In: Biology
1. The main function of the small intestine is nutrient absorption. Which of the following structural qualities of the intestine increase absorption? Select all that apply.
a. Very long tube of almost 6 meters in length when relaxed.
b. Internal wall covered with fingerlike projections.
c. Cell membrane of epithelial cells with multiple foldings.
d. Higher pH than in the stomach in part by secretion of bicarbonate.
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1. What are the advantages of an open circulatory system? Select all that apply.
a. Blood moves at high pressure to the tissues.
b. It can circulate large amounts of oxygen rapidly.
c. It is energy efficient.
d. It can be used for other purposes, such as movement.
e. Oxygenated and deoxygenated blood never mix.
Small intestines are about 20 foot long which is approximately 6 metres. The internal walls of small intestine have finger lije projections known as vili. The vili also contains microvili which helps in increasing the area of adsorption. The epithelial cells of small intestine contains foldings which slows down the movement of food so that maximum absorption can be attained. The pH of food is higher than the stomach because of bicarbonate ions. The lower pH inside the stomach could damage the inner lining if intestines resulting in poor absorption.
So all options are correct.
2. An open circulatory system is present in lower invertebrates where the size of body is smaller and the metabolism rate is low. The open circulatory system pumps the blood directly into the bidy cavity. This type of pumping is very liw in pressure and carries oxygen in very less amount. So we can say that it is energy efficient.
The oxygenated and deoxygenated blood never mix in a clised circulatory system with four chambered heart.
So the only option correct is c.