Tissues

Cells are grouped into tissues, and each tissue type is specialized to perform specific functions. The four basic tissue types are epithelial, connective, muscular, and nervous tissues. Epithelial and connective tissues are the most diverse of the four tissue types and are components of every organ. They are classified according to the structure. Muscular and nervous tissues are defined mainly according to their functions.

Epithelium consists of cells that have very little extracellular material between them. Epithelium covers surfaces, e.g., the outside of the body and the lining of the digestive tract, the vessels and many body cavities. It also forms structures, e.g., glands. Most epithelia have basement membranes. The basement membrane is a specialized type of extracellular material. It is secreted by the epithelial cells and attaches the epithelium to the underlying tissues. Blood vessels do not penetrate the basement membrane to reach epithelium. Epithelia are classified according to the number of cell layers and the shape of the cells.

Connective tissue consists of cells separated from each other by nonliving extracellular matrix. The extracellular matrix results from the activity of specialized connective tissue cells. Connective tissue is classified according to the type of protein and proportions of protein and fluid in the matrix. Connective tissue is subdivided into adipose tissue (fat), fibrous connective tissue, bone, and blood. Connective tissue forms the dermis of the skin, inner portion of the skin, bones, tendons, ligaments, the walls of large arteries, bone marrow, liver and others. Blood is somewhat unique among the connective tissues because the matrix between the cells is liquid. Thus, although the cells of most other connective tissues are more or less stationary within a relatively rigid matrix, blood cells are free to move within a fluid matrix.

Muscular tissue has the ability to contract. The three types of muscular tissue – skeletal, cardiac, and smooth muscle – are classified according to both structure and function. Skeletal (striated voluntary) muscles attach to bone and are responsible for body movement. Cardiac (striated involuntary) muscles are responsible for pumping blood through the circulatory system. Smooth (nonstriated involuntary) muscles form the walls of hollow organs, the pupil of the eye, and other structures.

Nervous tissue is characterized by the ability to conduct electrical signals. It consists of neurons, or nerve cells, which are responsible for conductive ability, and support cells (neuroglia). Neuroglia (nerve glue) is the support cells of the brain, spinal cord, and peripheral nerves.

Ex. 12. Translate the following words and word-combinations into English:

Прикріплювати, зв'язувати; визначати, давати визначення; епітелій; поверхня; тканина; нагнітати; спинний мозок; проводити; різноманітний, різнотиповий (різний); залоза; дерма; зв'язка; жорсткий, твердий; сполучна тканина; покривати; слизова оболонка.

Ex. 13. Translate the text "Tissues" into Ukrainian.

Ex. 14. Answer the following questions:

1. What is the tissue? 2. What types of tissue do you know? 3. What is the epithelium composed of? 4. What does the connective tissue consist of? 5. What groups is connective tissue subdivided into? 6. What types of muscular tissue are there? 7. What is the nervous tissue characterized by?

Ex. 15. Crossword:

	1.				t
2.					i
			3.		s
				4.	s
		5.			u
			6.		e

1. One of the types of tissue, which can be simple, stratified, pseudostratified, and transitional.

2. Noncellular substance surrounding the cells of connective tissue.

3. Bone-forming cell.

4. One of the types of muscular tissue.

5. Cells in the nervous system other than neurons.

6. The fundamental unit of every living organism.

Ex. 16. Write out key words of the text "Tissues".

Ex. 17. Compose the plan to the text "Tissues".

Ex. 18. Speak on:

Epithelial tissue;

Connective tissue;

Muscular tissue;

Nervous tissue.

Ex. 19. Memorize the following terms:

Дата добавления: 2015-07-11