BIOLOGY 2 Marks Questions

	Dense regular connective tissues		Dense irregular connective tissues
1.	In dense regular connective tissues, collagen fibres are present in rows between parallel bundles of fibres.	1.	In dense irregular connective tissues, fibres are arranged irregularly.
2.	They are present in tendons and ligaments.	2.	They are present in the skin.

Prostomium	Peristomium
Prostomium is a small fleshy lobe, which overhangs the mouth of an earthworm. It helps the organism push into the soil and is sensory in function.	The first body segment in the earthworm is called the peristomium. It surrounds the mouth opening.

1. Afferent (Sensory) Nerve Fibres: The afferent nerve fibres carry the nerve impulses from the sense organs to the central nervous system (brain and spinal cord).
2. Efferent (Motor) Nerve Fibres: They carry nerve impulses from the central nervous system to the effector organs (muscles and glands).

Areolar connective tissue serves as a support framework for epithelium. It contains mast cells, macrophages and fibroblasts.

Striated muscles are also known as voluntary muscles. All those movements which are under our conscious control, are facilitated by voluntary muscles. Smooth muscles are also known as involuntary muscles. All movements, which are beyond our conscious control, are facilitated by involuntary muscles. Cardiac muscle is also involuntary in nature.

Form- Elongated, ovoid, dorsoventrally, flattened body. Size- About 38 mm long and about 12 mm wide. Colour- Brown or black in colour. Symmetry- Bilateral.

Smooth muscles are found in the walls of all body viscera i.e., gastrointestinal tract, respiratory tract, urinary tract, reproductive tract. They are therefore, also called visceral muscles. These muscles are also present in the walls of blood vessels, dermis, iris and ciliary body of the eye, etc.

Different cell junctions found in tissues are followed:

1. Tight junctions.
2. Adhering junctions.
3. Gap junctions.

	Vital capacity (VC)		Total lung capacity (TLC)
1.	It is the maximum volume of air that can be exhaled after a maximum inspiration. It includes IC and ERV.	1.	It is the volume of air in the lungs after maximum inspiration. It includes IC, ERV, and residual volume.
2.	It is about 4000 mL in the human lungs.	2.	It is about 5000 – 6000 mL in the human lungs.

1. Malpighian tubules.
2. The Malpighian tubules are located at the junction of midgut and hindgut.
3. They collect the nitrogenous wastes from the body fluid, convert them into uric acid and pass it into the hindgut.
4. Nephrocytes, fat bodies and urecose glands also help in excretion.

These are the parts of legs of cockroach.

1. Coxa: It is a small, hard podomere, which articulates with the thoracic segment in between the pleuron and the sternum.
2. Trochanter: It is a hard, small podomere which lies next to the coxa.

In each segment of cockroach body, i.e., head, thorax and abdomen, exoskeleton has hardened plates called sclerites, that are joined to each other by thin and flexible arthrodial membrane.

Lymph is derived from the tissue fluid by means of fine and irregular lymph capillaries. Though the composition of the lymph varies, about 94% of the lymph is water and 6% is dissolved substances, i.e., proteins, fat drops, carbohydrates, non-protein nitrogenous wastes, hormones, inorganic salts, gases, etc.

The columnar or aiboidal epithelial cells which are specialised for secretion constitute glandular epithelium.Example:
Unicellular - goblet cells in alimentary canal Multicellular - salivary glands

The entire body of cockroach is covered by a hard chitinous exoskeleton(brown in colour) made of tough plates called sclerites. These are formed of chitin, a polymer of acetoglucosamine polysaccharide molecule. The exoskeleton protects the body and provides space for the attachment of muscles.

The intercalated discs are unique and distinguishing features of the cardiac muscles. They are dark and zig-zag partitions between the adjacent cardiac muscle cells. These discs serve as the firm adhesion between the adjacent cells, electrical coupling to spread the excitation as well as contraction.

Differences between tendons and ligaments are:

S. No.	Tendons	Ligaments
1.	The tendons are dense regular connective tissues, which attach the muscles to bones.	The ligaments are dense regular connective tissues, which attach the bones at the joints.
2.	It is formed of white fibrous connective tissue	It is formed of yellow elastic connective tissue.

1. Brood pouch in a female cockroach is formed by the boat-shaped 7th sternum and the 8th and 9th sterna.
2. It contains a gonopore at its anterior end, spermathecal pores and collaterial glands.

Gap junctions facilitate intercellular communication by allowing small signaling molecules to pass from cell to cell. These are fine hydrophilic channels between two adjacent animal cells that are formed with the help of two protein cylinders called connexus. Each connexus consists of six proteins subunits that surround a hydrophilic channel. pH and concentration controls, opening or closing of channels.

1. Brush-bordered cuboidal epithelium is present in the PCT.
2. Here, its main function is absorption of substances from the filtrate.
3. The microvilli on the cells increase the surface area for absorption.

1. Ciliated epithelium lines the bronchioles.
2. The ciliary movement propels the particles, free cells or mucus in a specific direction over the epithelial surface.

Sheets are located in the dermis of skin, periosteum of the bone, perichondrium of cartilage, pericardium of heart, etc. Sheets provide strength. Tendons are located between skeletal muscles and bones. They connect muscles with bones.

1. Blood platelets.
2. Nervous tissue.
3. Monocytes (blood), macrophages (cells of connective tissue).
4. Red bone marrow (skeletal tissue).

Earthworms are protandrous, i.e., the testes mature earlier than the ovaries. Self-fertilisation is not possible in them because of the relative position of the openings of male and female reproductive organs.

1. Brood pouch in a female cockroach is formed by the boat-shaped 7th sternum and the 8th and 9th sterna.
2. It contains a gonopore at its anterior end, spermathecal pores and collaterial glands.

1. They provide place for attachment of muscles and help in movement and locomotion.
2. Bone marrow is the site of manufacture of blood cells.
3. Bones provide protection and support to the soft tissues/ organs.
4. The long bones of the limbs serve the weight bearing function.
5. They provide the main structural frame of the body.

	Smooth Muscles	Cardiac Muscles
1	Cells are spindle shaped.	Cells are cylindrical and branched.
2	Striations are absent.	Striations are present, but faint.
3	Intercalated discs are absent.	Intercalated discs are present.
4	They do not have automatic rhythmicity.	They have automatic rhythmicity.

S.No.	Bone	Cartilage
1	It is a solid, non- pliable connective tissue.	It is a solid, pliable connective tissue.
2	Osteocytes occur singly in a lacuna.	Chondrocytes occur in clusters of 2 or 3 in each lacuna.
3	Matrix is deposited with salts of calcium and phosphorus.	No calcium and phosphorus salts are present in the matrix.
4	Haversian systems are present.	Haversian systems are absent.
5	Matrix is in the form of concentric lamellae.	Matrix does not show any concentric lamellae.

1. The gizzard has an outer layer of thick circular muscles.
2. The inner thick layer of cuticle forms six chitinous plate-like teeth.
3. The movement with the help of muscles and the teeth-like structures help in grinding the food.

Cutaneous respiration means diffusion of gases through the skin. This type of respiration occurs in insects which have no respiratory organs. Pulmonary respiration is the respiration through lungs. For example: Humans, etc.

Segments 14-16 are covered by a prominent dark band of glandular tissue called clitellumin a mature earthworm. This secretes mucus and albumen that help formation of cocoon and is used for fertilization of eyes and sperms.

1. Axon: It is a very long fibre that develops from the cyton of a single neuron.
2. Osteocytes: These are the bone cells that occur entrapped inside the matrix.
3. Chondroblasts: These are the special resident cells of the skeletal connective tissue.
4. Tendons: These are white fibrous cords, which connect muscles to bones.

1. Sclerites: The body of cockroach is externally covered by hard brown chitinous plates called sclerites, which constitute the exoskeleton.
2. Arthroidal membrane: The sclerites are joined with one another by thin flexible, soft articular membrane called arthroidal membrane.

The entire body of cockroach is covered by a hard chitinous exoskeleton (brown in colour) made of tough plates called sclerites. These are formed of chitin, a polymer of acetoglucosamine polysaccharide molecule.The exoskeleton protects the body and provides space for the attachment of muscles

1. Locomotory organs of earthworm.
2. Excretory organs of earthworm.
3. Study segmentation in the morphology of earthworm.

1. Tip of nose.
2. Pinna of ear.
3. Between adjacent vertebrae in the vertebral column.
4. Joints in the limbs.

S. No.	Ciliated Epithelium	Brush-Bordered Epithelium
1	The cells bear cilia on their free surface.	The cells bear microvilli on their free surface.
2	Ciliated epithelium helps in the movement of substances by the ciliary action in a particular direction.	Microvilli increase the area of absorption.

Pseudostratified epithelium is a type of simple epithelium tissues.

Neuroglia cells are packed around the neurons in brain, spinal cord and ganglia. Neuroglia cells have various functions like myeline formation, transport of materials to neurons, maintenance of ionic balance and phagocytosis.

The level of organization in sponges is of cellular level. The cells in sponges do not organize to form tissue, although they possess thousands of independently associated cells. The cells may be solitary or colonial and function more or less independently. The cells show division of labor for performing specialized functions.

1. Labrum- A- Sensory setae B-Muscles.
2. Mandible– A– Prostheca, B-Condyle, C-Denticles.

2. (4), (2), (1), (3).

Explanation:
Adipose tissue stores fat, stratified epithelium forms the upper layer of skin, hyaline cartilage is a part of nose and blood is a type of fluid connective tissue.

Connective tissue connects different tissues or organs and provides support to various structures of animal body. Bone and cartilage are called connective tissues because they support and protect the various organs. Blood is a fluid connective tissue which transports the materials from one place to the other.

Special venous connection between liver and intestine is known as - Hepatic portal system. Special Venous connection between kidney and intestine is known as - Renal portal system.

1. Collagen fibres and elastin fibres are found in the connective tissue.
2. They provide tensile strength, flexibility and elasticity to the tissues.
3. They also prevent displacement of organs.

As the name suggests, stratified epithelium is made up of many strata of layers. The main role of stratified epithelium is protection against mechanical and chemical stresses. Hence, this tissue has limited role in secretion.

Crop: It stores the food temporarily. Gizzard: It is the site where the food particles are ground. Tracheoles: Exchange of gases occurs in these. Compound eyes: They are meant for nocturnal vision (mosaic vision)