Science Answer the questions.[Bio-3M]

1. Parenchyma Functions:

1. The main function of parenchyma is to store and assimilate food.
2. Transport of materials occurs through cells or cell walls of parenchyma cells.

2. Collenchyma Functions:

1. It provides mechanical support and elasticity.
2. It provides tensile strength to the plants.

3. Sclerenchyma Functions:

1. It is mainly mechanical and protective in function.
2. It gives strength, rigidity, flexibility and elasticity to the plant body.

The different types of plant tissues are:

1. Meristematic tissues: It is of three types: Apical, Lateral and Intercalary.

2. Permanent Tissue: It of two types: Simple and Complex tissues.

Simple tissues are of three types: Parenchyma, Collenchyma and Sclerenchyma.

Complex tissues are of two types: Xylem and Phloem.

Structure: Parenchyma is a simple, permanent living tissue which is made up of thin-walled cells. The cells of this tissue are oval, elongated, and loosely packed with large intracellular space. Their cell wall is made up of cellulose. Each cell encloses a large central vacuole, cytoplasm and a prominent nucleus.

Location: The parenchyma tissue is present in soft parts of the plant such as cortex, pith, palisade and some parts of the flower.

Functions: Parenchyma tissue provides support to plants and also stores food. In some situations, it contains chlorophyll and performs photosynthesis.

Collenchymas is a type of permanent tissue which is found few layer below the epidermis of leaves and stem. The cells of this tissue are living, elongated and tightly packed with no inter-cellular space. The cells have small nucleus, large vacuoles and thin cell wall but irregularly thickened at the corners.

Collenchyma tissue provides flexibility to plants so that they can easily bend without breaking. It also provides mechanical support to plants.

It is the most fundamental type of connective tissue which is found all over the body. This tissue is present in spaces in between the skin and muscles, around blood vessels and nerves and in the bone marrow.

Areolar connective tissue has homogenous, semi-solid gel like ground substance called matrix in which various types of cells and collagen fibres and elastic fibres are embedded. It contains fibroblast cells, mast cells and macrophages. It fills the space inside the organs, supports internal organs and helps in repair of tissues.

Smooth muscles also called as unstriated muscles as they lack transverse striations. They are not under the control of one’s will, hence they are also called involuntary muscles. These muscle cells are long with pointed ends (spindle shaped) and arranged in bundles. Each cell is uninucleated (having a single nucleus).

Smooth muscles are found in alimentary canal and blood vessels. The movement of food in the alimentary canal or the contraction and relaxation of blood vessels are involuntary movement. These are also found in the iris of the eye, in uterus and in the bronchi of the lungs.

Plants are autotrophic organisms, so prepare their own food by photosynthesis. Moreover plants are stationary or fixed organisms; they do not have to move from place to place in the search of their food. Since they do not consume or need much energy, so most of the plant tissues are supportive, which provide them with structural strength. Animals are heterotrophic organisms. They have to move in search of food, mate and find shelter, so they need more energy as compared to plants. Most of the tissues they contain are living.

1. Ligament is a form of connective tissue which holds two bones together at joints. When ligament get overstreached, it causes sprain.
2. Heparin is an anticoagulant present in blood that prevent it from clotting. If heparin is absent in blood, blood will be coagulated inside the blood vessels.
3. Striated muscle contraction causes fatigue due to accumulation of lactic acid.

1. Apical meristems are the growing parts of the roots and stems and are present at the tips of roots, branches, leaves and shoots. If the apical meristems are damanged or cut, the growth of that part of the plant will stop.
2. If cork is not formed in older stems or roots, the outer tissues will rupture due to increase in girth which expose the interior to dessication and infection.
3. Lymph is transported through lymph vessels of the lymphatic system. If lymph is not returned to blood, the blood volume will decrease during passage of materials from tissues to blood and vice versa.

1. Bone is a solid, rigid and stong connective tissue. Its matrix is hard. The matrix is made up of organic as well as inorganic (e.g.calcium and phosphorus) components. Calcium and phosphorus make the bone matrix hard. When a bone is dipped in HCI, bone become soft and pliable as its inorganic components get dissolved in the acid. Only organic matter is left.
2. When a bone is dried, its organic matter get destroyed. Only mineral matter is left.

• Bone: It provides skeletal support to the body.

• Cartilage: It provides support and flexibility to the body parts.

• Ligament: It connects bones to bones.

Simple tissues: These tissues are composed of cells which are structurally and functionally similar.

There are three types of simple tissues:

1. Parenchyma: Parenchyma cells are living and posses the power of division. The cell wall is thin and encloses a dense cytoplasm which contains a small nucleus and surrounds a large central vacuole.

2. Collenchyma: It tissues also consists of living cells. It is characterized by the deposition of extra cellulose at the corners of the cells. In collenchymas, intercellular spaces are generally absent. Collenchyma cells are elongated in shape. They often contain a few chloroplasts.

3. Sclerenchyma: Sclerenchyma cells are dead cells and they are devoid of protoplasm. The cells walls of sclerenchyma are greatly thickened by the deposition of lignin. The cells of sclerenchyma are closely packed without intercellular spaces.

Sclerenchyma is a supporting tissue. It is the tissue which make plant hard and stiff.

Location: This tissue is present in stems, around vascular bundles, in the veins of leaves and in the hard covering of seeds and nuts.

Structure: The cells of this tissue are dead. They are long, elongated, narrow, thick walled and lignified. These consists of fibres and sclereids.

A neuron or nerve cell is the structural and functional unit of nervous system. A typical neuron consists of cell body or soma, dendrites and axon.

Muscular tissue is a contractile tissue made up of muscles. Muscles consists highly specialised cells called muscle fibres. This tissue is responsible for movement in our body.

Striated muscles are also called voluntary muscles as their movement is under our will. The cells of striated muscles are long, narrow, cylindrical, unbranched with blunt ends. They have multi nucleus.

These muscles are also called skeletal muscles because they are mostly attached to bone and help in body movement. These muscles show alternate light and dark band or striations when stained appropriately. As a result, they are also called striated muscles.

Lymph is a colorless or slightly yellowish fluid. It is a medium of circulation in human body which flows only in one direction from body tissues to the heart.

The functions of lymph are:

1. Lymph helps in removing the waste products.
2. Lymph carries digested fat from the small intestine to the entire body.
3. Lymph nodes contain lymphocytes which kill the germs or foreign bodies.

The different tissues in animals are:

1. Epithelial Tissues: These are the protective tissues of the animal body. Depending upon the shape and function of the cells, the epithelial tissues are classified as follows:

1. Squamous epithelium.
2. Cuboidal epithelium.
3. Columnar epithelium.
4. Glandular epithelium.
5. Ciliated epithelium.

2. Muscular Tissues: The muscular tissues form the contractile tissues and are made up of muscle cells. On the basis of their location, structure and function, there are three types of muscular tissues:

1. Striated muscles.
2. Smooth muscles.
3. Cardiac muscles.

3. Connective Tissues: The connective tissues are specialised to connect and anchor various body organs. They are of five types:

1. Aerolar connective tissue.
2. Dense regular connective tissue.
3. Adipose tissues.
4. Skeletal tissues.
5. Fluid connective tissues.

4. Nervous Tissues: These tissues are specialised to transmit messages within our body. Brain, spinal cord and nerves are all composed of nervous tissues.

A permanent tissue is a group of cells which temporarily or permanently cease to divide.

The cells of this tissue have smaller nuclei and well developed vacuoles. They may be dead or alive, thin walled or thick walled.

Meristematic tissues are the tissues in which the cells divide continuously and help in increasing the length and girth of the plant.

According to their position in the plant, meristems are of three types:

1. Apical Meristems: These are situated at the growing tip of the stems and roots and increase the height of the plant.

2. Lateral Meristems: These are found beneath the bark and in vascular bundles of dicot roots and stems. These are responsible for the growth of cambium and hence increases the girth of the plant.

3. Intercalary Meristems: They are located at the base of leaves or internodes or below the nodes. It increases the length of the plant
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Simple tissues: These tissues are composed of cells which are structurally and functionally similar.

There are three types of simple tissues:

1. Parenchyma: Parenchyma cells are living and posses the power of division. The cell wall is thin and encloses a dense cytoplasm which contains a small nucleus and surrounds a large central vacuole.

2. Collenchyma: It tissues also consists of living cells. It is characterized by the deposition of extra cellulose at the corners of the cells. In collenchymas, intercellular spaces are generally absent. Collenchyma cells are elongated in shape. They often contain a few chloroplasts.

3. Sclerenchyma: Sclerenchyma cells are dead cells and they are devoid of protoplasm. The cells walls of Sclerenchyma are greatly thickened by the deposition of lignin. The cells of sclerenchyma are closely packed without intercellular spaces.

1. Collenchyma.
2. Sclerenchyma.
3. Parenchyma.

Parenchyma, collenchyma sclerenchyma, Tracheids, vessels, companion cells, sieve tubes.

• Osteoblast: It provides shape to the body.

• Chondroblast: It provided support and flexibility to the body parts.

• Goblet cells: It is a mucus secreting epithelial cell which secrets mucus.

• Neuron: The dendrites receive impulses and the axon takes impulses away from the cell body.

• Muscle cell: They undergo rapid contraction for locomotion.

• Neuron: Nervous Tissue..

• Dendrite: Nervous Tissue.

• Cilia: Ciliated Epithelium.

• Collagen fibres: Connective Tissue.

• Elastin fibre: Connective Tissue.

Functions:

1. It transports nutrients, hormones and vitamins to the tissues and transports excretory products from the tissues to the liver and kidney.
2. The RBCs carry oxygen to the tissues for the oxidation of food stuff.
3. WBCs fight disease by engulfing and destroying foreign bodies.

Functions of Epithelial tissues are:

1. The cells of the body surface form the outer layer of skin. These cells protect the underlying cells from drying, injury, and chemical effects.
2. Inside the body, epithelial cells form lining of mouth and alimentary canal and protect these organs.
3. Epithelial tissues help in absorption of water and nutrients in small intestine.
4. Some epithelial tissues perform secretory function such as sweat, saliva in skin and mouth cavity.

It is fat storing connective tissue which is found mainly beneath the skin. The adipose tissue consists of several spherical or oval adipose cells (adipocytes or fat cells). Each adipose cell contains fat globules. It is found below the skin, around the internal organs like heart, kidneys and eyeballs.

Functions:

1. It acts as an insulator.
2. Provides support and protection to the vital organs.
3. It acts as a storage of fat.

Xylem is a complex vescular tissue which is composed of several types of cells. Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres.

The cells of this tissue have thick walls and many of them are non-living.

1. Tracheids: These are long elongated tubular cells. Tracheids cells are dead. Its main function is conduction of water and minerals from root to stem.

2. Vessels: These are pipe-like structure. Vessels are dead and have lignified cell wall. They also participate conduction of water and minerals.

3. Xylem parenchyma: These are living cells which store food material.

4. Xylem fibres: These are dead cells provide mechanical support to the plant.

Cartilage is compact with widely spaced cells. Its solid matrix is composed of proteins and sugars. The cells of cartilage are called chondrocytes. They don’t have blood vessels.

Cartilage is present in the tip of nose, outer ear joints, between adjacent bones of the vertebral column, limbs and hands in adults. Cartilage smoothens bone surfaces at joints. It provides support and flexibility to the body parts.

The neuron consists of three parts:

1. The Cyton or Cell body: It contains a central nucleus and cytoplasm with deeply stained particles called Nissl's granules.

2. Dendrites: The dendrons are short processes arising from the cyton and branches into dendrites.

3. Axon: It is a single, long cylindrical process which forms fine branches terminally. It has a swollen structure at its end called synaptic knob or bouton. It is also termed as the nerve fibre.

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The functions of blood:

1. Transport oxygen from the lungs to different parts of the body.
2. Transport CO₂ from the body tissues to the lungs.
3. Transport digested food i.e., glucose, amino acids, etc. from alimentary canal to various parts of the body for energy, growth and repair.
4. Transport excretory waste product called urea from the liver to the kidneys for removal as urine.
5. Plasma regulates water balance in the body.
6. Regulates the body temperature.

1. Striated Muscles: It occur in the muscles of limbs, body wall, face, neck, etc. Striated muscles present in tongue, pharynx, diaphragm and upper part of oesophagus are called visceral straited muscles.

2. Smooth Muscles: Smooth muscles are found in the walls of the hollow (tubular) visceral organs except that of the heart. They occur in the wall of alimentary canal and internal organs, ducts of glands, urogenital ducts and blood vessels.

3. Cardiac Muscles: The cardiac muscles occur in the heart.

A: Striated muscle.

B: Smooth muscle.

C: Cardiac muscle.

Blood is a fluid connective tissue which circulates in our body. The main components of blood are plasma (55%) and blood corpuscles (45%).

Plasma is straw-coloured fluid which contains 85-90% water and 5-10% other substances like proteins, salts and hormones.

There are three types of blood corpuscles:

• RBC (Red blood cells).
• WBC (White blood cells).
• Platelets.

It is composed of a single layer of cube- like cells. It is found in kidney tubules and salivary glands. It provides mechanical support to organs and helps in absorption and excretion.

Bone is a strong and non-flexible tissue. The cells of bones are called osteocytes. Bone cells are embedded in a hard matrix that is composed of calcium and phosphorus compounds. Each cell is enclosed in a small cavity called the lacuna.

Functions:

1. It provides shape to the body.
2. It forms the framework that supports the body.
3. It anchors the muscles.
4. It protects the vital body organs like brain, lungs, etc.

Phloem is made up of four types of elements: Sieve tubes, companion cells, phloem fibres and the phloem parenchyma.

1. Sieve tubes: These are tubular cells with perforated walls. These cells are responsible for transportation of food and nutrients.

2. Companion cells: These cells are found associated with sieve tubes and connected with it by simple pits. These cells are long, narrow and thin walled. These cells are living.

3. Phloem fibres: They have thick cell wall and they provide mechanical support to plant.

4. Pholem parenchyma: These cells are living and often cylindrical in shape.

The transport of food from leaves to other parts of the plant is called translocation

1. Tendons is a dense connective tissue which connects a bone with a muscle.
2. Ligaments are elastic structures which connect bones to bones. 
3. Cartilage is tough, flexible connective tissue found in all vertebrates. Its solid matrix is composed of proteins and sugars. The cells of cartilage are called chondrocytes. They don’t have blood vessels.
4. Cartilage is present in the tip of nose, outer ear joints, between adjacent bones of the vertebral column, limbs and hands in adults.

Muscular tissues form the muscles in the body and are responsible for movement and locomotion. Muscle cells are elongated and are called muscle fibres. They are capable of contraction and relaxation.

There are three types of muscular tissues:

1. Striated Muscles or Skeletal muscles: These are called skeletal muscles as they are found attached to the bones and help in the body movements. The cells are cylindrical, unbranched, striated and multi nucleated. They are involuntary in nature.

2. Non-Striated muscles or smooth muscles: The cells are spindle shaped, uni-nucleated, elongated and have no striations. They are found within the walls of elementary canal, bladder and blood vessels. They are involuntary in nature.

3. Cardiac Muscles: These are found exclusively in heart. They are cylindrical, non-tapering, branched with faint striations. They have one or two nuclei in each cell. They are involuntary. Their function is rhythmic contraction and relaxation throughout life.

A: Striated muscle.

B: Smooth muscle.

C: Cardiac muscle.

Meristematic tissue: It is a group of cells which constantly divide and produce cells indefinitely throughout the life of a plant. Meristematic tissue is found in all the growing parts of a plant such as root tip, shoot tip, etc.

Characteristics of meristematic cells:

1. The cells of this tissue are very active. They have dense cytoplasm.
2. The cell wall is thin and made up of cellulose.
3. They lack vacuoles.
4. They have big nucleus.

These muscles are exclusively present in the heart. These muscles of the heart show rhythmic contraction and relaxation throughout life. They are striated but involuntary muscles. Heart muscle are cylindrical and uninucleated. They are branched and form a network in the walls of the heart.

1. Cardiac muscle fibres (Fig A) and striated muscle fibre (Fig B).

2. X: Intercalated disc.

Y: Light band.

Z: Dark band.

3. Intercalated disc of cardiac muscle acts as an impulse booster
4. Striated muscles are also known as voluntary muscle as their movement is under control of our will.

1. Figure A: squamous epithelium.

Figure B: columnar epithelium.

2. Squamous epithelium is also known as tesselated epithelium or pavement epithelium.
3. Simple columnar epithelium lines the gastrointestinal tract and epiglottis.
4. Simple squamous epithelial cells are extremely thin and flat which allows diffusion of substances through it.

1. Tendon.
2. Muscle.
3. Ligament.
4. Bone.

1. It is neuron, structural and functional unit of nervous system.
2.  

1. Dendrite.
2. Cyton or cell body.
3. Axon.

3. It is located in brain and spinal cord.