Tissues

Sclerenchyma tissues are the strengthening tissues found in plants having dead cells. Their walls are thick because they have lignin deposited in their walls.
Parenchyma are living tissues found in all organs of a plant, concerned with storage of food. Collenchyma tissues are living tissues that are thickened at angles. They provide mechanical support to plant and epithelial tissues are living cells found as the outermost layer of an organ that function in secretion, protection, absorption, sensing etc.

The incorrect sentence is “apical and intercalary meristems are permanent tissues”. The rest a, b and d are correct sentences.

Apical and intercalary tissues are meristematic tissues and not permanent tissues. Apical tissues are present on the tips of root and stem, they increase the length; intercalary tissues are present in the internodes, they increase the length between the nodes.

The rest options are correct.

Lateral meristems are present on the lateral side of stem and roots. They increase the girth of the stem.

Apical meristem increases the length and intercalary meristem increases the length between the nodes.

Tracheids cells have lignified cell wall but they lack perforated walls. They are responsible for water conduction in xylem.

Companion cells are found in phloem tissue of plants and have thinner cell walls.

Sieve tubes are formed from elongated cells in phloem tissue of plant and vessels are water conducting tissues of plant found in xylem.

Columnar epithelium cells are found in the intestine and are responsible for absorbing nutrients from digested food.

Stratified squamous epithelium cells are found in the lining of mouth and esophagus; they protect areas that undergo wear and tear. Spindle fibers are responsible for the division of chromosomes during nuclear division. Cuboidal epithelium cells are found in organs like a salivary gland, kidney tubules and are concerned with secretion and diffusion.

Dislocation of bones occurs when the joints that are held by ligaments get separated abnormally. So ligament break caused the dislocation of the bones of the hand.

In case of a tendon, tendons join skeletal muscles to bone and tendon break causes inflammation. Break of skeletal muscles cannot be responsible for dislocation of bones as bones are joined by ligaments. Areolar tissues are found around muscles, nerves and blood vessels so they are not concerned with bones anyhow.

Skeletal muscles are voluntary muscles i.e. they work according to our will. While doing work and running, we move our hands and legs, skeletal muscles contract and they pull the tendon, connecting muscles to bones, to move the bones and they do not pull the ligament as that will cause a sprain or stretch. Smooth muscles are involuntary i.e. not under our control so they are not involved in moving organs as that require control.

Smooth muscles have no striations of light-dark bands and are usually found in alimentary canal, uterus, and iris of the eye. They are involuntary as they do not work according to our will. Cardiac muscles too are involuntary, present in the heart they contract and relax to pump blood.

Striated muscles and skeletal muscles have a dark and light band and are voluntary i.e. they move according to our will. They are cylindrical, un-branched and multinucleated.

Meristematic tissues are found on regions of the plant that grow thus they are localized. These are tissues that have the power of cell division i.e. dividing.

They are neither limited to certain regions nor do they grow in volume. They are not permanent tissues too as permanent tissues are a different class of tissues which are classified into simple and complex tissues further.

Epidermis is the outermost layer of, leaves, flowers, stem, and roots in plants. Epidermis protects the plant from adverse conditions like infection or decay. It regulates gas exchange and also reduces transpiration in plants that grow in a dry climate to conserve water.

Tendon is a white fibrous tissue that is strong, elastic and joins skeletal muscles to bones. It has great strength but is not much flexible.

The Rest of the given options are correct.

Cartilage is a firm connective tissue that provides support and flexibility to various parts of the body. It is found at joints of bones, in nose, ear, larynx and trachea.

Cuboidal epithelium tissue forms the renal tubules and corpuscles in kidney.

Adipose tissues are loose connective tissues found below the skin and between the internal organs. They store energy in the form of fat and act as an insulator.

Cuboidal epithelium tissues are found in kidney and are concerned with absorption, excretion and secretion. Bones and cartilage are connective tissues that provide support to various organs of the body.

Bone is composed of organic and inorganic components. The bone cells are embedded in a hard matrix that contains calcium and phosphorus salts- calcium hydroxyapatite and osteo-calcium phosphate.

Muscles have contractile proteins. The contraction and relaxation of these contractile proteins brings about the movement of body parts.

Bones are supporting tissues that form the structure of body.

Blood is a fluid connective tissue that transports oxygen and nutrients and cartilage provides support and flexibility.

Voluntary muscles are those muscles that our under our will i.e. those muscles that can be controlled. Limbs are made of voluntary muscles; their actions are under our control.

Alimentary canal, iris of eye and bronchi of lungs are involuntary and they are regulated on their own in a specific pattern.

Nervous tissues regulate and control activities and functions of body.

Tendons are connective tissues that join skeletal muscles to bones. No nervous tissues are found in them as they have no role in tendons.

Brain, spinal cords have nervous tissues as they are associated with regulation of body activities. Nerves are made of nerve cells/neurons that form the nervous tissue.

Axons, nerve endings and dendrites are a part of neurons (nerve cells).

Neurons do not contain tendons as they are connective tissues that join skeletal muscles to bones

Areolar tissue is a loose cellular connective tissue that holds organs in place, attaches epithelial tissue to other tissues and also combats foreign toxins. It joins skins to muscles, fills spaces inside the organs and acts as supporting and packing tissue between organs lying in body cavity.

Cardiac muscles found in heart are involuntary muscles that function throughout the life continuously without getting tired. These muscles are striated (have light-dark banding pattern), cylindrical and branched. They contract and relax rapidly in a rhythmic pattern to help in pumping of blood and work without fatigue.

Skeletal muscles are voluntary and they act according to our need i.e. they are under our control. Smooth muscles are involuntary muscles found in alimentary canal, urogenital ducts etc. They remain contracted for a long period of time.

Chondrocytes are found in cartilage. They produce and maintain the matrix of cartilage.

Most cells are a type of white blood cells that are involved in defense against pathogens and in healing the wounds. Basophils are granulocytes of white blood cells that contain heparin, an anti-coagulant that prevent blood from clotting too quickly in case of an injury. They also help in body defense by engulfing foreign substances. Osteocytes are bone forming cells that get entrapped in bone matrix.

Phloem fibers are thick walled, spindle shaped dead cells which provide mechanical support to the tissue.

Companion cells provide energy and nutrients to sieve elements so that they perform their cellular function. Phloem parenchyma are thin walled living cells that store food and conduct it laterally to plant parts and sieve tubes are elongated cells of phloem that transport sucrose in plant.

Companion cells do not lose their nucleus at maturity as sieve tube elements are dependent on these cells; these cells are always metabolically active.

Red blood cells, vessels and sieve tube cells lose their nucleus at maturity.

Cuticle is a protective waxy covering produced by epidermal cells of leaves and other plant parts.

In desert plants, cuticle reduces the rate of water loss through transpiration and helps in conserving water as there is always a shortage of water for desert plants.

Stomata are involved in gas exchange during the process of photosynthesis. Lignin hardens the cell wall and gives flexibility to it. Suberin is present in the cork cells of plants and acts as a barrier for movement of water from the cells.

Xylem vessels are made up of hollow cells that carry water and minerals from roots of plant to the trunk.

Collenchyma cells are elongated cells having irregularly thick walls; they provide support and structure. Xylem parenchyma are the living cells in xylem; they store metabolites. Parenchyma are thin walled cells found in stems, roots and leaves, they serve as food storage tissue of plants.

Intercalary meristem are located at the base of leaves and nodes that leads to the increase in length.

Apical meristem gets removed if the tip of plant is removed as it is found in apices of growing roots and stem. Cambium is a plant tissue found between xylem and phloem that divides to form vascular tissues and lateral meristem increases the stem girth.

Nail remains at the same position in the trunk of the tree because apical meristem which is responsible for the growth in length is found only in apices.

Parenchyma cells are thin walled, unspecialized in structure. The cells are oval round, polygonal or elongated in shape. These cells possess the power of division.

Collenchyma are living cells that contain cellulose. They provide mechanical support, elasticity and flexibility to those organs where they are found.

Sclerenchyma provides strength to tissues in plants. Parenchyma cells are concerned with storage and photosynthesis. Chlorenchyma are a type of parenchyma.

Suberin is present in the cork cells of plants. It acts as a barrier for movement of water and gases from the cells i.e. makes the cork cells impervious to water and gases

Survival of plants in terrestrial environment has been made possible by presence of conducting tissues in plants that are xylem and phloem. Xylem is responsible for conducting water from roots to other parts of plant. Phloem transports food from leaves to various parts of plant.

Epithelial tissues have no intercellular spaces between them as they are tightly packed and they form a continuous sheet.

Rest of the options are correct.

Gymnosperms are characterized by presence of tracheids as major conducting tissue. Tracheids are elongated dead cells with hard lignified walls. They conduct water.

Subcutaneous layer or adipose tissues are the fat depositing layers found just below the skin or in between internal organs. They reduce the heat loss from the body and act as a good insulator. Animals of colder regions and fishes of cold water have thicker layer of subcutaneous fat, in order to retain heat in their body and thus maintaining the body temperature. Thicker the layer of subcutaneous fat, lesser will be the heat loss from the body.

a) Fluid Connective tissue - v) Blood

Blood is a fluid connective tissue, it transports nutrients, oxygen and hormones to the tissues and excretory products from tissues to kidney.

b) Filling of spaces inside the organs - iv) Areolar tissue

Areolar tissues are supporting and packing connective tissues that fill spaces inside the organs and join skin with muscles.

c) Striated muscles - iii) skeletal muscles

Skeletal muscles are also called striated muscles as they possess light and dark banding patterns alternatively, known as striations.

d) Adipose tissues - i) Subcutaneous layer

The hypodermis that stores fat is made of subcutaneous tissue. The subcutaneous layer is known as adipose tissue.

e) Surface of joints - ii) Cartilage

Cartilage covers the surface of joints and provides support and flexibility to the body parts.

f) Stratified squamous epithelium - vi) Skin

Stratified squamous epithelium has keratin present in them that line the skin and covers it.

a) Parenchyma - i) thin walled packing cells

Parenchyma cells have thin primary walls that remain alive on maturity. They are found in soft parts of the plant.

b) Photosynthesis - ii) Carbon fixation

In photosynthesis, Plants take up CO₂ from the atmosphere and in turn produce oxygen and food in the form of carbohydrates which have carbon in them, thus fixing the carbon that they took from the atmosphere.

c) Aerenchyma - iv) Buoyancy

Aerenchyma is a type of parenchyma which has large air cavities in them. The presence of these large air cavities gives buoyancy to the plant.

d) Collenchyma - iii) Localized thickening

Collenchyma cells have cellulose deposited at their corners i.e. localized thickening at corners.

e) Permanent tissue - v) Sclerenchyma

Sclerenchyma is a type of permanent tissue. Sclerenchyma are formed from cells that have thickened and lignified walls. They provide strength to a plant.

Water vapor appears on the wall of a glass jar due to the phenomenon of transpiration. During transpiration water escapes from the stomatal openings of the leaf. This water vapor is seen on the walls of a glass jar if a potted plant is covered with it.

The different components of xylem are- tracheids, vessel elements, xylem fibers and xylem parenchyma. Tracheids, vessel elements and xylem fibers are dead cells of the xylem. The only living cells of xylem are parenchyma cells. Either tracheids or vessel elements are found in one xylem tissue.

Living component of xylem is Xylem parenchyma.

There are 4 elements of phloem- Sieve tubes, companion cells, phloem parenchyma and phloem fibers.

Phloem fibers are the dead cells of phloem. Sieve tubes, companion cell and phloem parenchyma are the living cells of phloem. Components of phloem work together in transporting food made in the leaf of plant to various other parts of the plant.

a) True

Epithelial tissue protects the body from physical, chemical and biological wear and tear.

b) True

Lining of blood vessels, lung alveoli and kidney tubules are all made of squamous and cuboidal epithelial tissues.

c) False

Epithelial cells have no intercellular spaces between them as they are tightly packed.

d) True

Epithelial layer is permeable and is found where small molecules cross the membrane by diffusion and filtration.

e) False

Epithelial cells allow regulation of materials between body and external environment. They allow selective transfer of materials between body and external environment and also contain carrier proteins which regulate the absorption of materials.

a) Voluntary V

Jumping of frog is under the control of frog’s will so it is coordinated by voluntary muscles.

b) Involuntary IV

Pumping of heart are by involuntary muscles i.e. the cardiac muscles that are not under our will. They work tirelessly and rhythmically.

c) Voluntary V

Writing with hand is under our control so it is coordinated by voluntary muscles.

d) Involuntary IV

Movement of chocolates in intestine fall under the category of involuntary muscles as it is not under our control. The movement in the intestine takes place on its own according to bodily functions.

a) Squamous epithelium

Squamous epithelium are single layer of flat cells and are often permeable. Lining of blood vessels are made up of squamous eithelium.

b) Columnar epithelium

Columnar epithelium are uni-layered cells. They line most of the organs of digestive tract.

c) Cuboidal epithelium

Cuboidal epithelium consists of single layered of cube like cells. They are found in the lining of nephrons (kidney tubules).

d) Respiratory tract

Epithelial cells with cilia occur in our respiratory tract. Cilia move back and forth to help the movement of particles.

Water hyacinth floats on water surface due to presence of large cavities in parenchyma tissues. These type of parenchyma tissues are known as aerenchyma tissues which make the hyacinth float on water.

Also, water hyacinth has a lot of surface area that lies above the water, this increases its buoyancy and it floats on water.

The dermal tissue of the plants i.e. the epidermis and hard cuticle that covers the plants body, protects the body against invasion of parasites.

a) Suberin

Suberin present in the cork cells of plants acts as a barrier for movement of water and gases from the cells.

b) Sieve tubes of phloem

Sieve tubes found in phloem have tubular cells with perforated walls. They are living cells.

c) Calcium and phosphorus

The hard matrix of brain is composed of calcium and phosphorus salts.

Epidermis is important for the plants for a number of functions it performs-

i. It protects the plant from parasitic invasion.

ii. Epidermis prevents the plant from desiccation and infection.

iii. It prevents water loss from transpiration. This is especially beneficial to the plants found in desserts where there is scarcity of water always.

iv. Epidermis helps in exchange of gases and it absorbs water minerals and nutrients.

a) Xylem and phloem

They are forms of complex tissue that perform the conduction of water and food in plants.

b) Stomata

Stomata have guard cells which regulate the closing and opening of stomata for exchanging gases.

c) Suberin

Cork cells have suberin which makes them impervious to water and gases.

d) Schlerenchyma

Husk of coconut is made of Schlerenchyma tissues which are dead tissues but they are long, thin and strong tissues.

e) Collenchyma

Collenchyma are living cells that contain cellulose. They provide elasticity and flexibility.

f) Xylem and Phloem

Xylem and phloem are conducting tissues that conduct water from roots to parts of plant, and food from leaves to various parts of plant.

g) Water and minerals

Xylem transports water and minerals from roots of plant to various parts of the plant.

h) Food, Leaf

Phloem transports food that is made in leaf of plants to other parts of the plant.

Epithelial tissue is a type of animal tissue that line the cavities and surfaces of blood vessels and organs in the body. Epithelial tissue originates from the ectoderm. All glands in our body are made of epithelial cells. Epithelial tissue cells are tightly packed and form a continuous sheet. They have no intercellular spaces between them. The shape of the cells depends on the location and function of the tissue.

They are classified as- Simple squamous epithelium, Stratified squamous epithelium, Columnar epithelium, and Cubodial epithelium.

1. Simple squamous epithelium- They are a single layer of thin flat, plate like cells. This type of epithelium is permeable and occurs where molecules can cross the membrane either via filtration or diffusion. Tongue, esophagus and the lining of the mouth are made up of squamous epithelium. It protects the underlying parts of body from mechanical injury, germs, and from drying.

2. Stratified squamous epithelium- it consists of squamous epithelial cells arranged in layers that protect from wear and tear. They lack intercellular spaces and are found in areas in body that are subject to constant abrasion. It forms the outermost layer of the skin and the inner lining of the mouth, esophagus and vagina.

3. Columnar epithelium are of two types, ciliated and non-ciliated. They are uni-layered. They line organs of the digestive tract including the stomach, small and large intestine and also the uterus. Ciliated epithelium helps the movement of ova in the fallopian tubes and the movement of mucus in the respiratory tract.

4.Cuboidal epithelium- They consists of single layers of cells that are equally tall and wide. They perform secretion and absorption and are found in the small collecting ducts of the kidneys, pancreas, and salivary glands.

5. Glandular epithelium- Epithelial cells that acquire properties of gland cells to secrete substances at the surface of the epithelial tissues are known as glandular epithelium. These substances are water based fluids and contain proteins.

Skeletal, Cardiac and Striated muscles are the three type of muscles found in human body.

a) Meristematic cells are continuously dividing cells of the plant body. Division is facilitated by nucleus and cytoplasm; but they lack vacuoles because vacuoles are used for storage in plants and meristematic tissues do not require vacuole.

b) Sclerenchymatous tissues are dead simple permanent tissues of the plant, made of lignified cell walls. They have no intercellular spaces because they function to provide strength and elasticity to the plant.

c) We get a crunchy and granular feeling, when we chew pear fruit because they are made of sclerenchyma tissue whose cell walls are lignified.

d) Branches of a tree move and bend freely in high wind velocity due to the deposition of collenchyma cells which have cellulose at the corners of tissue. Collenchyma is a mechanical tissue that provides elasticity and support to the branches. Therefore, the branches move and bend freely in high wind velocity.

e) It is difficult to pull out the husk of a coconut tree as they are made of sclerenchyma tissue. The cells of sclerenchyma tissues are closely packed without intercellular spaces. A thin layer of connecting substances that contains pectin, lignin and protein exists between them, known as middle lamellae.

Characteristics-

Cork is the outermost waterproof protective covering of stems and roots. It consists of dead cells when it gets matured, which are packed and lack intercellular spaces between them.

Cork contains a chemical suberin that makes the cork cells impervious to water and gases.

Cork is found as a tissue in vascular plants.

Formation- It is formed from the cork cambium of the plant. The outer protective tissue keep on changing as the plant grows. A strip of secondary meristem replaces the epidermis of the stem. Cells that are cut on the outer side by this secondary meristem are called cork.

Role of Cork- They prevent loss of water due to the presence of suberin in them, a chemical that makes cork cells impervious to water. Cork protects the plant from parasitic invasion. Cork is used in manufacturing insulation boards etc.

Xylem and Phloem are called complex tissues because they are composed of more than one cell type and they perform many functions necessary for the plant.

They are different form each other in following aspect-

● Xylem has 4 types of cells- tracheids, vessel elements, xylem fibers and xylem parenchyma. Tracheids, vessel elements and xylem fibers are dead cells of the xylem. The only living cells of xylem are parenchyma cells. Either tracheids or vessel elements are found in one xylem tissue.

● Phloem is also made of 4 types of cells namely- sieve tubes, phloem parenchyma, companion cells and phloem fibers. All the cells of the phloem are living except the phloem fibers. They are the dead cells in phloem.

Differentiation- The process of meristematic tissues, that have lost their ability to divide, to become permanent in their structure and function is known as differentiation.

● Simple permanent tissue- these are group of cells that originate similarly, have similar structure and function. Eg- Parenchyma, Epidermis, Collenchyma and Sclerenchyma.

Parenchyma provides support to plants and stores food. Epidermis protects from pathogens, regulates water loss from plant’s body etc. Collenchyma gives strength to the plant and sclerenchyma makes the cell wall strong and impermeable to water.

● Complex permanent tissue- These tissues contain more than one type of cells that form a unit and work collectively. Eg- Xylem and Phloem ; Xylem is composed of 4 cells(tracheids, vessel elements, xylem fibers and xylem parenchyma) that work together in carrying water and minerals up and down in the plant. Phloem is too composed of 4 cells (sieve tubes, phloem parenchyma, companion cells and phloem fibers.) that work together in transporting food from leafs to other parts of plant.