divided into three main categories: red blood cells, or erythrocytes; white blood cells, or leukocytes; and platelets, or thrombocytes, which are fragments of cells.

II. POST-READING TASKS.

I. Define the following concepts: blood, plasma, serum.

II. Name: a) the main types of tissue, b) the kinds of connective tissue, c) the constituents of plasma, d) types of blood cells.

III. Explain what differentiates: a) blood and lymph from other tissue types, b) blood from lymph, c) blood from water.

IV. Write an essay describing the structure of blood.

UNIT 8

1. PRE-READING AND READING TASKS.

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

break up (v)	['breIk'Ap]	разбивать
chew (v)	[tSu:]	жевать
expel	[Ik'spel]	удалять
repair (v)	[rI'peq]	восстанавливать
secrete (v)	[sI'kri:t]	выделять
swallow (v)	['swPlqV]	глотать
bump	[bAmp]	выпуклость
chyme	[kaIm]	пищевая кащица
coiled-up tubing	['kOIld 'Ap 'tju:bIN]	свернутые трубки
esophagus (pl. esophagi)	[I'sPfqgqs] [I'sPfqgaI]	пищевод
fundus	['fAndqs]	дно
lining	['laInIN]	выстилка
pancreas	['pxNkrIqs]	поджелудочная железа
sac	[sxk]	мешочек
stomach	['stAmqk]	желудок
villi	['vIlaI]	ворсинки
crescent	['kres(q)nt]	серповидный
esophageal	[I"sPfq'dZi:ql]	относящийся к пищеводу
gastric	['gxstrIk]	желудочный
longitudinal	["lPndZI'tju:d(q)nql]	продольный
oblique	[q'bli:k]	наклонный, косой
pyloric	[paI'lPrIk]	пилорический
tubular	['tju:bjVlq]	трубчатый

2. Make sure you know the meaning of these words and word combinations:

carbohydrates	bloodstream
enzyme	circular
gastric juice	contraction of muscles
rectum	sphincter
hydrochloric acid	carbohydrates

3. Read the text carefully to fulfil the tasks that follow.

Дата добавления: 2015-09-03