Question

Read the folloning statements and select the correct option. Statement 1 :\\} The human sma" intestine is the longest portion in the almentary canal Statement \(2:\) Absorption of digested food requires a very large surface area. (a) Both statements 1 and 2 are correct and statement 2 is the corret explanation of statement 1 . (b) Both statements 1 and 2 are corred but statement 2 is not the corred explanation of statement \(\mathbf{i}\). (d) Statement 1 is correa and statement 2 is incorrect (d) Both statements 1 and 2 are incorrect.

Short answer

Both statements 1 and 2 are correct, but statement 2 is not the correct explanation of statement 1. The correct option is (b).

Step-by-step solution

Analyzing Statement 1

Examine Statement 1 to determine if the human small intestine is indeed the longest portion of the alimentary canal. Research in human anatomy indicates that the small intestine is one of the longest sections, usually around 6 meters in length in an adult, when measured after death. So, statement 1 is correct.

Analyzing Statement 2

Evaluate Statement 2 to decide if the absorption of digested food requires a very large surface area. Physiologically, the small intestine, with its villi and microvilli, increases the surface area significantly to optimize the absorption of nutrients. Therefore, statement 2 is also correct.

Determining Relationship Between Statements

Determine if statement 2 is the correct explanation of statement 1. Statement 2 explains the necessity of a large surface area for nutrient absorption which is provided by the lengths and structures within the small intestine. However, while related, statement 2 does not directly explain why the small intestine is the longest portion; it explains how its design accommodates its function. Thus, statement 2 is not the correct explanation for statement 1.

Selecting the Correct Option

Based on the analysis, we can conclude that both statements are correct, but statement 2 does not serve as the correct explanation for statement 1, making option (b) the correct answer.

Key concepts

Human Alimentary Canal

The human alimentary canal, also known as the digestive tract or gut, is a complex series of organs connected in a long, winding tube from the mouth to the anus. This system plays a critical role in our survival by allowing us to take in food, break it down into nutrients, and absorb those nutrients into our bodies.

Beginning with the mouth, where digestion starts with mastication, the process involves numerous organs, each with a distinct function. The food then passes through the esophagus to reach the stomach, where it undergoes further breakdown by stomach acids. Following this, the semi-digested food moves to the small intestine, which is pivotal in digestion and absorption.

Despite the term 'small' in its name, the small intestine is remarkably long, measuring about 6 meters post-mortem in adults. It's coiled and folded within the abdominal cavity. This length is essential, as it provides the surface area needed for the intricate process of nutrient absorption. Additionally, the alimentary canal includes the large intestine, where water and electrolytes are absorbed, and solid waste is eventually formed for excretion.

Digestive System Anatomy

Delving deeper into the digestive system anatomy, it’s fascinating to observe how each organ contributes to the overall digestive process. The anatomy of this system is designed to efficiently convert food into energy and building blocks for the body while discarding unusable waste.

The stomach, for instance, is equipped with muscles that churn food, mixing it with digestive juices. Next in the lineup is the small intestine, which is comprised of three sections: the duodenum, jejunum, and ileum. Each segment has specific roles in the digestion and absorption of food components.

The inner walls of the small intestine are lined with tiny, finger-like projections called villi and even smaller hair-like structures known as microvilli. These structures play an instrumental role in increasing the surface area for absorption exponentially. The rest of the digestive system includes the pancreas, liver, and gallbladder, each contributing enzymes, hormones, or bile to aid digestion before waste is finally processed in the large intestine.

Nutrient Absorption

When discussing nutrient absorption, we're referring to the complex process by which the body retrieves essential vitamins, minerals, amino acids, fats, and sugars from the food after digestion and sends them into the bloodstream. This primarily takes place in the small intestine, the epicenter for absorbing these valuable resources.

The extensive network of villi and microvilli in the small intestine provides a tremendous surface area akin to a vast landscape within a small patch of land. To maximize nutrient uptake, several transport mechanisms are at play, including active transport, passive diffusion, facilitated diffusion, and endocytosis.

Carbohydrates are typically broken down into simple sugars like glucose, which are absorbed through the intestinal lining. Proteins are split into amino acids or small peptides, while fats form micelles and are absorbed via the lymphatic route as chylomicrons. The efficiency of this process is vital to health, highlighting the importance of the small intestine's length and intricate internal structure in our overall well-being.