Question

Lining of intestine of man is (a) brush bordered (b) ciliated (c) non-keratinized (d) keratinized.

Short answer

The lining of the intestine of man is (a) brush bordered.

Step-by-step solution

Identifying the Characteristics of Intestinal Lining

The intestinal lining has specialized features to aid in nutrient absorption and digestion. One of these features is a 'brush border,' which is made up of microvilli that increase the surface area for absorption.

Eliminating Incorrect Options

The options 'ciliated', 'non-keratinized', and 'keratinized' can be excluded as they do not accurately describe the lining of the intestine. Cilia are more common in the respiratory tract, non-keratinized cells are present in areas like the mouth, and keratinized cells are found on the skin surface.

Selecting the Correct Answer

Based on the feature of increased surface area for absorption due to microvilli in the intestine, the correct answer is 'brush bordered'.

Key concepts

Brush Border Microvilli

One of the marvels of the human digestive system lies in its ability to process and absorb the nutrients from the food we consume. This process takes place significantly within the small intestine, where the lining exhibits a specialized structure known as the brush border. Like the bristles on a brush, these tiny, finger-like projections known as microvilli protrude into the intestinal space. Their primary function is to drastically increase the surface area of the intestinal lining, creating a vast expanse for nutrient absorption.

The presence of microvilli is one of the key factors that make the intestinal lining highly effective at its job. Each microvillus contains membrane proteins that act as transporters or enzymes which facilitate the breakdown of nutrients into smaller, absorbable units. Without this expanded surface area, our bodies would struggle to extract enough nutrients from our diets to sustain health and energy levels.

Learning about brush border microvilli is fundamental in understanding how nutrients are absorbed and why certain digestive disorders impair nutrient uptake.

Nutrient Absorption

Nutrient absorption is a critical process that occurs in the small intestine and depends heavily on the anatomy and functionality of the intestinal lining. After the mechanical breakdown of food by the stomach, the small intestine takes over as the primary site for chemical digestion and nutrient absorption. The intestinal walls are lined with specialized cells that have the ability to absorb different nutrients through various mechanisms.

Some nutrients, like simple sugars and amino acids, are absorbed by the cells via active transport, which requires energy. Other substances, such as water and alcohol, can pass through via simple diffusion. Fatty acids and monoglycerides, meanwhile, are absorbed through simple diffusion and are then reassembled into triglycerides within the cells.

The efficiency of this process can be affected by the health of the brush border microvilli, as any damage or alteration can lead to malabsorption and a host of digestive problems. Understanding the specifics of nutrient absorption mechanisms is essential for grasping how the body extracts and utilizes the food we eat.

Biology Education

The field of biology education plays a crucial role in helping students comprehend complex biological processes, such as those involved in digestion and nutrient absorption. By breaking down these intricate concepts into more digestible information, educators can make learning more accessible and engaging. A deep understanding of the biology behind brush border microvilli and nutrient absorption opens doors to higher learning and can even spark interest in medical and health-related careers.

Educational strategies often involve interactive models, cross-sectional diagrams of the intestinal tract, and even microscopic imaging to give students a closer look at the structures they study. Advanced biology classes may also provide lab experiences where students can observe and study the cellular makeup of the intestinal lining. By incorporating real-life applications and encouraging critical thinking, biology education not only conveys information but also develops scientific literacy and analytical skills among students.