Neural Tissue## Neural Tissue Nervous tissue exerts the greatest control

over the body’s responsiveness to changing

conditions. Neurons, the unit of neural system are excitable cells (Figure 3.8). The neuroglial cells which constitute the rest of the neural system protect and support the neurons. Neuroglia makes up more than one-half of the volume of neural tissue in our body.

When a neuron is suitably stimulated, an electrical disturbance is generated which swiftly travels along its plasma membrane. Arrival of the disturbance at the neuron’s endings, or output zone, triggers events that may cause stimulation or inhibition of adjacent neurons and other cells (You will study in detail in Chapter 10)

Diseases of Nervous System:

1. Parkinson’s disease: A degenerative disorder of the nervous system that affects movement, often including tremors.

2. Alzheimer’s disease: It is a chronic neurodegenerative disease which includes the symptoms of difficulty in remembering recent events, problems with language, disorientation and mood swings.

Biopsy is an examination of tissue or liquid removed from a living body to discover the presence, cause or extent of a disease. Autopsy is a post-mortem (dissection of a dead body) examination to discover the cause of death or the extent of disease. The field of Forensic science effectively uses the histological techniques to trace out crimes.

Summary The body cells combine to form

four different types of tissues; epithelial, connective, muscle and nervous tissues. Though the cells of these tissues share certain features in common, by no means they are identical. They belong together because they have basic fundamental resemblances. The important concept to carry away with you is that tissues, despite their unique abilities, cooperate to keep the body safe, healthy, viable and whole.

Activity _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1.Students are asked to identify the unlabelled slides of tissues and to classify them. Similar exercise can also be accomplished by projecting unlabelled histological images on a screen. They can identify the slides of different tissues through microscope 2.The preparation of smear of stratified squamous epithelia from the inner lining of cheek allows the students to make their own slides using biological stain. They will have the experience of examining their cheek cells.

Evaluation 1. The main function of

the cuboidal epithelium is

a. Protection b. Secretion c. Absorption d. Both (b) and (c) 2. The ciliated epithelium lines the a. Skin b. Digestive tract c. Gall bladder d. Trachea 3. What type of fibres are found in

connective tissue matrix? a. Collagen b. Areolar c. Cartilage d. Tubular 4. Prevention of substances from leaking

across the tissue is provided by a. Tight junction b. Adhering junction c. Gap junction d. Elastic junction

The Online Epithelium’sURL:

http://www.epithelium3d.com/index.html

ICT Corner The Online E

Step – 1 Use the URL to open ‘The Online Epitheli to view the interactive epithelial tissues p

Step – 2 Click the play icon to load the 3D intera degree by click and drag of the mouse.

Step – 3 Roll the mouse over the interactive diagra description of the parts will appear, descrip the bottom of the activity window.

Step – 4 Additional information regarding the part descriptions given below the 3D interactive

Let’s explore the anat functions of Epithelium

* Pictures are indicative only

5. Non-shivering thermogenesis in neonates produces heat through

a. White fat b. Brown fat c. Yellow fat d. Colourless fat 6. Some epithelia are pseudostratified.

What does this mean? 7. Differentiate white adipose tissue from

brown adipose tissue. 8. Why blood is considered as a typical

connective tissue? 9. Differentiate between elastic fibres and

elastic connective tissue. 10. Name any four important functions of

epithelial tissue and provide at least one example of a tissue that exemplifies each function.

11. Write the classification of connective tissue and their functions

12. What is an epithelium? Enumerate the characteristic features of different epithelia.

pithelium

um’page. Click any of the organ given in the list resent in that organ. ctive. The loaded 3DTissue can be viewed 360

m and click the number on the diagram. A brief tion can be viewed by selecting the parts given at

icular epithelial tissue can be learned from the diagram.

omy and Tissues.