Question

Read the following four statements (i) - (iv) with certain mistakes in two of them. (i) Adipose tissue is a type of dense connective tissue located beneath the skin. (ii) In each body segment of earthworm except the first, fifth and clitellum, there are rows of S-shaped setae, embedded in the epidermal pits in the middle of each segment. (iii) Most of the cartilages in vertebrate embroys are replaced by bones in adults. (iv) Smooth muscles are 'involuntary' as their functioning cannot be directly controlled. Which of the above statements have mistakes? (a) (ii) and (iii) (b) (iii) and (iv) (c) (i) and (iii) (d) (i) and (ii)

Short answer

(c) (i) and (iii)

Step-by-step solution

Identify the Correct Statements

Examine each statement for accuracy based on scientific knowledge.(i) Adipose tissue is a type of loose connective tissue, not dense connective tissue.(ii) The statement about setae in earthworms is correct.(iii) The statement about cartilage is correct as most cartilages are replaced by bones in adult vertebrates.(iv) The statement about smooth muscles being involuntary is correct as their functioning cannot be directly controlled by consciousness.

Determine Incorrect Statements

Review for the statements with mistakes.Incorrect: (i) Adipose tissue is not dense connective tissue.Incorrect: (iii) The statement almost suggests that all cartilages are replaced, but some cartilages remain in the adult human body, such as in the joints, ear, nose, etc. Thus, while most cartilage is replaced by bone, not all of it is, so statement (iii) contains a mistake in its absoluteness.

Select the Correct Option

Based on the analysis above, the two statements with mistakes are (i) and (iii). Therefore, the correct option is:(c) (i) and (iii)

Key concepts

Adipose Tissue Function

Adipose tissue, commonly referred to as body fat, has critical roles beyond the commonly assumed function of storing excess calories. In contrast to the mistaken identification within the exercise as a dense connective tissue, adipose tissue is a form of loose connective tissue that provides a storage depot for energy in the form of fats.

• It serves as insulation, helping to maintain the body's temperature.
• It offers mechanical cushioning to protect internal organs from trauma.
• Adipose tissue acts as an endocrine organ, releasing hormones like leptin that regulate appetite and fat metabolism.
• It also plays a role in the inflammatory process and immune system response.

Understanding adipose tissue function is essential for comprehending energy balance and metabolic health in the body.

Earthworm Setae

Setae are bristle-like structures on earthworms that provide critical functionality for movement and anchorage in soil. They are often mistaken for being uniform across all segments. However, correct observation identifies that they are absent from the first, last, and the clitellum segments.

• Setae are tiny, hair-like structures located on each segment of an earthworm's body except where noted.
• They help the earthworm grip the soil as it contracts muscles to move forward.
• The S-shaped setae can be extended or retracted, which helps the worm anchor itself in the soil to prevent backsliding during movement.

This understanding is pivotal for appreciating how earthworms interact with their environment and contribute to soil aeration and composting.

Cartilage and Bone Development in Vertebrates

The development of the vertebrate skeletal system is a dynamic process involving the replacement of cartilage by bone in a process known as ossification. While it's true that much of the embryonic cartilage is replaced by bone in adults, it's a misconception that all cartilages convert to bones.

• During development, cartilaginous structures act as a precursor to where most bones will form.
• Ossification starts from the center of the cartilage, proceeding outward, maintaining cartilage at the ends of bones that form joints, known as articular cartilage.
• Some regions, such as the nose, ears, and parts of the rib cage, retain their cartilaginous state even in adulthood.

The intricacies of this process are fundamental to the study of developmental biology and orthopedics.

Smooth Muscle Control

Smooth muscle tissue is found in various organs and systems within the body, playing a pivotal role in involuntary actions. Unlike skeletal muscle, which can be consciously controlled, smooth muscle operates under the control of the autonomic nervous system.

• Smooth muscles line the walls of organs such as the stomach, intestines, blood vessels, and the urinary bladder, enabling the movement of substances through these organs.
• They are responsible for functions such as peristalsis in the gut, vasoconstriction in blood vessels, and dilation of the pupil in the eye.
• The regulation of smooth muscle is primarily through involuntary reflex pathways and can be influenced by hormones, neurotransmitters, and local factors.

Grasping the mechanisms of smooth muscle control is vital for understanding the functionality of various physiological processes, including the circulatory and digestive systems.