STUDY OF CELLS - TISSUES

1. STUDY OF CELLS - TISSUES BIOLOGY 10TH GRADE

2. TISSUES Tissues : Groups of cells which have a common origin, with similar structure and function. They exhibit great variety in their structure including shapes of cells, thickness of cell walls and other characteristics. Organ : Different types of tissues together take up a particular function and form an organ. Organ System : A group of organs performing a set of common functions is called an organ system. Histology : The branch of biology which deals with the study of tissues and their organization in organs, is called histology. As we go higher up in the ladder of evolution, the body organization in plants and animals becomes more complex. The body consists of specialised tissues and organs to perform various metabolic activities. Thus, specialisation of the tissues in higher organisms has enabled them to perform life processes more efficiently.

3. PLANT TISSUES In an angiosperm plant body there are different types of tissues to perform a variety of functions such as growth, protection, absorption, photosynthesis and conduction of water and minerals.

4. Plant Tissues – Different types of tissues Kindly paste the below link to watch the you tube video on Plant tissues : http://www.youtube.com/watch?v=uN_vBFyu_-g

5. PLANT TISSUES In an angiosperm plant body there are different types of tissues to perform a variety of functions such as growth, protection, absorption, photosynthesis and conduction of water and minerals.

6. PLANT TISSUES (SIMPLE PERMANENT TISSUE) Simple permanent tissues are composed of cells which are similar in structure and function. There are three types of simple permanent tissues

7. PLANT TISSUES (COMPLEX PERMANENT TISSUE) “Tissues which are composed of two or more types of cells but contribute to a common function are called complex tissues. Xylem and phloem are the complex permanent tissues. They together form the vascular bundle hence known as Vascular tissues” Phloem and xylem are complex tissues that perform transportation of food and water in a plant. They are the vascular tissues of the plant and together form vascular bundles. They work together as a unit to bring about effective transportation of food, nutrients, Minerals and water

8. PLANT TISSUES (COMPLEX PERMANENT TISSUE)

9. PLANT TISSUES (COMPLEX PERMANENT TISSUE)

10. ANIMAL TISSUES Animal tissues are more complex in structure and function when compared to plant tissues. The animal tissues can be broadly classified as follows.

11. ANIMAL TISSUESEpithelial Tissue EPITHELIAL TISSUE : You are familiar with the skin which is the outer covering of the body. The inner wall of the body is also lined with a similar tissue. These outer and inner layers are made up of a type of tissue called epithelial tissue. • The epithetial tissue consists of a single layer of cells called simple epithelium. If it contains more than one layer, it is called stratified epithelium. • Simple epithelium consisting of flat plate like cells is called squamous epithelium. It is found in the alveoli of lungs, and in oesophagus, in blood vessels, blood capillaries and chambers of the heart. This tissue is referred to as endothelium. • It permits materials to diffuse through it. The epithelial tissue containing elongated cells is called columnar epithelium. It is found in the inner layer of the stomach, small intestine, pharynx, larynx and oviducts.

12. ANIMAL TISSUESEpithelial Tissue Simple Epithelium: A simple epithelium has a single layer of cells. Stratified Epithelium: A stratified epithelium has multiple layers of cells.Likewise, the shape of the cells on the free surface can be:Cuboidal : Analogous to the shape of dice.Columnar : Analogous to the shape of bricks on an end.Squamous : Analogous to the shape of flat tiles on a floor.By combining the terms for shape and layers, we can derive epithelial types such as stratified squamous epithelium or simple columnar epithelium.

13. ANIMAL TISSUESEpithelial Tissue The mucus secreted by the cells in the stomach protects the wall of the stomach from acidic contents and digestive enzymes. The mucus produced in the intestine lubricates the passage of food. The epithelium bearing numerous cilia is called ciliated epithelium. Epithelium consisting of cube shaped cells is known as cuboidal epithelium. It forms the lining of many ducts such as pancreatic duct, salivary duct and sweat ducts.Inmany glands like salivary glands and thyroid gland, cuboidal epithelium is involved in secretion.

14. ANIMAL TISSUES - FUNCTIONS OF EPITHELIAL TISSUES The epithelium forms a thick tough barrier and protects the underlying tissues in the form of external skin. The epithelium of the skin also helps in controlling the body temperature constant. 2. The ciliated epithelium helps in the movement of materials. 3. The epithelium cells in glands facilitate secretion. 4. Epithelium helps in absorption of nutrients and excretion. 5. The epithelium in sense organs contain receptor cells.

15. ANIMAL TISSUES – Tissue and Muscles Muscular Tissue MUSCULAR TISSUE Muscular tissue is concerned with the movements of the body. It is made up of muscle cells, which appear like fibres. Hence they are called muscle fibres (myofibres). The muscle fibres are specialised cells capable of contraction and relaxation. This property is responsible for movement of limbs and bending of the body. The movements of internal organs like heart, stomach and alimentary canal are caused by muscles. These muscles are not under the control of the animal. Hence they are called involuntary muscles. The muscles of organs like limbs which are under the control of the animal, are called voluntary muscles. The muscles are classified into three types based on the structure, function and location. They are (1) Unstriped muscles (2) Striped muscles (3) Cardiac muscles.

16. ANIMAL TISSUES – Tissue and Muscles Muscular Tissue

17. ANIMAL TISSUES – Tissue and MusclesConnective Tissue CONNECTIVE TISSUES The tissues which connect various other tissues of the body and provide support are called connective tissues. They occur in all parts of the body. Connective tissues basically consist of cells and fibres enclosed in a ground substance. The non-living substances like fibres and other materials surrounding the living cells form the matrix. It may be soft or hard or liquid. The connective tissues are identified on the basis of the nature of the matrix and classified into three types. They are (1) Loose connective tissues (2) Dense connective tissues (3) Fluid connective tissues.

18. ANIMAL TISSUES – Tissue and MusclesConnective Tissue LOOSE CONNECTIVE TISSUES : The fibres in the matrix are loosely arranged is called loose connective tissue. The areolar tissue, adipose tissue and reticular tissue are included under this group.

19. ANIMAL TISSUES – Tissue and Muscles Dense Connective Tissue • DENSE CONNECTIVE TISSUE : • The connective tissues consisting of hard matrix are called dense connective tissues. The cells are embedded in a dense matrix. • The major functions of dense connective tissues are : • They form the skeletal system of the body providing an internal supporting frame work. • They enclose the internal organs. The skull protects the brain, ears, eyes,noseand other organs in the face. • The rib cage protects heart and lungs. • The vertebral column protects the spinal cord. The organs of digestion, excretion, reproduction and many other organs in the abdomen are protected by the pelvic girdle and limbs are provided with support.

20. ANIMAL TISSUES – Tissue and Muscles Dense Connective Tissue Cartilage Tissue Bone Tissue

21. ANIMAL TISSUES – Tissue and Muscles Fluid Connective Tissue FLUID CONNECTIVE TISSUES : The blood and the lymph are the liquid connective tissues of the body. They have a fluid matrix.

22. ANIMAL TISSUES – Tissue and Muscles Nervous Tissue Nervous Tissue is one of the basic characteristics of living organisms. This property is very well developed in nervous tissue. The nervous tissue responds to external and internal stimuli of the body. It transmits nerve impulses from all parts of the body to nerve centres very quickly and brings back the responses. The structural and functional unit of nervous tissue is the ‘nerve cell’ or neuron. The part consisting of a prominent nucleus is the cell body. The short brush like structures arising from the cell body are called dendrites. The long extension of the cell body is the axon. The axon ends in a bunch of branches. The axon is covered by a fatty sheath called myelin sheath. Dendrites carry the impulses towards the cell body. Axons carry the messages away from the cell body. There is a tiny gap between two successive neurons. This gap is known as synapse. The impulses are transmitted from the axon of one neuron to the dendrite of another neuron across the synapse through chemical substances

23. Did you know ???? The middle ear bones are the smallest bones Bone consists of 30% organic substances, collagen fibres and glycoprotein. 70% is made up of salts out of which 85% is calcium phosphate. The human heart beats 65 times per minute on an average. In 70 years total number (70 x 365 x 24 x 60 x 65) of beats will be 2391480000. The most wonderful pump ever! Help these muscles to serve you for life time. Avoid smoking, obesity, and using saturated fats in the diet. The longest bone in the human body is the thigh bone called Femur The fastest nerve impulses in humans travel at 8 metres per second The muscles can contract nearly 100 times per second, when a person is doing hard work. The red pigment haemoglobin in RBC absorbs oxygen and becomes oxyhaemoglobin