Tissue its types, structure and function

Tissue is group of cells, which have similar in origin, structure and function are called as “Tissues”.

1. Chapter # 02 TISSUE Amjad Khan Afridi

2. Tissue is group of cells, which have similar in origin , structure and function are called as “Tissues”. Tissue is the groups of cells which perform specialized activity of the body. The word tissue comes from a form of an old French verb meaning “to weave بُننا ”.  The study of tissue is called “Histology”. In plants, tissues are divided into three types: vascular, ground, and epidermal.

3. According to the structure and function the body tissues can be grouped . Fundamental types of tissues – there are 4 types of human tissues In plants, tissues are divided into three types: vascular, ground, and epidermal.

4. Epithelial tissue Epithelial tissue , or epithelium, covers the surfaces of organs including the  skin , the trachea, the reproductive tract, and the digestive tract’s inner lining. Function: Protection: It creates a barrier that helps protect the underlying organs from friction and injury. Secretion: it also has roles in absorbing water and nutrients, secreting enzymes or hormones and removal of waste,.

5. All of the body’s glands are formed from ingrowths of epithelium. Some common epithelial tissue diseases are skin diseases like eczema and psoriasis, which both cause rashes. When cancer develops from epithelial tissue, it is called a  carcinoma .  Epithelial cells  in the airways are also responsible for asthma, which is characterized by inflammation of the airways that leads to shortness of breath.

6. Epithelial Tissue can further classified as; Simple epithelium Compound epithelium Simple Epithelium Its made of a single layers of cell Its subdivided into 4 types Squamous epithelium Cuboidal epithelium Columnar epithelium Ciliated epithelium

7. I. Squamous epithelium The squamous epithelium is  composed of epithelial cells  that are particularly flat, cells are wider than tall, and appear polygonal when viewed atop. It gives a smooth, low-friction surface, which allows easy movement of fluids over it.

8. II. Cuboidal epithelium This type of epithelium consists of  a single layer of cuboidal  (cube-like) cells which have large, spherical and central nuclei.

9. III. Columnar epithelium The columnar epithelium is  composed of epithelial cells that are column-shaped . The cell comprising the columnar epithelium is taller than it is wide. Its height is approximately four times its width.

10. IV. Ciliated epithelium Ciliated epithelium is  a thin tissue that has hair-like structures on it . These hairs, called cilia, move back and forth to help move particles out of our body. We find ciliated epithelial tissue in our respiratory tract and in the fallopian tubes of women.

11. I. Stratified squamous epithelium Composed of more than one layer of epithelial cells. Stratified squamous epithelium is a type of tissue found covering and lining parts of the body.  In this tissue, cells are flattened, joined tightly together, and stacked. Found in the outermost layer of the  skin  and the linings of esophagus,  mouth , and female reproductive organ.

12. I. Stratified squamous epithelium

13. I. Stratified squamous epithelium The stratified squamous epithelium provides protection against; Mechanical stress, Chemical abrasions, Pathogens, Desiccation and even radiation. The keratinized epithelium present on the surface of the skin blocks out the harmful radiation and prevents the exposure of internal tissues and organs to the radiation.

14. Its composed of multi layers of cells (4 to 6 layers) These cells are called transitional because they can undergo a change in their shape and structure Also called  urothelium because it lines urinary ducts, urethra, urinary bladder and renal calyxes  Its variable in appearance In relaxed state its looks like stratified cuboidal epithelium, while when stretched the cells become squamous shaped. Location: Found urinary ducts, urethra, urinary bladder and renal calyxes  II. Transitional epithelium

15. Columnar / Cuboidal cells Polyhedral Cells / Intermediate cells Umbrella cells

16. 2. Connective Connective tissue  connects or separates groups of other tissues. It is found in between all the other tissues and organs in the body. Connective tissue is made up of cells and ground substance, which is a gel that surrounds cells. Most connective tissue, except for  lymph  and  blood , also contains fibers, which are long, narrow proteins.

17. Fibers can be collagenous , which bind bones to tissues; Elastic fiber, which allow organs like the lungs to move; or reticular fiber, which provide physical support to cells. Connective tissue also allows oxygen to diffuse from blood vessels into cells. About 1 in 10 people are have a disorder involving connective tissue. Some connective tissue disorders include sarcomas, Marfan syndrome, lupus, and scurvy, which is a Vitamin C deficiency that leads to fragile connective tissue.

18. Major functions of connective tissue include: Binding and supporting, Protecting, Insulating, Storing reserve fuel, and Transporting substances within the body

19. Types of connective tissue Connective tissue proper Cartilage Bone Blood

20. 3. Muscle Tissues Muscle tissue  comprises all the muscles in the body Have the special ability to shorten or contract in order to produce movement of the body parts There are three types of muscle tissue:  Skeletal muscle ,  Cardiac muscle , and  Smooth muscle . 

21. Skeletal muscle anchors tendons to bones and allows the body to move. Cardiac muscle is found in the heart and contracts to pump blood. Smooth muscle is found in the intestines, where it helps move food through the digestive tract, and it is also found in other organs like blood vessels, the  uterus , and the bladder.

22. 4. Nervous Tissue Nervous tissue  is found in the brain, spinal cord, and peripheral nerves, which are all parts of the  nervous system . It is made up of neurons, which are nerve cells, and neuroglia , which are cells that help nerve impulses travel. Nervous tissue is grouped into four types: gray matter and white matter in the brain, and nerves and ganglia in the  peripheral nervous system .

23. The main difference between gray and white matter is that axons of the neurons in gray matter are unmyelinated, while white matter is myelinated. Myelin is a white, fatty substance that insulates neurons and is vital for nervous system functioning.

24. Functions of the Nervous Tissue Memory and learning Voluntary movement control Regulates & controls body functions Generates & transmits nerve impulses Supports and protects impulse generating neurons.

25. Thank You 2 nd December, 2021