Which of the following sttements regarding small intesitine are incorrect?
(i) Throughout the small intestine, there are crypts of lieberkuhn at the base of the villi.
(ii) In douodenum, there are, in addition, small rounded peptic glands.
(iii) The small intestine is strongly self-rotective, by means of a copious production of mucus and a mechanism of the rapid replacement of cells damaged by contact with food and digestive juices.
(iv) Each villus is richly supplied with blood capillaries only

Options

A. i and iv
B. ii and iv
C. iii and iv
D. i and iii

Explanation

To determine which statements regarding the small intestine are incorrect, let's analyze each statement one by one:

### Step 1: Analyze Statement (i)
**Statement (i):** "Throughout the small intestine, there are crypts of Lieberkühn at the base of the villi."

- **Analysis:** This statement is **true**. Crypts of Lieberkühn are indeed present throughout the small intestine at the base of the villi, and they play a role in secretion and absorption.

### Step 2: Analyze Statement (ii)
**Statement (ii):** "In the duodenum, there are, in addition, small rounded peptic glands."

- **Analysis:** This statement is **incorrect**. Peptic glands are primarily found in the stomach, not in the duodenum. The duodenum does have Brunner's glands, but not peptic glands.

### Step 3: Analyze Statement (iii)
**Statement (iii):** "The small intestine is strongly self-protective, by means of a copious production of mucus and a mechanism of the rapid replacement of cells damaged by contact with food and digestive juices."

- **Analysis:** This statement is **true**. The small intestine does produce mucus to protect itself from digestive juices, and it has a high turnover rate of epithelial cells to replace those damaged by food and enzymes.

### Step 4: Analyze Statement (iv)
**Statement (iv):** "Each villus is richly supplied with blood capillaries only."

- **Analysis:** This statement is **incorrect**. Each villus is not only supplied with blood capillaries but also contains lymphatic vessels (lacteals) that are important for the absorption of fats.

### Conclusion
The incorrect statements are:
- Statement (ii): "In the duodenum, there are, in addition, small rounded peptic glands."
- Statement (iv): "Each villus is richly supplied with blood capillaries only."

### Final Answer
The incorrect statements regarding the small intestine are **(ii) and (iv)**.

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