Tissues- When a group of cells of a similiar origin come together to perform a common function, a...

1. Plant Tissues- Primary function is to provide strength. Plants have more dead tissues. The growth of plants is limited to only a few areas

1.1. Permanent Tissue- Once the meristematic tissues lose their ability to divide, they take up a specific role and form a permanent tissue. This process of conversion of meristematic tissue to permanent tissue is called differentiation.

1.1.1. Complex Permanent Tissue- Agroup of different types of cells comes together to perform a specific function

1.1.1.1. Xylem- Ascent of sap (Water and minerals). Only one way, roots to leaves. Dead tissue

1.1.1.1.1. Trachieds + Vessels- Both aare dead tissue. Trachieds is a tissue with lignin thickening except at stops called pits. Vessels are tubular structures. They both help in the ascent of sap

1.1.1.1.2. Xylem Parenchyma- Only living tissue. Help in storage of food and sideways conduction of water

1.1.1.1.3. Xylem Fibres- Mechanical strength

1.1.1.2. Phloem- Distribution of food from leaves to every part of the plant. Two way. Living tissue.

1.1.1.2.1. Sieve Tubes + Sieve Cells- They help in the upward and downward movement of food. They have purforated walls called sieve plates.

1.1.1.2.2. Companion Cells- Smaller cells that help in the movement of food

1.1.1.2.3. Phloem Parenchyma-- Storage of food

1.1.1.2.4. Phloem Fibres- Only dead cells of phloem. Provides mechanical strength

1.1.2. Simple Permanent Tissue

1.1.2.1. Parenchyma- They are the most abundant tissue in plants. It fills any cavity and hence is called packing tissue. It is an unspecialized cell with a primary function of storage and provides support. It is a versatile tissue. Thin cell walls and large intercellular spaces

1.1.2.1.1. Aerenchyma- In aquatic plants, parenchyma have cavities filled with air which help in the buoyancy of the plant.

1.1.2.2. Collenchyma- It provides tensile strength to the plant. It prevents the tearing of the plant under high winds. It allows the stem to bend easily. It has irregularly thickened walls (pectin) around the corner of the cell. It has small intercellular spaces. Found in the leaf stalks near the epidermis.

1.1.2.3. Scelrenchyma- It provides strength to the plant. It is long and narrow with thick lignified walls. It is found in the outer covering of nuts, veins of leaves or near the vascular bundle.

1.2. Meristematic Tissues- Tissues that are able to divide themselves and help in the growth of plants. They are living tissues

1.2.1. Apical Meristem- Meristematic tissues found at the root and shoot tip aid in the growth in length of the plant.

1.2.2. Lateral Meristem- Meristematic tissues that help in the increase in girth of the plant

1.2.3. Intercalary Meristem- Meristematic tissue that are found in the internodes of the twigs or base of the leaves. Help in the growth of leaves and twigs

1.3. Other Plant Tissues

1.3.1. Episdermis- Outermost protective layer of the plant. Usually 1 cell thick. In desert habitats, it may be thicker to prevent water loss. It is covered with cuticle In aerial parts of the plant, it secretes a waxy substance which protects the plant from mechanical injury or from parasitic fungi.

1.3.2. Cork- As the plants go older, a layer of meristem covers the epidermis which forms the bark of the tree. They are dead cells without any intercellular spaces and are impervious to water and gases due to the presence of suberin.

1.3.3. Stomata- These are small pores on the epidermis. They are formed by two guard cells which are responsible for opening and closing the stomata. Exchange of gases and transportation are its functions

2. Animal Tissues- There are more living tissues as animals need movement to survive. Cell growth is more uniform. The whole body of the animal grows.

2.1. Epithelial Tissue- It forms the skin of the body. It is found in the side of all cavities like mouth, throat, intestine. Creates a barrier to keep all body sytems separate. It regulates the exchange in material between 2 body parts or between the body and the environment Cells are tightly packed and form a continuous sheet Small amount of cementing material and almost no intercellular spaces. All epithilea are separated from the underlying tissue by a extracellular basement membrane.

2.1.1. Squamous Epithelial Tissue- They are flat cells.

2.1.1.1. Simple- Found in alveoli or blood vessels. Transportation takes place through semi permeable membranes

2.1.1.2. Stratified- The epithelial tissue in skin is arranged in multiple layers to prevent wear and tear.

2.1.2. Columnar Epithelial Tissue-They are pilllar like. Found in stomach, intestine and gall bladder. Responsible for absorption and secretion

2.1.3. Ciliated Epithelial Tissue- They are either cuboidal or coulmnar with cilia Found in urinary tract, wind pipe or oviduct. Helps in movement of mucous, urine or eggs.

2.1.4. Cuboidal Epithelial Tissue- They have cube-like structure. It provides protection.

2.1.5. Glandular Epithelial Tissue- Sometimes a portion of the epithelial tissue folds inwards and a multicellular gland is formed. Glandular tissue secretes substances at the epithelial surface. It lines glands like the gastric and intestinal glands

2.2. Connective Tissue- Responsible for joining two tissues of the body, supporting and packing together different parts of the body. Cells are imbedded into an intercellular matrix

2.2.1. Areolar Connective Tissue- Most abundant, matrix is composed of white collagen and yellow elastic fibers. Commonly called packing tissue. Fills spaces in the organs, near the nerves and blood vessels. It helps in binding the skin to underlying parts and repair of tissue.

2.2.2. Dense Regular Connective Tissue

2.2.2.1. Ligament- Joind bone to bone. Very elastic. Matrix is yellow elastic fibres

2.2.2.2. Tendon- Joins muscles to bones. Made of collagen.

2.2.3. Adipose Connective Tissue- Fat storing tissue. Found below the skin and between organs. Acts as an insulator and fat absorbing cushion near various organs Filled with fat globules.

2.2.4. Skeletal Connective Tissue- Forms a rigid skeleton that supports an animal's body. Helps in locomotion and provides protection to organs.

2.2.4.1. Bone- Very strong but zero flexibility. It forms a framework of the body that anchors the muscles and the internal organs. Matrix is made up of calcium and phosphate

2.2.4.2. Cartilage- Widely spaced cells. Hard but flexible. Matrix is made up of proteins and sugars. Smoothens the joints is presence in nose, pinna and larnyx.

2.2.5. Fluid Connective Tissue

2.2.5.1. Blood- Matrix is called plasma. It has three parts: WBC, RBC and platelets. Transports gases, excretory subtstances, and digested food all over the body.

2.2.5.2. Lymph- It is a colorless, extracellular tissue that helps in transport between blood and tissue cells.

2.3. Muscular Tissue- It consists of muscle fibres responsible for all movement in the body. Contractile proteins help contract and relax.

2.3.1. Striated/ Voluntary/Skeletal Muscular Tissue- They have alternate dark and light bands. They are multinucleated. We can control these muscles. These muscle tissues are connected to the skeleton and hence aids in movement. These have long, narrow, unbranched cells with blunt ends. It is found in a special plasma membrane called sarcolemma.

2.3.2. Non-Striated/ Involuntary/ Smooth Muscular Tissue- These muscles do not have striations. These are spindle-shaped with a single nucleus. We do not control them. Found in the alimentary canal, iris, bronchi.

2.3.3. Cardiac Muscular Tissue- They are found near the heart. They undergo rhythmic contraction and relaxation throughout life. They never get fatigued They are cylindrical, branched and have faint cross striations. They are uninucleate

2.4. Nervous Tissue- It is found in brain, spinal cord and nerves. It is responsible for coordinationg all the body movements and activities.

2.4.1. The cells that make up the nervous tissues are called Neurons.

2.4.1.1. Axon - It is the longest dendron which recieves electrical impulse from the cell body. It is covered with a layer of fat containg schwann cells called myelin sheath. This layer acts like an insulated layer for flow of electrical impulse. Myelin sheaths have gaps called Node of Ranvier

2.4.1.2. Cyton or Cell body - the cell body has a cytoplasm inside it which contains nucleus and other cell organelles. It contains fiber-like structure called dendron which branch further to form dendrites. The dendritic tips are present in contact with the receptor cells present in the sense organs. Stimuli triggers a chemical reaction in the receptor cells. The dendritic tip converts the chemical substances into electrical impulse which is then transferred to the cell body.

2.4.1.3. Axon terminal - the axon divides into many branches. these branches are called axon terminals and their tip is called synaptic blob. The synaptic blobs convert the electrical impulse into nuerotransmitters like acetycholine at the gap present between it and the dendritic tip of next neuron.This gap is called synapse