Science Do as directed; [1 M ]

Goblet cell is a simple columnar epithelial cell which is modified to secrete mucus. It is seen in the intestine and other parts of the alimentary canal.

Themuscular tissue is responsible for movement in our body.

Skeletal muscles are called striated muscles because when we observed this skeletal muscles under the microscope they have a striped like appearance & they also show alternate dark and light striations or bands. They are long or elongated, non tapering and cylindrical, unbranched. They are multinucleated.

Smooth muscles.

Cardiac muscle cells are located in the walls of the heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow visceral organs, except the heart, appear spindle-shaped, and are also under involuntary control.

Sclerenchymatous tissue.

1. The common name of xylem is wood.
2. The common name of phloem is bast.

Glandular epithelium is a type of epithelial tissue which covers the glands (both exocrine and endocrine) of our body. Coming to their function, Both endocrine and exocrine glands produce their secretions through the glandular epithelium via special cells called goblet cells.

The main components of xylem are:

1. Xylem tracheids,
2. Xylem vessels,
3. Xylem parenchyma,
4. Xylem fibres.

1. Xylem tracheids and xylem vessels are responsible for the conduction of water and minerals because they are elongated tubular channels with wide lumen.
2. Xylem tracheids possesses pits with pores and vessels possess perforated plates through which they are able to conduct water and minerals from one cell to the another.

On the basis of arrangement of layers, epithelial tissue is classified into two types:

• Simple epithelium
• Stratified epithelium.

Skeletal or striated muscle gets fatigued very soon. These are voluntary muscels.

Tissue which is composed of two or more types of cells but contribute to a common function is called complex tissue.

Companion cell is living cell which is attached to the lateral side of sieve tube.

Stomata are tiny pores present on the leave’s surface which help in the exchange of gases and in transpiration.

The cells of bones are called osteocytes. Bone cells are embedded in a hard matrix that is composed of calcium and phosphorus compounds.

It is also called tigroid body, found in neurons. it was named after Franz Nissl, German neurologist.
Function:

1. These granules are rough endoplasmic reticulum (with ribosomes) and are the site of protein synthesis.
2. Nissl bodies show changes under various physiological conditions and in pathological conditions they may dissolve and disappear (karyolysis).

Cork is the example of protective tissue in the plants.

Blood platelets help in clooting of blood at the site of injury.

1. Multinucleate muscle fibre: Striated muscle fibres which are present in limbs, tongue, hands.
2. Spindle shaped Fibre: Unstriated muscle fibres which are present in iris of the eye, bronchi.

The striated muscle cells are long, cylindrical, unbranched and multinucleate.

Division of labour is adaptation of different parts of an organism to carry out different functions.

Squamous epithelium is also called pavement epithelium as it is made up of single thin layer of flattened cells.

The types of simple tissues are parenchyma, collenchyma, sclerenchyma and aerenchyma.

Connective tissues perform a variety of functions including support and protection. The following tissues are found in the human body, ordinary loose connective tissue, fat tissue, dense fibrous tissue, cartilage, bone, blood and lymph, which are all considered connective tissue.

Ligament connects two bones together at joints.

Epidermis having thick cuticle and dermal tissue to prevent the invasion of parasites and other harmful agents.

A tissue is a group of cells of the same type or mixed type having a common origin and performing a common function.

Connective tissue with a fluid matrix → Blood.

Lignin is deposited in the cell wall of sclerenchyma.

The main function of vascular tissues is to transport water and food in the plant. The Xylem is known to conduct water and Phloem conducts food in the form of sugars.

Each stomata is surrounded by a pair of guard cells. Guard cells regulate the opening and closing of stomata.

Connective tissues are most abundant and widely distributed in the body of complex animals.

Collenchyma is a simple permanent tissue which provides mechanical strength as well as flexibility to the plant organs.

Nerve impulse travel along the axons and dentrites. Nerve impulses enter a neuron along the dentrites and leave the neuron along the axon. Thus, the correct sequence through which nerve impulse is transmitted is: dendrites, cell body, axon, nerve endings.

The cells of phloem are called sieve tubes. Sieve tubes are conducting element of phloem which is responsible for transportation of food.

Meristematic tissue is present in plants but absent in animals.

Root nodules: It contain nitrogen fixing bacteria and fixes atmospheric nitrogen in soil.

A coverslip must always be places very gently while mounting in order to avoid the entry of air bubbles.

Sclerenchyma is the simple tissue used for making ropes. It is the tissue that makes the plant hard and stiff as seen in the husk of the coconut. On the walls of sclerenchyma is lignin that provides tensile strength which is good for making ropes.

A permanent tissue is a group of cells which temporarily or permanently cease to divide have assumed a definite form and size.

1. Apical meristem: Shoot apes.
2. Lateral meristem: Cambium.

Leaves, fruits, and flowers are the regions where the parenchyma tissue is present.

Although the nervous system is very complex, there are only two main types of cells in nerve tissue. The actual nerve cell is the neuron. It is the "conducting"cell that transmits impulses and the structural unit of the nervous system. The other type of cell is neuroglia, or glial, cell.

Stomata: It helps in gaseous exchange between the plant and atmosphere. Transpiration also takes place through stomata.

Tissue is a group of cells that are similar in structure and are organized together to perform a specific task.

Synapse is the junction between the terminal part of one axon and the dendrite of the adjacent neuron. Synapses helps in the transmission of impulses from one neuron to another.

Collenchyma tissue is irregularly thickened at the corners due to the depositon of pectin and cellulose.

Three types of simple tissues of plants are:

• Parenchyma.
• Collenchymas.
• Selerenchyma.