习题与答案五

《组织学与胚胎学》习题与答案五

是非题1

1.Covering epithelia cover the external and internal surfaces of the body, including the linings of vessels and other small cavities.

2.Epithelium usually has a free surface and a basal surface, both of which possess the same structure but different function.

3.The core of the microvilli contains fine actin filaments, which interconnected with the terminal web.

4.The core of a microvillus is composed of nine outer doublet microtubules and two ce ntral singlet microtubules.

5.Between opposing cell membrane, where the gap junction occurs, numerous connexo ns span. Ions and small molecules can pass freely between opposed epithelial cells via the gap junction.

6.Between the epithelium and the underlining connective tissue is the basement me mbrane.

7.The basement membrane provides for a strong connection, increases the basal surfac

e area and serves as a semi-permeable membrane.

8.Blood vessels and nerves never pass through the basement membrane and penetrate into epithelial tissues.

9.Plasma membrane infoldings promote transportation of water and ions without e nergy consume.

10.Specializations of the basal surface of epithelium are basement membrane, desm osome, hemidesmosome, and plasma membrane infolding.

11.Epithelial tissues line most body cavities and tracts and also specialize to form glan ds.Glands are mainly composed of glandular epithelia.

12. The secretions of exocrine gland are discharged through a duct system and the sec retions of endocrine glands are directly released into the bloodstream.

13. The cells in connective tissue usually have polarity.

14. The only significant function of connective tissue is to provide structural support for other tissues.

15. Adipose tissue is also termed the areolar tissue.

16. Hyaluronic acid is the principal constituent of ground substance in soft connectiv

e tissues.

17. The fine structure of the fibroblast is typical of a cell involved in secreting steroid hormones.

18. Mesenchyme is the embryological precursor of all connective tissues, including soft and skeletal tissuses.

19. Mast cells exhibit the property of metachromasia when stained with certain blue

basic dyes.

20. Elastic fibers are also called yellow fibers because they are yellow in fresh state. 56. Lipid is contained in a large membrane bound vesicle in adipocytes.

21. Reticular tissue is mainly composed of fibroblasts and reticular fibers.

22.Cartilage and bone tissues belong to connective tissue proper.

23.Three types of cartilage can be distinguished by reference to the differences in q uantity and type of cells.

24.Chondrocytes in fibrocartilage are completely enclosed by cartilage matrix and occup y small laculae.

25.The inner layer of perichodrium is rich in osteoprogenitor cells, which are responsibl

e for appositional growth o

f cartilage.

26.Osteoblasts secrete fibers and organic ground substance and embed themselves into the bone matrix, thus the osteoid tissue is formed.

27.Osteocytes and their processes are suspended in tissue fluid within lacunae and c analiculi, thus the nutrients and metabolites can be exchanged between the blood and the osteocytes.

28.Osteoclasts secrete lysosomal enzymes, which break down the collagen and organic ground substance, thus the bone matrix is absorbed.

29.The structural form of bone matrix is bone lamellae, which are present in the comp act bone but not in the spongy bone.

30.In the bone tissue, the collagenous and elastic fibers are embedded in the amorpho us ground substance, and characteristically arranged in lamellae.

31. Osteons consist of Haversian lamellae and a central Volkmann’s canal in which bloo

d vessels and nerves pass through.

32.Blood is a specialized form of connective tissue proper, consisting of blood cells and plasma.

33.For examining the morphology of blood cells, blood smear is usually used and stain ed with Wright or Giemsa stain.

34.The special shape of erythrocytes facilitates gaseous exchange.

35.The biconcave shape of red blood cells is maintained by microtubules and microfila ments.

36.The young erythrocytes in the bloodstream often containing ribosomes are terme

d reticulocytes.

37.According to having granules in their cytoplasm or not, leukocytes are classified into two groups: granulocytes and agranulocytes.

38.The cytoplasm of basophils has specific granules containing heparin and histaminase.

39.Monocytes are capable of crossing capillary walls, and differentiate into lymphocyt es.

40.All cells in blood are end cells, which no longer divide.

41. Erythrocytes functions within blood vessels, while leukocytes function mainly outsid