Science Que-Ans (Each of 4 Mark )

Functions of connective tissue:

1. It binds different structure with another like skin with muscles and muscles with bones, etc.
2. It forms a supporting framework of cartilage and bones in the body.
3. Blood flows and transports gases, digested food, hormones and waste materials to different parts of the body.
4. Adipose tissue helps in the storage of fats.

There are three types of blood corpuscles:

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

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. A: Transverse section of collenchyma.

B: T.S. parenchyma.

C: T.S. sclerenchyma fibres.

2. Sclerenchym tissue has heavy deposition of lignin.
3. Collenchyma tissue provides both mechanical strength and flexibility.
4. In aquatic plants, large air cavities are present in parenchyma tissue to given buoyancy to the plants to help them float. Such a modified parenchyma is called aerenchyma.
5. Fibres of Hemp and Jute are obtained from the sclerenchyma fibres.

1. Squamous Epithelium: These are thin, flat cells that are closely packed. The squamous epithelial cells line the cavities of the mouth, oesophagus, alveoli, and blood vessels. This tissue gives protection against mechanical injury and also blocks the entry of germs. If the squamous epithelium is arranged in many layers, it is a compound squamous tissue called the stratified squamous epithelium. We find these kinds of tissues in the skin and also the lining of the oesophagus.

2. Cuboidal Epithelium: These cells are cuboidal in shape. They are found in the salivary glands, kidney tubules, sweat glands etc. Their main function includes absorption, secretion, and excretion. If the cuboidal epithelium is arranged in many layers it forms the stratified cuboidal epithelium. It is found on the inner side of the pancreatic ducts and salivary glands. They mainly help in protection.

3. Columnar Epithelium: The columnar epithelium has cells that are pillar-like and column-like. We can find them in the lining of the stomach and intestine. Its functions include absorption and secretion.

4. Ciliated Epithelium: When the columnar epithelial tissues have cilia, then they are ciliated epithelium. They are present in the lining of the trachea, kidney tubules etc. The rhythmic movement of the cilia helps in the movement of material in one direction.

5. Glandular Epithelium: These are modified columnar epithelial tissues. They are large cells that present in the tear glands, sweat glands etc. Their main function is secretion.

1. Epithelial tissue: Functions of epithelial tissue:

• The cells of the body's surface form the outer layer of skin.
• Inside the body, epithelial cells form the lining of the mouth and alimentary canal and protect these organs.
• Epithelial tissues help in absorption of water and nutrients.

2. Connective tissue: Connective tissues are fibrous tissues made up of cells separated by non-living material, which is called an extracellular matrix. This matrix can be liquid or rigid. For example, blood contains plasma as its matrix and bone's matrix is rigid. Connective tissue gives shape to organs and holds them in place. Blood, bone, tendon, ligament, adipose, and areolar tissues are examples of connective tissues. One method of classifying connective tissues is to divide them into three types: fibrous connective tissue, skeletal connective tissue, and fluid connective tissue.

3. Muscular tissue: Muscle cells form the active contractile tissue of the body known as muscle tissue or muscular tissue. Muscle tissue functions to produce force and cause motion, either locomotion or movement within internal organs. Muscle tissue is separated into three distinct categories: visceral or smooth muscle, found in the inner linings of organs; skeletal muscle, typically attached to bones, which generate gross movement; and cardiac muscle, found in the heart, where it contracts to pump blood throughout an organism.

4. Nervous tissue: Cells comprising the central nervous system and peripheral nervous system are classified as nervous (or neural) tissue. In the central nervous system, neural tissues form the brain and spinal cord. In the peripheral nervous system, neural tissues form the cranial nerves and spinal nerves, inclusive of the motor neurons.

5. Plant tissues: In plant anatomy, tissues are categorized broadly into three tissue systems: the epidermis, the ground tissue, and the vascular tissue.

• Epidermis: Cells forming the outer surface of the leaves and of the young plant body.

• Vascular tissue: The primary components of vascular tissue are the xylem and phloem. These transport fluids and nutrients internally.

• Ground tissue: Ground tissue is less differentiated than other tissues. Ground tissue manufactures nutrients by photosynthesis and stores reserve nutrients.

6. Meristematic tissues: Meristematic tissue consists of actively dividing cells, and leads to increase in length and thickness of the plant. The primary growth of a plant occurs only in certain, specific regions, such as in the tips of stems or roots. It is in these regions that meristematic tissues are present. Cells in these tissues are roughly spherical or polyhedral, to rectangular in shape, and have thin cell walls. New cells produced by meristem are initially those of meristem itself, but as the new cells grow and mature, their characteristics slowly change and they become differentiated as components of the region of occurrence of meristematic tissues.

7. Permanent tissues: Permanent tissues may be defined as a group of living or dead cells formed by meristematic tissue and have lost their ability to divide and have permanently placed at fixed positions in the plant body. Meristematic tissues that take up a specific role lose the ability to divide. This process of taking up a permanent shape, size and a function is called cellular differentiation. Cells of meristematic tissue differentiate to form different types of permanent tissues.

There are three types of permanent tissues:

• Simple permanent tissues.
• Complex permanent tissues.
• Special or secretory tissues (glandular).

1. It is section of a bone.

2. W: Periosteum.

X: Haversian canel.

Y: Canaliculus (plural canaliculi).

Z: Endosteum.

3. The chemical composition of material of bone includes:

1. Ossein (30-40%).
2. Mineral matter (60-70%) of calcium and magnesium carbonate and phosphate.

4. Haversian canal tends to carry nutrients to the interior of the bone.

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. It is a section of phloem, a complex tissue. Phloem transports food from leaves to the other parts of the plant.

2. V: Phloem parenchyma.

W: Seive tube.

3. X: Sieve plate.

Y: Companion cell.

Z: Sieve pores.

4. Sieve tube are associated with companion cells. A mature sieve tube is living but it lacks a nucleus. Companion cells are living and associated with the sieve tubes. Living state of the mature sieve tube cells is regulated by nucleated cornpanion cells. These cells supply the RNA and proteins that keep the sieve tube alive. is associated with companion cells.

1. A- Tracheid B- Vessel C- Xylem parenchyma.
2.  

1. Tracheids- It helps in transmission of water.

Vessels- It helps in transmission of minerals.

Xylem parenchyma- It stores food and helps in conduction of water.

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.

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​​​​​​​
   

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.
   

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. 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.

• Cell body or cyton.
• Axon.
• Dendrons or dentrites.

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.

1. Xylem: Xylem is a vascular and mechanical tissue which conducts water. Xylem is composed of cells of four different types:

1. Tracheids.
2. Vessels or tracheae.
3. Xylem parenchyma.
4. Xylem Sclerenchyma.

Except xylem parenchyma, all other xylem elements are dead and bounded by thick lignified walls. Vessels are shorter and wider than tracheids. Vessels are very long tube-like structures formed by a row of cells placed end to end. Tracheids are elongated cells with tapering ends. They also conduct water.

2. Phloem: Phloem is also a vascular tissue which transports food from the leaves to the various parts of the plant. It is composed of:

1. Sieve tubes: Sieve tubes are slender, tube-like structures composed of elongated thin-walled cells, placed end to end. Their end walls are perforated by numerous pores and are called sieve plates.

2. Companion Cells: It is a small thin-walled cell containing dense and very active cytoplasm and large elongated nucleus.

3. Phloem parenchyma: These are thin-walled, living cells of parenchyma of phloem. They have two functions, storage and slow lateral conduction of food.

4. Phloem Fibres: These are thick-walled, elongated spindled shaped dead cells which posses narrow lumen. They provide mechanical strength to the tissue.

1. Squamous: The cells are flat and polygonal and are arranged as tiles. These tissues occur in skin, lining of alveoli of lungs, blood vessels etc. Its function includes protection, diffusion and osmosis.
   
2. Cuboidal: The cells are cube like. These occur in glands, germinal layer of ovary, kidney tubules etc. Its function is secretion and absorption.
   
3. Columnar: The cells are pillar or column like resting on a thin membrane. Such tissues occur in the lining of stomach, intestine etc. Its function includes protection, absorption and secretion.
   
4. Ciliated: It has cuboidal, columnar cells with fine hair like structures called cilia. It is present in the lining of respiratory tract, fallopian tube, nephron etc. Its function is protection, spreading of mucus and motion of gases and liquids by cilia.
   
5. Glandular: The cells are cubical. These can be branched or unbranched. Such tissues are present in glands. Its main function is secretion.
   

1. Areolar: This tissue is a loose and cellular connective tissue. Its matrix consists of white collagen fibre and yellow elastic fibre. It joins skin to muscles, fills spaces inside organs and is found around muscles, blood vessels and nerves.
   
2. Dense Regular Connective tissue: It is fibrous connective tissue having densely packed fibres and cells. It is the principal component of tendons, ligaments and aponeuroses.
   
3. Adipose tissue: It is an aggregation of fat cells or adipocytes. The fat cells are arranged into lobules separated by partitions of collagen and elastin fibres. These are found abundant below the skin, between the internal organs and in yellow bone marrow.
   
4. Skeletal tissue: It is a supporting tissue which includes cartilage and bone. Both these tissues form the endoskeleton of a vertebrate body. Cartilage is located in ear pinna, nose tip, epiglottis etc. Bone forms the endoskeleton in human beings and provides shape to the body.
   
5. Fluid tissue: It links the different parts of the body and maintains continuity in the body. It includes blood and lymph.
   

1. RBC's or Erythrocytes: These are bi-concave, denucleated, disc like. They contain red coloured respiratory pigment called haemoglobin that helps in the transportation of oxygen.
   
2. WBC's or leucocytes: These are irregular, amoeboid, phagocytic cells with one to many lobed nucleus. These cells protect the body against the diseases by producing antibodies.
   
3. Blood platelets or thrombocytes: These are spindle shaped cells which help in the clotting of blood.
   

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.

1. The cells of epithelial tissue are tightly packed and form continuous sheets.
2. Epithelial cells have small amount of cementing material between them and almost no intercellular space.
3. The surface of cells may be smooth, columnar or cuboidal.
4. The cells of the lowermost layer rest on non-cellular basement membrane which separates it from the underlying connective tissue.

1. It protects the organs which it covers.
2. It absorbs water and other nutrients inside the body.
3. Some epithelial cells secrete ear wax, mucus and digestive juices.
4. It keeps different organs separate.

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.

1. A- Tendon

B- Bone

C- Muscle

D- Ligament

2. A- The main function of a tendon is to connect skeletal muscles to bones. Tendons are a type of connective tissue, and the primary building blocks of tendons are collagen fibers.

B- Bones have many functions. They support the body structurally, protect our vital organs, and allow us to move. Also, they provide an environment for bonemarrow, where the blood cells are created, and they act as a storage area for minerals, particularly calcium.

C- the main function of the muscular system is movement, but it also helps stabilize our joints, maintain our posture and generate heat during activity. Movement of our body can be voluntary and controlled by the skeletal muscles, or it can be involuntary and controlled by smooth muscles.

D- Ligaments attach two bones or cartilages,it helps in supporting and keeping the organ in position, it is made of fibrous tissue.