Question

Consider the following statements (i) - (iv) each with one or two blanks. (i) Bones have a hard and non-pilable ground substance rich in \((1)\) and \((2)\) which give bone its strength. (ii) Some of the columnar or cuboidal cells get specialised for secretion and are called \(\underline{\text { (3) }}\) epithelium. (iii) (4) junctions help to stop substances from leaking across a tissue. (iv) The prostomium in earthworm is (5) in function. Which one of the following options, gives the correct fill ups for the respective blanks from (1) to (5) in the statements? (a) (3)-glandular, (4)-Tight, (5)-sensory (b) (1)-calcium salts, (2)-collagen fibres, (3)-compound, (4) - Excretory (c) (3)-glandular, (4)-Adhering, (5)-respiratory (d) (1)-magnesium salts, (2)-elastic fibres, (3)-compound, (5)-sensory

Short answer

The correct options for the blanks are (1) - calcium salts, (2) - collagen fibres, (3) - glandular, (4) - Tight, and (5) - sensory, which correspond to option (a).

Step-by-step solution

Identify correct terms for blanks (1) and (2)

Analyze the given statements to determine what substances give bones their strength. Recall what you know about bone composition.

Identify the correct term for blank (3)

Identify the specialized columnar or cuboidal cells that are known for secretion.

Identify the correct term for blank (4)

Determine the type of junction that prevents substances from leaking across a tissue.

Identify the correct term for blank (5)

Consider the function of prostomium in an earthworm to ascertain its correct feature.

Match the correct fill-ups with the given options

Review each option and cross-reference with the answers from the previous steps, then select the option that accurately fills all blanks.

Key concepts

Biology Bone Composition

Bones provide our bodies with structure, protect our internal organs, and play essential roles in movement by anchoring muscles. The remarkable strength and resilience of bones come from their unique composition.

The ground substance of bone is primarily composed of calcium salts and collagen fibers. Calcium salts lend the bone its hardness, while collagen fibers offer flexibility and tension resistance. This combination allows bones not only to support weight but also to endure stress without breaking. In an educational context, visualizing this as a construction framework can help illustrate how the materials contribute to the overall sturdiness of the building – a balance between firmness and elasticity.

Understanding the role of minerals like calcium in bone health can also underscore the importance of a balanced diet for maintaining strong bones. Moreover, medical conditions such as osteoporosis are directly related to the deterioration of bone composition, making this topic relevant both academically and practically.

Epithelial Tissue

Epithelial tissue, or epithelium, serves as a lining for both external and internal surfaces of the body, including organs and blood vessels. It is a hallmark of the body's protective layers.

Epithelium comes in various types, one of which is the glandular epithelium. Glandular cells are specialized columnar or cuboidal epithelial cells that have the function of secretion. They might be part of larger glands, like the thyroid, or exist independently, secreting substances directly onto surface epithelia. The role of glandular epithelium is crucial in maintaining homeostasis, producing necessary enzymes, hormones, mucus, and other vital elements.

Different types of epithelial tissue, characterized by the number of layers (simple vs. stratified) and the shape of cells (columnar, cuboidal, squamous), serve diverse functions ranging from absorption and filtration to secretion and sensory reception.

Cell Junctions

Cells within tissues are often held together at their membranes by specialized structures called cell junctions. These junctions serve various functions, including structural support, forming permeability barriers, and facilitating intercellular communication.

One important type of cell junction is the tight junction. Tight junctions are crucial because they form a seal that prevents the passage of materials between cells. This barrier function is essential in tissues that line organs and body cavities, like the digestive tract, where they prevent the leakage of enzymes, acids, and waste material into the surrounding tissues or bloodstream.

Other types of cell junctions include adherens junctions, which connect the cytoskeletons of adjacent cells, and gap junctions, which allow for the direct transfer of small molecules between cells. Each type of junction has a specialized role that contributes to the overall functioning and integrity of tissues.

Earthworm Anatomy

The earthworm is an excellent example of an organism adapted to its habitat through its anatomical structure. Its body is segmented, and each segment is equipped with muscles that aid in locomotion.

The prostomium, a lobe or extension over the mouth, is an important sensory structure for the earthworm. It is sensitive to light, vibrations, and chemicals, enabling the earthworm to navigate through the soil and respond to environmental cues. As an extension of the earthworm's nervous system, the prostomium is not involved in respiration or excretion but serves a sensory role, crucial for an organism that lives underground.

Studying the anatomy of an earthworm helps illustrate how evolution shapes the form and function of an organism's body to fit its environment, providing an excellent lesson in adaptation and anatomy.